Signalling system No. 7 (CCS7) is a central channel sign alling system in digital networks and was defined primarily for ISDN. This signalling system is not bound to the transmission channels of the user information.
Central channel signalling differs from channel-bound signalling methods in that the control information is transmitted separately from the 64 kbit/s user channels in special "central" 64 kbit/s signalling channels shared by many user channels.kbit/stransmission rate, but can also be used with other speeds.
The CCS7 is an ANSI standard as SS7 and a CCITT standard as SS7.