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Cellular telephone usage monitoring system

  • US 5,233,642 A
  • Filed: 08/27/1991
  • Issued: 08/03/1993
  • Est. Priority Date: 05/24/1991
  • Status: Expired due to Fees
First Claim
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1. A usage monitoring system for a cellular transceiver having an adaptor which provides a simulated telephone line for connection to a conventional telephone device, comprising:

  • a mobile unit having;

    a voltage detector which detects the voltage on the simulated telephone line and generates a voltage level signal;

    a dual-tone multi-frequency (DTMF) detector which detects dialed DTMF digits on the simulated telephone line and generates a dialed digit signal for each dialed DTMF digit;

    a real-time clock generating a clock signal;

    a memory;

    a microprocessor having a program and being coupled to the simulated telephone line, said microprocessor also being coupled to said clock and said memory, said microprocessor receiving said voltage level signal from said voltage detector and detecting changes in the voltage on the simulated telephone line to determine on-hook, off-hook and ringing conditions of the simulated telephone line, said microprocessor further receiving said dialed digit signals from said DTMF detector and storing dialed DTMF digits in said memory, said microprocessor reading said real-time clock at transitions between said on-hook and off--hook conditions and storing information based on said clock signal indicative of usage of the telephone device in said memory; and

    a stationary unit having;

    a computer with a memory and an evaluation program, said evaluation program being operative to evaluate said information indicative of usage of the telephone device and said dialed DTMF digits; and

    a communications interface which transfers said information indicative of usage of the telephone device and said dialed DTMF digits from said memory in said mobile unit to said stationary unit for evaluation by said computer and said evaluation program.

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