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Cellular alarm backup system

  • US 4,887,290 A
  • Filed: 08/05/1987
  • Issued: 12/12/1989
  • Est. Priority Date: 08/05/1987
  • Status: Expired due to Fees
First Claim
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1. In a security alarm system comprising alarm detection means for generating an output signal indicative of an alarm condition, means responsive to said output signal for generating a telephone call to a central security station, said means responsive to said output signal being coupled to a line of a land-based telephone system for making a telephone call in response to the input therein of said output signals, and means coupling said means responsive to said output signal to the telephone land-based system, wherein the improvement comprises:

  • a backup cellular transmission system for alternatively sending an alarm call from said means responsive to said output signal via a cellular telephone system, said backup cellular system comprising a cellular transceiver, a cellular interface means coupled to said cellular transceiver, and a first switch means coupled between said means responsive to said output signal and said cellular interface and said means coupling said means responsive to said output signal to the telephone land-based system; and

    line fault detection means for detecting the inoperativeness of the telephone land-based system, said line fault detection means being coupled to said first switch means for controlling the state thereof to thereby automatically cause said first switch means to switch over from said telephone land-based system to the cellular system in response to said line fault detection mean'"'"'s detection of a line fault on the land line system; and

    a telephone set coupled to said first switch means for making a call over said cellular backup system when said means responsive to said output signal is not activated and when said line fault detection means is activated in response to the loss of the telephone land-based system.

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