Patent ID: 6967972

Claim:
A method of operating a telecommunications service for a telecommunications network comprising a first telephone set, a private branch exchange (PBX), a protocol conversion engine, a switch in a voice network, and a second telephone set, the method comprising the steps of: receiving a plurality of dialed digits from the first telephone set at the PBX; receiving, at the protocol conversion engine, a first call initiation message formatted according to a first protocol used by the PBX, wherein the first protocol is different from a second protocol used by the switch; instantiating, in the protocol conversion engine, a call instance for a call from the first telephone set to the second telephone set, wherein the call instance comprises: an originating call control configured for converting the first protocol to a generic internal protocol that is different from the first protocol and the second protocol; a universal call model coupled to the originating call control; a terminating call control coupled to the universal call model and configured for converting the generic internal protocol to the second protocol; and call context data coupled to the originating call control, universal call model and terminating call control; converting, using the originating call control, universal call model, terminating call control, and call context data, the first call initiation message into a second call initiation message that conforms to the second protocol, by inter-working the first call initiation message according to one or more inter-working rules; and communicating the second call initiation message to the switch, to result in setting up the call.