Central signalling of faults in communication service station - uses signalling unit with address generator which cyclically calls all transmitter addresses

摘要

Transmitters send messages to at least one signalling unit common to a group of transmitters, which have address comparators controlling switches, and the signalling unit (3) has a message interrogating device and a device for state comparison. The unit address signal generator automatically cyclically calls the addresses of transmitters, and is connected to the address comparators with corresponding address source. The state comparator is connected through at leastr one common wire to the transmitter switches.