Patent ID: 7843932

Claim:
A method of communicating in an asynchronous transfer mode distributed virtual tandem switching system, comprising: establishing at least one closed user group of communications equipment having authorized members, at an asynchronous transfer mode element management system that controls access to an asynchronous transfer mode switching network, wherein the authorized members of the closed user group comprise trunk interworking function components and at least one centralized control and signaling interworking function controller, and wherein the authorized members of the closed user group are restricted to communicating solely with other authorized members of the closed user group when communicating to each other via the asynchronous transfer mode switching network; receiving, at the centralized control and signaling interworking function controller in the asynchronous transfer mode switching network, narrowband signaling from a transfer node for a call originating at an end office; converting the received narrowband signaling to broadband signaling; and providing the broadband signaling to a plurality of trunk interworking function converters via the asynchronous transfer mode switching network, to establish a connection across the asynchronous transfer mode switching network, when the centralized control and signaling interworking function controller and the plurality of trunk interworking function converters are determined to be authorized members of a same closed user group, by the asynchronous transfer mode element management system.