Frequency responsive apparatus for reading a meter over a telephone line

• US 4,674,113 A
• Filed: 09/28/1984
• Issued: 06/16/1987
• Est. Priority Date: 09/28/1984
• Status: Expired due to Term

• Current Assignee: Neptune Technology Group Incorporated (Roper Technologies, Inc.)
• Original Assignee: Neptune Water Meter Company
• Inventors: Cottle, Charles A., Brennan, William J. Jr.
• Primary Examiner(s): Dwyer, James L.
• Application Number:
  US06/655,712
• Time in Patent Office: 991 Days
• Field of Search: 179/2 A, 179/2 AM, 179/5 R, 179/5 P, 179/6.3 R, 179/2 DP, 340/825.59
• US Class Current: 379/106.07
• CPC Class Codes: H04M 11/002 with telemetering systems telemetering in general G08C

Abstract

There is disclosed a system for reading a meter, e.g., a utility meter, over a telephone line. The system includes circuitry for detecting when an input signal within a predetermined frequency range is present. The input signal is fed to two timing devices. One of the timing devices is set to produce a constant output when the input frequency is above the higher limit of the predetermined frequency range. The other device is set to produce a constant output when the frequency is above the lower limit of the same range. The outputs of both timing devices are connected to logic circuitry. The two timing devices are connected to the telephone line. When a signal in the selected frequency range is received from the telephone exchange, the frequency detector acknowledges to the exchange the receipt of that signal, and activates a recorder in a meter reading apparatus at the subscriber'"'"'s location to transmit the recorded reading of the meter over the telephone line to the exchange, where it is suitably recorded. When the first timing device has a periodic output and the second does not, the logic circuitry produces an output indicating that the input signal is within the predetermined range of frequencies.

Claims

1. Apparatus for reading stored data over a telephone line, including:

a. means for detecting a reversal of the normal polarity between the conductors of said telephone lines;

b. frequency detecting means for detecting a signal whose frequency is within a predetermined range;

c. means responsive to the detection of said reverse polarity to supply energy to said frequency detecting means;

d. means responsive to the detection of a signal whose frequency is within said predetermined range by said frequency detecting means to establish a constant current flow on the telephone line;

e. means for translating said stored data into pulses transmittable over the telephone line; and

f. means for activating said translating means in response to said constant current flow to transmit said pulses over the telephone line.

2. Apparatus as in claim 1, including:

a. data storage apparatus;

b. means responsive to said constant current flow on the telephone line for supplying to said data storage apparatus a potential which remains substantially constant over a wide range of variation of resistance of the telephone line and causes the data storage apparatus to store said pulse transmitted over the telephone line.

3. Apparatus for connection between data storage means and telephone line conductors having a potential difference thereacross, comprising:

a. means response to an interrogating signal from the telephone line to establish a constant current flow across the telephone line conductors;

b. means responsive to said constant current flow for suppling to the data storage means a substantially constant potential which is unaffected by variations in the potential across the telephone line conductors; and

c. data translating means responsive to said constant potential for transmitting the data stored in said storage means over the telephone line conductors.

4. Apparatus for transmitting stored data from a remote location over telephone line conductors having a DC potential difference thereacross and selectively carrying an AC interrogation signal, comprising:

a. power-up means responsive to a reversal of said potential difference across the telephone line conductors to supply energy derived from the telephone line;

b. frequency detecting means operative in response to energy supplied by the power-up means for detecting whether an AC signal whose frequency is within a predetermined frequency range is present on the telephone line;

c. constant current means operative in response to energy supplied by the power-up means and to detection by said frequency detecting means of the presence on the telephone line of an AC signal whose frequency is within the predetermined range, to establish and maintain a constant current flow across the telephone line conductors; and

d. data translation means operative in response to said constant current flow across the telephone line conductors for translating data stored at the remote location into pulses transmittable over said telephone line conductors and for transmitting said pulses over the telephone line.

5. Apparatus as in claim 4 comprising:

a. data storage means at the remote location, storing data to be translated by said data translation means;

b. means responsive to said constant current to supply a constant potential to said data storage means and said data translating means; and

c. means for connecting the data storage means and the data translating means to permit the data translation means to translate data from the data storage means into said pulses but to provide electrical power isolation of the data storage means from the remainder of said apparatus.