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Remote meter reading method and apparatus

  • US 5,311,581 A
  • Filed: 11/02/1992
  • Issued: 05/10/1994
  • Est. Priority Date: 04/04/1989
  • Status: Expired due to Fees
First Claim
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1. For use in a meter reading system using a telephone line for communication of meter data, a transponder comprising:

  • detecting means for detecting a control signal on the telephone line, said control signal being comprised of a tone frequency,a microprocessor including a read/write memory,a meter pulse generating means coupled with said meter for producing an electrical meter pulse corresponding to a predetermined meter event,first coupling means for coupling the meter pulse generating means to the microprocessor,means for switching the microprocessor from a quiescent mode to an active mode in response to said meter pulse,the microprocessor being programmed to count pulses from said meter pulse generating means and for storing the pulse count in said read/write memory, and for switching the microprocessor to the quiescent mode after the pulse count is stored,a data signal generator coupled with the microprocessor,second coupling means for coupling said detecting means to said microprocessor,and means for switching the microprocessor from the quiescent to the active mode in response to said control signal which is comprised of said tone frequency, said microprocessor being programmed to determine whether said tone frequency is equal to a predetermined frequency and, if it is not, to switch said microprocessor to said quiescent mode, and if it is, to cause said data signal generator to transmit encoded data representing the pulse count stored in the read/write memory in response to a command signal and for switching the microprocessor to the quiescent mode after the encoded data signal is transmitted.

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