> 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/gsm-channels/signalling-channels/common-control-channels.md).

# Common Control Channels

**GSM CCCHs(Common Control Channels)** are used for conveying information from network to the Mobile Subscribers(MSs) and provide access to the Mobile Subscribers. GSM CCCHs include PCH,RACH,AGCH and CBCH.

Can be used on Uplink or Downlink but only one at time