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Communication system and apparatus

  • US 5,301,353 A
  • Filed: 07/29/1993
  • Issued: 04/05/1994
  • Est. Priority Date: 02/12/1990
  • Status: Expired due to Fees
First Claim
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1. A communication system comprising:

  • a first communication device comprising;

    first transceiver means for transmitting and receiving signals on a first communication medium selected from the group consisting of infrared waves, electromagnetic waves, ultrasonic waves, and radiation waves, when the first communication device is in an on-site area, the on-site area including a plurality of areas;

    second transceiver means for transmitting and receiving signals on a radio frequency communication medium, when the first communication device is in an off-site area; and

    determining means for determining when the first communication device is in the on-site area and when the first communication device is in the off-site area, the determining means being coupled to the first and second transceiver means; and

    network controller means comprising;

    means for determining if the first communication device is located in the on-site area; and

    alerting means responsive to the determining means of the network controller for providing an alert if the first communication device has not reached a select one of the plurality of areas in the on-site area.

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