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Central station alarm reporting system

  • US 4,342,986 A
  • Filed: 05/07/1980
  • Issued: 08/03/1982
  • Est. Priority Date: 05/07/1980
  • Status: Expired due to Term
First Claim
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1. In a central station alarm reporting system having a central station connected to at least one remote premises unit over a communication channel, said remote premises unit having means for providing at least two high frequency signals and at least two low frequency signals and having transmitting means for transmitting at least two bits of parallel digital information in a single transmission, said single transmission comprised of at least one of said low frequency signals and at least one of said highfrequency signals, said at least two low frequency signals, said at least two low frequency signals and said at least two high frequency signals having at least four combinations for single transmissions, said central station comprising:

  • receiving means for receiving said transmission from said remote premises unit; and

    ,decoding means having an input connected to said receiving means and having at least two output lines for providing at least a two bit digital word capable of completely describing the at least four combinations of said at least two low and at least two high frequency signals.

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