View source for Common plugs and connectors

{{#addbodyclass:tag_tech}}

Yes, this is largely biased to the stuff I deal with.

Ideally 'common' is true ''enough''.  Suggestions are welcome.


=Mixed use (analog, digital, home electronics, audio)=

===TRS (Tip, Ring, Sleeve) and variations===
[[Image:TRS-25_35_63.jpg|thumb|260px|right|3.5mm (1/8") TRS plug (bottom left),<br/>2.5mm TRS plug (top)<br/>6.35mm (1/4") TRS plug (right)]]

<!--[[Image:Microphone_jackplug.jpg|thumb|230px|right|3.5mm TRS plug with microphone symbol and PC99's microphone color]]-->

'TRS' may be clearer when distinguishing it from plugs in similar use, but the everyday names we use are more specific - and somewhat regional.

The 3.5mm is often known as '''headphone jack''', '''stereo jack''' {{comment|(if TRS, or '''mono jack''' if TS)}}, '''mini jack''', or '''3.5mm jack''', and sometimes things like mini-phone.

The 6.35mm was classically called '''phone connector''' (2-lead, TS) though perhaps the largest use today is guitars.



The history of plugs like these is complex[https://en.wikipedia.org/wiki/Phone_connector_(audio)], and there are some leftovers today that use less usual variants.

But what you're most likely to meet is primarily:

: The '''1/4"''' (which is '''6.35mm''' precisely)
:: originates from the design of the first telephone exchanges{{verify}}, which is why this (particularly the mono, TS variant) is also called a phone connector
:: These days they are mostly seen in audio use, seemingly as something not so easy to break
::: used for guitars, [[pro line level]] (balanced or not), and sometimes for consumer headphones

: '''3.5mm''' 
:: Americans often refer to it as 1/8"
:: best known for three-band ('''TRS''') in headphones for stereo sound, then often referred to as '''audio jack''', '''mini-jack''', '''jack plug''', '''stereo plug''', and others. (Sometimes phone connector but that suggests the 1/4" one)
::: often carries [[consumer line level]] audio signals, or [[consumer microphone level]] when it involves microphones (often electret)

: '''2.5mm''' 
:: Americans sometimes call this 3/32"


'''On units''' - The 1/4 size is standardized in inches because of its phone network origins{{verify}}, 
: ...while 2.5mm and 3.5mm are standardized in millimeters, and I do believe always manufactured to mm sizes, so the inch figures are ''names'', not measurements:
:: taking 3.5mm and calling it 1/8" is 10% away from the actual size (3.5mm is 0.138", not 0.125")
:: taking 2.5mm and calling it 3/32" is 5% away from the actual size <!--(2.5mm is 0.0984", not 0.0937)-->




[[Image:TRRS 3.5mm.jpg|thumb|226px|right|3.5mm TRRS plug]]
'''TS, TRS, TRRS, etc.'''

The original 1/4" had two contacts, so had a tip and sleeve (TS). 

It grew more bands over time, so e.g. 3.5mm is frequently seen in TS, TRS, and occasionally TRRS. TRRRS exists but is rare.

3.5mm TRRS is 
: is probably mostly associated with having headphones that include a microphone, around smart phones.
: has some other uses, like carrying audio and (composite) video on one plug (e.g. on [[raspberry pi]])




'''Not-really-compatible variants'''

A few synthesizers (Buchla and clones{{verify}}) use tini-jax which is .141" (~3.6mm) and basically incompatible with 3.5mm


[[Image:Blah 3.5mm.jpg|thumb|175px|right|3.5mm that can be screwed down]]
I've also seen a variant of 3.5mm that can be screwed down, which is quite useful for use on stage where you don't want a yank to stop the music - yet e.g. in the image on the right the screw-thread ring on this plug doesn't pull back so this particular plug won't plug properly into most other 3.5 sockets.




See also:
* http://en.wikipedia.org/wiki/TRS_connector

* https://en.wikipedia.org/wiki/Phone_connector_(audio)
<!--
* [[Electronics_project_notes/Device_voltage_and_impedance,_audio_and_otherwise#How_do_various_connections_relate_to_this.3F]]
-->


<br style="clear:both">

====TRS pinout====
{{stub}}

'''Pinout'''

Depends on the use. Things I've mostly dealt with:

* 3.5mm TRS in consumer stereo sound (unbalanced)
:: tip:    left
:: ring:   right
:: sleeve: ground

<!--
* mono-and-mic headsets with a single 3.5mm TRS plug (unbalanced), while fairly rare, seem to often be:
:: tip:    mic in 
:: ring:   mono out
:: sleeve: ground
-->

* 3.5mm TRRS for '''headphone, mic''' and/or '''buttons'''
:: The general standard ({{imagesearch|OMTP pinout|OMTP}})
::: tip: left out
::: ring: right out 
::: ring: mic in (and buttons{{verify}})
::: sleeve: ground
:: Apple being ''different'': ({{imagesearch|CTIA pinout|CTIA}})
::: tip: left out 
::: ring: right out 
::: ring: ground
::: sleeve: mic in


* 3.5mm TRRS '''combining audio and analog video''', such as
:: iPod's AV cable
::: tip: left
::: ring: right
::: ring: ground
::: sleeve: video
:: raspberry pi audio+video (same pinout)
:: there are pinout variants of this.
::: It's handy to have adapters with RCA, in that sometimes you can get around variations by plugging things differently. But don't count on it.


[[Image:6.35mm TRS in socket.jpg|thumb|right|180px|6.35mm TRS in socket.jpg]]
* 6.35mm TRS headphones   (unbalanced, same as 3.5mm consumer but sturdier; often with adapters to 3.5mm)
:: tip:    left
:: ring:   right
:: sleeve: ground

* 6.35mm TRS balanced audio (stage/pro audio)
:: tip: hot
:: ring: cold
:: sleeve: shield

* 6.35mm TS unbalanced audio (stage/pro audio)
:: guitar, instruments (unbalanced)
:: tip: signal
:: sleeve: ground

* 6.35mm TRS: mixer effect inserts (unbalanced)
:: tip: out
:: ring: in
:: sleeve: ground
:: [[Music_-_studio_and_stage_notes#Insert]]




Note that in many uses, sleeve is ground ([[shield]] where applicable)

====Headphone buttons====

The buttons don't need extra wires in a TRRS plug because they'll be using different resistor values between mic and ground pins.

For '''Android'''[https://source.android.com/devices/accessories/headset/jack-headset-spec]:
   0..70  ohm   Function A, play/pause/takecall
 110..180 ohm   Function D, typically voice commands
 210..290 ohm   Function B, volume up
 360..680 ohm   Function C, volume down
(The impedance of the microphone itself is considerably higher, and sense-wise acts as the default)



For '''Apple''', 
 ~0   ohm is play/pause/takecall
Everything else seems to be [https://web.archive.org/web/20211018015853/http://david.carne.ca/shuffle_hax/shuffle_remote.html proprietary signaling], 
which allows them to add functionality over time. And piss of imitators and DIYers.
<!--
 ~600 ohm is play next
 ~220 ohm is play previous
-->

<!--
: TRS in a TRRS socket shorts the mic and buttons, effectively just making them nonfuctional
: TRRS in a TRS socket will usually connect just one
:: what this does varies with pinout (and position of socket contact{{verify}})
: You can get adapters from TRRS to separate headphone and mic plugs (usually OMTP pinout because not-apple)
-->




===RCA===

<gallery mode="packed" style="float:right" heights="100px">
Image:Yellow RCA.jpg|RCA socket and plug
Image:RCA_AV.jpg|Bunch of RCA sockets {{comment|(for two types of audio output and two types of video output)}}
</gallery>

Used for audio, video (often composite, now also component), some simple data (like non-optical digital audio)

Named for its introduction by the Radio Corporation of America.

Other names include '''cinch connector''', '''phono connector''', and some odd ones out like the Dutch calling it a tulpstekker (after tulips, because of course).



See also:
* http://en.wikipedia.org/wiki/RCA_connector

<br style="clear:both">

===DIN===
DIN refers to a whole standardization body. 

Only with a number does it refer to a specific standard, of which there are ''many'.
Which includes connectors.

But no one remembers those numbers, so we say "DIN connector" and leave it to context.

Note that 
: some of these have since been effectively moved into international (IEC) standards,
: some DIN equivalents of something standardized elsewhere, 
: some are actively synchronized.

{{zzz|Some other DIN things you might see with some frequency:

* the larger circular DIN (see below)

* the smaller circular mini-DIN (see below)

* DIN 41651 (see below)

* DIN 41652 is [[D-sub]] (though it wasn't DIN that created it) {{verify}} (see below)

Some other common-enough electrically-related DIN things:
[[File:Speaker_din_male_and_female.jpg|thumb|right|215px|DIN 41529]]
* DIN 41612 backplanes (see below)

* DIN rail[https://en.wikipedia.org/wiki/DIN_rail]

* DIN 41529: 2-pin, historically seen in loudspeakers, though I've also seen them used for low voltage lighting 

* [[#Kleintuchel|DIN 41524, a.k.a. Kleintuchel]] (see below)

* [[#Grosstuchel|DIN 41624, a.k.a. Kleintuchel]] (see below)

* DIN 41585 antenna connector mostly used in cars

* "7/16 DIN" Connectors[https://en.wikipedia.org/wiki/7/16_DIN_connector], in RF

* TODO: more}}

See also:
* https://en.wikipedia.org/wiki/List_of_DIN_standards



====The larger circular DIN====
[[Image:DIN-miniDIN.jpg|thumb|200px|right|'''Left''': the 180-degrees 5-pin DIN.<br/>'''Right''': 4-pin [[#Mini-DIN|mini-DIN]] - see the next section]]

Around consumer devices it most commonly refers to the members of a specific series of circular plug/sockets of similar design, that have a 13.2mm-diameter round metal friction locking shield.  {{comment|(These come from at least five different DIN standards, though it seems these original DIN standards are out of print, and you now want to read IEC 60130-9, which also expanded the series {{verify}}) }}

This set includes:

[[Image:DIN-3 Diagram.png|60px|DIN 41524: 3-pin, 90°, 180°]] &nbsp;&nbsp;&nbsp;&nbsp;
[[Image:DIN-4 Diagram.png|60px|4-pin, 72°, 216°]] &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
[[Image:DIN-5 Diagram.png|60px|DIN 41524 / IEC/DIN EN 60130-9: 5-pin, 45°, 180°]] [[Image:DIN-5b Diagram.png|60px|5-pin, 90°, cube, 270°]]
[[Image:DIN-5c Diagram.png|60px|DIN 45322: 5-pin, 60°, 240°]]
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
[[Image:DIN-6 Diagram.png|60px|DIN 45522: 6-pin, 60°, 240°]] &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
[[Image:DIN-7 Diagram.png|60px|DIN 45329 / IEC 10: 7-pin, 45°, 270°]] &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
[[Image:DIN-8 Diagram.png|60px|DIN 45326 / IEC/DIN EN 60130-9: 8-pin, 45°, 270°]]
[[Image:DIN-8 262 Diagram.png|60px|8-pin, 45°/41°, 262°]]
<!--
DIN
41524 
45322
45326 
45327 
45329 
60574
60130
-->


Being an existing, relatively sturdy, relatively versatile, and relatively cheap style of connector, these once saw a lot of varied use, be it digital (e.g. MIDI, AT keyboard connector), audio/video (e.g. tape decks, microphones), and sometimes power.

Many of them were fairly specific to brands or devices {{comment|(e.g. Commodore 64 uses 7-pin for [https://www.c64-wiki.com/wiki/Power_Supply_Connector power], and 8-pin (5-pin in a few early models) for [https://www.c64-wiki.com/wiki/A/V_Jack audio and composite video])}}.


Many such uses have since grown more specific connectors. 
Which is probably good, to avoid smoky mistakes from too many distinct uses sharing a plug.

The only one that survived a lot longer in wide use is MIDI, with its 180 degree 5-pin din plug.


<!--
For example
* 5-pin 180&deg;
** [[MIDI_notes#Serial_MIDI|MIDI]]
** AT keyboard connector
** audio: tape decks (mostly in Europe), because it's enough for stereo in two directions
** audio: tuner interconnects
** DIN sync (for musical sequencers and such)

* 3-pin 180&deg;
** audio interconnect {{verify}}
** unbalanced mic {{verify}}
** balanced mic {{verify}}
** capacitive mic {{verify}}

* 7-pin 
** Commodore 64 power [https://www.c64-wiki.com/wiki/Power_Supply_Connector]

* 8-pin
** Tandy 1000 keyboard [https://nerdlypleasures.blogspot.com/2016/09/more-keyboard-adapters-tandy-1000.html]
-->

See also:
* https://en.wikipedia.org/wiki/DIN_connector#Circular_connectors
* http://www.muzines.co.uk/articles/interconnect/2828
<!--
Look a bit like
* [[XLR]]
* [[Circular metric]]
-->

====Mini-DIN====

'''Mini-DIN''' is a similar-looking variation also from DIN ({{verify}}, I can't easily find the number), with a 9.5mm round metal shield. Additionally uses plastic slots that makes plugging into other variants hard without a hammer.

These include:
[[Image:MiniDIN-3 Diagram.png|40px]]
[[Image:MiniDIN-4 Diagram.png|40px]]
[[Image:MiniDIN-5 Diagram.png|40px]]
[[Image:MiniDIN-6 Diagram.png|40px]]
[[Image:MiniDIN-7 Diagram.png|40px]]
[[Image:MiniDIN-8 Diagram.png|40px]] 
[[Image:MiniDIN-9 Diagram.png|40px]]


<gallery mode="packed" style="float:right">
Image:PS2.jpg|PS2 mouse and PS/2 keyboard (6-pin mini-DIN)
Image:S-video and RCA on scart adapter.jpg|S-video on the back on a [[SCART]] adapter (4-pin mini-DIN)
Image:MiniDIN apple desktop bus.jpg|[http://en.wikipedia.org/wiki/Apple_Desktop_Bus Apple Desktop Bus] (4-pin mini-DIN)
</gallery>
Probably best known for
: [https://en.wikipedia.org/wiki/PS/2_port PS/2 keyboard/mouse] (6-pin)
: [https://en.wikipedia.org/wiki/S-Video S-video] (4-pin)


Other uses include audio, video, some communication, and some fairly one-off video card adapters back when analog video was still a thing we wanted. 

Apparently the 8-pin mini-DIN connector was briefly used for iPods{{verify}}

I've also seen some used for power.

Warning: Assuming each of the unique connectors has multiple, unrelated uses,
before you plug something in.


See also:
* http://en.wikipedia.org/wiki/DIN_connector
* http://en.wikipedia.org/wiki/Mini-DIN_connector
<br style="clear:both">

====Mini-DIN lookalikes====
[[Image:7pin.jpg|thumb|100px|right|'''''Not''''' a standard 7-pin mini-DIN plug.<!-- This one is used on a video card that had analog outputs-->]]

There are a number of have the same 9.5mm housing as mini-DIN, but are '''not''' standardized or approved by DIN.

These include:
[[Image:Pseudo miniDIN-7 Diagram.png|40px]]
[[Image:Pseudo miniDIN-8 Diagram.png|40px]]
[[Image:Pseudo miniDIN-8b Diagram.png|40px]]
[[Image:Pseudo miniDIN-9 Diagram.png|40px]]
[[Image:Pseudo miniDIN-9b Diagram.png|40px]]
[[Image:Pseudo miniDIN-10 Diagram.png|40px]]
[[Image:Pseudo miniDIN-10b Diagram.png|40px]] 


Some are designed to be compatible with specific standard mini-DIN (e.g. to have a video card socket that accepts both standard S-Video plug but also its own connects-more-stuff variant).

Others are designed to be specifically ''in''compatible with standard mini-DIN.

<br style="clear:both">

=Audio(-only)=

===TOSLINK, mini-TOSLINK===
[[Image:TOSLINK.jpg|thumb|157px|right|RC-5720, often referred to as TOSLINK. {{comment|(what looks like copper is only there to protect and guide the fiber)}}]]

While '''TOSLINK''' specifies a few plugs, it is mostly associated with the optical EIAJ/JEITA RC-5720 plug, a.k.a. JIS F05 and CP-1201 - optical, mating with a square-ish shape.


In most contexts, this plug carries [[S/PDIF]] protocol (which itself can carry raw [[PCM]], [[DTS]], and [[AC-3]]). 

Note that the exact same S/PDIF signal can also be carried over copper, then often connected via RCA or BNC,
which involves fewer components and is really no more sensitive to EM noise - and avoids ''any'' conductor so cannot introduce ground loop issues.

You could argue lasers and fibers are cool, but really it's just a LED (because cheap and short-range), and something more akin to fishing wire (because more robust). That said, it was ahead of its time, and still not ''really'' replaced by another well known standard.




[[Image:Mini-TOSLINK.jpg|thumb|72px|right|Mini-TOSLINK, which carries fiber to the tip of a 3.5mm [[TRS|TS]]-shaped plug]]

'''Mini-TOSLINK''' looks like a stereo jack (3.5mm TRS style) but carries the light to its tip. 

This allows laptops (and other size-restrained devices) to have one small socket that provides ''either'' consumer 3.5mm analog audio, or SPDI/F style digital audio.   It was seen e.g. on some portable MiniDisc players, some Apple laptops, and while it still exists it was was never hugely common.


There are physical adapters from TOSLINK to mini-TOSLINK.


See also:
* [[AES/EBU]], a.k.a. [[AES3]]
* https://en.wikipedia.org/wiki/TOSLINK
* https://en.wikipedia.org/wiki/TOSLINK#Mini-TOSLINK

=Specialist (mostly audio)=
==XLR==
[[Image:XLR connector.jpg|right|thumb|305px|XLR3, XLR4, XLR6]]

This is about XLR as the whole connector family.

If you care about XLR3 as used around microphones, see [[Electronics_project_notes/Audio_notes_-_microphones#Microphone_cabling|Microphone_cabling]]

If you care about XLR3 or XLR5 being used for DMX lighting, see [[DMX]].

<!--
Sometimes called cannon, after the company that developed it{{verify}}
-->


Diameter: 

Exists in a number of variations
* XLR3, seen as:
** a [[balanced audio]] connector, primarily for microphones {{comment|(in the past also some equipment interconnections and speakers, including powered ones - now less so, probably due that last bit leading to some pricy mistakes)}}
** [[DMX]] in a lot of practice
** [[AES/EBU]] digital audio (mostly in some older digital gear)
<!--** Once also used to carry power to speakers, but this is not done anymore to avoid confusion and smoky mistakes-->
* XLR4 - used e.g. intercoms, and apparently once relatively universal for power for in TV and film industries <!--(12V, sometimes 24V?)-->, 
* XLR5 - in the [[DMX]] specs (but many simpler DMX devices use only XLR3 because two pins were never used)
* XLR6
...and various others, some of which are considered obsolete.



The two most recognisable uses are probably in the event industry:
* [[balanced audio]] (XLR3)
* [[DMX]] (in practice mostly XLR3, in theory XLR5)

(also note that audio cables and DMX cables, while they look similar, are '''not interchangeable''' for other reasons. It'll work fine on a test-bench scale, but will have issues on large scale)


<!--
There are also some lesser-seen and specific variants, such as 
* {{imagesearch|PDN connectors|PDN}} to go between amps and speaker 
* {{imagesearch|LNE connectors|LNE}}, that carries just mains power, but was apparently never really used
-->
<!--
'''XLR audio'''

XLR in pro audio is XLR3, and XLR3 is almost always a mono balanced (differential) line.

Note that there are some audio sockets that take both XLR, and 6.35mm (1/4 inch) TRS,
e.g. to save some space on mixers.


You ''can'' put stereo on XLR5, but since this isn't very standard, and when plugging things around
it's often more convenient to keep everything the same, i.e.e use two XLR3 cables.
-->

See also:
* http://en.wikipedia.org/wiki/XLR_connector




See also [[Electronic_coupled_noise#The_XLR_pin_1_problem|The_XLR_pin_1_problem]]

==Kleintuchel==

[[File:Kleintuchel.jpg|thumb|72px|right|Kleintuchel]]

DIN 41524, a.k.a. kleintuchel {{comment|(klein means small and Tuchel' is a company name -- so this is much like saying 'DIN plug' or 'RCA connector' - understood well enough, but only due to context)}}, or something slightly more descriptive like "DIN with a screw ring".

Seen around some older microphones.


Three pins, for differential output and a shield, so basically the same idea as XLR.

Apparently easily adapted to XLR, though note that some companies were inconsistent with polarity on kleintuchel plugs, so when you use more than one mic in a setup, you may want to make these adapters microphone-specific if you care about phase mistakes.


In that (slightly distorting macro) image, the top is the cable, bottom is the microphone. That center hole is not functional or typical{{verify}}.


<br style="clear:both"/>

==Grosstuchel==

[[File:Grosstuchel.jpg|thumb|227px|right|Grosstuchel]]

DIN 41624, a.k.a grosstuchel

Seen around some older microphones. 

<br style="clear:both">

==Small mic plugs==
{{stub}}


There are a few different small, XLR-looking plugs and sockets, 
mostly seen on worn wireless microphones, some field recording kits, and otherwise fairly rare.  

These seem to be used for being a locking plug that is fairly solid.


It seems that plugs can vary per manufacturer, 
pinouts can vary even if the same connectors are used (varying a little by brand and context),
and some aren't even differential (not as necessary for short cables).


This seems to frequently be the plug called {{search|Switchcraft TA3}} (The female TA3F on the microphone end).

"Mini XLR" doesn't really exist{{verify}}, and seems to often refer to Switchcraft TA3, sometimes others like it{{verify}}


There is also a variant that uses {{search|TA4 connector}} (4-pin, TA4F on the microphone end), also with slightly varying pinouts.


I've seen TQG and Tiny-QG refer to both TA3 or TA4. Presumably this is Switchcraft trying to apply a brand/trademark?{{verify}}.


Audio Technica seems to use a {{search|Hirose 4-Pin connector}}


I've also seen mention of [[LEMO]] plugs, and even just reuse of TRS.

The wiring link below seems a decent list.



See also:
* https://www.point-sourceaudio.com/support/wiring/

* https://wiringdiagram.2bitboer.com/wiring-diagram-4-pin-audio-technica/

* http://www.switchcraft.com/productsummary.aspx?Parent=792

==XLR+TRS combo==
[[File:Neutrik combo.jpg|thumb|right|86px|Neutrik combo, accepts both XLR and 6.35mm TS/TRS]]

A single socket that accepts both [[XLR]], and 1/4" (6.35mm) TS/[[TRS]] jacks.

Mainly used to save some space on audio devices that want to accept both of these pro-audio inputs in less (rack) space,
because the two are not electrically connected.
 

I'm unsure whether Neutrik developed these, but there seems to be no singular name or singular producer{{verify}} (anymore), 
yet 'Neutrik Combo' seems to be one of the better-understood references.




https://www.neutrik.com/en/neutrik/products/plugs-jacks/jacks/combo-i-series
<br style="clear:both">

==Speakon==
[[File:Speakon.jpg|thumb|right|340px|Speakon]]

Neutrik Speakon is used in some professional audio,
as a amp-to-speaker connection of an '''already amplified speaker signal'''.


It seems to have been introduced to be a unique, non-confusable plug, because it was (and still is) not uncommon to use TS plug that could carry either a voltage signal ''or'' already-amplified audio, which has the issue that plugging a powered output into a signal input would probably damage that input.  {{comment|(TS inputs are often protected against this, e.g. with a varistor, so that you don't blow up things so much)}}



See also:
http://en.wikipedia.org/wiki/Speakon_connector

==powerCON==

Neutrik's powerCON is a few related connectors that connect 3-pole '''mains power''' (20A or 32A).

Rated for a little more current than typical wallplug interconnects, and smaller than most of them.

There is no standardized voltage{{verify}}.
Connectors are rated for 250V, but in 120V countries they'll typically connect that{{verify}}.

There are variants that are rated IP65 ''while connected'', which makes them useful for outdoor events.


powerCON blue / grey [https://www.neutrik.com/en/products/power/powercon-20-a]
* Type 1 
:: source side
:: blue
:: locking (bayonet-style)
:: 20A
:: not disconnectable under load

* Type 2
:: drain side
:: grey
:: locking
:: 20A
:: not disconnectable under load

Type 1 and 2 are intentionally different, so that it should be impossible to plug a short.


* Powercon 32A [https://www.neutrik.com/en/neutrik/products/powercon/powercon-32-a]
:: 32A
:: source side only?


* TRUE1 (2011, now TRUE1 TOP?[https://www.neutrik.com/en/products/power/powercon-true1][https://www.neutrik.com/en/products/power/powercon-true1-top])
:: 
:: 16A
:: disconnectable under load


* type 1/2 variants redesigned to be disconnectable under load {{verify}}
:: 2020?



https://en.wikipedia.org/wiki/PowerCon

<!--
==etherCON==

Standard 8P8C style interconnect, but ruggedized, and some variants are weatherproof.

Used mostly in the event industry, and then mostly to carry audio (and sometimes LED display video).


Looks like the shells also seen on shells, but male on both ends.

It is now the shell that locks, not the 8P8C clip {{verify}}


-->

==Fiber==
<!--
While it's perfectly possible to send in both directions at once, it requires somewhat fancier optics and equipment.
which is typical depends on cost and on conventions.

In the context of larger in-building network setups it's often a pair of unidirectional.


This also relates to multimode[https://en.wikipedia.org/wiki/Multi-mode_optical_fiber] versus single mode[https://en.wikipedia.org/wiki/Single-mode_optical_fiber]. 
Roughly: multimode is the cheaper (both cables and [[SFP]]s, though the difference has gotten smaller), thicker, lower bandwidth-distance product, slightly less fragile variant, and you might see it in a building.



[[Image:ST fiber.jpg|thumb|right|120px|ST connectors, without and with protective plug]]
'''Connectors''

There are dozens of connectors, but these days it's probably largely LC, SC, and ST

ST - Straight Tip 
: bayonet fastening, similar to BNC

SC - Square Connector / Standard Connector
: locking tab fastening

LC - Lucent Connector
: smaller than the others



Mode is often correlated with connector color.


The protective caps that are on there help keep the endface polished. The polish (or, in some styles, angle) affects return loss (back reflection).



And perhaps you count TOSLINK even though that's more fishline than fiber because that's all its purpose needs.



MU (sometimes 'mini SC')- 

MT-RJ - Mechanical Transfer Registered Jack 

FC - Ferrule Connector or Fiber Channel
: usually single mode, so not used much anymore

Biconic 
: cone shape (to help align the fibers)
: fairly rugged
: but older and flaling out of style

https://en.wikipedia.org/wiki/Optical_fiber_connector




https://www.kientec.com/products/connectors/?gclid=EAIaIQobChMIwdPL_aTDggMVHzkGAB08oQYuEAAYAyAAEgI1lvD_BwE


-->

=Video cables/plugs=
{{stub}}

<!--
===On resolution===

The limits to any of these is bandwidth - in Hz, or in the usually closely related megapixels/second

And bandwidth relates mostly to the minimum quality of the cable, which the cable's length sort of divides down.

You could even express the limit as a bandwidth, but when we assume 60fps, and your general 2-or-3-meter cable,
we can express it as a resolution. Your mileage ''will'' vary.


Analog video doesn't get much further than roughly 700x500 (in part because of standards).


VGA has no explicit bandwidth limit
: on short high-quality cables ''could'' easily surpass single-link DVI (~350MHz)
: There is more variation in quality, so you can't count on that.
: Also, hardware may decide to cap its capabilities to what common cabling will support

DVI
: single-link is 165 MHz, which is roughly 1920x1200 at 60Hz

DVI, dual-link
: necesary to use resolutions around 2560×1600 at 60Hz

DisplayPort
: one, two, or four lanes, for 162, 270, 540, or 810 MHz


to be used on a single-link DVI video signal. The highest 60Hz-refresh VESA resolution supported by single-link connections is 



DVI (which replaced VGA) will go around it needs to be a double-link cable.

DVI needs to be dual link to support 

DisplayPort is essentially DVI's replacement

...though HDMI, initially targeted at TV and home video, can do much the same as DisplayPort.
-->


===Composite video===
[[Image:Yellow RCA.jpg|thumb|140px|right|Yellow RCA is associated with video use (much like red and black (or red and white) are with stereo sound)]]
'''Composite video''' (not to be confused with [[component video]]).

Usually plugs around in a one-yellow-[[#RCA|RCA]]-plug way, sometimes using a [[#BNC|BNC]] plug. 

Carries Y, U, and V signals with sync pulses {{comment|(and is also easy to broadcast - it is almost entirely the same as analog TV's format.
...in a baseband way, without modulation.)}}


The main upsides to composite is probably that it is easy to transfer video between devices with a single, simple, common plug.

The main downside is that it somewhat susceptible to various visual artifacts, including noise/interference, [[dot crawl]]. 

It arguably varies mostly with the quality of the encoding/decoding hardware, which indeed has varied, 
and which is internal so you have no control over.

The only thing you could change is cable length. Shorter cables sometimes help a little.


Composite video is sometimes called CVBS. {{comment|Depending on who you ask, that's short for 
"Color, Video, Blank and Sync", 
"Composite Video Baseband Signal", 
"Composite Video Burst Signal", or
"Composite Video with Burst and Sync".}}



'''RF modulators'''

There was once a time where TVs ''only'' took antenna inputs,
and therefore a time at which devices (like video tape recorders, early game consoles, and and some early computers) modulated their video a signal onto a local video channel, to then be decoded again by the TV.

That often amounted to composite + RF modulator = something TV understands.

===S-Video===
[[Image:S-video.jpg|thumb|110px|right|S-video plug, the wire carrying two pairs]]

'''S-Video''' (also ''Super Video'' or ''Separated Video'', and also sometimes called ''Y/C'') carries luma (Y) and chroma (C) signals on separate wire pairs, using standard 4-pin [[#Mini-DIN|mini-DIN]] plugs.


It carries the same information as [[composite video]], but avoids shoving the Y and C information together onto one wire. 

This will be better than the cheapest implementations of composite -- yet with good hardware and ideal conditions for composite, S-Video is no better than composite.


S-Video-to-Composite-video converter cables can just join the wires (although this may mean the colors are less saturated - something about the voltage amplitudes of these two signals?{{verify}}).
: ...and for the same reason you can ''not'' use that same wire to go from composite input to S-Video output (connecting it anyway puts the mixed Y+C channel on both the Y and C pairs, which the S-video decoder will partly understand, but will usually results in a black and white image{{verify}})



====S-Video-like====

[[Image:7pin.jpg|thumb|100px|right|[[#Mini-DIN_lookalikes|'''Not''' a standard 7-pin mini-DIN plug]]. This one is one end of a computer video card adapter cable]]

You may find some [[#Mini-DIN_lookalikes|Mini-DIN_lookalikes]] that resemble the 4-pin mini-DIN S-Video plug. This includes:

* a 9-pin variation called [https://en.wikipedia.org/wiki/Video-in_video-out VIVO (Video In Video Out)], seen on video cards, that allows S-Video in, S-Video out, component out, and composite out.

* I've seen some video cards come with a 7-pin plug. This is rarely a standard mini-DIN plug, and often has its plastic slot in the same place as on the 4-pin DIN plug, but wider, so that the video card socket will accept a standard S-Video plug, and also the plug on the cable supplied with the card which uses the extra pins to carry, usually, another type of video (often composite video, sometimes composite video).

* a different 7-pin connector (standard [[#Mini-DIN|mini-DIN]]) used on some professional (VCR) kits


<br style="clear:both">

===Component video (YPbPr)===
[[Image:Component RCA.jpg|thumb|255px|right|Red, Green, Blue RCA (...which suggests component&nbsp;video)]]

'''Component video''' {{comment|(not to be confused with [[composite video]])}}
could ''in theory'' refer refer to any system that sends video in multiple separated channels. 

...but it quite usually refers specifically to a Y,Pb,Pr setup, typically on three [[#RCA|RCA]] connectors (and sometimes on other things, like [[D-terminal]]), and for YPbPr these connectors are frequently red, green, and blue. 
: The green plug carries the Y signal (Luma), 
: the blue the Pb (blue minus yellow)
: and the red the Pr (red minus yellow) signal


...not to be confused with RGB video, which also exists, in multiple forms {{comment|(and which you ''could'' call component video in the wider sense)}}


See also [[Color_notes_-_color_spaces#YCbCr_and_YPbPr]]


<br style="clear:both">

===SCART===
[[Image:SCART.jpg|thumb|190px|right|Plug from a general purpose SCART interconnector cable]]
[[Image:SCART specific.jpg|thumb|190px|right|Two specific-purpose SCART plugs, with only the pins they need for audio and composite video in a specific direction]]
'''SCART''' (a.k.a. '''Euro AV''', '''EIA Multiport''') combines a bunch of analog audio and video formats used by various common plugs, making it somewhat easier to connect various common home devices.

