ALARM CIRCUIT INTERFACE UNIT

摘要

ALARM CIRCUIT INTERFACE UNITS Bidirectional communications between an alarm loop, comprising one or more alarm transmitters, and a remote receiver is provided through a digital transmission facility by a pair of interface units. Each interface unit, disposed at an end of the digital transmission facilities, provides encoding and decoding of signals to and from the alarm receiver. For greater reliability, each interface unit can be adapted to select signals received from different digital transmission facilities.