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Emergency telephone with automatic low-battery signaling

  • US 5,726,636 A
  • Filed: 12/05/1996
  • Issued: 03/10/1998
  • Est. Priority Date: 12/05/1996
  • Status: Expired due to Term
First Claim
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1. A wireless communication device operable in a plurality of states including a powered-off state and a battery test state, comprising:

  • a battery having a charge level for supplying electrical power to the device;

    a timer counter coupled to the battery and operable in the powered-off state for causing the device to enter the battery test state when a predetermined period of time has elapsed with the device in the powered-off state, and said counter controls a switch to apply power from the battery to a battery charge level monitoring circuit and to a processor during the battery test state;

    the battery charge level monitoring circuit switchably coupled to the battery for generating a battery charge level signal proportional to the battery charge level during the battery test state;

    the processor is switchably coupled to the battery charge level monitoring circuit for sensing the battery charge level signal during the battery test state, and generating an alarm signal if the battery charge level is below a predetermined level, andwherein generation of the alarm signal includes powering a communication circuit in the device to establish an automatic wireless communication to a preselected telephone number to transmit a low battery charge warning.

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