<!--
To the point that it lived for a decade or two and, on home video equipment (VCRs, TVs), and lived into the era of DVD and was only displaced by the likes of... HDMI, I think? At least in Europe - it was much less known in America

-->

SCART {{imagesearch|SCART pinout|can carry}}:
* Mono/Stereo Audio, both ways
* Composite video, both ways
* S-Video may be supported both ways, but isn't always implemented
* RGB (on newer hardware, by re-purposing some wires, so both ends need to support and both to specifically this (ab)use)

[[Image:S-video and RCA on scart adapter.jpg|thumb|right|180px|Back of a SCART converter to composite and S-video, and RCA audio. The switch on top lets it act as input or output for each of these]]
You can easily find adapters to one or more specific things, like RCA audio, composite video and/or and S-Video, and sometimes versions with a switch that selects whether you want to use the converter plug to act as input or output.



RGB is higher quality, but was non-standard and added later
* has to be supported by both sides
* can also not be used  at the same time as S-Video output 
* is only intended for one direction, player-to-display travel
: so is supported primarily by some more modern TV sets (receiving role) and recent media players (sending role)
* supporting players may only send RGB once you explicitly configure them for it, for compatibility reasons.


See also:
* http://en.wikipedia.org/wiki/SCART
* EN 50049-1

<br style="clear:both">

===VGA===
[[Image:DE15.png|thumb|105px|right|DE-15, also named HD-15 {{comment|(and also, somewhat incorrectly, DB15 and HDDB15)}}, used for VGA monitor connections]]

VGA technically refers to [https://en.wikipedia.org/wiki/Video_Graphics_Array Video Graphics Array, a specific video card from the late eighties] that set a graphics standard, including the 640x480 resolution (though any VGA card already did more than that)
<!--
, also interesting in the detail that it loosely resembles an NTSC TV signal{{verify}})
[https://en.wikipedia.org/wiki/Graphics_display_resolution#Extended_Graphics_Array but these resolution names are frankly a mess])
-->

As other graphics cards appeard, it came to refer to the connector used ([[DE-15]]) and the way it carries image signals, 
which stuck around for a ''long'' time and which supports much higher resolutions (over short cables). 

While it's a 15-pin connector, there's a lot of redundancy in there.  '''Most important''' are five signals, and ground:
* hsync
* vsync
* red pixel data
* green pixel data
* blue pixel data
* ground

Four further pins were reserved for [https://en.wikipedia.org/wiki/Display_Data_Channel DDC] (Display Data Channel) to help PCs identify monitor capabilities. {{comment|DDC saw a few different schemes and protocols over time (including pulldown resistors, one-directional serial, and [[I2C]]).
one pin is 5V to power the EEPROM used in some of these schemes, but is otherwise unused.}}


'''On ground''': Pinouts may show the center row all grounds and interconnected, but in most cables these are individual paths, a separate ground - e.g. red and 'red ground' in a twister for lower interference{{verify}}, etc. <!--{{comment|(in this regard, VGA may be ''theoretically'' better at analog signals than DVI-A because DVI-A shared one analog ground between r,g,b)}}-->


{{zzz|Limits
VGA made sense when monitors were [[cathode ray tubes]] and their scanning beam made them all-analog in nature - you had to convert it to analog ''somewhere'', and they chose to do it in the graphics card<!-- (see als [https://en.wikipedia.org/wiki/RAMDAC RAMDAC]s)-->.

Connecting flatscreens via VGA makes less sense electronically: We have a digital image with discrete pixels in the PC, the eventual screen pixels are discrete, but we convert it to analog, to carry as analog, then convert analog back to digital.
Yes, the timing is usually pretty good, but it's an unnecessary intermediate step, asking for mild analog signal losses, and the DAC-then-ADC steps means a little ghosting and similar can happen and aren't really resolvable. Particularly for the faster speeds required for higher resolutions and/or longer cables.
We moved on to digital communication for our monitors for a reason.

At the same time, I see pages being cautious about 1080p '''but''' we've had resolutions higher than that since the ''nineties'', and it's fine pushing through 1080p60 through any but the cheapest cables.  Yet being analog, this is also roughly the point it starts being a concern, because higher resolutions quickly start demanding ~300MHz of bandwidth. It's fine over a short, decent- quality cable, but cheaper and/or longer cables will be trouble, and certain conversions aren't ideal either)}}
}}


Also, it can be a fun to mess with those analog voltages - see also [[VGA hacking]]


<br style="clear:both">

===D-Terminal===
[[Image:D-terminal D4.jpg|thumb|240px|right|D-terminal plug]]
{{stub}}

D-Terminal {{comment|(not to be confused with [[D-Subminiature]] a.k.a. D-Sub)}} is probably most common in Japan, and seen elsewhere mostly in specific applications, e.g. digital satellite tuners.

In that use the wires carry [[#Component_video_.28YPbPr.29|component video]], and also signal lines that use logic-level voltages to signal the video's resolution, ratio, and whether it is interlaced/progressive. 

This has five modes, carrying analog 480i through 1080p, varying with the actual devices,
and sockets may be labeled with D1 through D5 as indication of what a device is capable of, which seems to include:{{verify}}
* D1 480i   (525i)： 720×480 Interlaced
* D2 480p   (525p)： 720×480 Progressive
* D3 1080i (1125i)： 1920×1080 Interlaced
* D4 720p   (750p)： 1280×720 Progressive
* D5 1080p (1125p)： 1920×1080 Progressive


Breakout cables to component video over RCA and BNC exist.{{verify}}


I'm not clear on how/whether this is related to (mini)-[[centronics]].{{verify}} - might this effectively be mini-MDR14?


See also:
* http://en.wikipedia.org/wiki/D-Terminal
<br style="clear:both">

==Digital video cables (high speed and/or uncompressed)==
{{stub}}

Such as:

====DVI====
[[Image:DVI.png|thumb|115px|right|DVI pinout chart (click for details)]]

'''On digital and/or analog'''

DVI can carry both analog and digital video, but specific wires and interfaces can choose to do just one.

[[Image:DVI-variants.png|thumb|115px|right|DVI connector variants (male)]]


There are roughly four variants. To tell them apart, 
* look at the plate on one side 
:: if there are pins around that plate {{comment|(red in the pinout image on the right)}}, the cable can carry '''analog''' video. 
:: if the nearest 3x3 pins is a full block, it can carry '''digital''' video
:: it's called DVI-A if it can carry only analog
:: it's called DVI-D if it can carry only digital
:: it's called DVI-I if it can carry both

* If everything is one solid block of pins (that is, includes the blue pins in the image on the right), it can do '''dual-link''' digital. 
:: If it's not full, it's '''single-link''' digital.




There are some other connectors that look roughly like DVI but are incompatible, such as:
* [http://en.wikipedia.org/wiki/M1-DA VESA P&D / M1-DA] (an extension to DVI from VESA) 

And two different many-pin connectors, often seen for many-monitor graphics cards, as each connector can be used for two monitors:
* [http://en.wikipedia.org/wiki/DMS-59 DMS-59] (59-pin)
* [http://en.wikipedia.org/wiki/Low-force_helix LFH60] 
Needs an adapter for things like DVI or VGA (doesn't carry them directly).
The absence of pin 58 in DMS-59 seems to be just for keying. It isn't used in LFH either{{verify}}, so you can use DMS-59 cables where you would otherwise use LFH.{{verify}}


See also:
* http://en.wikipedia.org/wiki/Digital_Visual_Interface
<br style="clear:both">

====MiniVGA, MiniDVI, MicroDVI, Mini DisplayPort====
[[Image:MiniVGA.jpg|thumb|right|180px|Mini-VGA (socket circled, plug on top)]]
'''Mini VGA'''
* mainly seen in Apple hardware (mostly MacBooks) circa 2005{{verify}}
* not standardized, died out fairly quickly
* replaced by Mini DVI (which could also go to VGA) and MiniDisplayPort (which does even more)
* http://en.wikipedia.org/wiki/Mini-VGA
<br style="clear:both">

[[Image:MiniDVI.jpg|thumb|right|180px|Mini-DVI plug]]
'''Mini DVI'''
* mainly seen in Apple hardware (mostly MacBooks) circa 2005{{verify}}
* not standardized, died out after a while
* didn't really support non-Apple converters to VGA
* http://en.wikipedia.org/wiki/Mini-DVI
<br style="clear:both">

'''MicroDVI''', again mostly Apple, was used on some Macbook Airs. 
* confusable with USB ports. 
* not standardized, died out after a while
* There are adapters to VGA and to DVI-D (not DVI-A or DVI-I{{verify}}). 
* http://en.wikipedia.org/wiki/Micro-DVI
<br style="clear:both">

All of the above were discontinued circa 2010, in favour of Mini DisplayPort.



<br style="clear:both">
[[Image:Mini DisplayPort.jpg|thumb|right|Mini DisplayPort (again, for a Macbook)]]

'''Mini DisplayPort'''
* Initially in Apple laptops, now adopted by VESA and used by other vendors
* There are converters to VGA, (Dual-Link) DVI, HDMI, Displayport, and probably more
* ''May'' also carry audio, may not.
* http://en.wikipedia.org/wiki/Mini_DisplayPort

<br style="clear:both">

====Other Apple connectors====


=====Lightning=====
[[File:Lightning plug.jpg|thumb|right|92px|Lightning plug]]
Thunderbolt is, by name, somewhat confusable with [https://en.wikipedia.org/wiki/Lightning_(connector) '''Lightning'''] (introduced 2012, now being displaced by USB-C {{comment|(slower than you might expect, possibly because of proprietary sales reasons)}}).

Lightning is the thin flat reversible plug with little strips of connector. 

There are eight pins, carrying 
* Vcc and Gnd (charging), 
* two differential pairs that can carry USB (and has active adapters to HDMI, VGA, Audio, and apparently SD card reading).

It is almost exclusive to iPhone, iPad, iPod, and a handful of Apple accessories. 
Lightning replaced the earlier dock connector (and e.g. lightning headphones made sense to make where 30-pin dock headphones didn't really).

<!--
Lightning cables seem rated for 30W charging, though without talking USB-PD will only deliver ~12w (5V 2.1A)

which seems to be why part of Apple is now courting USB-C on more devices.

-->


=====Dock connector=====

[https://en.wikipedia.org/wiki/Dock_connector#30-pin_dock_connector 30-pin dock connector] (since 2003, and mostly disappeared since Lightning in 2012).
[[File:Apple30pindock.jpg|thumb|right|121px|Apple 30-pin dock plug]] which seems to carry:
* USB
* stereo audio in
* stereo audio out
* [[S-video]]
* FireWire
* Serial (used by iPod?   19200 baud?)
* pin that let accessories indicate roughly what they are, e.g. used for "please output audio into me" {{verify}}
* 3.3V
* 5V
* 12V (for firewire)
* various Gnd (separate for power and some of the signals)

{{comment|(the connector itself seems to be a non-standard variant of JAE DD1. Apple seems to have intentionally made it hard to get, though you can e.g. still get some breakout boards)}}

<br style="clear:both">

====HDMI====
[[Image:Connector-HDMI.jpg|thumb|125px|Typical HDMI plug (Type A, 19 pins)]]
High-Definition Multimedia Interface (HDMI) [http://en.wikipedia.org/wiki/High-Definition_Multimedia_Interface]

Can carry digital video, and digital audio.

There are plug variants.  [[Image:Connector-HDMI-ABCDE.png|thumb|425px|HDMI variants]]
* Type A is by far the most common, what you usually use

* {{comment|Type B has more data lines, designed for very-high-bandwidth applications, but never got used. DisplayPort now make more sense in practice}}

* Type C is the mini variant  (meant for small/mobile devices)
:: seen e.g. on Raspberry Pi Zero

* Type D is the micro variant (meant for small/mobile devices)
:: seen e.g. on Raspberry Pi 4

* Type E is an automotive variant - locks in place, more resistant to moisture and dirt
:: you can also get type A in a harness, giving similar features while being compatible with existing cables


{{comment|(For computers it can be relevant that HDMI can carry DVI-D fairly directly - though this will probably only work if the DVI device supports [https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content_Protection HDCP] (copy protection), because the HDMI side is likely to require it)}}




'''CEC''' (Consumer Electronics Control) is for simple commands between a set of interconnected devices, e.g. 
allowing  your TV remote to control some common functions of a set-top or DVD player, have a device turn the TV on and to it as a source, control volume, transfer a preferred device name, things like that.

CEC is mostly known under names like '''Anynet+''' (Samsung), '''1-Touch Play''' (Roku), and various names involving 'Link' (lots of brands). 

Electrically it is a one-wire bidirectional serial bus, separate from HDMI communication so that everything but this can sleep, and is very slow (~400bit/s) because it doesn't need to be faster.

See also:
* http://en.wikipedia.org/wiki/High-Definition_Multimedia_Interface
* https://en.wikipedia.org/wiki/Consumer_Electronics_Control


<!--
'''ARC''' (Audio Return Channel) is a little more interesting to explain.

HDMI carries audio, and is mostly just a 'carried alongside' thing.

Consider that when you have multiple devices with HDMI (blu-ray, gaming, etc), 
that would easily mean you your setup must have a place where all HDMI concentrates and gets switched.

That could be the TV itself, but if you want room sound, how does your amplifier get involved? 
Best option wuold often be running some analog audio from its line out to your amp, but HDMI does digital sound,
and many amplifiers understand that these days, so a better option would be to have an amp that switches for you,
but that's less convenient as the TV now doesn't control.

ARC gives you a third option: Wire the sources to the TV directly, and have that TV send its audio to your HDMI-connected amp.




However, ARC is not always implemented, or as fully as you want (e.g. may not do better than stereo audio).
-->


<!--
'''On HDMI cables'''

tl;dr:
* a cable certified for a speed will always support everything that keeps under said speed
: and yes, this needs to be said, to the golden cable crowd

* fancy cables don't mean better images. When signals are digital, it either works or it is broken.
: A High Speed cable can cost, order of magnitude, 1-2 Euro per meter. Paying more is often a waste of your money

* most cables are High Speed (except for some from early days)



: '''Cable features and specs'''

There are two distinctions in cables:
* with or without ethernet
: There are currently few devices that can use it.

* Standard Speed, High Speed, Premium High Speed, and 48G (see below)


...and, spec-wise, nothing more.

Whether a cable is in spec is ''purely'' about bandwidth, not about features.
'''if both ends support a feature, and the cable supports the bandwidth, that feature will work'''. 
If one side does not support it, that feature will not work. ''period''.

So products like "HDMI 1.4 cable", "3D HDMI cable", "ARC HDMI cable" and such '''do not exist'''.
This is marketing for consumers who want to buy the more expensive thing because ''surely'' it's better.


The shorter the cable, the fewer problems it has to deal with, so a good number of short (&lt; 3m / 10ft) standard-speed cables may actually do higher speeds than they are certified for, and may e.g. do 1080p60 perfectly, even if the specs don't guarantee that. 

Your devices don't know what your cable is labeled at, so it will either work, or not. {{comment|(There is a ''very'' narrow zone where you get ''some'' errors, or maybe semi-dramatic degradation. You'll probably rarely or never see this)}}




: '''Cable speed'''

The way higher-speed communication works, 
the amount of Gbps a cable ''could'' support relates mostly to cable length and wire gauge. 

This is basically relevant for prefabricated cable, because either it's in spec, or not.

To avoid buyers having to get lost in details, there are two standardized certifications since HDMI 1.3{{verify}} (around 2006), and some added later:
* Category 1, a.k.a. Standard, tested at 74.5 MHz
: most cables quickly moved to high speed, because Standard isn't enough for 1080p60

* Category 2, a.k.a. High Speed
: enough for almost everything

* "Premium High Speed" (since 2015) ensures 18Gbps

* "48G" (since 2017) which ensures 48Gbps


The last two are mostly relevant if you have &ge;4K, deep color, 3D type things -- and even then it will probably only need it if it does multiple of these things at the same time, which is not common.

So if a particular cable is certified, it is guaranteed to work at the related speed. 
{{comment|(...there are also non-certified cables out there, and you can argue about which made-in-china specs are truer than others, but that's another issue)}}.



: '''So what needs what speed?'''

Standard speed cables will do 720p, 1080i, and probably 1080p/24 but various devices have no need for the last.
This is enough for cable/satellite (1080i), game consoles that go up to usually 720p or 1080i, and things like 720o Apple TVs.


It does not do 1080p/60, quite relevant in that computer monitors have done at least that for years, which is a good part of why most HDMI cables are High Speed.

High speed supports resolutions like 
: 1080p/60 (including Blu-ray, and computer monitors)
: and WQXGA (2560x1600) and 2160p24 (see also [http://en.wikipedia.org/wiki/4K_resolution 4K])
: usually those resolutions combined with 3D ''or'' Deep Color.
: some 120Hz / 240Hz screens, when they are actually post-procesing 60-or-less fps, rather than rendering and transferring that rate



: How much better are the pricier, Gold Plated Ultra Monster cables?

They do not affect picture quality or speed.

It's true that HDMI chooses not to checksum its video, it's realtime send-and-forget.
So ''in theory'' you can get interference affecting display.

However, in most cases something that would interfere wouldn't be selective on pixels - it'd extremely easily keep the entire thing from working at all. 

So it's still hard to think of pathological cases where this even ''could'' make a useful difference.

The only case I can think of is that extra shielding may help in environments with stray RF so strong that most of your cabling would have these issues - and even then you've got a wider problem that you should probably fix at the source.


''Some'' of these fancy cables could sustain much higher speeds than they are certified for,
meaning you won't have to buy a new cable in 5 years when upgrading to a 4K 120fps 3D TV.

But you won't know what speed, you're buying something expensive now for something that isn't even guaranteed to work later.



Ferrite beads are usually there to meet ''emission'' standards, so on a HDMI cable they may help avoid influencing nearby analog signals.
But do almost nothing to protect your HDMI signal.



http://www.bluejeanscable.com/articles/hdmi-cable-information.htm

http://www.bluejeanscable.com/articles/speed-rated-hdmi-cables.htm
-->


<br style="clear:both"/>

====DisplayPort====
[[Image:Connector-DisplayPort.jpg|thumb|right|100px|DisplayPort plug]]


Digital transfer; can carry video, audio, data, and a little power (for adapters?).

Because it was aimed to be a replacement of [[HDMI]], [[DVI]], [[VGA]], and things like [[FPD-Link]], it was made with compatibility in mind.


The signaling is not ''directly'' compatible with DVI or HDMI, but adapters are not complex.
While VGA adapters have to be active, they ''can'' be powered through the DP cable (if short{{verify}}, which most are).




'''Cable length''' 

Specs say 2 or 3 meter max. 

This is a cautious figure and decent cable quality may go a little longer, 
in part because it's only higher speeds that run into trouble.

But don't count on more than 10-20m, and then only for for lower(-data-rate) resolutions.

'''Active cables''' could go up to 15-30m at somewhat higher rates/resolutions in a more compliant, less fragile way. 
(Note that active cables must be connected in the right direction - passive cables don't care).

If you want more than that, you probably want fiber DP instead of copper DP (at high enough rates and distances, the issue is capacitance and sort of unavoidable).



A '''Dual-mode''' DisplayPort output (a.k.a. DP++) supports the use of an adapter to single-link DVI or HDMI. {{comment|(a '''passive adapter''' in that the output itself already speaks the right thing, the adapter only changes voltages)}}

Without this, only an '''active adapter''' (something that does a conversion between different video formats inside it) would work.

Other conversion formats (e.g. to VGA) always require this.



'''Bandwidth'''

A single lane (differential pair) in a DP cable can be run at one of four speeds, 
* 1.6GBit/s raw, ~1.3GBit/s data in RBR (reduced bit rate)
* 2.7GBit/s raw, ~2.1GBit/s data in HBR mode
* 5.4GBit/s raw, ~4.3GBit/s data in HBR2 mode {{comment|(introduced in DPv1.2)}}
* 8.1GBit/s raw, ~6.5Gbit/s data in HBR3 mode {{comment|(introduced in DPv1.3)}}

Cables made for higher speeds will often be 4-pair, which means:
* 4-pair HBR  is ~8 Gbit/s	{{comment|(~10Gbit/s raw minus 20% coding overhead)}}
* 4-pair HBR2 is ~17 Gbit/s	{{comment|(~21Gbit/s raw minus 20% coding overhead)}}
* 4-pair HBR3 is ~25 Gbit/s	{{comment|(~32Gbit/s raw minus 20% coding overhead)}}



Your average monitor will just work on most any cable. Making 1080p fail on a short cable would take effort.


You would only care about these numbers if you use a ''combination'' of 4K, deep color, 120fps, and 3D, e.g. 
: 3840×2160@120fps requires HBR2, 
: 5120x2880@60Hz require HBR3
: multiple displays on a single port can be done



=====Mini-DisplayPort=====

[[Image:Thunderbolt socket.jpg|thumb|60px|right|Actually thunderbolt, but it's the same socket]]
Like it says - a smaller plug that carries [[DisplayPort]].

Seen used on laptops in general, and Apples in general, for monitors

Also used on Apples for [[Thunderbolt]] (1 and 2)

See also:
* https://en.wikipedia.org/wiki/Mini_DisplayPort

<br style="clear:both"/>

====GVIF====
{{stub}}

Gigabit Video Interface (GVIF), carried by a single twisted pair of wires,
also allowing a data channel.

Plugs vary.

Used mostly in a few automotive uses, and then largely video-only.
Up to 10 meters, up to ~2GBit.


(Not to be confused with [[GSIF]], GigaSampler InterFace)

https://en.wikipedia.org/wiki/Gigabit_Video_Interface

====UDI====

UDI (Unified Display Interface) [http://en.wikipedia.org/wiki/Unified_Display_Interface] [http://images.google.com/images?q=Unified+Display+Interface]

Seems to never have made it out the door, 
apparently deprecated in favour of [[DisplayPort]]{{verify}}

====SDI====
{{stub}}

SDI (Serial Digital Interface) is an uncompressed digital video (and audio) signal, originating around 1989 and to this day mostly seen in professional use.

Electronically: 
: '''BNC connectors''', coax with 75 Ohm [[characteristic impedance]] (which was the same cabling as analog video setups, which helped upgrades, but also some confusion)
: 800 mV peak to peak {{comment|(but receiver can deal with lower, meaning in clean environments you could have maybe 300m runs of ~270 Mbit (SD-)SDI without repeaters - though that's pushing it in ways you often don't want to, and will be have to be rather shorter in messier environments)}}.



'''Speed variants over time:'''

SD-SDI: ~170..360 Mbit, allows 480i, 576i 

ED-SDI: ~500 Mbit, allows 480p, 576p 

HD-SDI: ~1.5GBit, allows 720p, 1080i (common for a long time?)

Dual link HD-SDI (2002): ~3GBit, allows 1080p60

3G-SDI (2006): ~3 GBit, allows allows 1080p60 (and can be easier than dual-link HD-SDI)

6G-SDI (2015)

12G-SDI (2015)
<!--

24G-SDI (in development)
-->

See also:
* https://en.wikipedia.org/wiki/Serial_digital_interface

====HDBaseT====

<!--

Its own protocol, 
single dedicated link,
not routable



Communicates 
HD video (uncompressed)
digital audio
DC power
Ethernet
USB 2.0
RS-232 and Consumer IR

Latency: 0.1ms over dedicated cable

-->


https://en.wikipedia.org/wiki/HDBaseT

====NDI====

Network Device Interface (NDI) is a ''protocol'' that amounts to video over IP (with [[mDNS]] for discovery).


It's not a connector - but that said, hardware devices that speak NDI (cameras, monitors) tend to have a gBit ethernet interface ([[8P8C]] connector, 'RJ45'). {{comment|(You ''could'' run it over wifi, but due to the bandwidth requirements, this may not work well except in some wifi-quiet places - but in practice that means you will have little  control over potential problems)}}


The protocol focuses on being fairly low latency
* the classical ('Full Bandwidth') NDI codec is lowish compression to get that low latency <!--(around 16ms)-->
* NDI HX uses H.264, NDI HX2 uses H.265, considerably less bandwidth but both with higher latencies <!--(80+ ms)-->

<!--
If you can't guarantee your network is never at its limit, you might consider dedicated wiring (but usually don't need to).
-->

See also [[Local_and_network_media_routing_notes#NDI]] for a few more implementation details.


See also
* https://en.wikipedia.org/wiki/Network_Device_Interface
* [[Local_and_network_media_routing_notes#NDI]]

====Specialized  or  internal display connectors====
{{stub}}

'''SlimPort''' (an implementation of Mobility DisplayPort)[https://en.wikipedia.org/wiki/DisplayPort#SlimPort]
: over micro-USB connector, but not standard USB so both devices must specifically support it. 
: Seems intended for supporting phones/tablets{{verify}}


'''MHL''' (Mobile High-Definition Link)[https://en.wikipedia.org/wiki/Mobile_High-Definition_Link]
: intended for supporting phones/tablets, designed to use existing connector like micro-USB, and to HDMI


'''PDMI''' (Portable Digital Media Interface)[https://en.wikipedia.org/wiki/PDMI]
: a 30-pin connector that carries DisplayPort, USB, analog audio



'''Display Serial Interface''' ('''DSI''')[https://en.wikipedia.org/wiki/Display_Serial_Interface] \:aimed at being a simpler thing for mobile use.
: Also seen referred to as MIPI, the ones who specced it.
: Seen e.g. on Raspberry Pi, some STM32.
: Note that Camera Serial Interface (CSI) may be possible on the same connector{{verify}}
: The connection is one clock lane and one or more differential data lanes, and seems tested to about 1Gbps/lane{{verify}}
: There is no singular connector, but there are not a lot either. For example, 
:: Raspberry Pi settled expose 2 lanes on a 15-pin connector. 
:: Compute Module 4 puts 4 lanes on a 22 pin, smaller-pitch connector (you can connect 15-pin screens with an adapter cable)
: In practice, what MIPI cameras/monitors monitors actually have may well be the limiting factor for many hobbyists. 
:: Many will say "For raspberry pi" or such.
: If it mentions 800x480, that's at least partly because that's roughly the limit of 2-lane DSI{{verify}}


'''MDDI''' (Mobile Display Digital Interface) - 


'''LVDS LCD''' - ?


'''FPD-Link''' (Flat Panel Display Link)[https://en.wikipedia.org/wiki/FPD-Link]
: used in ''many'' laptops
: based on LVDS


'''OpenLDI''' - based on FDP-Link[https://en.wikipedia.org/wiki/OpenLDI]
: ended up mostly used for some specific things like medical devices, construction equipment


'''iDP''' - fewer wires than FDP-link


=Power - wall plugs=

'''The types''' are a less formal{{verify}} way of indicating the common plugs to use around the world.

See:
* http://en.wikipedia.org/wiki/Mains_power_around_the_world
* http://en.wikipedia.org/wiki/Power_plugs 
* http://commons.wikimedia.org/wiki/Mains_socket


Some of the more common plugs are listed below 
(lettering system as used by some US document on worldwide power)


<!--
North America, the EU, Russia, Australia, some of Africa have simplified to one plug (occasionally with a direct variant or two).

South America, China, much of Africa, and others have multiple plugs.


Note that a plug fitting doesn't necessarily mean the device will work:
* Devices should be made for the same order of voltage -- there are various voltages in world, those in the 200V-240V range, and those in the 100V-127V range. Simple devices tend to work well enough with any other voltage in the same range, though there are exceptions)
* Some devices are built around the assumption of the AC being 50Hz or 60Hz and will not work on the other.


Much of the world runs on approx. 230V and 50Hz, while the US and Canada run on ~110V / 60Hz, 
a number of areas use slightly higher or lower variants of one of these, and a few haven't made up their mind and have more than one.

Most of the EU runs on 230V, as a unification between 220 and 240 that existed previously.

Almost all power is 50Hz or 60Hz, while there are more variations of voltages in the 200-240V range and in the 100-127V range.
Most combinations exist (including ~110V/50Hz and ~220V/60Hz) somewhere, though in some cases it's a single country.
-->


Some practical knowledge before traveling: https://www.electricalsafetyfirst.org.uk/guidance/advice-for-you/when-travelling/travel-adaptors/





===Type F / Schuko / CEE 7/4===
(Europe)
<gallery mode="packed" style="float:right" heights="150px">
Schuko_plug.jpg|Type F plug
Schuko_socket.jpg|Type F wall socket
</gallery>



Type F plugs/sockets, also known as Schuko {{comment|(short for Schutzkontakt, roughly meaning 'protective contact', referring to having a contact for [[protective earth]])}}, and standardized in CEE 7/4, are round sockets/plugs with two earth clips on the side, and two guides for a more robust fit in the embedded socket.

It is used in much of (western) Europe, commonly seen in wall sockets and power strips.

Not polarized, though there is an Argentinian variant that apparently is.

<!--
Most sockets are rated at 16 A, so there are very few other sockets needed.
-->


<br style="clear:both"/>
The Russian [http://en.wikipedia.org/wiki/GOST_7396 Gost 7396] looks and is similar, but has thinner prongs, so while you can often plug Gost into Schuko sockets, Schuko plugs often don't fit into Gost sockets{{verify}}.

<br style="clear:both">

===CEE 7/7 plugs===

[[Image:CEE 7-7.jpg|thumb|CEE 7/7 plug]]

Worth mentioning because it is designed to work in ''multiple'' distinct earthed sockets:
: [[#Type_F_.2F_Schuko_.2F_CEE_7.2F4|Type F]] style earth (most of western Europe) and 
: [[#Type_E|Type E]] style earth (France, Belgium, also Poland, Czech Republic, Slovakia, Denmark).


Seen in wires that ''must'' be earthed (so can't be [[europlugs]]) and meant for wide sales (that is, catching both type E and type F countries with the same plug). 
One good example is computer power supply cables, which are usually CEE 7/7 to [[#IEC connectors|C13]].


<br style="clear:both">

===Other, non-earthed European plugs: Type C, Europlug, CEE 7/16, CEE 7/17===

'''Type C''' exists in round and flat variants.


[[Image:Europlug.jpg|thumb|right|CEE 7/16, Europlug, also common on [[wall-wart]] adapters]]

'''flat type C''', also formalized as CEE 7/16, and regularly called ''' 'Europlug' ''', is an unearthed plug that fits most European-style sockets (Type C, E, F, others).

Some power strips have a few thin-type-C sockets (and Schuko otherwise), because you'll always have a few devices with these and it saves space in that case (and in that case only, as these sockets accept ''nothing'' else).

See also:
* http://en.wikipedia.org/wiki/Europlug

[[Image:CEE 7-17.jpg|thumb|150px|right|CEE 7/17 plug]]

The '''CEE 7/17 plug''' is a something of an unearthed adaptation of 7/16 to mate with Type E, Type F, and round type C sockets.

<!--
There is a (fairly rarely seen) socket that accepts no earthed plugs, by being a type E socket but instead of an earth pin, have a plastic pin and a strip of plastic from where it would be all the way to the edge. 
This seems to be used on 2-wire extension cords, to make sure you can't plug in an earthed appliance and forget that it ''isn't'' actually earthed (...and possibly to be legal to sell at all{{verify}}).
-->

<br style="clear:both">

<br style="clear:both">

<gallery mode="packed" style="float:right" heights="150px">
Image:Round type C plug.jpg|Round type C plug  (CEE 7/2)
Image:Round type C power strip.jpg|Round type C (CEE 7/1) sockets, on an old power strip
</gallery>


There is also an unearthed '''round Type C'''. This is typically considered old, and rarely seen sold anymore, for a few reasons.
[https://en.wikipedia.org/wiki/CEE_7_standard_AC_plugs_and_sockets#CEE_7/1_unearthed_socket_and_CEE_7/2_unearthed_plug socket is CEE 7/1, plug is CEE 7/2].

While the socket (7/1) will accept most any European-style plugs (C, E, F; 7/4, 7/7, others), the round type C ''plug'' (7/2) will only really plug into the 7/1 socket, and roughly nothing else, notably not the Schuko socket - it will not plug into Type E or F sockets (blocked by the plastic that guides the earth).

New installations will very typically use only earthed sockets, so the 7/1 socket is harder to find now.


<br style="clear:both">

===Type E===
[[Image:Type E socket and plug.jpg|thumb|370px|right|Type E socket (CEE 7/5) and plug (CEE 7/6)]]

Seen mostly in France, Belgium, Poland, Czech Republic, Slovakia, Denmark{{verify}}

Looks much like Type C, except for the male ground pin that sticks out. 


