Patent ID: 8462767

Claim:
An Internet Protocol compliant private branch electronic exchange which conducts switching control of terminals, the terminals including Internet Protocol compliant phones connecting to the Internet, an intranet, or a Local Area Network (LAN), and an Internet Protocol terminal adapter accommodating terminals not compliant with Internet Protocol and attaching Internet Protocol to the non-compliant terminals, the private branch electronic exchange comprising: a call control data master table provided on a multimedia gateway controller, the multimedia gateway controller performing call-control-processing tasks and retaining call control data for controlled terminals; a plurality of terminal interfaces connected to one of a system bus and an expansion system bus of said multimedia gateway controller; call control data slave tables provided respectively on each of said plurality of terminal interfaces, each slave table having a copy of a portion of said call control data master table, a failed terminal interface being one of the plurality of terminal interfaces that has failed to perform procedures for call control for corresponding controlled terminals; and a unit for copying the call control data for the corresponding controlled terminals of the failed terminal interface from said call control data master table to the call control data slave table on another terminal interface; each of said terminal interfaces includes a function of converting a call control protocol applied within the system of said multimedia gateway controller into a call control protocol for communication with a terminal connecting to said LAN, and vice versa, for call procedures between said multimedia gateway controller and the terminal connecting to said LAN; a function of transferring a call control protocol between said multimedia gateway controller and the controlled terminals; functions of performing fault supervision, processing, and retransmission, and a function of supervising the controlled terminals; and an upper limit to the number of terminals that can be controlled by each of said terminal interfaces can be set individually.