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Radio-telephone system employing a manner of changing a channel and a privacy digital code and interstoring them between a stationary apparatus and a portable apparatus by wireless and a method of changing the privacy digital code

  • US 5,201,066 A
  • Filed: 07/22/1991
  • Issued: 04/06/1993
  • Est. Priority Date: 07/25/1990
  • Status: Expired due to Term
First Claim
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1. A method of changing a privacy digital code in a radio-telephone system, the radio-telephone system employing a manner of changing a channel and a privacy digital code and interstoring them by wireless, said system having a stationary apparatus connected to a standard telephone line and portable apparatus connected by wireless to the stationary apparatus for transmission and reception of voice and data, said stationary and portable apparatus each having (+,-) charging terminals, wherein said stationary apparatus comprises:

  • base MPU means containing a first ROM for storing software for controlling the whole operation of the system and also containing a second RAM;

    charging power supply and sensing means connected between said base MPU means and said stationary apparatus (+,-) charging terminals, for supplying a charging power to said stationary apparatus (+,-) charging terminals and sensing a contact of said stationary apparatus (+,-) charging terminals with said portable apparatus (+,-) charging terminals to output an acknowledge signal in accordance with the sensed result to said base MPU means;

    first duplex radio transmitting and receiving means connected to said base MPU means, for transmitting and receiving a generic voice signal and transmitting a selected channel and privacy digital code data to said portable apparatus and receiving reception completion signal data from said portable apparatus under a control of said base MPU means;

    first transmitting and receiving PLL means connected to said base MPU means and to said first duplex radio transmitting and receiving means, for determining a plurality of transmission and reception channel frequencies in accordance with channel data from said base MPU means and removing a frequency error in a PLL manner to perform a channel locking;

    line connecting means connected among said base MPU means, said first duplex radio transmitting and receiving means and said standard telephone line, for providing intercommunication with a generic telephone network; and

    first antenna means connected to said first duplex radio transmitting and receiving means; and

    wherein said portable apparatus comprises;

    hand MPU means containing a first RAM for storing the privacy digital code given by said base MPU means in said stationary apparatus;

    second duplex radio transmitting and receiving means connected to said hand MPU means, for receiving the selected channel and the privacy digital code data transmitted from said stationary apparatus in the charging of its battery and performing the signal transmission and reception from and/or to said stationary apparatus having the same code;

    second transmitting and receiving PLL means connected to said hand MPU means and to said second duplex radio transmitting and receiving means, for determining a plurality of transmission and reception channel frequencies in accordance with channel data from said hand MPU means and removing a frequency error in a PLL manner to perform a channel locking;

    charging means connected to said portable apparatus (+,-) charging terminals, for supplying a charged power to said hand MPU means and said second duplex radio transmitting and receiving means; and

    second antenna means connected to said second duplex radio transmitting and receiving means;

    said method comprising the steps of;

    (a) setting said second RAM to zero, clearing all flags to zero, performing a privacy digital code get routine, designating an initial value and performing a charging delay for a constant time period, during the contact between said charging terminals of said stationary and portable apparatus for the charging of the battery, in said stationary apparatus; and

    performing a first RAM clear routine and designating an initial value, in said portable apparatus;

    (b) checking if the charging state is continuously maintained after the charging delay for the constant time period, in said stationary apparatus;

    (c) performing a privacy digital code transmitting program, in said stationary apparatus; and

    performing a receiving main routine, in said portable apparatus;

    (d) checking whether a preamble and a start bit are present among data received by wireless from said stationary apparatus, storing the privacy digital code in a receiving buffer if a preamble and a start bit are present among the received data from said stationary apparatus, determining if command data existing among the received data is in accord with privacy digital code change request data, performing a privacy digital code change completion data transmitting program if the command data existing among the received data is in accord with the privacy digital code change request data, comparing the privacy digital code in said receiving buffer with contents in said first RAM if the command data existing among the received data is not in accord with the privacy digital code change request data, and performing an operation according to the command data only when the privacy digital code in said receiving buffer is in accord with contents in said first RAM, in said portable apparatus; and

    (e) checking whether a preamble and a start bit are present among data received by wireless from said portable apparatus and then whether the privacy digital code change completion data has been received, and unless the privacy digital code change completion data is received, performing repeatedly a transmitting operation of the privacy digital code change request data until the privacy digital code change completion data is received, in said stationary apparatus.

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