While it has a fixed orientation, there is no polarization standard. {{comment|(possibly because that would not apply to other european-style plugs it is fairly compatible with)}}

<br style="clear:both">
[[Image:CEE 7-7.jpg|thumb|CEE 7/7 plug is made to be compatible with E as well as F]]
Also compatible with others, including {{comment|(mostly things specifically designed for C, E, and F sockets)}}
* [[#CEE 7/7 plugs|7/7]] plugs (european earthed round plugs)
* [[#Other.2C_non-earthed_European_plugs:_Type_C.2C_CEE_7.2F16.2C_CEE_7.2F17.2C_Europlug|7/17 plugs]] (the unearthed but still roundish one)
* and [[#Other.2C_non-earthed_European_plugs:_Type_C.2C_CEE_7.2F16.2C_CEE_7.2F17.2C_Europlug|7/16]] plugs (flat unearthed europlug)

<!--
Not compatible 
* older unearthed round type C plugs
-->

<br style="clear:both">

===Type A, Type B, household NEMA variants, JISC C 8303 Class II===
(North America, Japan, some other places)
[[Image:A plug.jpg|thumb|210px|right|Type A (NEMA 1-15) plug]]
[[Image:B plug.jpg|thumb|180px|right|Type B (NEMA 5-15) plug]]

http://en.wikipedia.org/wiki/NEMA_connector
[[Image:Type B socket.jpg|right|thumb|NEMA 5-15 wall socket (a.k.a. Type B)]]
[[Image:5-20 socket.jpg|right|thumb|5-20 socket]]

Mainly:
* NEMA '''1-15''' is the typical 2-prong non-earthed plug, a.k.a. '''Type A'''

* NEMA '''5-15''' is the typical 3-prong earthed plug, a.k.a. '''Type B'''

...both rated for 15 amps {{comment|(with a suggestion of doing no more than ~1300W, because there's a rule that a continuous load should stay under 80% of the rating)}}.



'''NEMA actually defines a ''lot'' more plugs than that'''
: mostly for 
:: higher currents - 20, 30, 50, 60A, and/or 
:: higher voltages, and/or
:: doing so on 3-phase (rather less common than split-phase)
:: (...all three of which are fairly rare outside of commercial or industrial settings)
: ...most of which you won't see in everyday life
:: you may well have seen {{imagesearch|NEMA 5-20}} (horizontal blade on plug, T-shape on socket to accept both 5-15 and 5-20) in commercial settings
:: and the four-prong 14-30 (once also the three-prong 10-30 that had no ground), for power-hungry 240V devices at home (like driers)

See also https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#North_American_and_IEC_60906-2

<!--
The Japanese JISC C 8303 basically overlaps with a lot of NEMA, 
which is why Japan mostly uses 1-15 and 5-15,
though it has its own numbering/naming, and some of their own extensions (e.g. hospitals)

-->


'''Polarity'''

US socket polarization was once ''central'' to basic safety, so basically all sockets are polarized.

At the same time, apparently the oldschool 2-pin plug was symmetrical (and the 3-pin wallsocket wasn't required until the seventies)

Many modern ''devices'' won't care, and when they use an unearthed (2-pin) 1-15 ''plug'', they can allow it to be plugged in both ways. 
When they ''do'' care about polarization, they do so by having one of the plug's prongs be wider (that's neutral) than the other (that's hot),
which will only plug into typical 2-pin or 3-pin sockets one way.

The 3-pin ''plugs'' often don't need to bother{{verify}} with these different sizes, because the presence of the ground pin enforces the polarity.

So yes, you can wire a socket wrong, which is technically unsafe, 
though practically only for ''very'' old devices that connect the chassis to neutral{{verify}}.


'''Holes?'''

Various plugs have holes in the prongs. 
This is not, as some believe, for more friction, or to slot into anything.

It's a manufacturing side effect.  In fact, NEMA seems to intentionally spec that if they're there, they should specifically be away from the actual mating part of the surface, so that it doesn't reduce contact area. [https://www.youtube.com/watch?v=udNXMAflbU8]



<br style="clear:both">

===Type G, BS 1363 (UK)===
{{stub}}

Used in the UK and a dozen other countries[https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets:_British_and_related_types#BS_1363_three-pin_(rectangular)_plugs_and_sockets]


[[Image:Type G plug and socket.png|thumb|380px|right|Type G plug and socket]]

* Oriented

* polarized in the standard {{comment|(though many everyday devices won't care)}}


Safety features:
* Earth prong is longer, so a device is earthed before it gets power
* Sockets may have safety shutters (actuated by the longer earth prong)
* Newer variants have the non-ground pins half shielded so it's very hard to reach live copper
<!--
* the paths the wires take in the plug means
-->


Other apparent design considerations:
* All sockets are the same (there is no unearthed socket design)
* Fuses in the plug - often easier to replace than those in the devices
* Wire from bottom means people won't often try to pull it out from the wire, so few break that way (though possibly more break ''un''intentionally)



See also:
* http://en.wikipedia.org/wiki/BS_1363



BS 1363 replaced the earlier BS 546 in the 1940s, 1950s.  
BS 546 is still in use elsewhere, see [[#Type_D.2C_M|Type D, M]]



There is also a distinct shaver socket, [https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets:_British_and_related_types#BS_4573_(UK_shaver) BS 4573],
which looks like a thicker variant of europlug.





<br style="clear:both">

===Type I===

[[File:Type I power plug and socket.jpg|thumb|right|265px|Type I plug and sockets]]
(Australia, New Zealand, China, Argentina)

<br style="clear:both"/>

===Type N===
South Africa, and a variant seen in Brazil

https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Type_N

===Type H===

Israel

https://commons.wikimedia.org/wiki/File:Israeli-type-H-plugs-and-socket.jpg

https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Israel_SI32_(Type_H)

===Type J===
{{stub}}

Switzerland, also seen in Lichtenstein

Europlug will plug into this, earthed variants (or other variants) from elsewhere in europe will not. 


Not to be confused with type N


https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Swiss_SN_441011_(Type_J)

===Type L===

{{stub}}

Italy mostly sees type L, C, and F

https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Italy_(Type_L)

===Type K===

{{stub}}

Denmark

Phase and neutral distance and pins compatible with Schuko/europlug.



Earth is a half-round pin on the plug, 

Danish grounded plugs will only fit into a grounded socket.

However, non-Danish european plugs (type E, type F) plugs will mate, but without connecting ground.



https://commons.wikimedia.org/w/index.php?search=type+K+plug&title=Special:MediaSearch&go=Go&type=image

https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Danish_Section_107-2-D1_earthed_(Type_K)



Less-common Danish variants include
* one pin flat, used in hospitals<!--, and is typically UPS/generator backed-->

* phase and neutral pins slanted, for computer equipment, though reportedly this is more annoying than it is useful.

https://www.plugsocketmuseum.nl/Danish2.html

===Type D, M===
{{stub}}


BS 546 is the older british plug,
and also seen in India, Pakistan, some East African countries, South Africa,

Note that these countries may have other plugs. For example, it seems that:
: India sees C, D, and M
: Pakistan mainly sees C and D
: South Africa sees C, D, M, and N


Three round pins.

There are three different plugs, with larger pins spaced further apart, each with their own current rating.

Because of the three distinct sizes, the three varied plugs will only plug into a socket rated for the same current,
although there are sockets that take multiple variants.

The 2 A and 5 A plug are considered Type D, the 15 A plug Type M.




https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#BS_546_and_related_types_(Type_D_and_M)

https://www.plugsocketmuseum.nl/OldBritish1.html

===Type O===

<!--
https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Thai_three-pin_plug_TIS_166-2549_(Type_O)

-->




===When does wall polarity matter?===
<!--

If your house's wiring or devices do not use ground, or are not due to much regulation, polarity can help you be more safe.

In a lot of cases, though this is now more of a historical artifact than something that still helps much.



'''When your house has no ground wires at all'''

The US electrical system barely used earthed sockets or plugs before 1950,
meaning that a chassis, if wired to anything, would be wired to neutral (where we'd use ground today).

It could make for a tingle when you touch two devices (indirectly due to wire resistance), but that's fine.

More importantly, if you got the plug polarity wrong, that would wire the hot leg to the chassis always.


Since the fifties, pretty much all US installations are grounded, 
and if a chassis is wired to anything it'll be wired to ''ground'',
and its plug would be required to be grounded.

So a live chassis due to polarity reversal mistake basically cannot happen on hardware younger than about seventy years.

Still, just forgetting the polarity doesn't really ''give'' you anything,
and because you can't be sure that 100% of installations and devices in use comply to this,
you just keep it, even if it does basically nothing.




'''What risks are there to having hot and neutral swapped?'''

That depends mostly on how well devices are designed.

In terms of devices, modern and international regulations usually make exposing neutral as much a violation as exposing hot{{verify}}.

So what does it take to make it a risk?



Well, '''consider a lamp'''

The simplest you could make: An Edison screw fitting, a single-pole switch in the wire.

''If'' the wires coming in are polarized (i.e. you know which one is neutral), then you can 
* ensure that the outside of the fitting is neutral 
and/or
* ensure that the switch is on the hot wire


Either will mean that, if the switch is turned off, you can touch the bulb's metal base without being zapped.

You can do this in the ceiling easily, because your house wiring is polarized while in the walls.

You can this it from a polarized plug (assuming all your sockets are correctly wired).

You can't do it from an unpolarized plug.




What's the safety design flaw here?

You can argue for:
* The fact that you can touch potentially-live metal at all 
:: a good reason to phase out edison screw eventually 

* the existence of single pole in-wire switches 
:: because you are intentionally leaving have the circuit connected
:: Yet realistically, single pole switches are going to keep getting sold.



There is a very practical 'however' to the lamp example: '''you can unplug it when switching the bulb''' (or not stick your fingers inside).


Also, '''the real safety design flaw here''' is the Edison screw fitting itself. 
It is roughly the only device where we accept that we can stick our fingers directly onto the hot wire.
Introduced today, it would immediately fail safety regulations.
The only reason we have it is that it predates the entire concept of electric safety regulations,
and we haven't gotten rid of it ''yet'' because people are used to it, but it ''is'' on its way out.
 


'''What other cases might be risky only without polarity?'''

The best example I can think of is  apower strip with a single pole switch, 
because it'd be 50-50 whether you disconnect neutral or hot, 
meaning the hot may still make it to a device with the switch off.

...but I'm moderately certain those all use double throw for exactly that reason.












-->



=Power - device side=

==Low/medium voltage, device side==
...e.g. adapters, battery packs, solar panels, and such.

Meaning up to a dozen volts, generally up to an amp or two.



===DC connectors, EIAJ power, coaxial and more===
[[Image:Some power plugs.jpg|thumb|120px|right|A bunch of them (see list on the left)]]
{{stub}}


A lot more plugs get used for this - because particularly under 20V there are few requirements,
so a lot of plugs are fine to use in physical terms.

Perhaps the most recognizable is the concentric barrel-style (some of them within the EIAJ set, some not),
which is probably also the subset least likely to be used for other things.

Most are not so much standardized as they are used by convention.

Low-voltage power, usually DC. 
<!--I've rarely seen this use for AC, or more than 12V or so though there seems to be no fundamental reason to not do either-->


The image on the right is a selection of connectors from one of those "20 in one DC adapter kit".  

From top to bottom:
* 2.5mm TS
* 3.5mm TS (confusable with audio)

* 5.0mm barrel (~6.2mm tip) {{verify}}
* EIAJ-01 (2.35mm barrel, 0.7mm inner diameter)
* 3.5mm barrel (1.35mm{{verify}} inner diameter)
* EIAJ-02 (4.0mm barrel, 1.7mm inner diameter)
* 5.5mm barrel, for 1.5mm pin
* 5.5mm barrel, for 2.5mm pin

<br style="clear:both">
[[Image:DC plug 5.5mm 2.5mm.jpg|thumb|120px|right|The common 5.5mm&nbsp;thick DC plug with 2.5mm&nbsp;pin (socket and plug)]]
Terms, standards, plugs:
* '''IEC 60130-10''' (:1971) defines five/seven connectors
** Type A: 5.5 mm outer diameter, 2.1 mm inner diameter (seems the most common?)
** Type A: 5.5 mm outer diameter, 2.5 mm inner diameter 
** Type B: 6.0 mm outer diameter, 2.1 mm inner diameter
** Type B: 6.0 mm outer diameter, 2.5 mm inner diameter
** Type C: 3.8 mm outer diameter, 1.4 mm inner diameter
** Type D: 6.3 mm outer diameter, 3.1 mm inner diameter
** Type E: 3.4 mm outer diameter, 1.3 mm inner diameter

* 'EIAJ connector' usually refers to one of the EIAJ RC-5320A connectors, rather than the other two:

* '''EIAJ RC-5320A''' [https://en.wikipedia.org/wiki/EIAJ_connector#Types] defines five different thicknesses of barrel pairs rated for 2A. Yellow-tipped DC connectors are likely to be one of these.
** EIAJ-01: 2.35mm thick barrel, 0.65mm thick pin {{verify}}
** EIAJ-02: 4.0mm thick barrel,  1.65mm pin  {{verify}}
** EIAJ-03: 4.75mm thick barrel, 1.65mm pin  {{verify}}
** EIAJ-04: 5.5mm thick barrel,  3.4mm pin  {{verify}}
** EIAJ-05: 6.5mm thick barrel,  4.4mm pin  {{verify}}
** {{imagesearch|EIAJ RC-5320A}}
:: note that this is simplified -- these have inner and outer diameter for both plug and socket

* EIAJ RC5322
** Barrel type connectors, 6mm outer, 3.1mm inner radius. Pin is 1.0mm
** wide (6.5mm) plastic tip, apparently to avoid contact in cars and such
** {{imagesearch|EIAJ RC-5322}}

* EIAJ RC5321
** [[TRS]]-like connectors, different radii
** {{imagesearch|EIAJ RC-5321}}



Telling which one you have or need is sometimes be a bit of a challenge.

Small mismatches on the slightly-smaller side tend to be okay, because these are often held by spring contacts.

Barrel sockets often don't have a solid inside but two (spring?) contacts.
: So e.g. a socket made for 5.5mm outer, 2.1mm inner diameter
: will likely also accept 4mm 2.1mm,
: and probably 5.5mm 2.5mm.
: though a 5.5mm outer, 3.4mm inner may not make contact.

However, a socket with a 2.5mm pin won't accept a 2.1mm inner-diameter.

<!--
For example, a 5.5mm barrel can come with a 2.1, 2.5, and 3.4mm hole/pin.
(...from just the above, more common ones. Less commonly you can apparently[https://en.wikipedia.org/wiki/Coaxial_power_connector#Listing_of_DC_coaxial_connectors] also find 1.5, 1.7, 2.8, 3.0, and 3.3mm)
-->



The polarity for DC barrel type is typically tip-positive, i.e. the pin-inside is positive, the outide is negative. 

The main notable exception is [[audio effect pedals]].



<!--
* Mini IEC Plug
-->



See also:
* http://en.wikipedia.org/wiki/DC_connector
* http://en.wikipedia.org/wiki/Coaxial_power_connector
* http://en.wikipedia.org/wiki/EIAJ_connector 
* http://en.wikipedia.org/wiki/Coaxial_power_connector#DIN_45323_power_connectors
* http://www.accesscomms.com.au/reference/outputplugscb.htm

<br style="clear:both"/>

===3-Pin and 4-Pin DC Plugs===
[[Image:Snap and lock 4-pin power.jpg|thumb|right|160px|Apparently KPPX-4P]]
{{stub}}


When you see pins thick enough to do more than signal, you are often looking at DC power plugs.

There seem to be a bunch of these, most probably unrelated in origin, 
probably unified mostly in "seems solid, had has the two/three/four thick-enough pins I need",
some of which seem to be niche de facto standards.

Many don't seem to have any singular standard, name, or pinout,
though I've seen various with specific keying shapes that ''do'' make them a very specific plug. 

I've not made a selection of these to show here - you're on your own for now.


Everyday names seem to include:
* snap and lock (though not all variants lock),

* (incorrectly{{verify}}) power mini-DIN, power DIN - misleading as this does not mate with any mini-DIN plugs or sockets, because of the thicker pins than DIN, and often larger shell {{comment|(the ones I saw were ~10mm instead of mini-DIN's 9.5mm)}}


Often used to deliver two different voltages, possibly at a little more current than basic DC plugs are comfortable with.


<br style="clear:both">


<!--
===LEMO===

Seen around cameras, seen carrying power, sync 

No standards even within 



2-pin (12V)

4-pin (12V)

4-pin (camera sync)


often seems to be B-series?{{verify}}





===D-tap===

12V, but might be a little higher

Mostly used around cameras

you'll e.g. see adapters to V-mount, gold mount


-->

===Seen in cars or RC===


====Cigarette lighter plug====
[[Image:Cigar lighter plug.jpg|thumb|164px|right]]

Known as cigar(ette) lighter plug, vehicle receptible, and others. 
Also called a 12V plug, since this is ''usually'' what is provided (some exceptions).


Note that there are actually '''three variations''' of this plug, with mildly different sizes. 

Since many have plugs with multiple millimeters of spring on the side, they tend to be more or less interchangeable,
though some combinations may be too loose, or too tight. 


See also:
* http://en.wikipedia.org/wiki/Cigar_lighter_receptacle

<br style="clear:both"/>

====More specific, less standard (car, low voltage/data)====
=====OBD-II=====
{{stub}}
[[File:OBD-II.jpg|thumb|right|195px|OBD-II plug]]

On-Board Diagnostics is only required is to transmit emission-related data{{verify}},
but typically also exposes a bunch of other information useful for mechanics to give clues to problems - mostly live values from the engine, 
and logged errors[https://en.wikipedia.org/wiki/OBD-II_PIDs].


There were a few mostly-proprietary things that had implemented this idea.

OBD-II was the first wider standardization of the idea.


In the plug, aside aside from power (12 or 24V battery, and chassis ground)

It can carry three different standard things:

* [[CAN]] (ISO 15765-4, SAE J2284)

* [https://en.wikipedia.org/wiki/On-board_diagnostics#SAE_standards_documents_on_OBD-II SAE J1850], which is specific to OBD{{verify}}, and is itself either 
: a 41.6Kbps PWM (on two wires, plus ground) or
: a 10.4Kbps Variable Pulse Width (on one wire, plus ground)

* [https://en.wikipedia.org/wiki/On-board_diagnostics#ISO_standards ISO 9141-2 / ISO 14230-4]

...plus seven pins of "whatever the manufacturer thinks up" 




https://en.wikipedia.org/wiki/On-board_diagnostics#OBD-II_diagnostic_connector

{{imagesearch|OBD-II pinout}}

=====SAE connector=====
[[Image:S-S connector.jpg|thumb|142px|right|SAE&nbsp;connector (and a die for size reference)]]

DC power.

Mates with an identical plug. Seen in motorcycles, cars, batteries for such, some solar panels, and such.

Meant to be wired so that the exposed lead from the power source may safely touch the car chassis.

See also:
* http://en.wikipedia.org/wiki/DC_connector#SAE_Connector
* http://images.google.com/images?q=%22SAE%20connector%22

<br style="clear:both"/>

====Mostly seen in RC applications====
<!--
Pricy, fancy, current-drawing remote controlled vehicles.
-->


<br style="clear:both">
=====Deans ultra=====

[[Image:Deans ultra.jpg|thumb|180px|right|Deans ultra]]


The '''Deans Ultra''' is a polarized connector made to carry serious current for its size (smaller than e.g. Tamiya), largely because of the connector shape.

I've seen connectors called "T plug" that seem to be knockoffs.

Flat contacts, one side with springs that push the other side for good contact area.

Rated up to 60A.
(but there are some cheap imitations that you ''don't'' want to push that high - I recall some rated at 10A{{verify}})

* http://www.wsdeans.com/index.html
* {{imagesearch|(deans connector) OR (deans ultra)|image search}}


There is also a smaller '''micro Deans''', rated for a dozen amps.



<br style="clear:both">

=====Powerpole=====
[[File:powerpole.jpg|thumb|right|175px|PP30{{verify}}.<br/>You shouldn't be able to touch those contacts once in the shrouds.<br/>Mixing colors to show how they mate, you should probably ''not'' do that in practice.]]
{{stub}}

The plug mates with another copy of itself, and shields its contacts from direct touch, and e.g. touching a car chassis.
<!-- The first isn't necessary for human safety since this tends to be used for low voltage battery packs, the latter can be a very good idea given the current capabilities. -->

Powerpoles are somewhat larger than other choices - but unless you don't have the space, that can be a feature in that it makes it mechanically easier to pull apart (than some other high-amp choices), and may last somewhat longer.

Due to the shape of the contacts they should never fall apart, but if you're worried (e.g. in moving mechanisms) there are retention clips.


Anderson '''Powerpole''' (also known as sermos{{verify}}) refers to a family of connectors, apparently mostly:
* PP10-30
* PP15/45
* PP75
* PP120
* PP180

{{comment|Note that Anderson is a wider company with many other products, some of which even ''look'' like powerpoles, like {{imagesearch|Anderson SB50}},
which also seem to use the same contacts as PP75 {{verify}}, but have casings with specific keyings.}}



'''Spec-wise'''

When people say 'powerpole' they often mean PP15/45 - which are three{{verify}} variants that share the same housing.

The number relates to amperage spec, which has slightly different contacts good for 15A, 30A, or 45A{{verify}},
{{comment|(though the specs suggest options in which it can be higher and lower than what the model number suggests)}}
and takes different thicknesses of wire more easily.

<!--
The number also relates to how the wire side of the connector, specifically the intended thickness it is comfortable with, 
and there is often more than one option per intended housing, presumably to give better fit for specific uses.
e.g. 
PP75 contacts exists for 12 to 10, for 8, and for 6 AWG, 
15/45 seem to come in at least two variants (20 to 16 AWG, 16 to 12 AWG, and I've seen 10AWG mentioned for 45A)
PP10 16-14AWG

Connectors seem to be intended for crimping, soldering is typically also sensible.

https://eu.mouser.com/new/anderson-power-products/anderson-pp15-pp45-powerpole-connectors/
-->



'''Combinations'''

The plastic can also slot into the next side by side, horizontally and/or vertically.

There seem to be variants that amount to two of these already bonded side by side (either direction)

There are also shells without plugs, that let you collect individual and/or bonded variants{{verify}} into a larger sort of plug.


<!--
'''Practically'''

Anderson suggests colors could be used to relate to voltages, 
in practice they correlate to specific uses,
but in many applications they are not very meaningful. 

Generally used for DC applications that are disconnected and/or deal with higher currents,
like RC toys and automotive uses (often but not always battery related), forklifts, amateur radio, and such,
some of which use specific connector variants (with a specific name).

e.g. forklift may be SB50{{verify}}, which use the same contacts as PP75, 
but is a two-pin housing with a specific keying{{verify}}.
-->



See also:
* {{imagesearch|(powerpole connector) OR (anderson powerpole)|image search}}

=====Tamiya=====
[[Image:Tamiya Connector.gif|thumb|150px|right|Tamiya connector]]

'''Tamiya''' is regularly seen in RC battery packs. Seems to refer to the plastic's plug/hole shapes {{comment|(resembles a 2-pin Molex Mini-Fit Jr.)}} that make this a polarized connection (the square one is positive, the rounded-on-one-side one is ground).

Tamiya seems to be considered a cheapish choice that is good enough for up to a few amps. Or more, depending on the shape and material of the actual connectors{{verify}}.

Also exists in mini variation.
* {{imagesearch|tamiya connector|image search}}

<br style="clear:both">

=====EC3=====
[[File:EC.jpg|thumb|780px|right|EC2, EC3, EC5 and EC8]]

'''EC3''' is a polarized plastic plug around banana-style connectors, and rated to approx 60A. They're relatively cheap{{verify}}, so are handy all-round plugs.

People report them being a little easier to separate than Deans.
The plastic may deform when things do heat up, though.

Of the variants, EC3 seems most common, but there seem to be at least a EC5, a small EC2, and a chunky EC8 as well.



<!--
And like some other choices not always so easy to unplug (may apply to the earlier version and not the improved one, though)
-->

<br style="clear:both">

<!--
=====Bullet=====
'''Bullet connectors''' are a solid tube and a solid pin. They may be good for a few dozen or even a hundred amps or so.

Since they are really just two bits of metal, they're probably also the cheapest thing you could call a connector.
Of course, without a plug around it (and with some cheap plastic plug designs) you expose metal in ways that easily lets you short things out.

Note that when it comes to moving a bunch of current, the fact that there are multiple differently produced things, 
that often won't fit each other very well, will matter.


Confusable with [[#Banana_plugs|banana plugs]]. 
Cheap banana plugs may count on their smallish spring for contact, which means little contact area and so not be good for high currents. Better designed banana connectors may be almost equivalent to bullet plugs.


See also
* * {{imagesearch|bullet connector|image search}}


<br style="clear:both">
-->

=====XT60=====
[[File:XT60_XT90.jpg|thumb|365px|right|XT60 and XT90]]
'''XT60''' is a polarized bullet-based plug rated for ~60A, and uses plastic that deals with temperature better (...though 60A is a ''bunch'').

There are more variants of this, like '''XT30''' and '''XT90'''

See also
* * {{imagesearch|(XT60 connector)|image search}}



<br style="clear:both">

<!--
====Unsorted RC-ish power connectors====


Mentioned by [https://web.archive.org/web/20100921185914/http://www.flyrc.com/articles/connectors_1.html http://www.flyrc.com/articles/connectors_1.html]
: Astro Zero loss 2-pin
: Astro Zero loss 3-pin

: Sermos power poles

: Duratrax power poles

: Castle Creations 13- AND 16-gauge power poles

-->

==Mains power, device side==
===IEC 320 connectors===
Refers to IEC 60320 (IEC 320 before the renumbering), the plug/socket system commonly used on devices which can use various socket-to-device wires.

The male and female versions of a type connector have different numbers.  

C1 through C24 are defined. 

For a few there are variations (e.g. C7/C8), and some are variants of other IEC plugs (e.g. C17/C18 is unearthed variant of C13/C14).


The most common are probably:
[[Image:IEC_C14.jpg|thumb|115px|left|C14<br/>(pairs with C13)]]
[[Image:IEC_C13.jpg|thumb|115px|right|C13<br/>(pairs with C14)]]

<div style="padding-left:170px">
* C13/C14, commonly associated with PC power supplies, and other devices that may need its moderate current rating (over e.g. C5/C6), including some professional audio equipment.
** Rated at 10A
</div>
<br style="clear:both"/>

<br style="clear:both"/>
[[File:IEC 60320 C19 Plug.jpg|thumb|160px|right|C19]]
<div style="padding-left:170px">
* C19/C20
** Rated at 16A
** seen where you may need a bit more current than C13/C14 gives
::: e.g. computer racks may have C19-to-C14 or C19-to-C20 {{imagesearch|Power Distribution Units}}
</div>

<br style="clear:both"/>
[[Image:IEC_C6.jpg|thumb|100px|left|C6<br/>(pairs with C5)]]
[[Image:IEC_C5.jpg|thumb|145px|right|C5<br/>(pairs with C6)]]
<div style="padding-left:170px">
* C5/C6, regularly seen in laptop power supplies and other PC-related power supplies (smaller than C19/20, still grounded)
** rated for 2.5A
</div>


<br style="clear:both"/>
[[Image:IEC_C8.JPG|thumb|110px|left|C8<br/>(pairs with C7)]]
[[Image:IEC_C7.jpg|thumb|140px|right|C7<br/>(pairs with C8)]]
<!--[[Image:IEC_C7_polarized.jpg|thumb|140px|right|polarized C7<br/>(pairs with polarized&nbsp;C8), not part of the standard]]-->
<div style="padding-left:170px">
* C7/C8 (a.k.a. 'figure eight', 'shotgun'), unpolarized, ungrounded, is seen on various lower-power devices, from radios to VCRs, some laptop power supplies, game consoles.
** rated at 2.5A
** polarized C7 won't fit into unpolarized C8, which is rarely a problem{{verify}}
** unpolarised C7 connectors can be inserted into polarized C8 sockets, but this can sometimes be a bad idea
** A little larger than C1/C2
</div>


<br style="clear:both"/>
<div style="padding-left:170px">
* C1/C2, commonly seen on shavers.
** Rated at 0.2A
** Looks like C7/C8 but without the dents that make it figure-8
</div>



Variants with higher temperature rating include:
* {{imagesearch|IEC C15|C15/C16}} 
:: very similar shape to C13/C14, but notched so that only the higher temperature cables are accepted
:: rated for higher temperatures (120&deg;C)
:: e.g. used for electric kettles

* {{imagesearch|IEC C15A|C15A/C16A}}, similar
:: rated for higher temperatures (155&deg;C)
:: notched like C15 ''and'' blockier on the other side, to be ''more'' selective (C15 devices will accept C15A cables as well, but not the other way around) 


Less common
<br style="clear:both"/>
[[Image:IEC_C10.JPG|thumb|120px|left|C10 socket<br/>(pairs with C9)]]
[[Image:IEC_C9.jpg|thumb|120px|right|C9 plug<br/>(pairs with C10)]]
<div style="padding-left:170px">
* C9/C10, unpolarized, ungrounded
** rated at 6A
</div>


<br style="clear:both"/>


See also:
* https://en.wikipedia.org/wiki/IEC_60320#Appliance_couplers

<br style="clear:both"/>


===Vehicle chargers===
{{stub}}
[[File:Tesla-type-1-inlet-tesla02-outlet-iec-type-2-outlet-background-blur.jpg|thumb|460px|right|Type 1 (SAE J1772), Tesla proprietary, Type 2 (Mennekes).<br/>Not depicted: either CCS plug]]


Interestingly, '''those boxes on the wall that we call chargers''' (and are actually called 'electric vehicle supply equipment', EVSE) are typically little more than 
* some safety interlocks - they don't switch on power until they're pretty sure there's a car on the other side
* communicate how much power this box can safely pass through - because most cars can draw more than smaller EVSEs and/or home circuits can deliver

...and '''almost nothing more'''. 
It's the ''car'' that does the actual charge management, decides how much to draw, does any any necessary rectification of AC, and voltage conversion.


...that is, as long as we're talking about the AC chargers - which is all that Type 1 and Type 2 can do. 
AC charging was meant to be simple and convenient, because it amounts to just plugging it into the wall -- if often on a separate circuit.


<!--
'''proximity pilot''' is often implemented with a resistor, sSo that the car can detect there physically is an EVSE on the other side, even if that's unpowered or dead - presumably largely so that the car can refuse to drive away while still plugged in

Various plugs also have a microswitch, so that the car can know the plug is ''about'' to be pulled out, and stop pulling current slightly before contacts disconnect, and avoid most arcing


'''control pilot''' is a still-simple but more meaningful signal
: a PWM signal generated by the EVSE
: basically to have it signal "I not only exist, but am ready to deliver power"
: with the duty cycle signalling power output
: the car will change the resistance to signal a few basic things to the EVSE


https://www.youtube.com/watch?v=RMxB7zA-e4Y
-->
<br style="clear:both">

<!--

https://en.wikipedia.org/wiki/IEC_62196#Configurations
-->
=====IEC Type 1, SAE J1772=====

IEC 62196 Type 1, a.k.a. SAE J1772, J plug, Yazaki

https://en.wikipedia.org/wiki/SAE_J1772

=====IEC Type 2, a.k.a. Mennekes=====

IEC 62196 Type 2, a.k.a. Type 2, Mennekes


Used e.g. in Europe, can carry 1-phase AC, 3-phase AC, or DC.

(And this makes little sense in the US because 3-phase power is rare in domestic settings. You see the plug, but it will )

https://en.wikipedia.org/wiki/Type_2_connector

=====IEC Type 3, a.k.a. Scame=====

Refers to two distinct variants.

Briefly used, mostly in France and Italy,
but replaced by Type 2 (and Type 1)

=====Combined Charging System (CCS)=====
{{stub}}

For context: Type 1 and type 2 as mentioned above are AC charging, 
which means that charger on your wall can be nothing more than
just feeding through your regular wallplug power with little more than a few [[contactors]] for safety (the actual conversion is done in the car). 



DC charging involves more complexity and a more expensive box on your wall -- but ''can'' be faster, so we added that later.

Since Type 1 and Type 2 plugs already existed, we just added separate DC lines, to both, for easier backward compatibility.


"CCS Combo 1" a.k.a. CCS1
: adds DC to Type 1
: US, mostly


"CCS Combo 2" a.k.a Combo 2, CCS2, 
: adds DC to Type 2
: Europe - the EU has basically mandated CCS combo 2.


