A modular PCM switching network with automatic routing and virtual channels to control the route selection for distributed-control telephone exchanges

摘要

The PCM switching network is based on the use of switching units (UC1a ... UC8c) each equipped with a local controller using a microprocessor (CTR1a ... CTR8c), ancillary circuits for diagnosis (CDTE1 ... CDTU5), ancillary circuits for exchanging messages relating to network control between the local controllers (CRT1a ... CTR8c) and between local controllers and the distributed telephone control units (CTFa ... CTFc), and ancillary circuits (RTBE1 ... RTBU5) providing virtual channels (on the speech channels themselves) for transmission of said messages in a direction opposite to that of speech. …??Said switching units (UC1a ... UCBc) make it possible to provide self-routing modular PCM switching network structures for distributed-control telephone exchanges.