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Dial inbound meter interface unit (MIU) for automatic meter reading using no subscriber line access controller

  • US 5,134,650 A
  • Filed: 01/22/1991
  • Issued: 07/28/1992
  • Est. Priority Date: 01/22/1991
  • Status: Expired due to Term
First Claim
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1. A method of providing a meter interface unit (MIU) which may be called from a central station without any special equipment in the telephone central office, said method comprising the steps of:

  • (a) monitoring a telephone line until a ring signal is detected;

    (b) waiting until the telephone stops ringing;

    (c) determining whether the telephone is on-hook or off-hook when the telephone stops ringing;

    (d) waiting until the telephone has been hung up if it was off-hook in step (c);

    (e) detecting that the phone line has been hung up;

    (f) seizing the phone line to prevent a disconnect from taking place;

    (g) waiting a predetermined period of time for a signal indicative of an attempt to communicate with the MIU; and

    (h) connecting the MIU to the central computer if a signal indicative of an attempt to communicate with the MIU is present within said predetermined period of time, and releasing the telephone line if said signal is not present within said predetermined period of time.

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