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Access control system

  • US 4,148,012 A
  • Filed: 09/26/1975
  • Issued: 04/03/1979
  • Est. Priority Date: 09/26/1975
  • Status: Expired due to Term
First Claim
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1. An access control system responsive to an access signal comprising:

  • a central processing unit, at least one card reader terminal, said card reader terminal comprising at least one first signal generating means for transmitting a first signal responsive to the presence of a proper first code on a card key;

    said first signal enabling at least one reading means for reading and transmitting to said CPU a second signal, said second signal corresponding to a second code on said card key, said CPU having access signal transmitting means for transmitting an access signal responsive to receipt by said CPU of said second signal.

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