Non-circuit related signalling

Telecommunication services have evolved from basic telephony to services like freephone, televoting and mobile telephony. Hand in hand the networks have evolved to become digital with stored program control switches and some with centralised intelligence (for example ISDN, intelligent network and GSM network). To support these services and network architectures, Common Channel Signalling systems were developed. The first Common Channel Signalling system defined by CCITT was C6. It was developed for international networks but it can also be used for national networks. It provided a more efficient signalling system for supporting telephony in a processor controlled environment. However, it is the development and continued evolution of C7 that has made it possible to support advanced services on modern networks. The paper considers non-circuit-related (NCR) signalling aspects of C7