Communication waiting service using IP multimedia core network subsystem; Conformance testing – Part 1: Network side; and user side; Protocol implementation conformance statement (Study Group 11)
"The present Recommendation provides the protocol implementation conformance statement (PICS) of the communication waiting (CW) service@ based on stage three of the IMS simulation services specified in the protocol specification as specified in [ITU-T Q.3622 v.1] ""Communication waiting using IP multimedia core network subsystem ?C Protocol specification""."