Patent ID: 7769383

Claim:
A method for utilizing supplementary services in a mobile communications device capable of communicating over one or more access networks, comprising: establishing a call in a cellular domain having an anchor in a voice call continuity server in an IMS (Internet Protocol Multimedia Subsystem) domain, wherein the call further comprises a call path between a public switched telephone network and the mobile communications device through a media gateway and the cellular domain; exchanging signaling via the cellular domain with a call session control function in the IMS domain, wherein the signaling comprises an indication of a state of a supplementary service; wherein the exchanging further comprises: determining an appropriate dual-tone multi-frequency (DTMF) code that relates to utilizing the supplementary service from a set of DTMF codes outside of call control signaling codes used by the cellular domain for handling calls, wherein the appropriate DTMF code is interpreted by the cellular domain as an end-user application signaling code and is interpreted by the call session control function in the IMS domain as a supplemental service signaling code; and sending the appropriate DTMF code to indicate the state of the supplementary service transparently through the cellular domain to the call session control function in the IMS domain.