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Redundant security system

  • US 8,456,305 B2
  • Filed: 02/02/2007
  • Issued: 06/04/2013
  • Est. Priority Date: 11/22/2005
  • Status: Active Grant
First Claim
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1. A redundant security sensor, comprising:

  • a photoelectric cell;

    a security switch;

    a passive identification tag to transmit a binary value modified according to a condition of said security switch; and

    a processor to monitor for a passive identification tag radio frequency field from a remote passive identification tag reader, and if said passive identification tag radio frequency field is not detected, to trigger a backup wireless transmitter, distinct from said passive identification tag, to wirelessly transmit said stored binary value with power generated from said photoelectric cell.

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