Method and apparatus for fault segmentation in a telephone network
OwnerFrank R. Bauer, Kurt E. Schmidt +1inventors
InventorsFrank R. Bauer, Kurt E. Schmidt, David J. Groessl
Life of this patent
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Abstract
An automated telephone line test system that is well suited for determining the location of faults within a telephone network. The telephone line test system uses time domain reflectometry to aid in locating the faults. The time domain reflectometry unit is connected through a switch in the network so that the time domain reflectometry unit can be connected to multiple lines without human intervention. Parameters of the time domain reflectometry signals are controlled so that reflections from the switch do not interfere with measurement of parameters on the faulty line.
Claims15
Measurement apparatus connected to a switch in a telephone network, the network having a plurality of lines and each line having at least a pair of wires, said measurement apparatus comprising:
- a) measurement hardware having at least two terminals and a control input, comprising:
- i) means for generating a voltage pulse at the two terminals in response to a control signal at the control input;
- ii) means for recording a representation of the reflected signal at the two terminals, the representation including representations of the a pulse reflected from a plurality of points on the line;
- b) access means, having a control input, for connecting the two terminals of the measurement hardware to a selected one of the plurality of lines through the switch in response to a control signal at the control input;
- and
- c) a computer processor having control lines connected to the control inputs of the measurement hardware and the access means.
A telephone network having a switch connected to a plurality of subscriber lines, the network further comprising:
- a) a measurement unit having:
- i) a measurement section having circuitry to generate pulses and measure reflections, the measurement section being connected to the switch;
- and
- ii) computerized control circuitry connected to the switch and the measurement circuitry;
- b) a computerized control unit connected to the computerized control circuitry of the measurement unit, the computerized control unit having computer software to direct the sending of control signals that connect the measurement section to a selected subscriber line, whereby time domain reflectometry measurements are made on the subscribe line through the switch;
- and
- c) computer data storage media having stored thereon information defining the maximum expected wire length within the switch between the measurement unit and a subscriber line and wherein the software accesses this information to determine the duration of the pulses.
A method of operating a system to test subscriber lines in a telephone network having a plurality of subscriber lines connected to a switch, the method comprising the steps of:
- a) connecting a time domain reflectometry unit to a subscriber line through the switch;
- b) operating the time domain reflectometry unit to send signals through the switch to a selected subscriber line;
- c) operating the time domain relectometry unit to receive reflections from the telephone line through the switch;
- d) analyzing the reflections to segment a fault in the selected subscriber line;
- e) wherein the step of operating the time domain reflectometry unit to send signals comprises selecting the duration of a pulsed signal to exceed the propagation delay through the switch and sending a pulse of this duration.
Dependencies are inferred from the claim text.