Notes:
* each area uses 'CCS' to refer to ''their'' variant of it.

* Because the plug (Type 1, Type 2) relates to how the power grid is set up (the EU has three-phase power in most places, the US ''rarely'' does that on residences), that is the part that means CCS1 and CCS2 are as incompatible as the Type 1 and Type 2 they are based off..

=====Tesla=====


Tesla has a plug that used to be very proprietary.

It allows both AC charging and DC charging, and over the same pins, 
so can be a smaller plug, at the cost of the car ''and'' charger being a little more complex and expensive.


This is in part Tesla doing their own thing -- but to be fair,  but the plug was planned when the others (particulary CCS) barely existed.

=====NACS=====

{{zzz|For context
The EU had mandated a universal thing (Type2, or Type2 Combo2 {{verify}}), so everything sold in the EU used that (incuding Tesla),
so Tesla's proprietary plug was mostly just used in the US.

Then the US noticed that without standardization, they had more of a mess of variations of both plugs,
and the capability of things behind that wire, and called for a [[#North American Charging Standard]].


The outcome is that manufacturers now all seem to be committing to the Tesla plug.

That Tesla plug and protocol was previously proprietary (which was why their charging stations were unusable by anyone else),
but opened up the standard for the occasion.}}


The plug is physically the same as it was on Teslas, but it does more things now, 
and moved to become more compatible with CCS,
so in theory things will become more compatible, though in practice there are some exception cases. 

{{comment|(Remember how universal-but-not-really-and-it's-hard-to-explain-why USB charging is? (and how USB-C managed to make that better but ''not'' actually solve it?) Ideally that won't still happen here.)}}

See also:
* https://en.wikipedia.org/wiki/North_American_Charging_Standard


<!--
The history is somewhat interesting, because it solves a problem that Europe avoided by having standards earlier (and a less-sleek plug).
Basically things ''must'' use CCS2, so Teslas sold in Europe have CCS2. 
CSS2 always had both AC and DC, and always had three-phase option, so means you can support almost anyone, and avoid the retrofitting Americans may need to do.

-->


https://en.wikipedia.org/wiki/North_American_Charging_Standard

=====CHAdeMO=====

DC charging, Japan


https://en.wikipedia.org/wiki/CHAdeMO

=====GB/T=====

GB/T 20234.3


DC charging, China


https://en.wikipedia.org/wiki/GB/T_charging_standard

=====ChaoJi=====


Proposed DC-only standard to replace CHAdeMO and GB/T

https://en.wikipedia.org/wiki/ChaoJi

=====Avcon=====

https://en.wikipedia.org/wiki/Avcon

=Mains power - wire-to-wire connectors=


<!--
Note that current ratings are ''somewhat'' approximate. 
It's not so much how much they move, but how much they heat in the process,
which has more to do with contact area than with anything else.
-->


<!--
Which of these are commonly used, preferred, and criticised varies by country.

It also varies by the type of socket, say, the UK sets up as rings and sockets always take three wires letting you use them as connector blocks, making rings without any separate connectors.

Other countries have a more tree-like approach (called radial for some reason) and tend to splice from ceiling boxes downwards.

Other countries do radial spur and end up with a lot more breakers.

(Most countries also have a varying history)



Note that '''for higher power connectors, solid wire is preferred over stranded''',
largely because in the long term, stranded is more likely to slowly lower contact area,
which increases resistance, which will more easily heat (remember we're talking high-current devices),
which can accelerate that same problem,
until something runs very hot - or burns through the cable and can sparks.

This is part of why your house is wired with solid wire - safety.


This issue is more likely to happen when the connection is a small area and/or sharp itself, e.g. from a screw.
As such,
: crimping a solid connector (like using {{imagesearch|Cable ferrules}}) also makes more solid connections from stranded cables.
: Soldering the stranded wire may be a little better, but in a long enough term not necessarily much

Even so, solid wire is preferred when you have the choice.

-->
<br style="clear:both">


==Screw terminals==
[[Image:Screw terminals2.png|thumb|right|199px|Screw terminals {{comment|(with some spade and loop lugs on the bottom one)}}]]

Screw terminal blocks, terminal strips and others names are used interchangably, making some ambiguous with others. {{comment|(e.g. screw terminal block might refer to what this page calls [[#PCB mount screw terminals|PCB mount screw terminals]])}}



Not all types are rated for mains voltages, though the ones with separators often are{{verify}}


Often refer to a screw-and-nut through a flat strip - which are not always the easiest to use on braided wire, and you may prefer to attach forked spade lugs (or loop lugs)
[[Image:Forked spade lug.jpg|thumb|right|89px|Forked variant of a [[spade lug]] (cf. spade connector)]]

<br style="clear:both">

===Luster terminals===

[[Image:Screw terminals.jpg|thumb|right|185px|Luster terminals]]
Luster terminals, a.k.a. lustre terminals, which seems to come from the german [https://de.wikipedia.org/wiki/L%C3%BCsterklemme Lüsterklemmen], seem to be mostly used around Europe.
[[Image:Screw terminal inside.jpg|thumb|right|55px|Luster terminals's actual contacts look something like this (varies, not always this solid)]]



Originally porcelain and of larger and simpler design (a screw clamping two wires together), 
and often intended to be heat isolation as well so you could use it in enclosed walls and such.

These days often plastic encased, and much more specifically rated connecting piece.


The typical sizes of these are rated for 10A or 15A, but there are a bunch more, 
down to 3A and up to maybe 100A or so, but both extremes are less common.


[[Image:Ceramic screw terminals.jpg|thumb|right|120px|ceramic screw terminal]]
You still sometimes see a ceramic version of the ''newer'' design, but only for specific uses, e.g. in saunas.


<!--
Often come in arrays of ''many'', with plastic isolation because each is individual  (specced to a wire thickness and current) 
and it's useful to have two or three or just one depending on use.


They are used mostly as a easy, isolated, reusable way, 
not so often in walls but as a connector that you can have reachable, e.g. for lighting on your ceiling,
or things like replacing device cables.

-->
There are a few local names, like [https://nl.wikipedia.org/wiki/Kroonsteen kroonsteen] (Dutch), suikertje (Flanders).



<!--
Upsides:
* screws means you have decent feedback over how solid the connection is

* reusable, as the bottom of the screw won't damage


Limitations:
* technically a little better to use on solid than stranded
: (slightly destructive of strands, particularly if fastened hard, though less so than some alternatives)

* not so useful for splicing as you can't put more than one solid-cooper wire in a hole
: you may manage, particularly with braided wire, but there are simpler options
: ...though there are variations, e.g. 

* moderate on the scale of 'easier to under-tighten or over-tighten'
: as with most things, pulling is a good test

* Current ratings not as clear (frequently not marked)
-->

<br style="clear:both">

==Spade connectors==

[[Image:Spade connectors.jpg|thumb|right|199px|Spade connectors]]

Spade connectors are a solid bit of metal, and the female part a good amount of area clamping down so these tend to connect very sturdily. (Some also have a clip to make it harder to slide unintentionally)


Various sizes may be rated something between 3 and 24A (order of magnitude).


The female type is frequently shrouded, for isolation.


<!--
Upsides:
* solid contact

* can be disconnected and reconnected many times
: so e.g. useful on things you plan to replace


Limitations:
* higher currents only for the large sizes, so more useful for device wiring and less so for wall wiring


* The metal properties matter
: Too think and/or too soft and it will not hold a connection well over time. Professional repair 
: this actually goes for almost anything that is crimped

-->

You see {{imagesearch|spade connector bars}} to connect various circuits together in this style.



Related are the eye and fork variants, which are easier to screw down.



<br style="clear:both" />

==Push-in connectors==
[[Image:Push-in connectors.jpg|thumb|right|220px]]

Push-in style connectors will often push a pushing into a flat contact that is also a spring construction, that tends to dig in a little

Tend to not let you pull out solid core without a bunch of force and/or twisting, which is a feature in that it retains the wire.

You can often find these rated for something on the order of 24A.

<!--
Has other names, e.g. in US wall sockets this is called backstabbing


e.g. WAGO 773-164 but you see simpler, cheaper variants more often.


Upsides: 
* simple

* cheap

Limitations:
* not useful for braided cable , only for solid

* Some brands/models are not as good as others, having less contact area, so running hotter than others.
: various tests show that the current on most of these rating is conservative, though, so you should be fine, if you stick to a known-good brand

* slight damage to wire when you pull it out, so not ideal if you want to pull them out regularly

* shouldn't be used for aluminium wire{{verify}} (why?)


Arguables
* in theory, the pressure plate could get weaker over time, making for poorer connection
: not sure how true this is in practice
: and there are certifications for that{{verify}}




-->
<br style="clear:both">

==Lever locks==
[[Image:WAGO 222.jpg|thumb|right|140px|3-terminal WAGO 222]]
'''Lever locks''' clamp a spring down on a wire (varied designs, various of which are smarter than a basic basic pressure plate). 


There are a few models and brands, but WAGO's is probably best known (note they make other things as well).


Many are made for wires of sizes like 22AWG to 12AWG, and rated for at least 20A (usually listed on them), e.g: 
: WAGO 222 are spring-clamping connectors rated for 400V/32A
: WAGO 221 is a smaller variant of the WAGO 222, rated at a very similar 450V/32A (and 600V/20A)


<!--
Upsides:
* easy

* reusable 
:: (e.g. handy for some hobby needs)

* as it's held with a spring, it's less likely (than e.g. luster, push-in) to lessen contact area over time and with heat cycles, or be sensitive to over- or under-tightening.

* tend to have testing ports for thin multimeters leads

* Some variants, like the largely transparent WAGO 221, allow visual confirmation

* Usable on braided wire (unlike e.g. push-in)


Limitations:
* there are knockoffs that aren't as good

* rating isn't necessarily good enough for ''all'' house distribution
: ...so whether electricians love these or have something else as their default varies a lot with context

* I'm not sure the spring lasts forever (consider also heat cycles)

-->
<!--
I initially thought closing the handle was the thing that pushed contacts together.

The real construction is sturdier (and more reuable) than that: 

The spring is basically an extra loop around the contact/wire you push in (will only allow entry handle up), which at rest (handle down) pulls whatever is in there tightly to the real connector. 

The reason it takes reasonable force to open (and not to close) is that that's a strong spring.


See e.g. 
: https://youtu.be/-PfN_wwkujQ?t=34
-->
<!--
WAGOBOX - strain-relieved box for WAGO 222,
-->
<br style="clear:both">

==Wire nuts==
[[Image:Twist connectors.jpg|thumb|right|211px|Wire nuts<!-- - variants for roughly 22AWG to 10AWG-->]]

<!--
tl;dr:
* pretty good when done well
* but comes with some


Wire nuts (known under a handful of other names, including screw terminals, wing nut, twist cap, and more)
are seen around the US, Canada, and a handful of other countries.


Physically they consist of a plastic cover around a sharp conical spring.

The idea is that 
* you take solid wire and twist them together (before the wire nut get involved)

* you twist this cap onto thost twisted wires 
:: puts reasonable tension between all the wires in there (function)
:: and digs into the wires enough that the wire nut stays stay put (practical, safety)

{{comment|(so are distinct from [[end crimps]], which, well, crimp)}}



'''Review'''

Done correctly, twisting wires together is actually a good way to make a good amount of contact already,
itself already potentially better (so lower resistance) than various connectors.

The wire nuts arguably are just there to ensure they are and ''stay'' pushed together,
and beyond that are a good insulator - doing both these jobs better than e.g. tape would.


This upside is also the potential downside - the twisting is important enough that
it should not be left up to "I heard".

If it it takes more knowledge to use these correctly, they are less fool-proof than others -- then again, you shouldn't have fools as electricians, so...


Note that if you properly pre-twist the solid wire, those wires make decent contact (and thereby lower resistance) ''already''.




This is also roughly why there is no current rating of the nut itself:
The current should be going directly between the wires being pushed together - not through the nut's spring.




The choice of nut sizes relates mostly to the thickness (and amount) of wires you're combining.




-->

<!--

If you're not used to seeing these, they may seem cheaping out of doing it properly, old fashioned, and potentially dangerous.

Applied well, none of those things are true. 

Wire nuts have their own set of "don'ts", and you should know all of them, but it should also be said that 
applied poorly, any connector can be bad, and this one maybe only slightly more so.





Many countries avoid them, not because code doesn't allow it,
and more out of the same reason they ''are'' used in the US: habit.


It probably helps that when individual people are less likely to adopt them when it is less clear what their ratings are, what their failure modes are in correct and incorrect use
: how do you know it's fastened properly? 
: How much force can they stand and does that vary? 
: Won't they catch on things and pull off more easily?
: on twisting - why do
:: some people insist on pre-twisting 
:: the instructions on the box not mention it
:: some manufacturers recommend ''against'' it?

It's easier to understand a screw terminal.
If you can't estimate how safe they are, you are unlikely to adopt them over something you already know.

Which is both fair, and not really a reason not to learn how to properly do it another way.


And yes, there was a specific product from the 70s, a ceramic one that was likely to crack over time and expose their wires (...you had one job, dammit).


That ceramic variant was basically banned in most places, and long discontinued, now fairly rare to find in old installations, and the modern plastic variant does not have this issue.

And yet this seems to be the largest (and thereby pretty baseless) reason for the reason for "these are dangerous" idea.

...well, and perhaps from the idea that US electric code is somewhat lax.





Upsides:
* used properly, these actually connect wires with ''more'' surface area than some other options, so deal with decent current with less temperature

* the physical connection is quite strong (for few-wire combinations) - if used correctly

* take less space than some alternatives

* cheaper 
: (though note they take longer to install, so not necessarily for end users)


Take care / potential downsides:
* improper use used improperly, they aren't quite as good as they could be, and they are arguably harder to inspect
:: all the considerations are common sense - but there are more of them and easier to forget, not fit on the package / not read off the package, etc.

* choosing the right cap size for the gauge and amount of wires is important, and easier to miss by amateurs

* not a great choice for stranded wire - contact is good, but cuts are more damaging, the pull test is less meaningful, and other footnotes
:: also why they're used primarily in homes, and much less in cars (the vibration only makes it worse)

* not great for mixes of stranded with solid (shape doesn't mix), which will easily happen around light fixtures
:: or at least more instructions (suggestion is have the stranded be longer so you can twist it around the solid) to be as sturdy/safe

* can't see how good the connection is.

* More than 4 or 5 wires 
: must be pretwisted well, because if you don't, the cap won't twisting onto all, and a few wires will pull out more easily
:: and twisting that many wires isn't easy
: is harder to check for being done properly/safely (pulling on it is only a good test for few-wire splices)

* need a little more space to work with 


Arguables
* the cutting action won't damage thicker wires enough to matter - though repeated use ''may'' sometimes hold not quite as well
: and some things are tested regularly and need to be 
: and few people are going to shorten or replace the wire unless necessary

* the current rating is more up to the wires, and joining them well, and not really the cap
: which you can argue makes it potentially better, and a little more arbitrary



{{search|UL ListedWireCombinations.pdf}}




Whether people like or dislike these seems more defined by habit than anything else.


They can be very good connectors when used well, but have a few more issues when ''not'' used well,
and there seem to be be more footnotes for amateurs to miss.

The main reason these aren't being adopted elsewhere is probably largely habit,
but it doesn't help that it is not easy to find good resources - that don't contradict others in their details.

It probably doesn't help that they seem less inspectable, and thereby less predictable.


Also, between all those names (some of which are brands), there is variation in quality, and design,
and purpose.
Some have a sharp cut on the inside, which holds better - but also makes much less sense on stranded wire.


And there are cheap knockoffs, though of course this is true for other connector styles.

-->
<br style="clear:both">

=="quick wire connector"==
<!--

Spring wire connectors, 
quick wire connector, 
wire-to-wire spring connectors, 
wire-clamp connectors
I've not found a single name, but this seems the most common so far.

What these have internally varies a little,
but they amount to something like [[push-in connectors]] (you don't really need to press them if you have solid wire) that can be pushed to release.


In my personal experience, most of these release under worryingly little force.
This may be purely because I've only ever met cheap variants, but if there are so many cheap variants then maybe you should avoid them anyway.


-->

=="gel filled crimp connector"==
[[Image:Gel filled connector.jpg|thumb|right|220px|Cheap 2-wire and 3-wire gel filled connectors]]


<!--
Not sure what the varied names are 

"{{search|Scotchlok IDC butt connector}}" is one but there are probably more off-brands.
: ...also, there are other scotchlok-brand splicing connectors, so that's confusing.


Not watertight, 
but the gel seems to be anti-corrosion, presumably silicone?




As a type of IDC -- "insulation displacement connector" which basically just means "cuts through the insulation (and maybe a bit of the wire too)" -- you probably do not want to use these on wires that move a whole bunch of amps. This warning goes for a whole bunch of splice connectors, actually.

In theory there are 16A IP68-rated variants, but I have... doubts.


That said, they 
can be great for quick fixes on signal wire, and 
can be great at not leaving any exposed wiring.

-->
<br style="clear:both">



==wire-tap / splice connectors==
<!--
Not sure what the varied names are - I've seen tap splices, inline wire taps, vampire clips, and more.

In theory made only for solid wire?



Can under-strip, not really connecting well.

Can over-strip, effectively making the wire thinner


Depending on the variation, they might cut more over time.


They may be useful as a quick fix, but should probably not be considered your best option.



-->

===T-tap splices===

T-tap splices only splice one wire, and connect the new wire via a [[spade connector]]



<br style="clear:both">

==butt connectors==
{{stub}}

Butt splices, or butt connectors, come in a few variants



* '''solder seal butt connectors'''
: A variant of the previous but the central ring is soldering tin instead of glue.
: Needs more heat (a paint stripper is recommended), but is a better connection.


* '''crimp butt connectors'''
: Seem to be fairly solid in the hard-to-crimp-down sense 
: so probably only usable with the correct crimping tool - I have bad experience without.
<!--
: (do these also contain solder?)
-->
: may or may not have a separator in the middle, to ensure equal amounts of both wires are inserted


There seem to be more variants of the idea

<!--
* '''Heat-shrink adhesive butt connectors'''
: Often a central ring of what amounts to hot glue{{verify}},
: and heat shrink.
: Seem to be fine for stranded signalling wire, not ideal for anything carrying current
-->
<!--
: The color rings are not functional
-->

==On circuit currents and connector safety==
<!--



'''On the safety of connectors'''

If you go out and look, there is criticism of ''every single way'' of connecting two wires.

In part it is that most ''can'' be used badly.

In part it is that few are a known quantity - because there are knockoffs, and they are often not easy to identify.

In part it is that some might give worse connections ''over time''.
: say, there is an argument that anything that you tension once may loosen over time - luster terminals might lower contact area, in the way that something spring-loaded will not, and that wingnuts ''might''.




'''Thinking about connectors in relation to current'''


For reference, total residential service may be on the order of 100 to 200A, depending on where you are, not least of which your country's residential voltage.

At the same time, only the distribution board sees any wires pushing through that much - most of the ''point'' of the distribution board is is splitting into individual circuits, each of which not be more than order of 15A to 20A (a few more, such as for induction cookers, ACs, and dryers that are in a hurry), and no regular circuit or wallsocket sees more than two, three kilowatts.
Need more devices? Then add more circuits for them.

Need a single device to pull more? 
Get in an electrician.

Point is, most of the time you deal with 20A tops, usually less.


Remember that half the idea behind your array of breakers is that it trips ''before'' the wires in your wall could heat up significantly.

Consider that when any one socket must be able to give you 10A, and you plug in an extension cord that is rated for 2A,
you are sort of defeating the fire protection that your main breaker gives you (Maybe it's never an issue, maybe it's the reason your insurance won't pay for your kitchen fire).
(Americans are more afraid of this -- I never understood why, until I found out that they just sell a lot more thin extension cords that my country does)


Point is, if you use a ''connector'' that isn't comfortable with the current your breaker won't yet trip with, it's sort of the same deal.



'''Are you using these connectors for a single device, or to wire your house?'''


'''Device?'''

Most devices I have don't pull 2kW, so if I were to fix a power cord with any of these connectors I would ''electrically'' be safe (emphasis because they are still all a bad idea ''because you can pull on them'' and all of them will then reveal live wire).


Say, a single light is ''well'' under 1A (even less if LED), so any of the above connectors are perfectly fine for wiring light circuits.

But there aren't a lot of cables in your walls that will only ever light a light, but you could safely use thin wire for them (whether code allows that is a different matter. Code also thinks a little about future mistakes, and that's a good thing).

For individual wall sockets, you follow code, and probably overspec a little.




'''House?'''

This further depends a little on how your country does things.


The UK is an unusual case, with its ring circuits. 

Each socket is effectively a wire splice carrying much of the ring's current,
and the whole circuit is a ring that comes back to the same place it started off, so for each socket, both parts of that ring carry current.
In theory this means you can use thinner wires, but in practice not by much because it if the ring ever breaks, that would become a fire hazard.

UK electricians will also more easily (and sensibly) argue against cheaping out on connectors, basically because ''all'' junctions in a ring matter equally, in a weakest-link way, and while many rings are 20A, a few are 30A which is uncomfortably close to the ratings of some connectors.

...whereas in tree-style layouts, this may only be critical in the earlier branches (except you usually can't assume where all the current will be drawn, so actually still not).


Other places use junction boxes as split-off points, giving a more hierarchical layout where fewer wires (earlier in the layout) carry higher currents, so a section might be used just for lights. It's not ''great'' design in that you can forget this with changes over time.

Exactly how they can/can't fork off according to electrical code also varies.


This can get down to building styles - e.g. hollow internal walls (more common in e.g. the US) make it easier to do wiring horizontally in the wall (might serve more sockets in a wall), whereas where walls are typically solid the existing conduits may more frequently be vertical (and wire fewer sockets at a time). Attics and crawlspaces may be likely places for wires to go, and sometimes it's nothing more than habits.



US 240V is also slightly unusual. US service is 240V with a center tap that is ''generally'' only used in reference to that center tap, but its split-phase nature means you use both legs, i.e. two hot wires, rather than a hot and a neutral (as most circuits in 120V and all circuits in 230V countries are).
(there are actually a whole of different plugs, in part because three-phase ''also'' exists in the US. (And then, 30, 50, and 60 amp variants are typically the same idea but larger, though most of us will rarely see those))


This too can vary per country. For example, saunas in three-phase countries can be hooked up with three separate heating elements, one on each phase.
This is often more practical than running a single higher-current circuit and wiring those elements in series, though that can also be done)

-->


[[Category:Electronics]]


=Computer=

===Power supply===

<!--
====P9, P8====

AT was a mainboard design, including power connectors and thereby the type of PSU you would buy.
{{comment|(rarely seen today except in retro computing, as ATX has existed since the mid/late nineties)}}

P9 carries 5V, P8 carries 12V and 'power good'

-->



====AMP/Molex power and Berg power connectors====
[[Image:Molex.jpg|thumb|130px|right|AMP Mate-n-Lok / Molex 8981, plug (top) and socket (bottom)]]
{{stub}}

tl;dr: In the context of computers, calling something a Molex connector typically points to this one.



Like other plugs, this is a connector named for a company - Molex is a large company that makes ''many'' types of plugs.


{{comment|Except this one has a more confusing history than that. As far as I can tell right now:}}

[[Image:AMP and molex.jpg|thumb|260px|right|AMP Mate-n-Lok (left), Early Molex (right) that isn't any of these]]
: {{comment|There was a Molex connector (early 60s?) that resembles (but isn't compatible with) the plug we later knew in PCs (the right one on the image with blue background).}}

: {{comment|AMP in 1963 introduced Mate-n-Lok. Its use in PCs picked up later, maybe late seventies{{verify}}.}}

: {{comment|...and became common enough in PCs that 1983, Molex developed Molex 8981 which was fully compatible with AMP Mate-n-Lok. {{comment|(Well, the 4-position Mate-n-Lok -- Mate-n-Lok is actually a larger family[https://www.te.com/usa-en/products/brands/mate-n-lok.html] though I'm not sure it was back then{{verify}})}}.}}

: {{comment|As such, the thing we called Molex around computers for the next couple of decades (seen on larger floppy drives, on [[PATA]] HDD and CD/DVD drive connections of the time) in a practical sense is either AMP Mate-n-Lok or Molex 8981 (the difference mainly in sourcing, as they look the same).}}

: {{comment|And it was introduced by AMP, so calling it AMP Mate-n-Lok is slightly more accurate in that it doesn't ignore the decade of use that established the connector, calling Molex is much better understood, and practically there is no difference.}}

: {{comment|The argument is less relevant now that in most computer uses it has been displaced by SATA power plugs.}}

: {{comment|(also, AMP is now called TE, but the connectors are still called AMP for findability)}}


<br style="clear:both">
[[Image:Berg plug.jpg|thumb|98px|right|A Berg plug, AMP 171822-4]]
The '''Berg plug''' (apparently named after its designer) was mainly used on 3.5 inch floppy drives.

While sometimes called 4-pin mini-Molex, this one is also an AMP plug, specifically AMP 171822-4 for the cable socket, AMP 171826-4 for the right Angle PCB header.

These plugs are becoming as rare as floppy drives themselves.


See also:
* [[Electronics project notes/Mounts, chip_carriers, packages, connectors#Molex_connectors]]

<br style="clear:both">

====PCIe power, EPS power, etc.====
{{stub}}

These connectors seem to come from the [https://www.molex.com/molex/products/family/minifit_power_connector_solutions Molex Mini-Fit] family - most resembling a Mini-Fit Jr though actually seems to use a different keying{{verify}} <!--
most of them are not seen much outside of PSU context, and easily purchased {{verify}}
-->



[[Image:PCI_Express_Power_Supply_Connector.jpg|thumb|right|140px|8-pin PCIe ''and'' 6-pin PCIe sockets on a GPU (note the left three columns are the same)]]
The 'PCIe' naming seems to come from the fact that PCIe video card power draw is high enough that it is not sensible to get it through mainboard traces / the PCIe bus, so we decided to get it through a plug like this instead.{{verify}}

'''PCIe 6-pin''' {{comment|(mostly seen on GPUs)}}
: officially: two pairs of +12V-and-Gnd (the last pair is specced as NC)
: unofficially often three pairs of +12V and Gnd {{comment|(most such cables and PSUs allow real current draw on the third)}}


'''PCIe 8-pin''' - an expansion of the 6-pin {{comment|(mostly seen on GPUs)}}
: Three pairs of +12V and Gnd
: with the pin that the 6-pin variant listed as NC now guaranteed to be a +12V{{verify}}
: A plug may separate the 6+2, to be compatible with both 6-pin and 8-pin variants
:: the extra 2 add a Gnd and Sense

...and there are more footnotes than that.


There seems to now also be a 12-Pin variant for nVidia RTX 3xxx series, apparently for space reasons, because it's barely larger than an 8-pin but can carry more power.



----


[[Image:4-pin ATX 12V.jpg|thumb|right|84px|4-pin ATX 12V plug]]
'''4-pin ATX 12V''' {{comment|(mostly seen on motherboards)}}
: Two pairs of +12V and Gnd
: used for power more directly to the CPU, has been around since roughly the pentium 4

<br style="clear:both">
8-pin ATX 12V
: Doesn't exist and, assuming you said it because motherboard, will probably mean you're looking at 8-pin EPS12V {{verify}}


[[Image:EPS12V.jpg|thumb|right|120px|8-pin EPS12V socket on a motherboard]] 
'''EPS''' 12V [https://en.wikipedia.org/wiki/ATX#EPS12V] {{comment|(mostly seen on server motherboards)}}
: Mostly seen on server boards (and some higher-power consumer boards), meant for more current to the CPU.
: It is not ATX standard - but is effectively a derivative of it, defined by {{search|Server System Infrastructure|SSI}} 
: The 8-pin EPS connector is four pairs of +12V and Gnd
:: physically incompatible with PCIe 8-pin
: the 4-pin EPS connector is two pairs of +12V and Gnd{{verify}}
:: this plug seems less common than the 8-pin{{verify}} {{comment|(probably because 4-pin ATX 12V will do)}}



[[Image:4+4 EPS-ATX.jpg|thumb|right|120px|]] 
'''4+4 EPS/ATX''' {{comment|(on power supplies, plug only)}}
: Refers to plug only: splittable, so that a PSU needs fewer wires and plastic to accomodate both 4-pin ATX and 8-pin EPS motherboards sockets
: That split cheats a little, but it is hard to plug incorrectly unless you get particularly creative with adapters or hammers.
: In practice, a lot of consumer power supplies just give you both a 4-pin ATX and 8-pin EPS12V, which is less confusing




See also:
* https://en.wikipedia.org/wiki/PCI_Express#Power
* https://en.wikipedia.org/wiki/Power_supply_unit_(computer)#Entry-Level_Power_Supply_Specification

===Fan connector===
[[Image:PC Fan connector.jpg|thumb|66px|right|3-pin fan plug in 4-pin (intel-style) connector]]
{{stub}}

PC fans are often connected with a three-pin connector {{comment|(polarized variant from the [[Molex KK]] family)}} which supplies 12V, ground, and a sensor wire that the computer can use to count revolutions.

There were a few not-so-standard variation, such as Dell's. 


You now commonly see Intel's variation, with a fourth pin to the side.

'''3-pin''':
* 1 - Ground      (black)
* 2 - 12V         (often red)
* 3 - speed sense (often yellow)

'''4-pin''' adds
* 4 - PWM signal - seems to be a voltage signal{{verify}} so if used at all, it will be used by a transistor in the fan{{verify}}


'''6-pin''' (seen in servers) add:
* 5 - fan presence {{comment|(lets the computer do a simpler test to see there is one connected)}}
* 6 - fan fault led {{comment|(for visual feedback which one is broken, useful in datacenters because of cramped hardware layouts and loud environment)}}


As the larger sockets are physically an extension on the simper ones, this is often fairly compatible -- as long as you know which one is pin 1, which bits of keying plastic usually help with.



'''"Can I put a 3-pin fan on a 4-pin socket?"'''

Yes. 

That controller is most likely putting an PWM ''signal'' on the fourth pin, meaning 12V in the first three is just solid 12V - so the fan is likely to run at full speed.

{{comment|You ''could'' actually make a 3-pin fan into a 4-pin fan with a little soldering (and a 4-pin connector, transistor, suitable resistor. ...but since 4-pin fans basically cost the same, this is generally not worth doing.}}


'''"Can I put a 4-pin fan on a 3-pin socket?"'''

''Usually'', because many 4-pin fans are designed to work fine on a 3-pin header.

If they were not, they will probably not function at all - so if it spins up at all, it's ''probably'' fine.




'''Lower speeds, in general'''

If there is no PWM involved anywhere, 
you could undervolt a fan with a ghetto-ish fix: splice a fan between the +12V and +5V (e.g. from a molex plug) giving 7V.

However, not all fans reliably ''spin up'' at voltages like 7V (even if they will continue to run at 7V if already spinning), so check that it does, always, or you'll sometimes have very little cooling.

This is is also why using an inline potentiometer for speed control is less predictable than PWM.


Using PWM is the preferred method of speed control over lowering voltage e.g. with a [[potentiometer]], 
because PWM will typically work down to lower speeds than undervolting (for an combination of reasons that is a little complex ''and'' varies per actual fan).


Motherboards officially just put 12V on the power pin.  In the 3-pin-fan days some motherboards would PWM the 12V power pin, which works even on 3-pin fans, but has some footnotes - the 4-pin way is a more standard and somewhat more reliable way of doing PWM.


You can buy little speed control boxes that you plug between motherboard and fan.
Which are often but not always PWM based.

<!--
https://web.archive.org/web/20220412020638/https://www.maximintegrated.com/en/design/technical-documents/tutorials/1/1784.html-->

<br style="clear:both">

===Storage===

====SCSI====
{{stub}}
 
SCSI is now mostly understood as parallel SCSI (SAS is 'Serial Attached SCSI', it and SATA are effectively SCSI derivatives).

This comes from a time where companies sold their own lines, so while some connectors are more common, 
there are a bunch of peculiarities. 

