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Bidirectional, interactive fire detection system

  • US 4,470,047 A
  • Filed: 02/04/1982
  • Issued: 09/04/1984
  • Est. Priority Date: 02/04/1982
  • Status: Expired due to Term
First Claim
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1. A bidirectional, interactive communication system, comprising a controller connected to transmit a series of signal groups sequentially over a pair of electrical conductors, wherein each signal group includes a plurality of pulses, and a plurality of transponders coupled to said conductors, at least one of said transponders having means for replying to the controller by selectively modifying a portion of at least one pulse transmitted by the controller and thus encoding information on said one pulse, which reply is terminated by the controller with an overriding simultaneous transmission,wherein the controller includes means for sampling the pulse modified by the replying transponder at regular intervals to decode the information encoded on said modified pulse, and for providing an answer signal denoting said information.

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