Telephone exchange interconnection system using signalling protocol(s) from subscribers appts. - coordinated by super-signalling for dynamic acceptance of links between subscribers and PABX

摘要

A packet-switched data link (B-channel connection) is established via a public ISDN between a terminal (E1 or E2) and a selected virtual intelligent supersignalling exchange sited logically or physically in the PABX, and a branch exchange signalling protocol is established and initiated. Similar or different protocols may be implemented either in parallel or in succession, whereby either exchange site can be reached via one of these protocols set up by the terminal concerned. ADVANTAGE - Any terminal can act as a branch exchange for a distant installation and can take over functions of its central exchange enabling a subscriber of one PABX to dial subscriber of another PABX directly.