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SECURITY SYSTEM

  • US 3,761,683 A
  • Filed: 11/08/1971
  • Issued: 09/25/1973
  • Est. Priority Date: 11/08/1971
  • Status: Expired due to Term
First Claim
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1. A key system comprising a dielectric card, a plurality of optical tracks embossed on one face of said card, said tracks being individually coded for digital readout, at least one magnetic track embossed on said one face of said card, said magnetic track being coded for digital readout, a receptacle having a slot therein for receipt of said card, a plurality of optical reading means in said receptacle equal in number to said optical tracks, said optical devices arranged so as to produce outputs indicative of said optical tracks as said card is inserted in said slot, a magnetic reading means in said receptacle arranged so as to produce pulse outputs indicative of said magnetic track, a memory storage device, means for comparing the output of said optical and magnetic reading means with the data in said storage device, means for actuating at least one device in response to said comparison, magnetic write head means in said Receptacle arranged so as to change the code on said magnetic track when said card is removed from slot, and random number generating means coupled to said magnetic write head and said memory storage device for supplying said changed code.

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