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Access control system having centralized/distributed control

  • US 4,839,640 A
  • Filed: 03/17/1988
  • Issued: 06/13/1989
  • Est. Priority Date: 09/24/1984
  • Status: Expired due to Fees
First Claim
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1. An access control system, comprising:

  • a plurality of remote stations;

    a central station; and

    a data bus connected to said plurality of remote stations, whereinsaid central station includes;

    means for polling said remote stations, connected to said data bus to transmit to and receive data from a selected plurality of remote stations, whereinsaid means for polling is responsive to an interrupt signal to commence transfer of data on said data bus and is responsive to a count signal providing an indication of the quantity of data to be transferred;

    means for controlling said plurality of remote stations connected to said means for polling, anda plurality of FIFO data registers connected to said means for polling and said remote stations to provide access control at said plurality of remote stations by said means for controlling, whereinone of said plurality of FIFO data registers provides said interrupt signals to said means for polling to initiate receipt of data into said means for polling, and provides said count signal.

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