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ALARM TRANSMISSION LINE SECURITY SYSTEM UTILIZING PSEUDO RANDOM ENCODING

  • US 3,735,353 A
  • Filed: 10/28/1971
  • Issued: 05/22/1973
  • Est. Priority Date: 10/28/1971
  • Status: Expired due to Term
First Claim
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1. In a security system including a transmission line carrying alarm information from at least one protected area to a central monitoring area that is remote froM the protected area, means at said protected area for generating a monitor code comprising a selected sequence of code bits for transmission over the transmission line from said one protected area to the central monitoring area, means for modifying the code bits provided by said generating means to indicate an alarm, means at said central monitoring area for generating a reference code comprised of a selected sequence of code bits that is identical to the monitor code sequence, means for comparing the monitor code with the reference code, and means for providing an alarm indication whenever the codes are different.

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