# 2G

**2G** (Second Generation) is the **first digital generation of mobile phone technology**, launched in the 1990s. It replaced analog (1G) systems with digital standards like **GSM** (Global System for Mobile Communications).

**Key points:**

* Digital (not analog): clearer calls, less noise, better security (A5/1/A5/2 ciphering)
* Enabled SMS (text messaging) and basic data (GPRS/EDGE)
* Typical data speeds: 10–100 kbps
* Main standards: **GSM** (worldwide), **CDMA** (US/Asia)
* Still used for voice/SMS in many places, but being phased out for 4G/5G

**In short:**
2G = digital mobile, calls + SMS + basic data, tech foundation for today’s cellular networks.

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## Quick Navigation

```{toctree}
:maxdepth: 2
:caption: Menu 2G
gsm-basics.md
edge.md
osmocombb.md
a51.md
qemu-calypso.md
```