[[Image:Amphenol_50.jpg|thumb|right|320px|Amphenol/Centronics 50, a.k.a. CN50]]
[[Image:DB25.png|thumb|right|225px|DB-25]]
[[Image:DD50.png|thumb|right|260px|DD-50]]
[[Image:Micro D50.jpg|thumb|right|220px|Micro D50, a.k.a. HD50]]
[[Image:Micro D68.jpg|thumb|right|240px|Micro D68, a.k.a. HD68]]
[[Image:VHDCI.jpg|thumb|200px|right|VHDCI (68-pin)]]
[[Image:SCA-2.jpg|thumb|390px|right|SCA-2 (80-pin) on a drive]]

<!--
Includes:
* Amphenol/Centronics 50, a.k.a. CN50
:: more related to SCSI-1{{verify}}
:: which may recognize as a larger variant of the 36-pin Centronics connector used on printers

* Micro D50
:: more related to SCSI-2{{verify}}

* Micro D68{{verify}}
:: more related to SCSI-2{{verify}}

* DD25, mostly by Apple?
:: yes, regular D-sub, confusable with serial and parallel ports

* DD50, mostly by Sun and Data General?

* 60-pin Mini Delta Ribbon, mostly by IBM?

* VHDCI
:: SCSI-3 and later?{{verify}}


Less commonly:
* There was also the square-ish {{imagesearch|HDI-30 SCSI connector}} e.g. seen on laptops (mostly Apple?).

* DC-37 (D-sub)


Internally:
* both SCSI-1 and SCSI-2 might use IDC50

* Single Connector Attachment (SCA-1 and SCA-2 different uses of the same 80pin connector)
-->
<br style="clear:both">

====IDE, EIDE, PATA====
[[Image:IDE-PATA.jpg|thumb|110px|right|You can ''reasonably'' distinguish PATA from similar 40-pin plugs from that one filled hole. The plastic alignment notch is also fairly common)]]

'''IDE''' (Integrated Drive Electronics) a ''hardware'' bus primarily a ssociated with ATA and its protocol.

IDE can however also refer to some pre-ATA and other not-ATA things.


Once ATA was standard, IDE and ATA were used more or less interchangeably.

Once SATA existed, a distinction between SATA and IDE(-as-in-parallel) became convenient, so both IDE and ATA became a bit vague, and we started using SATA and the [[retronym]] '''PATA''' (Parallel ATA) became a clearer way to refer to this 40-pin connector.


Notes:
* If there are two devices on a single PATA cable, one is called master and the other the slave (jumpered that way, or sometimes implied via its position on the cable)
: These names are not official. They also do not refer to interaction between the drives at all - both drives operate independently, using their own controllers and both only talking to the host. It was just a way for the host to distinguish between two on the same cable.

* There was also '''EIDE''', Enhanced IDE, referring more vaguely to early adoption of some features of a then-future ATA standards. The term was also abused by marketing at that time

====ATAPI====

'ATA with Packet Interface Extension' is actually about protocol, not plug - it can be carried over PATA ''or'' SATA.

ATAPI is an extension based on SCSI protocol features, that made it more useful for certain (additional) drive types, such as CD, DVD, and tape drives.


In this context, '''ARMD''' ('ATAPI Removable Media Device') is practically use mainly used to refer to ATAPI drives ''other than'' CD/DVD drives. Often meaning tape drives.

====Early CD drives: Panasonic, Sony, and Mitsumi====


Before ATAPI caught on as the standard for CD drives (and having multiple ATA controllers was a given on motherboards), these three companies created proprietary interfaces (sometimes called AT-BUS and other things) to connect CD drives of their own styles.

[[Image:Early_cd_connectors_on_SB16.jpg|thumb|right|340px|the relevant end of a Sound Blaster 16 card]]
Certain expansion cards, e.g. the Sound Blaster 16, exposed these connectors as a simple way to connect these pre-ATAPI drives without needing to buy a specific separate interface card. (TODO: look up the details)


'''Panasonic''' and '''Mitsumi''' used 40-pin [[IDC/ribbon]] connectors (that were potentially confusable with PATA connectors, particularly once PATA (speaking ATAPI) later became the standard for CD drives as well).

'''Sony''' used a 34-pin [[IDC/ribbon]] connector.


These three use similar signalling (sony removes some unused pins, and squeezes together some ground pins),
and ca be vaguely seen as a ''sort of'' a subset of ATA.  Linux is interesting reference here - they chose to present it under a similar interface, but at the same time, the low-level differences can't be described very quickly[https://www.kernel.org/doc/html/latest/cdrom/cdrom-standard.html].


<!-- (SB16 was 82c924 brains + [[OPL3]] + an [[audio codec]]) -->


<br style="clear:both"/>

====Side note on ATA====
{{stub}}

'''ATA''' is short for "Advanced Technology Attachment",
effectively a set of standards that now encompasses Parallel ATA, ATAPI, Serial ATA (SATA), and more.



ATA versions and introduced features: [https://en.wikipedia.org/wiki/Parallel_ATA#Features_introduced_with_each_ATA_revision]
* pre-ATA standards had varied limits, particularly in the DOS era
* ATA-1 (1994) - PIO 1 and 2, 28-bit LBA for sizes up to 137GB
* ATA-2 (1996) - PIO 3 and 4, DMA 1 and 2 {{comment|(the terms 'EIDE' and 'Fast-ATA' appeard around this time)}}
* ATA-3 (1997) - SMART, connector for 2.5" drives
* ATA-4 (1998) - UDMA 0, 1, 2 ('UDMA 33')
* ATA-5 (2000) - UDMA 3, 4 ('UDMA/66')
* ATA-6 (2002) - UDMA 5 ('UDMA/100'), 48-bit LBA for sizes up to 144 PB
* ATA-7 (2005) - UDMA 6 ('UDMA/133'), SATA 1.0 ('SATA/150')
* ATA-8 (2008?{{verify}}; there is a working draft you can get.  Includes SATA 2.x and SATA 3.x?{{verify}} but those make more sense to get directly, SSD TRIM{{verify}}, and some details)
Since then, almost all development is in SATA, which is its own standard.


SATA has its own versioning: [https://en.wikipedia.org/wiki/Serial_ATA#Revisions]
* SATA 1.0
* SATA 2.0 (2004)
** SATA 2.5 (2005)
** SATA 2.6 (2007)
* SATA 3.0 (2009)
** SATA 3.1 (2011)
** SATA 3.2 (2013)
** SATA 3.3 (2016)
** SATA 3.4 (2018)
** SATA 3.5 (2020)

====SATA====
{{stub}}

<gallery mode="packed" style="float:right" heights="100px">
Image:SATA-fullsocket.jpg|SATA data sockets variant with shroud that makes it a little sturdier and accepts a clip
Image:SATA data noclip.jpg|SATA data plug (without clip)
Image:SATA power15.jpg|thumb|right|160px|SATA power connector (15-pin)
</gallery>
'''SATA''': Serial ATA, is part of ATA-6 and later. Has basically replaced PATA.

There are variants, but most of us care about the '''7-pin data cable''' (and the '''15-pin power cable''').


The data socket can be as minimal as just the plastic to hold the contacts, but most sockets are a variation with a plastic shroud (see first image), making it harder to break.  This will also accept the clip present on some cables.



Basic SATA's basic power connector has so many pins for scalability reasons - it provides three voltages (3.3V, 5V, 12V), with three pins each to be able to meet requirements of power hungry drives (while not exceepding 1.5A per wire), plus one signalling cable. 

This cabling is often not necessary, and there are slimline and micro versions of the power connector, which use simpler wiring, and are good enough for the drives they're meant for.

<!--
<br style="clear:both"/>
[[Image:SATA power15.jpg|thumb|170px|right|SATA power connector (15-pin)]]
-->
<!--
Notes:
* if the SATA connector comes from a [[Molex]] plug adapter, you cannot hot-plug/swap the power {{verify}}
* the 3.3V line is currently often unused
-->

<!--
<br style="clear:both"/>
[[Image:SATA express.jpg|thumb|250px|right|SATA express]]

SATA Express, part of SATA 3.2 (~2013), was an early way to speak PCIe/NVMe{{verify}} (hence the Express) over something that was sorta existing plugs - that is, the combination of two regular SATA plugs with one new part (the image here has two above each other).

It seems an attempt to carry on SATA (in fact moving PCIe was preferable over trying to double speed again), and would have been an alternative to putting SSDs in via PCIe slots.

{{comment|(Note that a SATA Express connection talks ''only'' PCIe, not SATA.  However, these plugs could ''alternatively'' be used as two separate SATA connectors).  The drive side was also slightly unusual, in that it might wish connection that supports PCIe but also still SATA.}}

So it was somewhat confusing.

As far as I can tell, it never took off at all.

In cases where you want NVMe on a PC, get a motherboard with M.2 slot(s) instead.

Servers seem to go for U.2 instead{{verify}} (which is adaptable to M.2) 

https://sata-io.org/sites/default/files/documents/Why_SATA_Express.pdf
-->


<br style="clear:both"/>
----



[[Image:ESATA.jpg|thumb|100px|right|eSATA plug]]

For external use there is '''eSATA''', which is pin-compatible and functionally identical.
The main differences lie in electronic, cable length, and physical specs, and the connector and socket are different enough so that you can't plug SATA cables meant for internal use onto external ports. {{comment|(There are dumb adapters, but you should be aware of what you're defeating, and will also have trouble around SATA ports that disable themselves at boot if there's no drive on there)}}


<br style="clear:both"/>
[[Image:ESATAp.jpg|thumb|100px|right|eSATAp socket, accepting eSATA and Type-A USB plugs. There are also combinations that accept USB3]]

There is also eSATAp (often marked eSATA+), which is a connector that adds power, and the ability to plug in USB into this same socket. Keep in mind that this may be either USB2 or USB3 (you can usually tell by the color).

'''eSATAp''' is a variant of eSATA that carries also carries power -- and also USB.


Only SATA's 5V line is guaranteed on this plug, the 12V line is optional.
Desktop computers typically provide 12V, while laptops often don't{{verify}}.

This means eSATAp sockets can typically power 2.5" drives (which only need +5V), but only the desktop variants can power external 3.5" drives (which also need 12V).

'''eSATApd''' unofficially refers to having both voltages.


See also:
* http://en.wikipedia.org/wiki/ESATA
* http://en.wikipedia.org/wiki/ESATAp

<!--
SATA versions
* SATA 1.0 (2003) - 1.5 GBit/s (150MB/s) (unofficially known as SATA150)
* SATA 2.0 (2004) - 3.0 Gbit/s (300MB/s) (unofficially known as SATA300)
* SATA 3.0 (2008) - 6.0 GBit/s (600MB/s) (unofficially known as SATA600)
* SATA 3.1 (2011) - {{verify}}
* SATA 3.2 ({{verify}}) - 16GBit/s

SATA-related terms:
* SATA II: the committee defining SATA. Because of widespread (ab)use of 'SATA II' to refer to 3Gb/s devices (SATA/300), that comittee was renamed to SATA-IO

* eSATA: Connector for SATA connection outside of enclosures. 
-->

<br style="clear:both"/>

====SAS====
{{stub}}

SAS and SATA have overlap and in many areas broadly compatible.

This is by design. 

You could see
* SAS (Serial Attached SCSI) as the fancier variant of SATA that targets the business market, adding more options and features, more practical variations in controllers, cables with more channels to attach more drives (and have cable failover), options to connect externally as well (e.g. drive bays), and other such options.

* SATA as the simpler, one-drive-at-a-time consumer variant 
: that is simpler to use and cheaper to make
: (well, with footnotes. There were things like SATA port multipliers but controller support varied)


The protocol is also very similar, though SATA's required commands are a subset of SAS's{{verify}}), both are switched, point-to-point, serial, full-duplex, can be assued to be good for approx. 300MByte/sec per port {{comment|(current typical; both have variations and plans)}}, and can be hot-plugged {{comment|(electrically, anyway. Your BIOS and OS may have their ideas about enabling and resetting ports)}}.


[[Image:SFF-8482.jpg|thumb|199px|right|SFF-8482 plug. Drive bays may have similar [https://commons.wikimedia.org/wiki/File:Supermicro_BPN-SAS3-213A_disk_backplane_with_SFF-8482_connectors.jpg mounted on PCBs] ]]
[[Image:SAS-drive-connector.jpg|thumb|right|199px|Back of a SAS drive, SFF-8482 style.<br/>Pin-compatible with SATA, but the plastic tab in the middle prevents mating SATA as-is]]
: '''Drive-wise'''

The SAS drive interface is SFF-8482. 

It looks a lot like SATA, and can indeed connect SATA as well as SAS drives. 

The SAS and SATA drive connections are closely related, and in fact pin-compatible.
You can physically plug SATA drives onto SAS controllers, the SAS drive connector (SFF-8482) allows it, and SAS can tunnel SATA.  This means server backplanes are easily designed to take SAS and SATA alongside each other.

SATA cannot tunnel SAS, and for this reason you cannot use SATA cabling on a SAS drive. 
Physically because of the extra plastic, but even if you find a physical adapter (they exist, though I'm not 100% on why), it probably won't work{{verify}}.




<!--
[[Image:SFF-8087.jpg|thumb|right|150px|SFF-8087, meant for internal connection of up to 4 devices. Also known as (internal) mini-SAS, mSAS, iSAS, iPass]]
[[Image:SFF-8088.jpg|thumb|right|205px|SFF-8088, basically the shielded variant of SFF-8087]]-->
: '''Beyond single drives'''

Because of varied use cases, there are a whole bunch of internal connectors standardized by SAS, e.g. to carry a handful of channels between drive bay backplane and controller.

Many of them are used more in servers, but some of them are obvious choices in handful-of-drives consumer RAID hardware as well.

See e.g. [https://en.wikipedia.org/wiki/Serial_Attached_SCSI#Connectors] 


See also:
* http://en.wikipedia.org/wiki/SATA
* http://en.wikipedia.org/wiki/Serial_attached_SCSI



<!--
There is now also U.2 (since ~2013{{verify}}), using the SFF-8639 connector, which is like SFF-8482 (as in SAS drives) but with more pins to carry PCIe/NVMe as well. 

It is aimed more at servers (though can be connected to [[M.2]] with an adapter)

U.3 is an update 
: aims to do have server backplanes speak all of SAS, SATA, and NVMe ('tri-mode') rather than, typically, one controller for SAS/SATA and one for NVMe 


https://en.wikipedia.org/wiki/U.2

-->

<!--
On multiple devices:
* '''SATA port multipliers''': addressing/multiplexing over one SATA cable. Cheap solution to have many disks on few controllers, not ideal speed. Typically allows only 4 or 5 drives. Not all SATA controllers support ATA port multipliers.

* '''SAS expanders''': tends to mean a multilane cable going to a(/each) SAS enclosure - think 'one cable for many drives'. Often 4 or 8 ports, for up to approx 120 drives (but typically 12, 24, 48). More bandwidth than SATA, easier for large amounts of drives.

* '''SATA Multilane''': similar to SAS expansion, cheaper than it for a smallish amount of drives

* maximum cable lengths: SAS (10m) &gt; eSATA (2m) &gt; internal SATA (1m), though note that there are different SAS cables


* Earlier versions of SATA were slower than SAS. The difference is now small (for few drives). {{verify}}


On drive differences:
* Higher-IOPS platter drives (10, 15Krpm) are often SAS, because businesses are much more likely to buy this sort of drive for large databases.
(Note this does not mean SAS does twice the IOPS, it means the drive does. It's just a correlation from what's more commonly for sale in which combination)

* On the flipside, the largest drives are frequently SATA {{verify}}


* SAS drives tend to give more guarantees under constant use, have better MTBF{{verify}} (again, because of the business target), and are almost always noticeably more expensive.

* When it comes to errors, SAS drives are likely to act like enterprise drives, SATA more like consumer drives. The difference is a tiny difference in their firmware:
** When consumer drives see errors, they retry a lot, which is nice when it can indeed recover the data.
** Enterprise drives give up much faster -- which is preferable for many-drive RAID, because it won't stall accesses, and you probably use parity-RAID for integrity anyway.

* SAS and SATA drives have very similar connectors. The pinout is the same, the only difference is physical: with SAS the power and data parts are on a single piece of plastic and in a single connector, where on SATA they have a spacer to let them be two different connectors.
: The result is that SAS drives won't mate on SATA cabling,  but you can fit both SATA and SAS drives to SAS cabling/enclosures.


* SFF-8484 - is a 32-pin multilane (2 or 4-) connector. Used for connecting four drives (other side will be SATA or SFF-8482 plugs{{verify}})
* SFF-8470 - 
* SFF-8086, SFF-8087, and SFF-8088 are three different connectors that implement SFF-8086
** SFF-8086 - 
** SFF-8087, "internal mini SAS"
** SFF-8088, "external mini SAS" 
[[Image:SFF-8484.jpg|thumb|180px|right|SFF-8484 plug]]
-->


<br style="clear:both">

====mSATA====

[[Image:mSATA and M.2.jpg|thumb|210px|right|mSATA (left) and M.2 (right) with M notching]]

Uses the more general [https://en.wikipedia.org/wiki/PCI_Express_Mini_Card PCI Express Mini Card] ('mPCIe') connector as a small drive connector (data+power). 
...which caused some confusion, because some sockets were mPCIe, and some mSATA-only {{verify}} (similar confusion exists around M.2 keyings, actually)

in laptops, mSATA has mostly been displaced by [[M.2]].  {{comment|(due to M.2 NVMe sticks becoming more common, M.2 in desktops is becoming more common, where mSATA rarely appeared)}}

See also:
* https://en.wikipedia.org/wiki/mSATA

====M.2====

A form factor spec for expansion cards in general, standardized around 2013 {{comment|(then known as NGFF (Next Generation Form Factor), before it was renamed to M.2)}}

Can carry include NVMe, SATA 3, USB 3, and (multiple lanes of) PCIe 3.


Consumers mainly see this used for storage, in which case you can consider it a replacement of PCI Express Mini Card connector (and its use for mSATA).  Note that M.2 storage can communicate either via SATA or NVMe.

If your PC doesn't have M.2 on-board, there are PCIe plug-in cards with M.2 sockets.
If your laptop doesn't, you probably can't use it.

Also keep in mind that it's new enough that not all current systems can boot off M.2 - in which case you can't (easily) use it for your system drive.
So you want to check that, because in this aspect there is no upgrade path other than upgrading at least half your computer's hardware.


<!--Does not support/guarantee hot-swap. But there are specific cases where this works.-->

'''Widths''' include 12mm, 16mm, 22mm (typical for storage) and 30 mm.

'''Lengths''' include 16, 26, 30, 38, 42, 60, 80 and 110 mm

'''The size shorthand''' is those two appended, e.g. 2280 for 22mm by 80mm

There a longer shorthand with more dashes, like WWLL-HH-K-K or WWLL-HH-K, encodes more details (like single/double-sided, maximum thickness of components, and more)



The '''notchings''' (specific gaps in the socket/connectors) seem intended to indicate when plugging in a thing almost certainly won't work. If you ''can'' plug it in, it should not damage anything, but it is also not guarantee to function. 

This also makes notchings loosely correlated with function.


For example:
: B and M are wider use (including PCIe lanes), in practice frequently SSD (speaking SATA and/or NVMe)
:: B has one side has short piece with 6 pins
:: M has one side has short piece with 5 pins
:: BM has both of those notches

: For WiFi you'll see A and E {{verify}}

There are about a dozen specific notch combinations, but half of them are currently reserved.



For more practical reasons, notchings are also somewhat correlated to sizes, e.g. 
: A and E are rarely longer than 30,
: while B and M may use up to the full length, and rarely as short as 30.

<!--
How B, M, and BM relate to SATA and NVMe is nontrivial.

Technically B takes away two PCIe lanes, that M doesn't.

M is more likely and more likely NVMe

BM is more likely SATA


It's both about device and host. Say, B, M, and BM can all carry SATA, 
-->
<!--
"Do NVMe SSDs need a heatsink?"

It seems they (specifically the controller?) can get quite warm if in constant (writing) use, 
and many will throttle if they get too warm.

So it shouldn't break if you don't, 
but both for peace of mind and performance reasons you may want one on at least your system drive.

On a storage drive it may be almost irrelevant as it will rarely get warm or throttle.

[[caveat emptor]]: don't assume this holds for all / cheap ones.
-->

See also:
* https://en.wikipedia.org/wiki/M.2



=====M.2's relation to NVMe=====

NVMe is storage over PCIe communication.


It is ''mostly'' relevant to connecting SSD drives
: but technically, NVMe platter exists (mostly for pluggability in datacenters, not performance)

For storage, NVMe could be considered an

For storage, NVMe could be considered an alternative protocol to SATA
: no but. NVMe can be faster, but for a lot of tasks this is easily overstated


This has led to some misconceptions
: M.2 and NVMe are often seen as roughly the same thing, and used as near-synonyms by some.
:: but M.2 is general, NVMe is storage only

: M.2 means storage
:: M.2 carries other things - PCIe, USB3, and others

: M.2 storage means NVMe
:: but M.2 can carry SATA, or NVMe or both, and which ones a device speaks is up to that device - there is M.2 that speaks just SATA, not NVMe, though not a lot


'''When M.2 carries NVMe''', it
allows higher bandwidth (which even most SSDs don't need yet), and also 
has queues that makes it easier to use the parallelism of fancier SSD designs (e.g. allowing parallel reads),
which makes it ''potentially'' faster and lower latency than SATA SSD.

''How much'' faster is frequently overstated, at least for most ''current'' devices, and most current uses.
It's much more a "''potentially'' better", and headroom to be a good interface for a good number of years, much less a ''guaranteed to be better right now''. 

More to the point, even if it would for best-case benchmarks, in practice it depends a ''lot'' more on the actual workload than the marketing graphs would like you to realize (which is the point of these graphs, of course) because those were made on very specific workloads.

Rather than five times faster everything, you may find increase on most everyday use is more like a few percent to a few dozen percent.  Cases that may see a little more may include some servers, some video editing, some games see a modest difference (in loading time, and then only to the degree it is not bound by something else). 

So whether the price/performance is worth it depends the same way.

That said, NVMe is at least slightly preferable for SSD, so is likely the preferred interface for SSD in the future{{verify}}.



See also:
* https://en.wikipedia.org/wiki/NVM_Express

====Apple's SSD connectors====
{{stub}}


[[File:Apple 2010 6 12 pin.jpg|thumb|100px|right|Apple 6+12 pin SSD connector]]
'''Apple''' has used various different connectors over time.

None of them are M.2 - which is half fair because half of them predate M.2, and half just because Apple doesn't like standards that it doesn't write. 

They include: 
* 'first generation', a 6+12 pin (around 2010) (carries mSATA III{{verify}})
* 'second generation', a 7+17 pin (around 2012) (carries mSATA III{{verify}})
* 'third generation', a 12+16 pin (around 2014) (carries PCIe {{verify}})
: with a later variation that uses a 40 pin mezzanine adapter {{verify}}
* 'fourth generation', (~2015) same connector, but higher speed {{verify}}
* 'fifth generation', (~2016) same connector, but higher speed and speaks NVMe {{verify}}
 

There are often physical adapters from M.2 (the protocols these things speak don't seem to differ),
letting you use more generic SSDs, but you ''must'' do the research both on protocol compatibility, and whether it will physically fit.


https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades

===USB===
[[Image:USB_shapes.jpg|thumb|230px|right|First years's most common set:<br/>mini-B&nbsp;plug, &nbsp; B&nbsp;plug, &nbsp; A&nbsp;socket, &nbsp; A&nbsp;plug]]
[[Image:USB shapes wiring.png|thumb|155px|right|Note that mini-A and micro-AB were not common to see]]

{{stub}}


'''What we mainly dealt with for a long time'''
* '''USB A''': The socket-and-plug almost invariably seen on the computer side of cables, and on both sides of and USB hubs (and sometimes elsewhere, e.g. on printers for direct camera connection)
:: ...until USB-C made C-to-C cables became a thing decades later, particularly on laptops, but even now A lives on

* '''USB B''': Used on the device side for bulkier devices, such as scanners and printers, where there are no space limitations
:: sockets are fairly sturdy, compared to mini and micro

* '''USB mini-B''': Used by not-overly-small devices, such as cameras, MP3 players, some early/chunky phones
:: sockets may be a little sturdier than micro-B in practice.
:: approximately 3mm by 7mm

* '''USB micro-B''' plugs and sockets, meant for use in thinner devices
:: was the go-to for smartphone data/charge cables, there now being displaced by USB-C
:: approximately 2mm by 7mm



'''What should make the rest of this list simpler'''
[[Image:USB-C.jpeg|thumb|60px|right|USB-C plug]]
* '''USB-C''' {{comment|(released ~2014)}} 
: plug is invertible (and C-to-C cables reversible), so intends to finally make life a little easier (''but'' the amount of footnotes is already moderate)
: {{comment|note that USB does ''not'' necessarily varry USB3, even if they were developed in parallel}}


'''The part of this list that really ''isn't'' simper'''
* '''USB mini-AB socket''' (socket only), relatively rare, can accept both Mini-A and Mini-B plugs.
* '''USB micro-AB socket''' (socket only) that can accept both Micro-A and Micro-B. Defined by USB On The Go (OTG) (2001 standard)
* '''USB micro-A''' plugs and sockets, meant for use in thinner devices
* '''USB mini-A''': was never seen that much, perhaps because it is confusable with mini-B.

* There are many non-standard plugs -- most from the USB2ish era -- that are relatively rare.
: Say, I've seen cameras use approximately-8-pin sockets with different cables that connect ''either'' USB, or things like audio+video. 
: such plugs are sometimes confusingly called things like "B-type"

<gallery mode="packed" style="float:right" heights="80px">
Image:USB3 A.jpg|USB3 A plug: the four classical pins, and 5 new ones further in
Image:USB3 B.jpg|USB3 B plug
</gallery>
[[Image:USB3 micro-B.jpg|thumb|155px|right|USB3 micro-B plug]]
* '''USB3 A''': Plug adds the extra lines for USB3, but remains the same size, and backwards compatible: socket can take earlier (USB1, USB2) USB A.
* '''USB3 B''': Plug adds the extra lines for USB3, and is bigger. Socket can often take earlier USB B.{{verify}}
* '''USB3 micro-B''' - basically USB2 alongside USB3{{verify}}, separated with a notch. Seen e.g. on 2.5" external hard drives, USB3 hubs.

* '''USB3 Micro-A''' (looks like USB3 micro-B but squarer) exists only as a plug, and seems rare
* '''USB3 Micro-AB''' (looks like USB3 micro-B but squarer) refers to a socket that takes USB3 Micro-A and USB3 Micro-B, also seems fairly rare
* '''USB3 Mini-B''' - adds pins to the original mini-B. Came much later than the original mini-B and seems to be a cost saver over USB-C that may not be standard?{{verify}} Seems rare?{{verify}}




Notes:
* '''USB and colors''' [https://en.wikipedia.org/wiki/USB_hardware#Colors]
:: '''Blue''' often means a USB3 port 
:: '''Yellow or red''' in ''sockets'' are often intended for charging, supporting higher-current capacity and/or ports that will charge things even if the host computer is powered off.
:: '''Green and purple''' indicate specific fast charging - green for Qualcomm Quick Charge (QC), purple for Huawei SuperCharge


* USB(1) exists since 1996, 1.1 since 1998
:: only type A and type B plugs were technically in the specs
:: 1.5 Mbps ('Low speed') and 12 Mbps ('Full speed')

* USB2 exists since 2000-ish ()
:: used roughly the same cabling, if produced to higher spec
:: also started introduced various of the mini and micro
:: adds 480 Mbps ('High Speed')
:: four pins
::: power lines are 5V and ground
::: data is 3.3V differential
::: the fifth pin on micro plugs is [[OTG ID]], and is either tied to ground (marking that side as host side) or floating (marking it as device side) {{verify}}

* USB3 exists since 2008ish
:: 3.0 adds SuperSpeed (5 Gbit/s), 3.1 adds SuperSpeed+ (10 Gbit/s)
: leaves all those USB2 pins there, adds five pins and lines to USB2:[https://en.wikipedia.org/wiki/USB_3.0#Pinouts]
::: two differential pairs
::: and a ground
:: technically the USB3 part is entirely separated from USB2 part (which made hubs more interesting)
:: often recognizable by the blue plastic in the plugs and sockets, ''or'' SS {{comment|(for Super Speed, the mode that USB3 adds)}}
::: micro plugs/sockets are often not blue, possibly because it would be hard to see anyway{{verify}}), and because they're less ambiguous that PC-side A sockets


See also:
* http://en.wikipedia.org/wiki/Universal_Serial_Bus
* http://en.wikipedia.org/wiki/Universal_Serial_Bus#Mini_and_Micro
* http://en.wikipedia.org/wiki/USB_On-The-Go


<br style="clear:both">

===8P8C / Ethernet cable===
[[Image:8P8C ethernet cable.jpg|thumb|200px|right|Ethernet cable (8P8C plug, with colors indicating TIA/EIA-568-B wiring)]]

For the series of connectors, see [[#Modular_connector_.28and_Registered_Jack.29.3B_.3FP.3FC]]

For the use of 8P8C in ethernet, see [[Network_wiring_notes_-_8P8C_/_RJ45#What_you_were_probably_looking_for:_Ethernet|8P8C / RJ45]]

<br style="clear:both"/>

===Firewire (IEEE 1394)===
[[Image:Firewire 6pin plug.jpg|thumb|110px|The 6-lead plug]]
[[Image:Firewire 6 and 4.png|thumb|110px|The larger 6-lead connector and smaller 4-lead connector<br/>both Firewire-'''400''']]
[[Image:Firewire 800.jpg|thumb|140px|The 9-pin Firewire-'''800''' plug, 'beta'<br/>which can also be used for S1600 and S3200]]
[[Image:Wiring 568B plugs - check.jpg|thumb|199px|IEEE1394c allows Firewire at 800MBit over 8P8C/Cat5 cabling]]
{{stub}}


IEEE 1394 is better known as FireWire (Apple), and sometimes i.LINK (Sony), and Lynx (Texas Instruments).

It was meant as a successor to parallel SCSI, and is also commonly used for some digital cameras, and for high-end audio and video devices. 
Was a potential competitor to USB in many areas, but while USB is somewhat slower {{comment|(depending on which variant of FireWire and USB)}}, USB is more popular for many things.


Connectors include:
* 4-lead
** smaller, e.g. used on more portable devices like cameras. Data-compatible with the 6-lead connector, but doesn't provide power. Initially developed by Sony, later more widely adopted{{verify}}
** two twisted pairs of data
* 6-lead ('alpha')
** two twisted pairs of data, power
* 9-lead ('beta')
** two twisted pairs of data, power, shield {{verify}}
* 8P8C connector (used in 1394c)



Standards:
* IEEE 1394, specifically IEEE 1394-1995
* IEEE 1394a, specifically IEEE 1394a-2000, also known as FireWire 400
** Uses the 4-lead and 6-lead ('alpha') connectors
* IEEE 1394b, specifically IEEE 1394b-2002, also known as FireWire 800 (Apple's name)
** adds the 9-lead ('beta') connector
* IEEE 1394c, specifically IEEE 1394c-2006, also known as FireWire S800T
** adds the 8P8C connector

<!--
the S1600 and S3200 modes were mostly defined in 1394b, and while not fully defined were often supported. They have been more formally defined since 2008
-->

See also:
* http://en.wikipedia.org/wiki/IEEE_1394
* http://pinouts.ru/Slots/ieee1394_pinout.shtml

<br style="clear:both">



===Thunderbolt===
[[File:Thunderbolt socket.jpg|thumb|right|60px|Thunderbolt socket]]
Intel and Apple developed '''[[#Thunderbolt|Thunderbolt]]'''.

{{comment|(Developed by Intel under the name Light Peak, since renamed)}}
<gallery mode="traditional" style="float:right" widths="60px">
File:Thunderbolt socket.jpg|Thunderbolt (1/2) socket
Image:USB-C.jpeg|USB-C plug. If it's got a bolt near it, or you'd expect it in context, it's thunderbolt 3.
</gallery>


Uses the same plug as Mini DisplayPort (well, the first version does).

Which is '''intentionally backwards compatible'''. 

But, for the same reason, '''also potentially confusing''', 
: It's a more generic bus like USB, but the expectations of such are probably still mostly monitor-y.
: so e.g. the same Apple monitor might do more on one laptop than another.  

It's safe to connect and will display, but any feature beyond that won't work.

You can tell by the logo:
: monitor-like logo &rarr; Mini DP
: lightning bolt logo &rarr; Thunderbolt.


Note that Thunderbolt 3 uses the standardized [[USB-C]] (which is now entering general use),
so mini-DP-style thunderbolt is now sometimes referred to as Thunderbolt 2 connector.

This at least is ''expected'' to be a generic interconnect.




'''Thunderbolt 1''' reuses the [[Mini DisplayPort]] connector; thunderbolt capability is indicated by a lightning symbol.
: Can carry DisplayPort, one or more PCI Express lanes, and up to 10W of power.
: Copper cables carry two 10GBbps (1.2GByte/s) lanes, of which any device can use only one (seems a fair-sharing thing)
: Assume ~3 meter max over copper{{verify}}
: Can daisy-chain a few devices (though individual devices have to have the plugs for it, and allow it){{verify}}.

