Coupling network for time-division telecommunication system

Abstract

A coupling network at the junction of several multichannel TDM/PCM links comprises a pair of switching networks each including a set of input group units receiving incoming messages from respective PCM links, a set of output group units transmitting outgoing messages to respective PCM links, and a switching matrix interconnecting the two sets of group units. The bits of a code word representing an incoming message sample, arriving at a line unit individually associated with the respective PCM channel, are delivered to the corresponding input group unit during a receiving period, are read out during a transfer interval via the switching matrix to the output group unit for which they are intended, and are thence fed to the proper line unit during a transmitting period. The two switching networks are identical and have their input and output group units connected to all the line units; a processor, controlling the establishment of interchannel connections through the switching matrix of either of these networks, designates one of them as a master and the other as a slave for standby purposes. A coordinating unit, connected to the output group units of both switching networks (or of corresponding subdivisions thereof), checks on the correlation of their operations and transmits error signals to the processor in the absence of such correlation; this coordinating unit also controls, in response to instructions from the processor, possible changeover from one switching network to the other in the event of a malfunction.