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Multi-hazard alarm system using selectable power-level transmission and localization

  • US 5,461,365 A
  • Filed: 10/27/1994
  • Issued: 10/24/1995
  • Est. Priority Date: 10/27/1994
  • Status: Expired due to Term
First Claim
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1. A personal alarm system, comprising:

  • a remote unit including radio transmitting means and radio receiving means;

    the remote unit transmitting means being able to transmit at more than one power level and defining a higher power level;

    a base station including radio transmitting means and radio receiving means;

    the remote unit and the base station being in radio communication and defining a separation distance between the remote unit and the base station;

    measuring means for determining whether the separation distance exceeds a predetermined limit;

    means responsive to the measuring means for causing the remote unit transmitting means to transmit at the higher power level when the separation distance exceeds the limit; and

    alarm means for indicating when the separation distance exceeds the limit.

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