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Method of transmission of information or measurement data and device for using the method

  • US 4,864,603 A
  • Filed: 09/16/1987
  • Issued: 09/05/1989
  • Est. Priority Date: 09/16/1986
  • Status: Expired due to Fees
First Claim
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1. A method of transmission of information or measuring data from a local measuring device, located at a telephone subscriber'"'"'s local station at a remote site, to a central interrogation station located at a central site where the data is processed, using a telephone line of a telephone network to which said subscriber subscribes while permitting the normal use of the subscriber'"'"'s telephone line, wherein the subscriber'"'"'s ringer is normally maintained inoperative, comprising the following steps:

  • maintaining the ringer inoperative;

    sending, during a first period of time, a first call from the central station to the local station over the telephone line, said period of time being at least equal to the time necessary for the central station to be able to verify that the line is not busy by receiving a ringing signal;

    sending a second call from the central station to the local station for a different period of time;

    establishing telephone contact with the local station;

    verification by the local station of the absence or presence of a carrier of a modem coming from the central interrogation station;

    executing a transmission procedure;

    reconnecting the subscriber'"'"'s ringer only during reception by the local station of a first call lasting a period of time greater than the first period of time, said reconnecting making the local station available for incoming calls from third parties; and

    rendering inoperative the ringer of the subscriber'"'"'s line at the end of such a call from a third party.

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