Thunderbolt 2
: Much like 1. Largest difference seems to be that a device can use both channels{{verify}}


'''Thunderbolt 3''' uses USB-C connectors. Plugs and sockets should bear the thunderbolt logo to lessen confusion.
: Speaks more protocols (DisplayPort, PCIe, USB 3, ...)
: Allows adapters to the previous MiniDP plug
: Not guaranteed to carry 10W as before (though USB could choose to do more than that) {{verify}}
: Assume it can do 20Gbps as before. Short or active cables could do 40Gbps{{verify}}



<br style="clear:both">

====On Thunderbolt 3, USB3, and USB-C====
{{stub}}

[[Image:USB-C.jpeg|thumb|60px|right]]
USB-C [[File:USB-C diagram.png|42px]] is a physical connector more than anything else, 
in that it is intentionally '''protocol-agnostic''', and there are already a handful of protocols that can be negotiated on top, including
:: USB3 (3.1 for 5 or 10GBps, USB3.2 for 20GBps)
:: USB2 (often Hi-speed, 0.48GBps) <!-- {{comment|(which is simpler to implement. So not all USB-C is USB ''3'', but that ''should'' be irrelevant in practice}} -->
:: USB Power Delivery (a simple protocol to negotiate transferring more power)
:: Thunderbolt 3 (10GBps, 20GBps, 40GBps{{verify}})
:: video (DisplayPort, HDMI, [https://en.wikipedia.org/wiki/Mobile_High-Definition_Link MHL])
: ...or some combination.


It is context-dependent which protocols the endpoints care to speak.

Which is both nice and potentially confusing. 
: Yes, it reduces the amount of cables and connectors you need and makes USB more universal.
: But also, there will be various cases of "doesn't work" that will not be easy to explain.

Say, Thunderbolt 3 chose USB-C plugs/cable (previous versions used [[mini-DisplayPort]]), so TB3 can in many contexts be seen as an extension of USB3. 
But a Thunderbolt3 device will do ''nothing'' on a USB3-only host. ''Probably.''



USB-C '''cables''' are created ''roughly'' equally.

...well, that was the plan, anyway.
Sure, most combinations will function, but there are footnotes that mostly technicians and gearheads will care for - except when not.

In practice, 
: USB-A to USB-C  might be USB2 or USB3, depending on the USB-A plug
::  (it also ''can't'' populate all lanes, because USB2 didn't have thay)

: USB-C-to-USB-C ''should''  populate everything
:: apparently even these exist in USB2- only variation, but this should be rare
:: but yeah, even C-to-C cables exist in half a dozen variants already (see the specs[https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%20August%202019.pdf])

: USB-C-to-USB-C do not all support the same speed
:: basics are roughly 480mbps, 5gbps, 10gpbs{{verify}}
:: but some variants may be capable of sustaining 20Gbit, 40Gbit{{verify}}
:: may mean some protocols, or some features within a protocol, may not work{{verify}}

: USB-C-to-USB-C do not all support faster charging
:: and if they pretend to do so, but are out-of-spec knockoff cables, this is somewhat riskier these days, because there is [[USB_notes#On_USB_power_and_charging|a bunch more current involved than in earlier USB]]


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===PS/2===
[[Image:PS2.jpg|thumb|200px|right|PS/2 plugs, on USB-mouse-to-PS/2 adapter and USB-keyboard-to-PS/2 adapters, respectively]]
{{stub}}

The name PS/2 comes from the [https://en.wikipedia.org/wiki/IBM_PS/2 IBM PS/2], a 1987 PC that was part of setting some standards in that market (e.g. 16550 [[UART]], 3.5-inch [[floppy disk]], the [[VGA]] graphics standard, and the PS/2 port.


These days, PS/2 most often seems to refer to the [[PS/2 port]],
which was a 6-pin [[mini-DIN]] connector used primarily for keyboard and mice,
initially replacing 
* the 5-pin DIN connector used for keyboards in PC/AT
* 9-pin D-sub (DE-9) serial connector for mice 

PS/2 port lived on on motherboards, even when USB keyboards and mice became the norm.


Because the mini-DIN connector has seen other uses, it is sometimes confused.

https://en.wikipedia.org/wiki/PS/2_port






Uses the 6-pin [[#DIN, mini-DIN|mini-DIN]] connector. For keyboards, this replaced the larger DIN plug used on AT style computers before PS/2. For mice, this became an alternative to serial port mice, though USB is now also quite common for keyboards and mice.

<br style="clear:both">

===D-sub (D-subminiature)===
[[Image:DSub.png|thumb|240px|right|The sizes (widths) of various D-sub plugs]]
[[Image:DE15.png|thumb|105px|right|DE-15 {{comment|(also seen named HD-15, DB15, HDDB15)}}, used for [[VGA]] monitor connections]]
[[Image:Dsubs.jpg|thumb|255px|right|Back of a computer with <span style="color:#7B1A43">DB-25F&nbsp;(parallel&nbsp;port)</span>, <span style="color:#002B82">DE-15F&nbsp;(VGA&nbsp;connector)</span>, <span style="color:#007788">DE-9M&nbsp;(serial&nbsp;port)</span>.<br/>The DA-15M held next to it is a MIDI-on-a-[[gameport]] cable]]

{{stub}}

D-subminiature have a keystone-shaped shell for seating and earthing, and typically fastened with screws.

Most have two rows of pins, some three. 

Spacing of pins within a row is 2.76mm, rows are 2.84mm apart. 
: the 'high density' (HD) variants have 2.3mm pin spacing, 2.0mm row spacing

Coding:
* The '''second letter''' indicates the '''shell size''' (A through E),
* followed by the '''number of pins''' ''present'', 
* and sometimes the M or F for male/female {{comment|(originally P and S for plug and socket)}}

Given the shell size and pin spacing, there is a ''typical'' amount of pins for each size of shell when there are 2 rows: 15 for A, 25 for B, 37 for C, 50 for D, 9 for E. 

There are however exceptions, like the three-row variants (e.g. DA-26, DD-50, DE-15), and sometimes other things in there (e.g. [http://images.google.com/images?q=DB13W3 DB13W3]).


Some common examples:
* DE-9:
** often a serial port (RS232) interface
* DB-25
** Parallel ports 
** Serial ports - though they were unnecessarily large, so quickly adapted to replaced with DE-9
** sometimes (older) SCSI {{verify}}
* DE-15: 
** [[VGA]] monitor connectors. {{comment|(Uses three rows of pins. Also technically called HD-15, where HD stands for the High Density of the pins compared to other D-Sub plugs)}} 
* DA-15: 
** [https://en.wikipedia.org/wiki/Game_port game port] (mostly seen on older PC sound cards), originally for joysticks, later also used for MIDI
** in earlier networking, the [https://en.wikipedia.org/wiki/Attachment_Unit_Interface AUI connector] was the way to connect distinct physical layers to a unified interface (analogous to the later [https://en.wikipedia.org/wiki/Media-independent_interface MII]<!--, and also [[SFP]]/[[QSPF]]-->), that with adapters could go to 10Base2, 10Base5, 10BaseT, and more


Some people abuse specific letter codes thinking that anything just refers to the D-sub plugs in general, and started patterns of misleading use for those that do know what they mean, e.g. DB15 to refer to DE15 (VGA) or DA15 (gameport).



There are smaller variants called Micro-D and Nano-D, mostly seen in military and space use.


* http://en.wikipedia.org/wiki/D-subminiature
* http://en.wikipedia.org/wiki/VGA_connector
* http://en.wikipedia.org/wiki/DB13W3 ('Sun video', or SGI/DCC)

<br style="clear:both">

====Micro D-sub====
{{stub}}

Smaller and denser variants of the D-shell and pins idea.

{{comment|(also called mini, but this is arguably extra confusing, in that (regular) D-sub is short for 'D-subminiature')}}
(is this sometimes called half-pitch D-sub?{{verify}})

Smaller pitches (at least 1.27mm/.050"), 
and may have pins aligned grid-like rather than in a triangle, 
though there are probably various distinct series that fit this vague description.

I'm not sure what series these are officially part of - sites now tend to categorize them under SCSI connectors, or computing miscellany. 


Ones I've come across:

[[File:Micro D50.jpg|thumb|right|200px|Micro D50]]
* '''Micro D50'''
: 1.27mm (.050") pitch
: aligned between rows

[[File:Micro D68.jpg|thumb|right|220px|Micro D68 (with a less-usual plastic shell)]]
* '''Micro D68''', which you may recognize as 'something to do with SCSI'
: 1.27mm (.050") pitch
: aligned between rows

* '''Micro D25'''
: 1.27mm (.050") pitch
: triangle alignment between rows{{verify}}



Adapters exist to e.g. [[#Micro_ribbon|Micro ribbon]] for SCSI

===Ribbon-cable-and-IDC===
[[Image:Ribbon IDC.jpg|thumb|220px|right|34-pin floppy cable plug on the left, a 40-pin parallel ATA plug on the right (the latter recognizable by the one filled hole, and the plastic alignment notch is also fairly common)]]

{{comment|(

{{zzz|Technically, this term is very vague, since
* '''[[ribbon cable]]''' is just the lots-of-wires-side-by-side part, which itself does not imply any connector
* '''[[IDC]]''' just says the connector stabs through a cable to connect to it

Even the combination of the two terms is still somewhat vague - hundreds of combinations would qualify - but specific contexts correlate with specific standards. For example, in computers, it typically means the {{imagesearch|DIN 41651}} series of connectors. 
}}

DIN 41651
: Its pin headers can be very basic, so this is a cheap yet solid thing to connect something low-pin-count, medium speed, that doesn't need to be changed very often.
: The pitch (hole spacing) is often 2.54mm (0.1 inch), though there are variations - for example, parallel ATA connectors for laptop disks often had 2.0mm pitch.
: once common for more devices, though now it's getting displaced (heh) by more specific standards for specific uses


Some that remain:
* Some motherboard-connected ports not directly on motherboard, e.g. 
** an extra serial port, audio connectors (varying pin details)
** extra USB2 ports (varying pin details), and more

* used internally in a lot of places
:: but may be entirely specific to a case, and less standard than various of the above.


Once common, no longer:
* 40-pin (2x20, 2.54mm pitch - 3.5" hard drive connectors (parallel ATA), 
: Mostly a 40 pin IDC connector wired straight through, but with pin 20 blocked
: 80-conductor cables still only use the same pins, but put a grounded wire between each to reduce crosstalk 
:: detectable as such because pin 34{{verify}} is grounded at the host side of the cable, instead of being wired into the cable (pin 34 which was reserved, and unused since early days{{verify}}) <!--
: (some notes about the various grounds sometimes being connected?)-->
: (note that such details make IDE cables not the best choice to reuse as non-IDE interconnecting)


* 34-pin (2x17), 2.54mm pitch - floppy connectors (controller side, and drive side for 3.5" floppy drives)
:: also old Sony CDROM drives, see above

* 44-pin (2x22), 2.0mm pitch  - 2.5" notebook hard drive connectors (parallel ATA)




See also:
* http://en.wikipedia.org/wiki/Insulation-displacement_connector
* http://en.wikipedia.org/wiki/Parallel_ATA

===Micro ribbon connector===
{{stub}}

'''Micro ribbon connector''' or '''miniature ribbon connector''' and some other names


The shell's shape is much like that in [[D-sub]] {{comment|(and see also the potentially confusable name in [[Common_plugs_and_connectors#Micro_D-sub|''micro-''D-Sub]])}},
but in micro ribbon connectors, the actual connectors are strips instead of pins. 
I think I've found connector counts like 14, 20, 26, 36, 50, and 68{{verify}}, 
but it seems there are a few specific selections for specific uses. 
Many are now rarely seen.


There are actually '''two sizes''' of this connector,
* the larger, more common one with a 2.16mm / 0.085" pitch
* the smaller with a 1.27 mm / 0.050" pitch - and this smaller variant doesn't seem to have a very official separate name. I've seen it referred to as '''mini-Centronics''', '''miniature delta ribbon''' ('''MDR'''), '''mini D ribbon'''.


The 'micro ribbon connector' name now seems somewhat odd
* it's not micro, it's not even small

* the larger one is/was more common and basically called micro, and then there's a mini version. 
:: So mini(-micro) is smaller than micro, great

* ribbon is easily understood as [[ribbon cable]] e.g. seen on [[IDC]] connectors, or perhaps [[flat flex cable]], neither of which are commonly used on this connector  (does ribbon actually refer to the style of contact?{{verify}})


<gallery mode="packed" style="float:right; border:1px solid #fff6" heights="72px">
Image:Centronics-36F.jpg|Female 36-pin micro ribbon connector
Image:Centronics-36M.jpg|Male 36-pin micro ribbon connector
</gallery>
<!--
[[Image:Centronics-36F.jpg|thumb|290px|right|Female 36-pin micro ribbon connector]]
[[Image:Centronics-36M.jpg|thumb|230px|right|The according male 36-pin micro ribbon connector]]
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[[Image:SCSI-1_female.jpg|thumb|390px|right|Female 50-pin micro ribbon connector, here used to connect SCSI-1]]

Example uses:

* [[IEEE 1284]] is parallel port style communication
: defines use of 
:: the 36-pin larger variant {{comment|(sometimes MDR36, sometimes HPCN36 'HPCentronics')}}. This use is known as the '''Centronics connector''' because [https://en.wikipedia.org/wiki/Centronics that company] basically introduced the use for printers, typically with DB-25 on the other side. Use in printers was displaced by USB.
::: {{comment|(people will easily call other micro ribbon connectors Centronics because of this association)}}. 
:: {{comment|(IEEE 1284 also defines the 25-pin [[D-sub]] often used on the other side, and the the 36-pin mini variant - see e.g. https://en.wikipedia.org/wiki/File:Mini-Centronics_36_pin_with_Micro-Centronics_36_pin.jpg )}}

* SCSI 
: I have yet to do a deep dive into the history of SCSI connectors, please do your own.
: but it seems to use at least the 50-pin connector in earlier days
: there were some vendors that used the mini-Centronics connector
: (SCSI it also used IDC headers, and what looks like a micro D-Sub, 50 and 68-pin variants, and some others)

* AAUI[https://en.wikipedia.org/wiki/Apple_Attachment_Unit_Interface] {{verify}}, 14-pin (Apple's proprietary answer to [[AUI]])

* a telco connector [https://en.wikipedia.org/wiki/Registered_jack#RJ21] {{verify}}, 50-pin

[[Image:MDR26.png|thumb|88px|right|mini MDR26 on a CameraLink cable]]
[[Image:MDR26 socket and DA15.jpg|thumb|202px|right|mini MDR26 socket (CameraLink), alongside a DA-15 for size reference]]
* [https://en.wikipedia.org/wiki/Camera_Link Camera Link] cables use the 26-pin mini variant
: standardish, but used mostly in somewhat older professional kit, so hard to get in shops

* TODO: verify whether Japan's [[#D-Terminal|D-Terminal]] is using mini-MDR14



See also:
* https://en.wikipedia.org/wiki/Micro_ribbon_connector
* https://en.wikipedia.org/wiki/IEEE_1284#IEEE_1284_connectors_and_cables

<!--
Fastening can be clips or screws (though there can be a strong correlation with any one connector. 
Also, I have seen sockets accepting ''both'').
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===Internal bus===

<!--
'''Desktop consumer PC'''

ISA (since ~1981)

PCI (since ~1992)
: PCIx (1998) was relatively rare

AGP (1997, graphics card only)
: was a video card standard for a while, being faster than PCI. Displaced by PCIx

PCIe (2003)





'''Laptops'''

PC card

PC Card refers to PCMCIA and its successor Cardbus,
which were basically nothing more than a ISA or PCI slot. 
Which meant you could do roughly anything

https://en.wikipedia.org/wiki/PC_Card

-->

=Mobile devices=

<!--
(see e.g. universal charging wires)
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=Phone (landline)=

===Modular connector (?P?C); Registered Jack===
[[Image:P-C-RJ.jpg|thumb|330px|right|8P8C plug, 6P6C plug, 6P4C plug, 4P4C plug, 6P6C socket]]

'''Modular connector''' (when it refers to a specific connector) were developed for phone uses, 
though have also found uses as e.g. board-to-board connectors when space is not cramped.


Variations of socket and plug are named by
* how many positions there could fill (which also implies the plug/socket width), and 
* how many conductors are actually present (typically filled out from the center positions)


For example, 6P2C has 6 positions and two conductors, 8P8C has 8 positions and has conductors in all positions.

The 4, 6, 8 positions/lead connectors are mostly standard, [https://en.wikipedia.org/wiki/Modular_connector#10P10C 10P10C] and further variations also exist.


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Smaller plugs fit in larger sockets, e.g. 4P and 6P plugs fit in 8P sockets, and only in one position because the clip centers the plug.

Within some specific uses, this is intentionally designed for this to be useful and safe.
In other cases, and more creative use, this doesn't help anything.
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See also:
* http://en.wikipedia.org/wiki/Modular_connector (plugs)
* http://en.wikipedia.org/wiki/4P4C



====RJ meaning analog phone====

[https://en.wikipedia.org/wiki/Registered_jack Registered Jack] refers to a handful of '''analog telephone pinouts / wiring standards, most of them on these modular connectors''' {{comment|(RJ that uses other plugs includes the [https://en.wikipedia.org/wiki/Registered_jack#RJ21 RJ21] centronics style connector, and some adapters)}}.

The ones familiar to consumers are mostly 4P on phone handsets, 6P for analog phone lines, and 8P for networking.


Once you get into the details and specific plugs, there is only '''loose association between specific connectors and likely uses'''.

This can be useful to know when you want to use these for other things, in that you may have more luck finding these plugs and sockets by the associated RJ uses.

Consider for example
* 4P4C ~ RJ22 - mostly used to connect handsets to phones (two pairs, one for the microphone and one for the speaker)
:: also RJ9, RJ10 but people seem to mix these quite vaguely so you can consider RJ9, RJ10, RJ22 as synonyms until you're doing the wiring
:: 4P2C exists, but is not used much

* 6P2C ~ RJ11 (one-pair, one telephone line)
:: {{comment|(You also see 6P4C sold as RJ11 though this is ''technically'' incorrect)}}

* 6P4C ~ RJ14 (two-pair, two telephone lines)    <!--, RJ13 -->

* 6P6C ~ RJ25 and RJ12 (three-pair, three telephone lines) 

* 8P8C ~ RJ45, RJ48 (ethernet, multi-line telephone, ISDN, T1 / DDS)<!--
:: Also RJ48, RJ49 (the plated-and-grounded variant?{{verify}}), RJ61 - and there are further variants with their own pinouts and idiosyncrasies (e.g. RJ-48C suggests T-1, RJ-48S suggests lower rates (56/64kbps DSU), apparently RJ-48X was used around T1 that terminate / become a loopback when unplugged, and there even seem to be some internal telco-specific wiring that should never bother ''you'')
-->


Notes:
* There are often two plugs for the same use, which seems to be because of the type of wiring, e.g. the stabs on the pins mean RJ12 is for solid, RJ25 is for stranded{{verify}}. 
: This is about wire crimping and such, and using the wrong type will typically work, but issues arise sooner rather than later, so in professional setups this is not a detail

<!--
https://forum.digikey.com/t/understanding-modular-connectors/21820


{{comment|(For larger lists, see e.g. [[http://en.wikipedia.org/wiki/Registered_jack#List_of_official_types Wikipedia: Registered_jack#List_of_official_types]])}}:

RJ25 either on 6 or 8?


do 4P plugs mate with 6C sockets?
: practically, no, the dimensions of the 4P plugs is smaller


do 6P plugs mate with 8C sockets?
: yes. While the plug is not as wide, the 
-->

See also:
* http://en.wikipedia.org/wiki/Registered_jack (telephone wiring)
<br/>

====RJ45 meaning ethernet?====

Well, no.  But that technicality was lost ''long'' ago.


When a few variants of wiring [[Ethernet]] (e.g. 10Base-T, 100BaseTX) started using the 8P8C plug ([[Network_wiring_notes_-_8P8C_/_RJ45#What_you_were_probably_looking_for:_Ethernet|this wiring]]), and became popular, RJ45 shifted to mean "Computers using Ethernet" {{comment|(and made us abandon and forget things like 10BASE2 and 10BASE5)}}.

...even though 
: the 8P8C plug is used by other standards as well (and by non-standards)
: RJ45 is a phone-wiring pinout
: Ethernet is a large set of standards with a multitude of connectors


The association with Ethernet is now strong enough that searching for RJ45 pinout shows you the TIA/EIA-568-B pinout instead,
and even some proprietary pinouts, before you get ''anything'' mentioning a phone. 
It's actually hard to do a web search for the original phone wiring, and you'll even get hits titled "Could RJ45 be used for telephone?"


To add to the confusion, 8P8C was for a time seen connecting networking ''and'' phones -- because a single analog phone line (middle pins) and 100MBit ethernet (which avoided the middle pins) could coexist on the same plug, which some offices used to reduce the amount of wiring and sockets to install.   (Today, the same offices would use VOIP phones and only care about networking)


See also:
* http://en.wikipedia.org/wiki/Fast_Ethernet#100BASE-TX

<br/><br/>

===Less standard ?P?C uses===

''Many.'' It's a fairly convenient connector that clicks in and won't fall out, cheap, and the wires are easy enough to get.

<!--
Other things seen on 8P8C include:
* firewire
* console on Cisco switches/APs {{imagesearch|Cisco Console Cable pinout}}
* DMX
* 
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<!--
[[Image:Modified Modular Jack.png|thumb|56px|right|Modified Modular Jack (MMJ)]]
There is a variation on 6P6C called [http://en.wikipedia.org/wiki/Modified_Modular_Jack MMJ] with the clip to one side. Used for some computer hardware, relatively old and rare now.
-->

===Landline wallplug===
[[File:dutch phone plug.jpg|thumb|right|330px|Dutch phone plug]]

A lot of countries have switched to [[RJ11]] within the house (and sometimes RJ45), often away from something more local. 


Countries that still haven't fully shed themselves of older plugs (often just in older houses) include...

* Britain - BS 6312 [https://en.wikipedia.org/wiki/British_telephone_socket]

* Germany - TAE [https://en.wikipedia.org/wiki/TAE_connector]
: Loosely resembles F-010 (flat things on the side)

* Austria - TDO [https://en.wikipedia.org/wiki/TDO_connector]
: Loosely resembles TAE

* France - F-010 [https://en.wikipedia.org/wiki/F-010]
: Loosely resembles TAE (flat things on the side)

* Australia - 600-series [https://en.wikipedia.org/wiki/600_series_connector]

* Netherlands - seems to just be known as phone plug, not sure whether it has a known name

* Brazil - Telebrás (named for a company)

* North America - Bell Systems 404A and 505A (60s), changed to RJ since the 70s

* South Africa - Protea (70s to 90s) 

* Poland - WT-4, GTN-4 {{verify}}

* Sweden, iceland - SS 455 15 50[https://en.wikipedia.org/wiki/Swedish_telephone_plugs_%26_sockets]

* Italy [https://en.wikipedia.org/wiki/Tripolar_plug]



Also, some countries had a distinct plug used only for ISDN (which now barely exists) or ADSL (now often also RJ)

=Memory cards=

See also 
* http://en.wikipedia.org/wiki/Comparison_of_memory_cards
* [[Flash memory]]

===SD and MMC===

[[File:SDMMCSizesPins.png|thumb|80px|right|Sizes and basic pins<br/>(not showing extra UHS pins)]]

'''Physical size:''' There's mainly 
* '''SD''' (24x32x2.1mm) (MMC was apparerently a little thinner?)

* '''microSD''' (11x15x1.0mm)
:: previously called TransFlash {{comment|(abbreviated TF and T-Flash)}}, and some parts of the world still prefer that name
* {{comment|(There's also '''MiniSD''', which never really took off)}}


The variants are pin-compatible (some footnotes on the faster ones with extra pins), so adapters to larger sizes exist, and the choice of which you want relates more to the device. For example, cameras and laptops and generic card readers often prefer SD, which is a little sturdier and less fiddly to move around, smartphones use microSD because of the smaller size and it being more or less permanently in there anyway.


'''Capacity types / families'''

* '''SD''' (now named SDSC, 'standard capacity', to distinguish it); since approx 2000
** size (somewhat artificially) limited to 1-4GB (and most were tens of megabytes large at the time)

* '''SDHC''' (high capacity), since approx 2006
** physically identical but conforming to a new standard that allows for higher capacity and speed.
** adressing limited to 32GB

* '''SDXC''' (eXtended-Capacity), since approx 2009
** successor to SDHC that allows for higher capacity and speed
** adressing limited to 2TB
** UHS was introduced since roughly then.
*** this "UHS to go faster" is optional, and is still not all that common

* Ultra-Capacity (SDUC), since approx 2018
** limited to 128TB

* '''SDIO'''
** allows more arbitrary communication, basically a way to plug in specific accessories ''on supporting hosts'' - not really an arbitrarily usable bus for consumers
** (supports devices like GPS, wired and wireless networking)


These acronyms are not so simple.
Practically this may be partly about function, partly about capacity.

It's also not entirely aligned with SD versions,
protocolwise it's even more interesting,
particularly with the extra buses for the faster (UHS and Express) modes.

I think most people have lost track of the details by now.


We have also passed the point where the newest generation of SD are ''not'' not guaranteed to work in the oldest readers (usually still do, though).



====MMC's relation to SD====

In today's context, '''MultiMediaCard (MMC)''' (since roughly 1997) was the predecessor for '''SD cards''' (since 1999).

SD has been more common than physical MMC card for a ''long'' while now 
''but'' variants of MMC (some of them specialized or local) have come out until recently,
and there is less difference than 'predecessor' might suggest.

Also, because SD builds on MMC both physically and in terms of protocol, many SD controllers will still accept MMC cards.

Like SD, MMC had some size variants (see e.g. MMCplus, MMCmicro).
: There is more MMC-based variation, in part because it was an open standard so let companies roll their own.


Worth mentioning is [https://en.wikipedia.org/wiki/MultiMediaCard#eMMC eMMC], basically a flash chip meant for internal use, that happens to be built on MMC. 
It was in common use for internal storage in phones and tables until it was displaced by [https://en.wikipedia.org/wiki/Universal_Flash_Storage UFS].

External/larger SD readers for a long while also had sockets for MMC cards, because MMC was the previous generation of roughly the same thing, and it was a a nice extra feature to put on the box even when MMC cards are becoming rare. 
:: this is now rare, also in part because SD is now more usually integrated



====SD speed====

'''Bus speed''' is the maximum the wiring can deliver data at. Classically there's
* Standard 
: 12MB/s max

* 'High-speed' - clocks SDSC and SDHC at double the rate
: 25MB/s max

* UHS-I
:: Introduced in version 3.01 (~2010, basically around when SDXC was introduced)
:: for SDHC and SDXC
:: one LDVS pair on the same row, ''bus speed'' specced at ~100MB/s max

* UHS-II
:: Introduced in version 4.0 (~2011)
:: for SDHC and SDXC?
:: an extra row of eight pins: two extra LDVS pairs, and more power and ground)
:: ''bus speed'' specced at ~300MB/s max

* UHS-III is only part of SDUC{{verify}}
:: introduced in version 6.0 
:: ''bus speed'' specced at ~600MB/s max
:: Also introduced "Video Speed Class" rating
: Express, which are primarily about extra speed -- 

* SD Express (introduced in version 7.0)
:: ''bus speed'' specced at ~900MB/s max

Notes:
* I'm still confused about how SD Express and UHS-III relate

* Remember that UHS require hardware support from the reader go at these speeds (or will go to the basic speed).

* external readers connected via [[USB2]] will often go no faster than 25MB/s (for both USB and cheaper-controller reasons),
so there is little point for them to support UHS.

* none of this says anything about the an actual SD card - they ''vary''



'''Card speed marking'''

[[File:SD speed labels.jpg|thumb|400px|right|This tells us it's a UHS-I card, it's video class 10, UHS class 1, and speed class 10]]
Marking-wise
* '''Speed class''' - looks like a circle with a number in it - one of 2, 4, 6, or 10
: (and a class 0, which doesn't specify performance so is meaningless)
: that figure is which is MB/s
: apparently this was intended as a minimum sustained write speed, but practice proves not everyone keeps to this, so if specs look optimistic, they probably are. It seems to vary with honesty, so a good Class 6 card may well perform better than a bad Class 10 one.
: there is no larger-than-10, no matter how much fast it actually is
: those details (and the fact that these days most SD can sustain 10MB/s) means this class system is no longer informative

* '''UHS speed class''' - looks like a U with a number in it (1, 2, or 3)
: 1 is 10MB/s
: 3 is 30MB/s
: ...so UHS speed class has very little to do with UHS version
: and since these seem to be the ''only'' two classes, this is almost as pointless as the classic up-to-10 speed class

* '''Video speed class''' - V with a number, V6, V10, V30, V60, or V 90. 
: again, it's just MB/s 
: These were introduced because recording not-too-compressed HD video tends to want [https://www.sdcard.org/developers/sd-standard-overview/speed-class/]
:: perhaps 10MByte/s for SD, 720p
:: perhaps 30MByte/s for 1080p
:: perhaps 60MByte/s for 4k
:: perhaps 90MByte/s for 8k
: These are apparently required to be sustained-average speeds{{verify}}

* Packaging may try to stunt with speed, but '''beware of the words "up to"''' (possibly in tiny print)
: For example, I have a card that says writes <small>up to</small> 80MB/s and reads <small>up to</small> 170MB/s, yet all the logos on it suggest it can't guarantee sustaining more than 30MB/s. Curious...
: so assume this is marketing bullshit in general

<!--
* Application class - 
: A1: Random read  at 1500 [[IOPS]], random write at 500 IOPS
: A2: Random read  at 4000 IOPS, random write at 2000 IOPS
-->

For video, you probably want 10MB/s for standard definition,  30MB/s for 1080p,  60MB/s for 4K,  and 90MB/s for 8K



'''Actual performance'''

Speed ratings can still... sort of lie.

There are '''two gotchas''' to speed ratings:
* due to the nature of flash, read is a lot more predictable, and often faster, than write
: how much faster/slower depends, but it's easily a factor 2
: whenever marketers can get away with it, they will specify the read speed
: note that the differences vary, due to differences in controlles. E.g. external card readers tend to be cheap shit, though there are some examples of slow

* writes can be faster in short bursts
: because you're actually talking to a storage controller, managing the flash (or the operating system buffers)
: You usually care about sustained average write instead
: And sometimes about the guaranteed speed, i.e. the minimum per second-or-so



<!--
Some use a an '''x rating'''

Units of 150kByte/sec (like CDs did).

For ''some'' numeric idea, though:
* 13x is ''roughly'' equivalent to class 2
* 40x is ''roughly'' equivalent to class 6
* 66x is ''roughly'' equivalent to class 10

* 300x is ~45MB/s
* 666x is ~100MB/s

Apparently these are '''not required to be sustained speed ''or'' write speed'''{{verify}}, or at least practice proves not everyone keeps to this, so if it looks dubious, it probably is.

-->

'''Latency'''

'''Read latency''' is often in the 1ms to 2ms range (with no hard correlation to speed class).

'''Write latency''' is not constant, because you're actually talking to a storage controller 
that typically buffers your data, and is managing flash blocks.

Each card may act differently, and there is no direct relation to speed class.

Writing ~1K blocks 
: you can assume at least 30ms as a longer-term average
:: usually many smaller, and one much longer one every so often
: on a shorter term can take anywhere from 15ms to 200ms
:: or more, but variants of the specs say ~200, 250ms, 500ms max{{verify}}
: with some outliers around 4ms and 700ms

The same cards will tend to do better average latency for larger write sizes, up to some amount.


As such, things like fast continuous sensor logging
will have to be able to buffer ~0.5 second of sampling,
and sample parallel to the writing.


See also:
* https://en.wikipedia.org/wiki/SD_card

* More technical details at: [[On_computer_memory#Secure_Digital_.28SD.2C_miniSD.2C_microSD.29.2C_and_MMC_details]]

* https://jitter.company/blog/2019/07/31/microsd-performance-on-memory-constrained-devices/


See also:
* https://en.wikipedia.org/wiki/MultiMediaCard

====SD at lower level====

'''Electrically'''

Power is 3.3V, though there are some lower-voltage details - in particular the LVDS being lower voltage (1.8V{{verify}}).

