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Keyless access control device

  • US 5,723,911 A
  • Filed: 03/17/1995
  • Issued: 03/03/1998
  • Est. Priority Date: 03/17/1994
  • Status: Expired due to Term
First Claim
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1. A device for controlling keyless access to a motor vehicle, comprising:

  • a transceiver to be carried by a user;

    tripping means;

    a transmitting unit disposed in a motor vehicle and being associated with said tripping means for broadcasting a challenge code signal when said tripping means are actuated;

    a distance detecting device for measuring a distance between said transceiver and the motor vehicle, said distance detecting device outputting a detecting signal independent of the challenge code signal and outputting a distance signal;

    said transceiver having a receiver for receiving the challenge code signal, and said transceiver having a transmitter for broadcasting a response code signal only whenever the distance signal states that the motor vehicle is located in the immediate vicinity of said transceiver;

    an unlocking unit; and

    a receiving unit disposed in the motor vehicle for receiving the response code signal from said transceiver and furnishing an unlocking signal to said unlocking unit if the response code signal matches a predetermined code signal.

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