Wireless alarm transmission for building monitoring

摘要

The disturbance, recorded by the report units, or a manual control transmitter generate signals, transmitted by a radio to a central office triggering an alarm. The control part, energising a trigger unit, consists of several transmitters and receivers. Different frequencies are allocated to pairs of transmitters and receivers, which are simultaneously transmitted and evaluated. Alternatively a pair of a transmitter and receiver handle simultaneously several frequencies. The signals arriving into the central office are pref. evaluated such that a strange radio recognition on one frequency does not trigger a sabotage alarm.