(MMC had 7 pins)

SD has 9 pins before up until UHS-II

SD with UHS-II adds 8 pins for a total of 17 pins
: two more [https://en.wikipedia.org/wiki/Low-voltage_differential_signaling LVDS] pairs, and more power and ground


MicroSD has 8 pins <!--(which is one less than SD, but it's just one less ground pin)-->

MicroSD with UHS-II has 17 pins


====SD formatting====
{{stub}}

SD cards are often partitioned{{verify}},
typically MBR style, though are also seen partitionless using the entire block device for a filesystem.

However, Windows has not always understood having more than one partition{{verify}},
but in recent times seems to deal fine with the mix of partitions that e.g. RPi often uses.


SD card partition(s) classically came formatted as FAT32 {{(and small ones occasionally FAT16 or FAT12 {{verify}})}}.

While FAT32 could be made to access 2TByte, historical code made assumptions that means above 32GByte people 
tend to use other things just to be safe -- in this context typically exFAT.
(so many tools will default to partition to a single FAT32 partition, at least up to 32GByte)



====SD protocol and DIY notes====
{{stub}}

Since there are a a few card types and more transfer modes over the years, 
supporting all the possible things a card can do is quite involved.

Asume you will ''not'' be using the faster modes, without some up-front planning, or at all.


You're talking to the flash controller, and it should support a handful of protocol variations,
that are basically negotiated from the most basic one.
Any fancy device ''will'' want to do that for speed, but for DIY that basic choice (SPI) is much simpler.
{{comment|(note there are some recent cards where SPI mode is optional, though{{verify}})}}


In SPI mode the pins are mostly just SPI's MOSI, MISO, SCLK, select, and ground, and Vcc.

Code-wise, you'll still want to find a library.
If you don't, you'll probably end up writing much of one anyway.


Even detecting what kind of card is there is interesting. 

You'ld think this is part of negotiation, 
but for historical reasons it's more of a "does it completely fail to respond to this kind of initialization? Then it's probably an this older type".

See e.g. https://electronics.stackexchange.com/questions/77417/what-is-the-correct-command-sequence-for-microsd-card-initialization-in-spi


<!--
{{comment|(Arduino's Sd2Card.cpp seems to follow that part of the spec well. Its type 1 and 2 refers to SDSC version 1.x and "2.0 or later". Larger capacity can be seen as part of "2 or later" or as their own thing{{verify}})}}

Frankly, you want to be using a library anyway,
because if you don't you'll probably end up writing much of one anyway.


MMC 1.0 ~ 3

MMC 4 to 4.3

MMC 4.4


SD version 1.0 ~ 1.01

SD version 1.1 ~ 2.0
: SDHC introduced in 2?

SD version 3
: SDXC introduced in 3?


https://www.sdcard.org/downloads/pls/index.html

http://uditagarwal.in/index.php/2018/03/17/understanding-sd-sdio-and-mmc-interface/

https://www.sdcard.org/downloads/pls/simplified_specs/archive/part1_301.pdf

http://elm-chan.org/docs/mmc/mmc_e.html
-->

==CompactFlash (CF)==
[[File:CompactFlash.jpg|thumb|210px|right|Type 1 Compact Flash (CF)]]
{{stub}}

Basically a PATA bus, and talking ATA, directly on the side of a memory card.


Often contained flash (which was initially fairly small), though initially also for very small hard drives ([https://en.wikipedia.org/wiki/Microdrive microdrives]).

It offered good features early on (compared e.g. to [[SmartMedia]]), 
but was later displaced by smaller and faster formats - though the sturdiness let it hold on in certain uses, e.g. photography where huge storage size is less important.


'''Physical size''': 36m high, 43mm wide 
: Type I is 3.3mm thick
: type II is 5mm thick

Type II was mostly used by microdrives, also because II is allowed to draw more current than I.
As microdrives were fairly quickly displaced by flash-based storage, most CF cards are Type I, and not all devices do not fit Type II cards{{verify}}.

There are derivations, like [https://en.wikipedia.org/wiki/CompactFlash#CFast CFast] (SATA bus) and [https://en.wikipedia.org/wiki/CFexpress#Cards CFexpress] (PCIe bus) but these are essentially different formats.



Initially, '''storage size''' was dozens to hundreds of MByts, because when it was designed (mid-nineties) a GByte was more storage than a lot of PCs had. In the 2000s they grew to dozens of GBytes. {{comment|(Recent CF5.0 allows ''much'' larger, though in a lot of uses a hundred GByte or so is more than you need, and larger may be better served by a more modern, faster format)}}


Because it's really just ATA, maximum '''transfer speed''' varies with ATA version. Original specs used PIO modes, at 25MB/s,
later UDMA modes supported up to 166MB/s. 
: {{comment|(and ''some'' CF even actually is that fast, which is still on par with modern [[SD cards]])}}.
: yet most regular cards didn't go above 20MB/s or 30MByte/s, and maybe single digits from cheap ones (note: also like cheap SD today).
:: {{(it's also relevant that readout was often done over USB2, which has a similar limit)}} <!--
{{comment|(probably in part because various ways of reading out didn't go much faster anyway - card readers were often USB2 at the time, which doesn't often go faster than 30MB/s, and some IDE to CF adapters lacked the faster modes{{verify}}. Also, older devices that used CF might not support newer (UDMA) modes without a firmware update, or at all.)}} -->
: The x speed rating is multiples of 150KB/s (like in CDs), so e.g. 
:: 133x is approx 20 MB/s
:: 1066x is approx 160MB/s. 
: Note that the listed speed is usually the ''read'' speed, not the write speed.

See also:
* https://en.wikipedia.org/wiki/CompactFlash
* {{imagesearch|Compact Flash|image search: Compact Flash}}

==Memory Stick (Duo, Pro, Micro (M2), etc.)==
[[File:MSst_duo_m2.jpg|thumb|right|230px|Physical sizes: 'standard', Duo, and Micro/M2]]
{{stub}}

The three sizes are electronically largely identical, and adapters from M2 to Duo-size and standard-size exist.

Seen on mobile phones, cameras, The PlayStation Portable, etc. Competed mainly with SD and CF at the time. 


Maximum space:
: original: 128MB
: PRO: 32GB (probably the most common)
: XC: 2TB


There are three '''physical sizes''' (which you could call Standard, Duo, and Micro):
* that of the Memory Stick Standard, PRO (longer and thicker than the Duo)
* that of the Memory Stick Duo, PRO Duo, PRO-HG Duo (shorter and thinner than the standard)
* that of the Memory Stick Micro (M2)

If you haven't seen some or all of these before:
: the Standard and Duo's angled corners make them somewhat confusable with [[SD]]. 
: The size of the micro (M2) makes it somewhat confusable with the [[microSD]].

See also:
* https://en.wikipedia.org/wiki/Memory_Stick

<br style="clear:both"/>

==xD==
[[Image:xD card.jpg|thumb|right|115px|xD card]]
A few types, sizes up to 512MB and 2GB varying with them.

Apparently quite similar to SmartMedia


https://commons.wikimedia.org/w/index.php?search=xD+card&title=Special:MediaSearch&go=Go&type=image
<br style="clear:both">

==SmartMedia (SM)==
[[File:Smartmedia.png|thumb|right|140px|Smartmedia]]

* quite thin (0.76mm), feels fragile for its other dimensions
* capacity limited to 128MB (...so not seen much anymore)

See also:
* https://en.wikipedia.org/wiki/SmartMedia

<br style="clear:both">

=RF/coax connectors=
Plugs desiged (mostly in terms of shielding and impedance) to carry radio frequencies, associated with carrying video, data, and more.


http://en.wikipedia.org/wiki/RF_connector

===Belling-Lee (IEC 169-2)===
[[Image:BL-longer.jpg|thumb|130px|right|Both ends of a Belling-Lee extender cable]] 

Used for in-your-house TV and radio connectors in some European countries, and Australia.

Diameter is around 9.5mm.


Some people seem to call this a PAL connector, which is apparently mostly an association with the countries this is mostly seen in.

Some call it a coax plug, which is even vaguer.



Note that on houses with more serious installations, it's not unusual to see these only in the eventual wall-plug and the cable that goes to the TV, while everything up to that point might se F connectors or such - in part because the Belling-Lee plugs are not ideal for VHF and UHF frequencies (but fine for MW and Shortwave) and there are some losses every time you connect them{{verify}} so you really don't want them more than once in your chain if you can help it.

See also:
* http://en.wikipedia.org/wiki/Belling-Lee_connector
<br style="clear:both">

===F Connector (IEC 169-24)===
[[Image:F connector plug.jpg|thumb|65px|right|F&nbsp;Connector]]

Diameter: ~14.5mm

Often used for cable television / cable modems, satellite television, and (American) TV aerial connections. 

A little less lossy for VHF and UHF than Belling-Lee is, so is seen in more places in infrastructure{{verify}}.


See also:
* http://en.wikipedia.org/wiki/F_connector
* Confusables: TODO

<br style="clear:both"/>


==='UHF connector'===
<!--
PL-259 (plug) and SO-239 (socket)


From the 1930s, associated with radio industry, 
though without an official standard{{verify}}.
 
Rated up to 100 MHz. Note that this is not modern [[UHF]];
those names got shifted as we got better at higher frequencies.

-->

https://en.wikipedia.org/wiki/UHF_connector

<!--
===N connector===

-->

===BNC===
<gallery mode="packed" style="float:right" heights="160px">
Image:BNC.jpg|BNC connector (socket/inner) on an old network card {{comment|(the plastic thread is meant for a fastening ring and is not part of BNC}}{{verify}})
Image:BNC2.jpg|BNC connector (outer)
</gallery>

BNC, Bayonet Neill-Concelman {{comment|(apparently also sometimes Baby Neill-Concelman connector, Baby N connector, British naval connector{{verify}}, bayonet nut connector)}} was once common for networking (e.g. [https://en.wikipedia.org/wiki/10BASE2 10BASE2], others).

Still used for some antennae, video (then often [[#composite video|composite video]]), oscilloscopes,
occasionally audio and other things, for the ability to carry higher bandwidth analog signals, the shielding, or both.


The plug is designed for a particular [[characteristic impedance]], often 50 or 75 Ohm, 
and while there are two different plugs, they have only slightly different dimensions and doesn't require a lot of force to mate them,
and while they often look different there is no simple definitive way to tell which is which.

This makes little difference under order of 10MHz, but high bandwidth applications ''will'' care about mismatches.

The dimensions vary a ''little'' between these two, but order of magnitude, the barrel is roughly 10mm and the plug's outer dimensions  roughly 15mm

<!--
The barrel is about 9.7mm, 11mm including the pins. 
The locking plug's outermost diameter seems 14mm but you may not want to assume it's less than 15mm.
-->



See also:
* http://en.wikipedia.org/wiki/BNC_connector

<br style="clear:both">

===TNC===
[[Image:TNC.jpg|thumb|92px|right|TNC connector]]
TNC, Threaded Neill-Concelman, is a variation on BNC with a screw thread system {{comment|(BNC uses '''b'''ayonet)}}.
<!--
Diameter: ~14mm
-->

<br style="clear:both">
[[Image:Reverse TNC.jpg|thumb|right|200px|R-TNC (Reverse TNC) connector for the antennae on a WiFi access point {{comment|(note that the smaller R-SMA is also common there)}}]]
Reverse TNC is reverse in that the inward/outward threading is switched between male and female plugs. 
This is seen e.g. in older/larger WiFi antennas, an area where the smaller [[R-SMA]] is also regularly seen for the smaller ones{{verify}}.


See also:
* http://en.wikipedia.org/wiki/TNC_connector
* http://en.wikipedia.org/wiki/TNC_connector#Reverse-polarity_TNC

<br style="clear:both">

===C connector===
[[Image:C_connector_plug.jpg|thumb|200px|right|C connector (left), beside a BNC connector (right) for an impression of size]]
{{stub}}


The Type C Connector looks like BNC, but is bigger. 

(BNC was developed as a smaller version of this [http://www.amphenolrf.com/products/bnc.asp])


See also:
* http://en.wikipedia.org/wiki/C_connector
<br style="clear:both">


===Some smaller RF connectors===

[[Image:SMA_male.jpg|thumb|130px|right|SMA (male)]]
[[Image:SMA_female.jpg|thumb|45px|right|SMA (female)]]

'''SMA''' is short for for SubMiniature version A (There are also SMB and SMC connectors)

Rated to 12 GHz or sometimes more.

Diameter: ~6mm for the thread/female, ~8mm for the male/outside

<br style="clear:both">
<gallery mode="packed" style="float:right" heights="80px">
Image:RP-SMA_male.jpg|RP-SMA / RSMA (male) (on a PCI WiFi card)
Image:RP-SMA_female.jpg|RP-SMA / RSMA (female) (on an antenna for that same card)
</gallery>
A variation called RP-SMA ('reverse polarity') is seen used in WiFi antenna connectors {{comment|(the larger R-TNC also sees use there, mostly on older APs)}}.

<br style="clear:both">



[[File:SMB connector.jpg|thumb|right|115px|SMB jack]]

'''SMB''' is similar in purpose to SMA (though only rated up to 4 GHz), but
: smaller (~4mm for the thread/female)
: snap-on rather than threaded.


'''SSMB''' is a smaller variant (2.7mm?{{verify}})


<br style="clear:both">

[[File:SSMB MCX SMA.jpg|thumb|right|235px|SSMB, MCX, MCX, SMA]]

'''MCX''' is similar to SMB (also snap-on rather than threaded, rated to 6 GHz), but smaller (3.05mm?) 

'''MMCX''' is an even smaller variant (2.5mm)


See also:
* http://en.wikipedia.org/wiki/SMA_connector

<!--
http://en.wikipedia.org/wiki/SMC_connector
-->

* http://en.wikipedia.org/wiki/SMB_connector

* https://web.archive.org/web/20110124205150/http://www.imscs.com/uploads/media/SSMB.pdf


* http://en.wikipedia.org/wiki/MCX_connector
* https://www.everythingrf.com/community/what-are-mcx-connectors


* http://en.wikipedia.org/wiki/MMCX_connector
* https://www.everythingrf.com/community/mmcx-connectors

<br style="clear:both">

==U.FL / MHF / I-PEX / IPAX / IPX / AMC / UMCC==
[[Image:TinyRF2.jpg|thumb|235px|right|Some size reference]]
{{stub}}
[[Image:TinyRF.jpg|thumb|170px|right|Close-up; '''U.FL''' connector on the left (top&nbsp;right of the PCB), and plug held in the calipers on the right.]]


These various names all refer to tiny (2.0mm) connectors for high-frequency RF signals (up to approx 6GHz), and seem mostly interchangeable{{verify}}. 
Seen in various mobile and wireless applications.

There are adapters to things like (RP-)SMA sold for applications such as WiFi, mobile modules (particularly machine-to-machine hardware), and others.


See also:
* http://en.wikipedia.org/wiki/Hirose_U.FL
* http://en.wikipedia.org/wiki/IPX_connector
<br style="clear:both">

==Unsorted RF connectors==

CRC-9 (3mm)

TS-9 (3mm)

MC-Card (2mm)

=Power - industrial and multiphase interconnects=

https://en.wikipedia.org/wiki/Industrial_and_multiphase_power_plugs_and_sockets


==IEC 60309 (Europe)==
{{stub}}

<!--
All have IP44 weather-proofing, some IP67 (while mated, or disconnected-and-capped), 
so useful where the connection may well be outside.

Current rating somewhere between 16A and 800A depending on plug and cabling.


Have a handful of different plugs

Keyed

Colour-coded, mainy: 
* red for 380–480 volts
* blue for 200–250 volts
* yellow for 100–130 volts

Some have a pilot contact, which is shorter so 
: when connecting can switch on the other connectors once they already have good contact 
: when disconnecting, can switch off the other connectors far before they are disconnected
...so is great against arcing in higher-power uses.


Many connectors are correlated to specific uses 

Seen around industry in general, building sites, event industry (where it's named CEEform), 
caravans and food trucks, marinas, sometimes data centers, healthcare, and some other industries.

Getting more international adoption, though some countries have existing, similar-purpose
and sometimes even similar-looking plugs (e.g. there is a similar NEMA plug in the US).
-->

See also:
* https://en.wikipedia.org/wiki/IEC_60309

=Lighting sockets=


===Edison screw===
[[File:Edison screw.jpeg|thumb|right|370px|Edison screw (E27, E14)]]

Typical for lightbulb/pear shapes.

The number is the outer diameter of the metal screw part in millimeters.


There's quite a few of them, but by far most common are:
* E26/E27 - common large screw variant
: Apparently there's a correlation where E26 is for 120V countries and E27 for 230V countries{{verify}}, 
: they're physically close enough to often fit {{verify}}

* The more common small variant is usually E14 (Europe) and E17 (US) {{verify}}



There are a handful of other diameters in use, e.g. 
: E11 (Europe), E12 (US) 'candelabra'

: E10 (miniature) in older flashlights, indicator lights, older bike lights
: uncommon now in all those uses, because e.g. LED is more efficient than incandescent

: E39/E40 (giant/'mogul') in industrial / older stage lighting


There are also a whole bunch of adapters,
because within the same country it's the same voltage, and you might want a different style of lamp,
deal with specific or chandeliers, etc.

<!--


The US also has E11, E26, and E39 ('mogul'), which are typically interchangeable with E10, E27 and E40 respectively

E5	5mm	Lilliput Edison Screw	LES
E10	10mm	Miniature Edison Screw	MES
E12	12mm	Candelabra Edison Screw	CES
E14	14mm	Small Edison Screw	SES
E27	27mm	Edison Screw	ES
E40	40mm	Giant Edison Screw	GES

-->


See also: http://en.wikipedia.org/wiki/Edison_screw#Fittings

==bi-post / bi-pin==
{{stub}}

Many bi-post are IEC 7004 {{verify}}

You may like overviews from image searches for terms like {{imagesearch|light bulb socket types diagram}}


The number specifies the pin distance.
Each distance tends to have a unique socket/plug design, in part to make them more easily identifiable.

<!-- Thoush some smaller sockets tend to accept a small range of sizes.
G4 through GZ6.35-->

[[File:GU10 GX53.png|220px|thumb|right|GU10 (on a 230V MR16 bulb), GX5.3 (on a 12V MR16 bulb)]]
[[File:G9.jpg|190px|thumb|right|G9 with its loops]]
'''Variants with smaller distances''' are typically small spots (classically halogen), for example:
* {{imagesearch|GU10}} - pins, 10mm distance, widened bayonet-style end (seems to be one of only a few G variants that has that bayonet)
* {{imagesearch|GX5.3}} - pins, 5.33mm distance
* {{imagesearch|G4+bulb|G4}} - pins (4mm distance, thinner)
* {{imagesearch|G9+bulb|G9}} - flat loops, 9mm between the centers of the loops
These may be easy to find in supermarkets and such - though the exact set varies a little with where you live.


<br style="clear:both">
'''Larger variants''' like 
* {{imagesearch|G23 socket|G23}} and {{imagesearch|G24 socket|G24}} are used in office lighting.

* {{imagesearch|G53 socket bulb|G53}} is used e.g. in larger [[PAR]] spots

----


'''On relations to the bulbs'''

<!--
There are quite a few '''variants of these G-''number'' bases''', which vary in:
* base shape
* pin distance (between center and center)
* pin thickness and length
* pin shape (round/flat)
-->


A few further details/associations are specified by the letters, e.g. G, GU, GX, GY, GZ.

For example, GZ bulbs use [https://en.wikipedia.org/wiki/Dichroic_glass dichroic glass], which means the glass conducts and dissipates heat, so lets out much of the heat at the back.

Power and beam angle may wel be specified [http://en.wikipedia.org/wiki/Multifaceted_reflector#ANSI_designations] though have some inconsistencies in specification.



While endless combinations between socket, bulb, and voltage ''could'' exist, there is a lot of consistency in what is actually produced at all - what type of bulb, reflector, and voltage is used on each connector

...so in practice most most further details are (only) implied from most specific references being unique{{verify}}.


For example:
* GU4 are often 12V MR11 bulb
* GU5.3 are often a 12V MR16 bulb

* GU10 are often mains-voltage MR16 (as are various others with >7mm pin spacing)
: GZ10 is like GU10 but does not have a beveled base, which means you can't use GZ10 in GU10 sockets (but can the other way around). The reason seems to be a heat/safety restriction: GU reduces heat to to the rear/socket, GZ does not.

* G6.35  (1mm thick pins)
* GY6.35 (1.25mm thick pins)

* GY6.35, G8, or G9 are more frequently JCD type.
: G9 is often mains, G6.35 is often low-voltage

'''But don't count on this''', because there are exceptions




'''Shapes and reflectors'''

: '''JC, JCD'''

Refers to a shape - just the small halogen bulbs, no reflector.
Can be 12V, 24V, or mains voltage.

Comes in a few base sockets, often one of G6.35, G4, G8{{verify}}

Apparenly frequently semi-permeable glass, which is why you shouldn't touch it with your oily fingers.



: '''MR, Multifaceted Reflectors'''

[[File:MR-Variations.jpg|430px|thumb|right|MR16 (GU10), MR16 (GU5.3) MR11 (GU4)]]

MR (e.g. in MR11, MR16) refers to a '''M'''ultifaceted '''R'''eflector, which produces a more focused beam than simple parabolic reflectors. (see also [[PAR]], which is more specifically an ''[[anodized]]'' reflector)

MR bulbs are mostly associated with G-style bases, including GU10, GX5.3, and G4.


The number in MR''something'' is the bulb diameter - in eighths of an inch, so MR16 bulbs are 5.1cm in diameter, MR11 are 3.5cm.

The combinations of diameter and socket aren't unique - which means it's fairly easy to walk into a store and buy a MR16 and discover you needed one with a GU10 and GU5.3 base and got the other.


You sometimes see specifications of diameter as well as power and beam angle - see [http://en.wikipedia.org/wiki/Multifaceted_reflector#ANSI_designations].




: '''On voltage'''

Different MR bulbs may be 12V (most) or higher voltage (some), so '''never blindly assume'''.


12V may still be AC, though are often DC in practice.{{verify}} 
LED-based MR-series often won't care since they need to rectify anyway.

Some of the 12V (switch-mode) adapters designed for a string of halogen MRs will not like the low power draw of LED variants. 
You need a transformer that is not trying to be clever, one designed for lower draw, attach more lights on a single adapter, 
or get one designed with LEDs in mind.



<!--
===You may know/remember===
* B22d

-->


===Other notes===

See also [[DIY_optics_notes#Stage_lighting]].


<!--
===See also===

* http://commons.wikimedia.org/wiki/Compact_fluorescent_lamp
* http://www.besthomesystems.com/learn/lighting_step4.html
-->

=Low power or signals=
{{stub}}

Sure, there are  many things you can ''abuse'' the other way, 
but there are also things that are more designed (or more accidentally quite fit) to carry both low current power, or signals. 

===Binding posts===
<!--
[[Image:Binding_post.jpg|thumb|300px|right|Binding post with four different connections]]


Binding posts have a threaded metal rod and a cap that screws down on it.

They evolved from general purpose fasteners - earlier, simpler versions may be seen on early telegraph keys, blasting machines,
and neither was insulated.

They later became
* insulated with plastic 
* color-coded



Binding post

"five-way binding post" a.k.a. "universal binding post" seems to refer to them being suitable for
* a wire around (screwed down)
* a wire through (screwed down)
* a 4mm banana plug
* pin connectors though (screwed down)
* a spade lug (screwed down)



Seen e.g. on 
* amplifiers
* speakers
* test equipment

In certain test equipment, safety banana jacks may be more common.





-->

===Testing things===

====Banana plugs====

[[Image:Banana plugs.jpg|thumb|355px|Banana plug (4mm) on the black plug on the left (these happen to be stackable, which they only sometimes are).<br/><br/>The thinner (2mm) not-so-banana plug on the right (adapter) that many would consider a multimeter probe]]

[[Image:Banana2.jpg|thumb|300px|I think I bought the top ones as '[[bullet connectors]]' but they're closer to banana]]


The banana plug is named for the curvy lengthwise springs that friction-lock the plug. 

Shapes vary, and not all such 4mm plugs have a friction-lock design, or the same one if they do.

''Length'' was typically 20mm, though e.g. the US seems to use 15mm, and there's more variation.


They ''might'' be rated for something like 30V, 15A -- BUT products vary and some are much flimsier and will not be rated like that.

It seems the main reason for the low voltage is not isolation in the arcing sense, 
but safety in the sense that the contact is exposed.

Names like "safety banana jacks" would refer to variants with fixed shrouds, or sleeves that retract, and may be rated for higher voltages.
These are more frequently seen on e.g. multimeters.



The 4mm version often carries lowish-current power or occasionally audio - it is seen on things like
* measuring devices, such as multimeters, bench power supplies, and such 
: these are often also stackable somehow (4mm hole in the back, or side)
: and e.g. banana-to-BNC for oscillosocopes (handy for non-HF frequency measurements)

* amp/speaker connections
: easy to replug
: capable of dealing with moderate current





There is a 2mm plug seen in similar situations - seemingly mostly multimeters, probably because it's a nice tradeoff in study enough to not break, and thin enough to poke at many smaller components. 

It's not really referred to as a (variation of) banana plug, because the lengthwise springs are not there,
but I haven't found a better place to group it under. 


See also:
* http://en.wikipedia.org/wiki/Banana_connector

<br style="clear:both">


<!--
====Binding posts====

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<br style="clear:both">

====Crocodile clips / Alligator clips====
[[File:Crocodile clips.jpg|thumb|right|345px|There are many variations in look and quality, these are three of them]]

Crocodile clips are useful for making a temporary electrical connection that will be decent and stay on.


The ones in the image here are a few cm large and don't carry much current.
Two of these plug onto banana plugs, for ease of use with multimeters. 


There are large ones, seen e.g. around car batteries, that are ''much'' beefier.

See also:
* https://en.wikipedia.org/wiki/Crocodile_clip
<br style="clear:both">

====IC clips====


====Test hooks / pincer clips / IC grabbers====

[[File:Testhooks.jpg|thumb|right|210px|Test hooks on some 2.54mm-spaced pins]]

...and probably other names.

Details vary, but generally these are small grabby springy things that extend and separate when pushed by hand, 
and pull in and close when you let go. 


This should give comfortable temporary connections on pins down to 2mm pitch or so, where alligator clips would already be troublesome due to their thickness.

The image shows a very cheap variant (one extended), but even they still work pretty well.



<br style="clear:both">

====Pogo pins====

Spring loaded conductive connectors.


Mostly used in automated testbeds, where a PCB often needs to be pressed into a handful of these, 
and in some other places where you want many points of non-permanent contact.

<!--
They represent more than zero engineering worry in the details, particularly at higher speeds
(e.g. the plunger must make good contact with the body or you may get inductance via the spring)
so for more permanent connections it makes sense to use plug-in connectors.
-->


<!--
...which won't be reliable unless there is some force, and wouldn't last long if there wasn't some give.
-->

<!--
Other places you see them
* sometimes seen connecting closely spaced PCBs more permanently.
* Apple's [https://en.wikipedia.org/wiki/MagSafe MagSafe] connector has 5 pogo pins (to avoid sideways force being able to break anything).
-->

See also:
* https://en.wikipedia.org/wiki/Pogo_pin

===Push-release terminals===

<!--
Perhaps the best known variant would be the speaker connector

And the second best the PCB-ish 


-->



===Smaller JST connectors===

JST refers to [http://www.jst.com/ a company that makes '''many''' series of plugs].

The below are mostly used as PCB (inter)connectors
useful for data signalling,
though many are rated for (on the order of) 1, 2, or 3A, so also useful to transfer some power.

A few of the series:

====JST RCY====
[[Image:Connector-JST RCY.jpg|thumb|right|150px|JST RCY,<br/>socket and plug]]

Pitch: 2.5mm pitch

Pins: 2 (not a series)

keying/mating: round shape that guides into shell

Seen in RC vehicle applications, there known as JST connector, BEC connector{{verify}}, P connector{{verify}}

Rated for 3A (with AWG22{{verify}}).

See also:
* https://www.jst-mfg.com/product/pdf/eng/eRCY.pdf

<br style="clear:both">

====JST XH series====

[[Image:Connector-JST XH various.jpg|thumb|220px|right|3, 4, 5, 6, and 7-pin XH sockets on a LiPo balance charger; one 3-pin XH plug]]

Pitch: 2.5mm

Pins: 2 to 20

Keying/mating: two slits near the side of one long end, with some slight bayonetting (works out more as a friction thing)

Rated for: 3A (with AWG22)

Perhaps most recognized as a connector commonly on lithium batteries {{comment|(2 or more pins depending on how many cells, for balance charging)}}


See also:
* http://www.jst-mfg.com/product/detail_e.php?series=277

====JST EH series====

[[File:JST EH.jpg|thumb|160px|right|JST EH]]

Pitch: 2.5mm pitch

Pins: 2 to 15

Keying/mating: socket one side unshrouded, plug one side wider; slits on short edges

Rated for: 3A (with AWG22)

See also:
* http://www.jst-mfg.com/product/detail_e.php?series=58

====JST SM series====

[[File:JST SM.jpg|thumb|140px|right|JST SM, 2-pin and 6-pin variants]]

Pitch: 2.5mm

Pins: 2 to 18

Keying/mating: locking clip in the middle (on 2-pin it's the entire width) and keying on middle of one long side, 'wings' on the short sides

Rated for: 3A


"SM2 connectors" seem to refer to the 2-pin variant{{verify}}


See also:
* http://www.jst-mfg.com/product/detail_e.php?series=238
<br style="clear:both"/>

====JST PH series====

[[Image:Connector-JST PH-9pin.jpg|thumb|100px|right|9-pin male PH-series connector]]
[[Image:Connector-JST PH-cropped.jpg|thumb|80px|right|Plugged 2-pin PH-series connector]]

Pitch: 2.0mm

Pins: 2 to 16

Keying/mating: plug has two slits on the one side long, socket is open between them (one slit and nothing open on the 2-pin variant)

Rated for: 2A (with AWG24)

See also:
* http://www.jst-mfg.com/product/detail_e.php?series=199

<br style="clear:both"/>

====JST ZH series====
[[File:JST ZH.jpg|thumb|160px|right|JST ZH (left), with SH on the right for contrast]]
Pitch: 1.5mm

Pins: 2 to 13

Keying/mating: two slits on the sides (the shortest ends)

Rated for: 1A (with AWG26)


See also:
* http://www.jst-mfg.com/product/detail_e.php?series=287

<br style="clear:both"/>

====JST SH series====
[[File:JST SH.jpg|thumb|170px|right|JST SH (right), with ZH on the left for contrast]]

Pitch: 1.0mm

Pins: 2 to 20

Keying/mating: slits on short end{{verify}}

Rated for: 1A (with AWG28)


See also:
* https://www.jst-mfg.com/product/detail_e.php?series=231

<br style="clear:both"/>



====JST VH series====
[[File:JST VH.jpg|thumb|149px|right|JST VH]]
Pitch: 3.96mm 

keying/mating: slots to the side, clip

Rated for 10A (with AWG16)

<!--
Confusable with: 3.96mm variant of [[Molex KK]] 
-->
See also:
* http://www.jst-mfg.com/product/detail_e.php?series=262
<br style="clear:both">

==Smaller molex connectors==

===Molex KK===
[[File:Molex KK-254 5pin.jpg|thumb|right|108px|5-pin Molex KK-254{{verify}}]]

Pitch: 2.54mm (the most common that I've seen)

Pins:  2 .. 36


Pitch: 3.96mm

Pins:  2 .. 24


Pitch: 5.08mm

Pins:  2 .. 12

Keying/mating: slits around socket's wall, ridge along wall for friction


See also:
* https://www.molex.com/molex/products/group/kk_interconnect_solutions

<br style="clear:both">

===Micro and pico variants===

https://www.molex.com/molex/products/group/micro_connectors


* picoblade
: 1.25mm pitch
: {{imagesearch|molex picoblade}}

<br style="clear:both"/>

==Smaller AMP connectors==
{{comment|(The company is now [https://en.wikipedia.org/wiki/TE_Connectivity TE Connectivity], previously Tyco Electronics, and AMP far before that, but we tend to still call them connectors AMP)}}


===MTA===
{{stub}}


{{imagesearch|MTA 100 connector}}
: single row, 0.1" / 2.54mm pitch

{{imagesearch|MTA 156 connector}}
: single row, 0.156" / 3.96mm pitch

{{imagesearch|mta-156 OR MTA-100}}

https://www.te.com/usa-en/products/connectors/pcb-connectors/intersection/mta-100-mta-156-connectors.html?tab=pgp-story


<br style="clear:both"/>

==Circular metric==
{{stub}}

{{imagesearch|Circular metric connectors|Circular metric}} and {{imagesearch|circular industrial connectors|circular industrial}} don't refer to any one connector or standard, but informally to connectors that are round. 

