DIGITAL TELEPHONE EXCHANGE COMPRISING MEANS FOR PROCESSING PACKET-SWITCHED DATA

摘要

Digital telephone exchange comprising a plurality of peripheral control domains PCD which are either connected to a digital trunk network DTN or are directly interconnected. Each domain comprises several digital subscriber interface units DSI, a group of digital subscriber sets SS being connected to each interface unit. The transmission of information over the subscriber line is effected in a b-channel for speech (64 kb/s) a b'-channel for circuit-switched data (0/8/64 kb/s) and a DELTA -channel for packet-switched data (8/16 kb/s). The subscriber line interface circuits SLIC comprise means (166) for identifying the packet-switched data signals and to apply them to a packet processing unit PPU. In this unit the packets are distinguished as firstly signalling information (s) and secondly telemetry and slow data (t+d'). The separately applied signalling information (s) and telemetry data and slow data (t+d') intended for a subscriber line are combined by the packet processing unit to form one packet-switched data signal ( DELTA ) for the subscriber line. In a data unit connected to the trunk network the signals S and (t+d') combined into messages are exchanged between the subscribers without loading the central control unit (CCU) of the telephone exchange.