Associated Control Channel(ACCH) is the GSM signalling channels associated with a user’s traffic channel or dedicated signalling channel. Two ACCH are defined for GSM Circuit Switched operation. These are SACCH (Slow Associated Control Channel) and FACCH (Fast Associated Control Channel). In GPRS packet operation, an ACCH is allocated in conjunction with a PDTCH (Packet Data Traffic Channel) and is termed as PACCH (Packet Associated Control Channel).