Metric seems to refer to a metric screw barrel, industrial to 'it looks sturdy' and probably to a few specific series of plugs that I'm not aware of yet.


It's a basic idea implemented in different ways by various companies,
which is why they exist in snap-in, bayonet, push-pull variants; metal and plastic barrels; various types of internal keying, and more variations. 


In my (very biased) recollection I've seen the metal variants more around larger and industrial machines,
probably because they're a way to have a sturdy, many-pin, and somewhat isolated control signal interconnection.



Device producers may favour one of them internally, so you probably see some of these more consistently than others.

And some are largely convention. 
Say, some specific LEMO plugs {{comment|(among many - like DIN and Molex and other cases, we're naming an entire company[https://www.lemo.com/en/products])}} are seen around cameras -- but with varying pinouts {{comment|(and of varied types, there's also e.g. LEMO optical and [[triax]] both used around video)}}.



Some are even standard.

Say, there's the {{imagesearch|GX connector|GX series connectors}} seen fairly consistently around aviation,
usually smaller and fewer pin (I see mention of GX16, GX20, GX12, the number is the barrel diameter in mm)



Down to some cheap plastic (but waterproof) connectors seen around garden/christmas lighting,
distinctly keyed (which in a few examples I found correlated with the voltages used).

...and seemingly everything inbetween.

=Mounts, chip carriers, packages, board connectors=

==PCB connectors==

('PCB connectors' is probably not the best name, I'll think of another)


===Headers===
[[Image:Headers as SIP.jpg|thumb|120px|right|Basic pin headers (male), here on the back of a small PCB]]

Known variably as '''pin headers''', just '''headers''', as '''breakaway headers''', as and under various other names. 

Often 2.54mm (0.1") pitch.

Also the things that jumpers (sometimes known as shunts) sit on.

And you could call a row of headers a [[#SIP|Single In-Line package (SIP)]] without too much of a stretch.



'''PCB headers''' are a fuzzy, wider concept, and can refer to pin headers as well as many more specific deivations, then often seen in shrouded and/or keyed (notched) form.

One simpler example is {{imagesearch|KK-family molex}}, which mostly add bits of plastic as polarity protection but will fit on basic headers as long as they have the same pitch.



<br style="clear:both">

===PCB mount screw terminals===
[[File:PCB Screw terminal.jpg|thumb|80px|right|]]

'''[[Screw terminals]]''' in general may be little more than screw to fasten down a wire to a metal plate.

The variant for PCBs, with pins underneath you can solder, is usually also shrouded.


Available in varied pitches, though mostly larger, like 2.54mm, 3.5mm, 3.96mm, 5.08mm, {{verify}}


Combining these with [[bootlace ferrules]] tends to look like fairly neat work.



See also:
* http://images.google.com/images?q=pcb%20screw%20terminals
* http://en.wikipedia.org/wiki/Screw_terminal
* http://www.google.com/images?q=luster%20terminal%20OR%20lustre%20terminal
<br style="clear:both">


====Ferrules====
[[File:Bootlace ferrules.jpg|thumb|right|120px]]

Ferrules also known under a few other names are sleeves meant to crimp onto stranded wire.

Among them 'bootlace ferrule', which seems to point out that this is halfway between an aglet and a crimp connector.


They are comparable to some variants of crimp pin:
They wrap a shell around all strands (so avoid some issues with a single strand whisker making contact you don't want).

They make particular sense around stranded wire, in that 
* there is less risk of one of the barely-visible strand going off to the side and touching something it shouldn't.
* screw terminals won't damage the strands (so the wires are a little more reusable) 

The wider plastic part means they're not great when there are many wires to be connected cramped side by side,
but this is not often a real issue - they're still fine in most sizes of screw terminals.


Compare also to [[butt splices]]

<!--
nl: adereindhulzen
de: Aderendhülse 
-->

<br style="clear:both">

===Euroblock===

[[File:PhoenixConnector.jpg|thumb|right|180px]]
Euroblock, also known as Phoenix connector, has screw terminals on one side and a snap-in connector on the other.

Can be convenient and fast working on semi-permanent setups, 
where you frequently want to re-plug things in the same way, 
and/or plug around comparable items.


It seems mainly used around 
few-wire control signals (e.g. RS-485),
and audio setups (often for [[balanced audio]]{{verify}}).


https://en.wikipedia.org/wiki/Euroblock


<br style="clear:both">

===DIN 41651===
{{stub}}

{{imagesearch|DIN 41651|DIN 41651 (image search)}} includes various series of fairly common insulation-displacement connectors, including IDC.


Usually two-by-many pins, also seen in four-by-many.

Often 2.54mm (0.1") pitch, smaller variants exist.

Variations:
* With or without alignment notch {{verify}}
* With or without strain relief
* With or without latches


<br style="clear:both">

===DIN 41612 / IEC 60603-2===

{{imagesearch|"DIN 41612" OR "IEC+60603-2"|"DIN 41612" OR "IEC+60603-2" (image search)}} resembles DIN 41651 (IDC and such), but applications are more specialized, and often has more connections (dozens is not unusual, up to over a hundred).

Commonly two-by-many or three-by-many pins.

Used by some pluggable rack systems, e.g. [https://en.wikipedia.org/wiki/VMEbus VMEbus],
which is why a lot of image hits will be the 3x32 variant.


<br style="clear:both">

===Flexible flat cable (FFC)===
{{stub}}
<!--
[[Image:Flexible Flat cable variants.jpg]]
-->
Could refer to any cable that is flat and flexible (and is thinner than ribbon cable),
but FFC usually refers to a fairly specific type commonly seen used as pluggable interconnects in tight spaces such as inside laptops and phones.

Seen in various colors - white, transparent brown/orange, gray, black, and others (color can correlate somewhat with size/pitch).

Common pitches include 0.5mm, 1 mm, 1.25mm, 2 mm.


'''FFC connectors''' often refer to the PCB sockets that accept the end of these cables (though a few designs opt for specific connectors that take less space).


See also:
* http://en.wikipedia.org/wiki/Flexible_flat_cable
* {{imagesearch|Flexible flat cable OR FFC connectors OR Flexible printed circuit|image search}}



Related are '''Flexible Printed Circuits''' (FPC), which are circuits built fairly directly onto these cables (often using small SMD components, and often fairly simple circuits) - {{imagesearch|Flexible Printed Circuits|image search}}

<!--
https://en.wikipedia.org/wiki/Flexible_electronics
-->

===(Card) Edge Connectors===
[[File:5.25 inch floppy card edge connector.jpg|thumb|390px|right|back of a 5.25" floppy drive with a card edge connector, notched to match the connector on the bottom]]


Refers to connections where one side is part of the PCB itself, with traces going to the edge in regular spacing, meant to plug into a spring connector socket,

That socket is often either fixed on a PCB (consider RAM, PCIx and similar),
or sometimes in the middle of a cable (consider 5.25" floppy drive connectors)


Consider e.g. 
* various buses for expansion cards ([https://en.wikipedia.org/wiki/Industry_Standard_Architecture ISA], [https://en.wikipedia.org/wiki/Peripheral_Component_Interconnect PCI], [https://en.wikipedia.org/wiki/Accelerated_Graphics_Port AGP], [https://en.wikipedia.org/wiki/PCI_Express#Interconnect PCIe], etc.)

* 5.25" floppy drives (two-sided, 34-pin)

* DRAM modules (rather smaller pitch than the above)

* various [http://en.wikipedia.org/wiki/ROM_cartridge game cartridges], including {{imagesearch|NES cartridge edge|NES}}, {{imagesearch|SNES cartridge|SNES}}, {{imagesearch|Sega cartridge|Sega}}, {{imagesearch|N64 cartridge|N64}}, {{imagesearch|Gameboy cartridge|Gameboy}}, {{imagesearch|DS cartridge|DS}}, {{imagesearch|Switch cartridge|Switch}}, and more[https://en.wikipedia.org/wiki/ROM_cartridge#Cartridge-based_video_game_consoles]
** ...with some gray area -- many [[memory cards]] do not technically qualify - they look the same as these cartridges, except that the contacts are often not traces on a PCB (presumably often for the good reason of putting less tension on the actual PCB?{{verify}})

May be one-sidede or two-sided.


See also:
* http://en.wikipedia.org/wiki/Edge_connector
* {{imagesearch|"card edge connector"|image search: card edge connector}}

===Board-to-Board connectors===
{{stub}}

Broadly refers to anything that does many-channel signaling between distinct circuit boards.

Can refer to 
* setups that directly fit boards together (often fairly specialized, small, pin-dense connectors)

* things only useful for board connectors, like [[FFC]]

* wire-to-board used to connect boards, like [[IDC]]

* Specific physical layouts, as simple as Arduino shields' specific layout of pin headers

...and more

====Micro Match====

{{imagesearch|Micro match connector}}


====Elastomeric connectors====
Elastomeric connectors, a.k.a. ZEBRA strips, 


https://en.wikipedia.org/wiki/Elastomeric_connector

==Mounts, chip carriers==
{{stub}}
<!--
[[Image:Elec-SOT.jpg|thumb|right|Small Outline Transistor package (SOT)]]
[[Image:Elec-DIP.jpg|thumb|right|Dual-In-Line Package (DIP/DIL)]]
[[Image:Elec-TO92.jpg|thumb|right|TO-92 package]]
[[Image:Elec-TO-3.jpg|thumb|right|TO-3 on a heatsink]]
-->

'''Packages''' refer to the specific design and size of something a particular component is housed in.

You will often see specific component types (and particularly specific models) in certain specific packages/mounts. For example, transistors are often seen in SOT or TO, diodes often in DO, LEDs often in what seems to be called T1, and so on.


Surface mount which may seem recent but has been around since the sixties. Surface mount has introduced a ''lot'' of specific smaller packages.
It's hard to summarize them and give a decent impression of which are more common.



===On pitch===
'''Pitch''' refers to the spacing of pins (more often mentioned in through-hole components, as those are fairly wide-purpose, while suface mount components tend to be more specialized packages)

Common pitches include
* 2.54mm (0.100")
* 2mm    (0.079")
* 1.27mm (0.050")
* 0.8mm (0.031")
* 0.5mm (0.019")


There are a number of different measures that can be relevant in addition to pitch. 

See for example
http://en.wikipedia.org/wiki/List_of_electronics_package_dimensions#Through_hole_pin_dimension_reference

===SMD/SMT versus though-hole===
There is a noticable distinction in through-hole versus surface mount:


'''SMD''' {{comment|('''Surface Mount Devices''')}} and '''SMT''' {{comment|('''Surface Mount Technology''')}} often means leads that end flat on the circuit board, to be soldered in place (often with reflow soldering, wave soldering, or such).

SMD seems to have become popular since approximately the eighties<!--, and can be said to have generations
-->. There are SMT variants of ICs, resistors, capacitors, and various other sorts of packages.

SMD/SMT can also be seen as the top of a hierarchy of a load of specific packages.

The style it is replacing has been (retroactively) named '''though-hole''', occasionally abbreviated to '''THT''' (though-hole technology).

<!--
Given that SMD is useful for tight circuit board packing, there are a lot of small-pitch packages that are primarily useful on specifically designed PCBs, which are a bit of a pain to deal with otherwise.
Some of the larger and few-pin SMD packages are even usable as THT with a little pin bending.
-->


See also:
* http://en.wikipedia.org/wiki/Surface-mount_technology
* http://en.wikipedia.org/wiki/Through-hole_technology
* http://en.wikipedia.org/wiki/Chip_carrier

===Packages, roughly from fewer to more leads===

<!--
====DO====

DO-41: 4mm long, ~2mm thick, 0.7mm leads

DO-201: 1.2mm leads, 
-->

====TO, SOT, SC, some small SMD====
{{stub}}

TO, SOT, SC, SOD refer to a style of making packages, all with quite a few variants, and usually with a small pin-count (often between 2 and perhaps 7, usually between 3 and 6).

While they have names referring to specific uses and sizes {{comment|(TO: 'transistor outline', SOT: 'small-outline transistor', SOD: 'small outlide diode')}}, most of these packages end up seeing many other uses - particularly those packages that handle more than average power (heat).

Note that a number of specific packages have names in more than one of these series.

Many of these are THT, some SMT, some usable as both as they have long pins (some bending involved for THT).



----


'''TO''' ('transistor outline')

TO is often used when there is more-than-negligible current involved (mostly because of the package's thermal capacity), e.g. for transistors, regulators, darlingtons, power resistors. 

<gallery>
Image:TO-92.png|TO-92
Image:TO-220.png|TO-220
Image:TO-226.png|TO-226
Image:TO-236AA.png|TO-236AA{{verify}} (SOT-23 looks very similar){{verify}}
</gallery>

<br style="clear:both"/>
[[Image:TO-18.png|thumb|34px|right|TO-18]]
[[Image:TO-3.png|thumb|116px|right|TO-3]]


Specific '''TO''' packages include:
* TO-220 ([http://images.google.com/images?q=TO220 images]) {{comment|(good heat dissipation, frequently used where power is involved)}}
<!--
** TO-220FP ([http://images.google.com/images?q=TO220FP images]) isolated variation?-->

* TO-92 ([http://images.google.com/images?q=TO92 images])
* TO-18 ([http://images.google.com/images?q=TO18%20package images])

* TO-3 (metal) ([http://images.google.com/images?q=TO3 images])
* TO-46 ([http://images.google.com/images?q=TO46%20package images])





* TO-236-AA (resembles SOT-23, but sizes are a little different)
<!--
TO-236AA = SOT-346 = SC59 ?


* TO-236-AB (same as SOT-23 {{verify}})   pitch 0.95 

* TO-243-AA  (same as SOT-89 {{verify}})

* TO-253-AA (same as SOT-143 {{verify}})

* TO-261-AA (same as SOT-223 {{verify}})
-->


[[Image:D2PAK.JPG|thumb|150px|right|D2PAK]]
* TO-252(-AA), a.k.a. DPAK (4.6mm pitch)

* TO-263(-AB), a.k.a. D<sup>2</sup>PAK (effectively 5.08mm pitch, because the middle isn't a pin{{verify}})
<!--
* D<sup>2</sup>PAK/A - acutally uses the middle as a pin (2.54mm pitch)
* TO-263-AA, a.k.a. D<sup>2</sup>PAK3 (variant with three pins, 1.27mm pitch)
* TO-263-5, a.k.a. D<sup>2</sup>PAK5 (variant with five pins, 1.27mm pitch)
* TO-263-7, a.k.a. D<sup>2</sup>PAK7 (variant with seven pins, 0.85mm pitch)

* TO-268, a.k.a. D<sup>3</sup>PAK (10.9mm pitch)
-->

* TO-262 a.k.a. I<sup>2</sup>PAK
* TO-251 a.k.a. IPAK


<br style="clear:both"/>


----

[[Image:SOT-23.png|thumb|46px|left|SOT-23 with 3 pins]]
<br style="clear:both"/>
'''SOT ''' ('Small Outline Transistor')

A surface-mount package, used for transistors, but also rectifiers, regulators, and more.


There are quite a few variations, many with pins that are wider for better heat transfer.


* SOT-23 - with different amounts of acually present pins, sometimes referred to as:
** SOT-23-3
** SOT-23-5
** SOT-23-6
** SOT-23-8

* SOT-89

* SOT-223 (three-terminal)

* SOT-232 (three-terminal)

* SOT-363

* SOT-353

* SOT-416 (SC-75) (three-terminal)

* SOT-723 (three-terminal)

* SOT-883 (three-terminal)


----

'''SC''' looks like SOT, but has thinner leads {{verify}}

* SC59
** SC59-5
** SC59-6

* SC-74A

* SC-70

<br style="clear:both"/>


----

<!--
'''SOD''' (Small Outline Diode) refers to a few sizes of two-lead designs often used for diodes

* SOD-523
* SOD-323
* SOD-123
* SOD-80C


----

'''MELF''' (Metal Electrode Leadless Face), mostly used for resistors and diodes

-->

===DO===

THT-style diodes are often seen in DO-xx, for example
* DO-35
* DO-15
* DO-41

<br style="clear:both"/>


LEDs often in [http://en.wikipedia.org/wiki/LED#Types]
* the circular plastic housing is often mentioned just by its radius, though seems to also be called:{{verify}}
** T-1     (3mm)  
** T-1 3/4 (5mm)
** T-3/4  (2mm)
seems to be called T1{{verify}} (but more commonly mentioned just by its radius)
* flat housings (THT connectors)
* SMT 


<!--
Pentawatt (two rows, ZIP-like)

SO-8


http://www.fairchildsemi.com/packaging/
-->

<br style="clear:both"/>

====SIP====
<gallery mode="packed" style="float:right" heights="100px">
Image:SIP package.png|SIP
Image:Headers as SIP.jpg|You can use pin headers as SIP package
</gallery>

Pitch: 2.54mm

Single Inline Package. Regularly 0.1" pitch. Hardly a package at all.

<br style="clear:both"/>

====DIP====
{{stub}}
Pitch: 2.54mm (most variants)

<gallery mode="nolines" style="float:right" widths="170px">
Image:DIP.jpg|16-pin DIP socket; 14-, 6-, and 4-pin DIP ICs<br/>(all 0.3" row spacing)
Image:DIP-0.3-0.6.png|DIP-24 with 0.3" row spacing<br/>DIP-24 with with 0.6" row spacing
</gallery>

'''DIP''' {{comment|(also '''DIL''')}}: dual in-line package, usually for ICs which need relatively few pins (up to 64 or so, usually fewer).


DIP often implies 0.1 inch (2.54 mm) pitch.

Most DIP chips have a row spacing of either 0.3 inch (7.62 mm) or 0.6 inch (15.24 mm). 
DIP is now often assumed to be 0.3" (which is also sometimes called skinny DIP{{verify}}).


Since DIP is largely about pin spacing, many things besides ICs can use or be compatible with DIP, or make DIP sockets useful for other things than DIP ICs.

For example:
* [http://commons.wikimedia.org/wiki/File:7-Segment_Display,_0.36in,_Single_%28shaded%29.svg 7-segment displays]


<!--

Size indications:
* Skinny DIP (sometimes SDIP) is sometimes used to refer to 0.3"-wide DIP (as opposed to the also common 0.6"-wide DIPs)
* Shrink DIP (sometimes SDIP) -- 0.7" (1.778mm) pitch  {{verify}}
* PCDIP (much thicker (~8mm?), wider than pins from bottom)
 
Material indications:
* PDIP (Plastic DIP) - the bulk of newer DIPs is plastic (and specifically black plastic)
* CDIP, CerDIP (Ceramic DIP) - some of which with a sealed glass window for UV erasing (not used much anymore)


* MDIP - Molded DIP
* FDIP - Windowed Frit-seal DIP

* HexDIP?

-->
<br style="clear:both"/>


<!--
====Zig-Zag Inline Package (sometimes ZIP)====
http://commons.wikimedia.org/wiki/File:Ic-package-ZIP.svg

Never particularly popular, but still used for a few things (though may instead see names like pentawatt, hexawatt, or some letter-variation of another package).

Row spacing often the same as the pitch.

http://en.wikipedia.org/wiki/Zig-zag_in-line_package
-->

====SO====
<!--
SO is sometimes used to group SOIC, SOJ, SOI, SOP
(SOT?)
-->
<!--
[[Image:SO QFN.jpg|thumb|600px|right|Some SSOP and SO packages]]
[[Image:SOT, SO, DFN.jpg|thumb|300px|right|SO and SOT, for comparison]]
<br style="clear:both"/>
-->


=====SOIC (Small-Outline Integrated Circuit)=====
{{stub}}
[[Image:SOIC_diagram.gif|thumb|120px|right|SOIC-14]]
Pitch: 1.27mm

Pin count variation:
* SOIC-8
* SOIC-14
* SOIC-16 
<!--
* SOIC-16 (wider variant)


Variants:
* SSOIC (Shrink SOIC)

-->

There are wider variants.

See also:
* http://en.wikipedia.org/wiki/Small-outline_integrated_circuit

<br style="clear:both"/>

======SOJ======
{{stub}}

Pitch: 1.27mm {{verify}}

SOIC with J-type leads (instead of gull-wing leads).

<!--
======SOI======
{{stub}}

Pitch: 1.27mm {{verify}}

SOIC with I-type leads

-->

=====SOP=====
{{stub}}

Pitch: 1.27mm, and also 0.80mm, 0.65mm, 0.5mm, 0.4mm

Followed SOIC{{verify}}


* TSOP (Thin Small Outline Package) [http://en.wikipedia.org/wiki/Thin_small-outline_package]
:: pitch: 0.5, 0.55, 0.65, 0.8, 1.27mm

* SSOP (Shrink Small Outline package) [http://en.wikipedia.org/wiki/Shrink_small-outline_package]
:: pitch: 1.27mm {{verify}}

* TSSOP (Thin Shrink Small Outline Package) [http://en.wikipedia.org/wiki/TSSOP]
:: Pitch: 0.65mm

* VSOP (Very Small Outline Package) [https://eesemi.com/vsop.htm]
:: 0.65 mm

* MSOP (mini SOP)
:: Pitch: 0.65mm

* QSOP (Quarter size SOP) [https://eesemi.com/qsop.htm]
:: Pitch: 0.625mm (25 mils), usually

* &#xB5;SOP (micro SOP)
:: Pitch: 0.5mm

* HSOP - SOP with heat wings

* HSSOP - SSOP with heat wings

* CSOP

====PLCC (Plastic Leaded Chip Carrier)====
[[File:PLCC44.jpg|thumb|right|120px|PLCC44 IC (1.27 mm pitch) in socket]]
{{stub}}


PLCC chips have J-shaped leads that wrap around the side and under the IC. 
: the side allows it to be seated in a PLCC socket (can be handy for replacement ability, or when heat is critical), 
: the fact that they wrap lets them also be soldered to surface-mount pads.

Pitch: 1.27mm


PLCC sockets have slots across one diagonal, for a specific PLCC extractor tool that eases removal.

Was also used in early CPUs, after DIP and before more specialized sockets.


Actually sits in a group called JLCC (J-Leaded Chip Carrier), subdivided into:
* PLCC (Plastic ~), which seems much more common of the two
* CLCC (Ceramic ~), which seems used mostly for in some high-temperature and prototypes{{verify}}


See also:
* http://en.wikipedia.org/wiki/Plastic_leaded_chip_carrier

====Flat no-leads package, Micro Leadframe====
{{stub}}

<!--

[[File:28_pin_MLP_integrated_circuit.jpg|thumb|right|80px|28-pin Micro Leadframe Package]]

Some are rather similar to QFP, BGA.

* QFN (Quad Flat No leads) [http://en.wikipedia.org/wiki/QFN]
:: Pitch: 0.5 mm

* MLP (Micro Leadframe Package) and variants [http://en.wikipedia.org/wiki/Micro_Leadframe_Package]
:: Pitch: 0.5 mm, 0.65 mm, 0.95 mm, 1.27 mm

* DFN (Dual Flat No-lead package) and variants
:: Pitch: 0.50 mm, 0.65 mm, 0.95 mm


https://en.wikipedia.org/wiki/Flat_no-leads_package

-->

====Chip Scale Package====
<!--

-->

====QFP====
{{stub}}

[[File:QFP44.png|thumb|right|100px|QFP44 (0.8mm pitch{{verify}})]]


Quad Flat Package is a number of related packages that use {{search|gull wing leads}} (out, down, and out again parallel with the SMD pad it's intended for)


There are a dozen named specifics, which mostly just vary in things like
* smaller-pitch variants 
* heat sinking
* material (plastic, ceramic)
* thickness (some are low profile)
 
Pitch: 0.80mm, 0.65mm, 0.5mm, 0.4mm, 0.3mm (more?)

<!--

* PQFP: Plastic Quad Flat Package
* BQFP: Bumpered Quad Flat Package - the corners extend (apparently to protect the pins - during handling?)
** BQFPH: Bumpered Quad Flat Package, with heat spreader
* HQFP: Heat sinked Quad Flat Package (PQFP with)
* CQFP: Ceramic Quad Flat Package
* FQFP: Fine Pitch Quad Flat Package (0.4, 0.5mm?)
* LQFP: Low Profile Quad Flat Package (0.4, 0.5, 0.65 or 0.80 mm pitch), with a lower height of 1.4mm
* TQFP: Thin Quad Flat Package (0.4 to 0.8mm pitch) - another low profile, of 1.0mm
* MQFP: Metric Quad Flat Package
* MQFP: Metal Quad Flat Package
* SQFP: Small Quad Flat Package
* VQFP: Very small Quad Flat Package
* VTQFP: Very Thin Quad Flat Package
-->
https://en.wikipedia.org/wiki/Quad_flat_package

====PGA====
{{stub}}

Pitch: 2.5mm, 1.27mm

Plastic or ceramic (PPGA, CPGA)
<!--

Pin count: ~50 to ~600

-->

====BGA====
{{stub}}

Pitch: 1.5mm, 1.27mm, 1.00mm, 0.8mm, 0.5mm
<!--

Pin amount: ~50 to ~1500

Mostly seen in more powerful things, like CPUs

Plastic, ceramic, metal (PBGA, CBGA, MBGA)

Variants:
* FBGA - Fine-pitch BGA (fine pitch in BGA means 1.00mm; also FPBGA, FCBGA, FMBGA)
* FBGA - Fine line BGA
* UBGA - Ultra fine line BGA (0.8mm pitch)
* FTBGA - Fine-pitch thin BGA

* Flip Chip BGA

* CSBGA - Chip Scale BGA   (0.8mm or 0.5mm pitch)
* CSP - Chip Scale Package (0.8mm or 0.5mm pitch)


See also:
* http://en.wikipedia.org/wiki/Ball_grid_array

-->

===See also===
* http://www.ic188.com/english/fz.asp
* http://www.cpushack.com/Packages.html

<!--
http://www.fpga-guide.com/package/package.html
http://www.xs4all.nl/~ganswijk/chipdir/package.htm
http://www.siliconfareast.com/ic-package-types.htm
-->

===Unsorted chip mounts===
<!--

SOEIAJ 

Flatpack http://en.wikipedia.org/wiki/Flatpack_%28electronics%29

CLCC,  Ceramic Leadless Chip Carrier
LFCSP, Lead Frame Chip Scale Package

TDFN, Thin Dual Flat No-Lead Plastic Package


http://en.wikipedia.org/wiki/Surface-mount_technology
http://www.siliconfareast.com/ic-package-types.htm
http://www.topline.tv/TO.html
http://www.topline.tv/TO236AB.html
http://www.topline.tv/sot.html
http://www.siliconfareast.com/sot.htm
http://www.topline.tv/drawings/images/sot/SC59temp.gif


-->

==Narrow-use but not ''single''-use PCB connectors (mostly around DIY)==


===Grove connector===
{{stub}}
[[File:Grove.jpg|thumb|right|80px|Grove sockets on an arduino shield]]

The {{imagesearch|grove connector}} is defined by seeed studio.

It's a 4-pin, 2mm-pitch connector (not a JST or molex plug, apparently NSTech PITCH 1125?)


They're intended to be a specific plug and, pinout (sort of), to make quick prototyping easier.


Pinout seems to be 
* VCC (5V or 3.3V depending on context)
* Gnd
* Sig1
* Sig2 

...where those last two may be wired ''one of''
* digital IO - two adjacent digital pins
* analog IO - two adjacent analog pins
* UART - TX, RX
* I2C - SDA, SCL
* no SPI?{{verify}}


It's ''not'' universal in the sense of "if it plugs in it will work",
because each grove socket is wired to just one of these four alternatives, 
so you still have to figure out what the device speaks and what socket you need to use for that.
: ...with ''some'' overlap, e.g. digital pins may overlap with UART or may be PWM capable.

Still, it's quite convenient that you can just plug it in (particularly for demonstrations).


See also:
* https://wiki.seeedstudio.com/Grove_System/


===qwiic===
{{stub}}

4-pin [[JST-SH]] to connect 
* 3.3V 
* I2C (IIC)

Notes:
* daisy-chainable
* a few hundred mA (and consider cable thickness and length)

https://www.sparkfun.com/qwiic


===STEMMA and STEMMA QT===
{{stub}}

'''STEMMA 3-pin'''
* [[JST PH]], 2mm, (like Grove)
* for Analog/Digital/PWM signals

'''STEMMA 4-pin''' 
* [[JST PH]], 2mm, (like Grove)
* for I2C

'''STEMMA QT''' (4-pin) 
* [[JST SH]], 1mm, (like qwiic)
* for I2C

Compatibility:
* STEMMA QT is compatbile with qwiic '''if''' you observe some voltage details (qwiic is 3.3V only, STEMMA QT can be switched between 5V and 3.3V){{verify}}

* STEMMA 4-pin or STEMMA QT is compatible with grove if you observe voltage details (grove, like STEMMA, can be 3.3V or 5V){{verify}}


See also:
* https://learn.adafruit.com/introducing-adafruit-stemma-qt/what-is-stemma
* https://learn.adafruit.com/introducing-adafruit-stemma-qt/what-is-stemma-qt

===Bee series socket===
{{stub}}
[[File:Bee and mikrobus.jpg|thumb|right|146px|(X)Bee socket, and Mikrobus for comparison]]

Two two rows of 10pin 2mm pins.

Mostly known for [https://www.digi.com/xbee XBee] (the Digi brand name for its [[802.15.4]] products), but there are other things connected with this, like Bluetooth, Wifi, GPS, 868MHz style wireless, [[LoRa]].

The socket is used on some Arduino and related boards (e,g, lilypad, seeduino stalker, dfrobot leonardo, waspmote).
<br style="clear:both">

===MikroBUS===
{{stub}}

[[Image:MikroBUS.jpg|thumb|right|230px|MikroBUS sockets, one with a [[4-20mA R click notes|4-20mA R click]] and one without anything, on an arduino shield]]

Two 8-pin 2.54mm pitch with specific pins wired to:
: 5V, 3.3V, Ground
: Reset
: Analog
: PWM
: SPI
: I2C 
: UART
: pin that supports interrupts (where possible)



mikroBUS is an open-standard socket from [https://en.wikipedia.org/wiki/Mikroelektronika mikroElektronika] that is meant to allow various sensors to be more plug and play 


It does not seem very common beyond Click boards {{comment|(which seems to be their own brand)}}, but there's [https://www.mikroe.com/click a whole bunch of them], so this certainly has its uses.

It can help that, because you can have adapters to arduino, raspberry pi, and some other DIY boards,
it works as something as a platform-agnostic pin adapter.





See also:

* http://www.mikroe.com/mikrobus/
* {{search|mikrobus_specification.pdf}}

=Unsorted=

<!--
===Molex connectors===

Molex actually refers to a company, one that makes a '''lot''' of different connectors.


When the name is used to refer to a plug, often often refers to plugs common to the context, such as
* in PCs:
** 5.25" peripherals and hard drives up to [[SATA]] {{comment|(though note that these are actually {{imagesearch|AMP MATE-N-LOK}}, and Molex's compatible {{imagesearch|Molex 8981}} came later)}}
** smaller floppy drives: {{imagesearch|AMP 171822-4}}
** pin headers with the plastic tab that covers most of their width as polarity protection - Molex KK and a few similar series {{comment|(Compare also to [[#JST connectors]] and others)}}
** ATX motherboard power: {{imagesearch|Molex Mini-fit Jr.}}

See also:
* http://images.google.com/images?q=Molex+8981
* http://images.google.com/images?q=Molex+KK
-->


==="IDC"===
{{stub}}

IDC stands for "insulation displacement connector".


IDC is not a connector. 

IDC is not even a family of connectors, though it sometimes gets used as such.


It's arguably about the ''other'' end of the actual connector: not the socket-plug part, 
but the part where either of those meets wires - it is a property of ''how'' that connection works:

What 'insulation displacement' means means is "has blades that cut through the insulation (and possibly a bit of the wire too)",
and includes things like [[splice connectors]], [[gel filled crimp connectors]], [[DIN 41651]], and a ''lot'' more.



As such, you probably do not want to use these on wires that move a whole bunch of amps. 
This warning goes for a whole bunch of splice connectors, actually.
: and yes, people do this anyway. In particular, see tap splices used in cars.

Luckily, "IDC" often means data/signal connectors

<!--

* "Ribbon cable and IDC"
#redirect [[Common_plugs_and_connectors#Ribbon-cable-and-IDC]]


* Pressed 8P8C ethernet is IDC

* *Scotch lock" refers to at least two IDC-style connectors

-->