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Pager operated control unit

  • US 5,798,707 A
  • Filed: 12/12/1995
  • Issued: 08/25/1998
  • Est. Priority Date: 03/16/1994
  • Status: Expired due to Fees
First Claim
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1. A pager operated control circuit for use with a pager receiver generating bursts of pulses of a first type and bursts of pulses of a second type and comprising power terminals for connection to a power supply, the control circuit comprising:

  • an input terminal connectable to a power terminal of the pager receiver;

    a detector circuit responsive to current flow in the pager receiver to generate a first detector output signal when pulses of the first type are generated by the pager receiver and to generate a second detector output signal when pulses of the second type are generated by the pager receiver; and

    a two state output device responsive to the first and second detector output signals to selectively assume first and second output states;

    the detector comprising first and second capacitors and a charge control circuit for alternately charging the first and second capacitors in response to sequentially occurring pulses of a burst of pulses generated by the pager receiver and output circuitry responsive to electrical charge on the capacitors to generate the detector output signals;

    the charge control circuit comprising an input circuit connected to the input terminal and responsive to a current flow in the pager receiver of a magnitude greater than a predetermined magnitude, indicative of the generation of pulses by the pager receiver, to generate an input control signal and circuitry responsive to the input control signal to alternately charge the first and second capacitors;

    the charge control circuit further comprising a flip-flop circuit having an input terminal connected to the input circuit and first and second output terminals and wherein the charge control circuit further comprises a first gating circuit connected to the input circuit and to the first flip-flop output terminal and a second gating circuit connected to the input circuit and to the second flip-flop output terminal, the first and second gating circuits responsive to the input control signal and the state of the flip-flop to alternately charge the first and second capacitors, respectively.

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