Electronics notes/Cell phone notes

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This is for beginners and very much by a beginner. It's meant to try to cover hobbyist needs, and as a starting point to find out which may be the relevant details for you, not for definitive information.

Some basics and reference: Volts, amps, energy, power · Ground · batteries · resistors · changing voltage · transistors · fuses · diodes · varistors · capacitors · inductors · transformers · baluns · amplifier notes · frequency generation · skin effect


And some more applied stuff:

IO: wired local IO wired local-ish IO · · · · Shorter-range wireless (IR, ISM RF, RFID) · bluetooth · 802.15 (including zigbee) · 802.11 (WiFi) · cell phone


Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes

Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids

Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer

Audio notes: basic audio hacks · microphones · amps and speakers · device voltage and impedance, audio and otherwise ·

Less sorted: Common terms, useful basics, soldering · Microcontroller and computer platforms · Arduino and AVR notes · ESP series notes · Electronics notes/Phase Locked Loop notes · mounts, chip carriers, packages, connectors · signal reflection · pulse modulation · electricity and humans · Unsorted stuff


See also Category:Electronics.

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


Note that many of these were never really made for indoor use. You can generally expect -10dB difference between outdoor and indoor near a window, more for some types of buildings/isolation/reinforcement (may make it impossible to phone in such a building).

Given speeds are download speeds (upload speeds may be lower), and ideally real-world (which may be ~70% of the lab-test speeds, and much less than the theoretical variant)


See also:


2G (second generation) - GSM family

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Speed: 0.3Mbps in theory, 0.1Mbps in practice Latency: ~500ms

GSM

GSM is digital communicated of voice calls.

Uses one of 850MHz, 900MHz, 1800MHz, or 1900MHz, depending on location.


CSD:

  • alternative to modem, using data rather than sound.
  • Uses a single time slot, for 9.6kbit/s

HSCSD:

  • improved variant of CSD: more efficient data coding (14.4kbit/s per time slot) and can use more than one time slot
  • Speed up to 57.6 kbit/s (four slots), theoretically 115.2kbit/s with eight.
    • Voice calls take precedence over data transfer, so speed is typically between one and four slot worth(verify)


Between second and third generation

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

GPRS

  • '2.5G'
  • Extension of GSM networks, that can work on existing GSM base stations(verify)
  • Not unlike HSCSD in speed/timeslot details.
  • seen as the predecessor of EDGE. Also has some relation to UMTS.
  • http://en.wikipedia.org/wiki/GPRS

EDGE

(GSM) EDGE, Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC)


EDGE Evolution, a.k.a. Evolved EDGE

CDMA2000

  • sort of 3G, backwards compatible with 2G CMDA standards(verify)
  • Not very widely used(verify)
  • Real-world speed: ~100kbit/s (In theory some up to ~2mbps in some variants?)(verify)
  • Regularly abbreviated to CDMA (does indeed use CDMA, Code Division Multiple Access)
  • http://en.wikipedia.org/wiki/CDMA2000

3G

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Note: 3GPP[1] (3rd Generation Partnership Project) is a collaboration to which most real-world third generation standards belong to.

UMTS (a.k.a. FOMA)

The common 3G network in Europe.

Speed: 7Mbps in theory, 1Mbps in practice Latency: ~200ms


See also:

HSPA: HSDPA, HSUPA, HSPA+ (Evolved HSPA)

'3.5G', and if you like that sort of thing, 3.75G, 3.9G and whatnot.

UMTS extension to support higher data speeds.

Speed: 50Mbps in theory, 2-10MBps in practice


See also:

UMTS-TDD: TD-CDMA, TD-SCDMA

Variation of UMTS (that is not compatible) that makes it more of a mobile internet, WiFi-style network.

See also:

(3GPP) LTE, (not yet 4G)

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

3G LTE, sometimes marketed as 4G.

≥100 Mbit/s? (peak)

E-UTRA

http://en.wikipedia.org/wiki/3GPP_Long_Term_Evolution


4G

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Speed: 100 to 1000Mbit/s in theory, 10-50mbps in most practice (verify) Latency: 50-150ms (varies with 4G variants)


The term has been so over-used in marketing, basically for anything that came after most basic 3G, that the term is almost meaningless.

It was not given a formal definition until years after it was used in marketing, at which point almost nothing qualified with what said marketing projected.

And of course marketing added 4.5G and 4.9G with fuzzy meanings. As usual.


http://en.wikipedia.org/wiki/4G

5G

https://en.wikipedia.org/wiki/5G

Android indicators

From what I can tell, the letters over the network icon:

(nothing)   Just GSM
G           GPRS     (2G)
E           EDGE     (2.5G)
3G          UMTS     (3G)    
H           HSDPA    (3.5G),   possibly also used for HSPA+?

R           Roaming?