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Multiple sensor intrusion detection system

  • US 4,321,592 A
  • Filed: 05/30/1978
  • Issued: 03/23/1982
  • Est. Priority Date: 05/30/1978
  • Status: Expired due to Term
First Claim
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1. An intrusion detection system comprising:

  • a control unit coupled to a multi-conductor cable extending along a predetermined path in a facility to be protected;

    a mode selector coupled to said control unit and providing mode control signals which are at respective signal levels corresponding to selected display modes of sensor indicators for control of the operating display mode of the sensor indicators;

    one or more intrusion sensors associated with the sensor indicators and connected to said cable and operative to provide an alarm signal upon intrusion detection;

    alarm means coupled to said control unit and operative to denote an alarm condition detected by one or more of said intrusion sensors;

    for each of said sensors, an interface circuit coupling its sensor to said cable and operative in response to the mode control signals received on one line of said cable from said control unit to determine the display mode of the sensor indicator, and operative in response to alarm signals from said sensor to convey an alarm signal on the same line of said cable to said control unit for actuation of said alarm means irrespective of the selected display mode of the sensor indicator specified by the mode control signals.

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