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Cellular telephone with transmission-on and radio-on timers

  • US 4,903,327 A
  • Filed: 02/03/1989
  • Issued: 02/20/1990
  • Est. Priority Date: 02/03/1989
  • Status: Expired due to Term
First Claim
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1. Timing apparatus for a radio switchably coupled to a battery and including a radio frequency (RF) signal transmitter, comprising:

  • means for repetitively generating an interrupt signal at a predetermined rate;

    volatile memory means;

    non-volatile memory means;

    processing means coupled to the RF signal transmitter for generating a transmitter key signal to turn the RF signal transmitter on, and coupled to the battery for sensing when the battery is switched to and from the radio;

    when said battery is switched to the radio, said processing means responsive to the interrupt signal for incrementing and storing an interrupt timer in said volatile memory means, incrementing and storing a radio-on timer in said volatile memory means, and incrementing and storing a transmission-on timer in said volatile memory means when the transmitter key signal is generated; and

    when the battery is switched from the radio, said processing means reading out from the volatile memory means the radio-on timer and transmission-on timer, reading out from the non-volatile memory means a previously stored radio-on timer and transmission-on timer, adding the radio-on timer and transmission-on timer read out from the volatile memory means to the previously stored radio-on timer and transmission-on timer, respectively, read out from the non-volatile memory means, and storing the summed radio-on timer and transmission-on timer in said non-volatile memory means.

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