Communications system for analogue telephone instruments

摘要

Communications system for analogue telephone instruments. Its purpose is to enable analogue telephone instruments to communicate with each other and to be connected to a pulse-code modulation (PCM) communications system, to which end it features a transceiver 1 which is connected to the PCM communications system and to a switching and signalling matrix 2 in order to set up the switching indicated by the transceiver 1. It further features a user interface 3 which is connected to the switching and signalling matrix 2 and to the analogue telephone instruments in order to match the various signals, and it also features a ringing-current generator 4 which is connected to the user interface 3 and serves to supply the ringing signal to the analogue telephone instruments. This is done to enable the analogue telephone instruments to communicate with each other and with any channel of the PCM system. <IMAGE>