> For the complete documentation index, see [llms.txt](https://gsm.learn-telecom.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gsm.learn-telecom.com/system-information-messages/system-information-2-si2.md).

# System information-2(SI2)

![](/files/dpOX7zuU1EP3UJZnVw4H)

#### System Information-2 (SI2)

**System Information-2 (SI2)** is a critical broadcast message used in cellular networks. It contains essential configuration details, such as:

* Access parameters for the Random Access Channel (RACH)
* Information on the broadcast control channel (BCCH)
* Timing Advance (TA) details

This information helps devices establish and maintain communication with the network efficiently.

![](/files/h2OrSXT8HV9PlFEyDx6r)