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Apparatus for monitoring and signalling system

  • US 4,303,801 A
  • Filed: 11/14/1979
  • Issued: 12/01/1981
  • Est. Priority Date: 11/14/1979
  • Status: Expired due to Term
First Claim
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1. In a monitoring and signalling system, apparatus comprising:

  • first and second apparatus at first and second locations, respectively, and interconnected by a transmission medium for allowing bidirectional communication between the first and second apparatus;

    said first apparatus at the first location comprising;

    first means operative under prescribed circumstances to produce an alarm condition;

    second means operative following an alarm condition produced by the first means to produce a first sensible alarm indication for a predetermined first interval of time;

    third means operative following the predetermined first interval of time to initiate communication with the second apparatus at the second location over the transmission medium;

    fourth means operative for the duration that the third means communicates with the second apparatus to produce a second sensible alarm indication distinguishable from the first sensible alarm indication and indicating that the third means is communicating with the second apparatus; and

    fifth means operative at the conclusion of the communication with the second apparatus to terminate the second sensible alarm indication produced by the fourth means thereby to provide a period of silence following the second sensible alarm indication indicating that the communication was received by the second apparatus; and

    said second apparatus at the second location comprising;

    sixth means operative under operator control to communicate with the first apparatus over the transmission medium to provide an additional sensible indication at the first apparatus following the period of silence for indicating that the communication to the second apparatus was received by the second apparatus.

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