Logical Channels in GSM

Broadcast Control Channel (BCCH): downlink only, used to broadcast Cell specific information, Usually Frequency used
Synchronisation Channel (SCH): downlink only, used to broadcast synchronisation and BSS identification information(BSIC decoding)
Paging Channel (PCH): downlink only, used to send page requests to Mobile Stations
Random Access Channel (RACH): uplink only, used to request a Dedicated Control Channel;
Access Grant Channel (AGCH): downlink only, used to allocate a Dedicated Control Channel;
Stand Alone Dedicated Control Channel (SDCCH): bidirectional, mainly used in Call setup procedures and Short Messaging services procedures.
Fast Associated Control Channel (FACCH): bidirectional, associated with a Traffic Channel, Mainly use for Fast decison making procedures like Handovers
Slow Associated Control Channel (SACCH): bidirectional, associated with a SDCCH or a Traffic Channel
Cell Broadcast Channel (CBCH): downlink only used for general (not point to point) short message information.