Transmission of alarm information over telephone lines

摘要

Apparatus for re-routing alarm information in a system in which the alarm information is transmitted from a subscriber's premises via a local processor and a central processor to one of a number of terminal stations. The apparatus includes a monitoring unit 59 for monitoring the condition of the transmission link between the central processor and each terminal station. If the unit 59 senses a fault on a transmission link it causes the alarm information which should have been transmitted over that link to its designated terminal to be redirected to another terminal station.