channel associated signalling (ATM) (CAS)
Channel Associated Signaling(CAS) is an inner-band signaling technique. In this technique, the voice signal and the signaling signal are transmitted on the same network infrastructure.
Channel Associated Signaling uses a type of circuit state representation where the state is indicated by one or more bits that are repeatedly transmitted.
As an alternative to Channel Associated Signalling, there is Common Channel Signalling( CCS) where the signaling data is transmitted separately from the user data.