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Door security system

  • US 5,923,249 A
  • Filed: 07/11/1997
  • Issued: 07/13/1999
  • Est. Priority Date: 01/11/1995
  • Status: Expired due to Term
First Claim
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1. A security system for monitoring door openings, the system including one or more door open detection devices, and first and second monitoring systems each connected to each of the one or more detection devices the second monitoring system being arranged with battery power supply means and the first monitoring system being arranged to allow the second monitoring system to continue operating when power to the first monitoring system is interrupted.

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