SACCH stands for Slow associated control channel GSM.
It is related to the traffic channel or SDCCH.
On the forward link, it is used to send regularly changing information like:
- Transmit power channel
- Broadcast messages
- Specific timing advance instruction for each user
On the reverse link, it carries information about
- Received signal strength
- Quality of TCH and BCH
- Measurement results from neighboring cells
- It is used to inform the base of power measurements made by the mobile of signal strength in the adjacent cells
- It is transmitted during the total 13th frame of every dedicated control channel multi-frame
- SACCH exchanges control information between the base station and mobile station a call or call set up