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Microcomputer controlled combination lock security system

  • US RE33,873 E
  • Filed: 07/03/1990
  • Issued: 04/07/1992
  • Est. Priority Date: 02/27/1986
  • Status: Expired due to Term
First Claim
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1. A security system for restricting access to a secure area to authorized persons, comprising, in combination:

  • (a) a microcomputer containing a first, selectively programmable read-only memory;

    (b) a key device having mounted thereon a second, selectively programmable read-only memory;

    (c) each of said first and second memories containing corresponding pluralities of corresponding, multi-digit, combination codes arranged in corresponding sequences;

    (d) key reader means connected to said microcomputer and having a receptacle for receiving therein a portion of said key device to establish electrical connections between said key device and said microcomputer;

    (e) means governed by said microcomputer for transferring data from said key device to said microcomputer;

    (f) a controlled access device governing physical access to said secure area; and

    (g) circuit means connecting said microcomputer and said access device, said microcomputer being effective to compare said multi-digit combination codes, one complete code at a time, and to compare said code sequences stored in said first and second memories and to control said circuit means to enable said access device when and only when such comparison shows equality of said multi-digit combination codes and their sequence.

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