Monitoring of code signals transmission from telephone channels - testing wire groups and channels and signalling results to central part during TDM transmission

摘要

The channels to be monitored cylically follow each other and connect a central part with code signal converters individually allocated to the channels in a signal converter unit. The latter is provided in a TDM transmission system between an interface at the exchange side and a multiplex unit. A test is made for break of wires in a wire bunch for code signal transmission from the central part to the channel signal converters. The test is made during transmission by one of the telephone channels. The channels are tested when signals are transmitted from the central part to the channel converters. The test result is signalled back to the central part. Faulty transmission on the loop between the peripheral and central components of a code converter caused by earthing or faulty switch contacts is thus detected.