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Automatic real-time highway toll collection from moving vehicles

  • US 5,485,520 A
  • Filed: 10/07/1993
  • Issued: 01/16/1996
  • Est. Priority Date: 10/07/1993
  • Status: Expired due to Term
First Claim
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1. An in-vehicle unit for use in an automatic highway toll collection system, said in-vehicle unit comprising:

  • an rf antenna having a radiation pattern disposed in proximity to an associated vehicle for communicating with a roadside collection station while moving therepast;

    rf circuits connected to said antenna for operating in either a first mode wherein a data uplink is established with a roadside collection station by modulating the reflectivity of said antenna or a second mode wherein a data downlink is established with a roadside collection station by demodulating received rf signals;

    a smart card controller connected with a smart card; and

    a link controller connected to said rf circuits and to said smart card controller and including circuits for causing operation in said first mode to repetitively transmit first data to a roadside collection station and in said second mode to receive second data, based at least in part on said first data, whereupon operation is switched back to said first mode for transmission of third data based at least in part on said second data, said first and third data together collectively comprising an encrypted electronic money transfer.

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