Monitoring method for stand-by circuits suitable for a multiplexing/demultiplexing apparatus

摘要

In a multiplexing/demultiplexing apparatus, readiness of stand-by circuits is monitored through a variety of switching arrangements, by routing a monitoring signal through the circuits. In one alternative embodiment, level correcting means are provided so that the monitoring signal is kept at the proper level, thus ensuring accurate monitoring of the stand-by circuits.