Integrated messaging services in an ISDN PBX network

This paper describes a set of advanced messaging features, all integrated into a comprehensive messaging service on the PBX. It then proposes functional application of these services across PBX networks. ISDN D-channel signaling is used as the vehicle for inter-PBX communication. Thus, if PBXs support standard messaging functions, and if they interconnect with standard interfaces using standard signaling protocols, then enhanced messaging services can be offered in multivendor PBX networks