Teradyne, Inc.

Tollgrade Communications, Inc.

Roger Faulkner

Kurt E Schmidt

Gregory M Nulty

Yun Zhang

Jeff Brzozowski

A system and method for testing lines to determine service-affecting conditions on a line, such as telephone wiring. Conditions may be identified from low frequency variations in a frequency spectrum measured on the line. The line may be stimulated with a broad spectrum signal, such as may be generated by a DSL modem operating in the L0 state or may be the result of noise on the line. Analysis of the low frequency variations may yield information about the nature of service-affecting conditions allowing conditions, such as un-terminated or poorly-terminated extensions to be identified. The method may be performed by a test device attached to premises wiring in a telephone network and used to determine whether the premises wiring will support VDSL2 or other high speed data services without modification or may indicate changes at the premises to enable the wiring to support high speed data services.

Pre-installation frequency domain premises wiring tests

A system for testing a conductor of a structure can include a test device connected to the conductor. The test device is configured to test an electrical characteristic of the conductor and to produce a test result based at least in part on the electrical characteristic. A service provider network may be configured to communicate with the test device to initiate a test and/or to obtain the test result. A customer may use a computing device to obtain information regarding the test result, as well as guidance for troubleshooting and resolving a problem detected with the electrical conductor, such as a fault.

Home wiring test system with missing filter detection

The present invention provides a method and apparatus for estimating the insertion loss of a telephone line. A complex waveform is applied to each wire of the telephone line being tested. Real and imaginary components of the resultant waveform are measured at a plurality of frequencies. Insertion loss of the line is estimated from a series of single-ended voltage measurements made at a plurality of frequencies. These measurements are captured and used to estimate the insertion loss of the telephone line.

Method of performing insertion loss estimation

A system for qualifying subscriber lines in a telephony system for high speed data services. The system includes a measurement unit that makes one ended electrical measurements on the subscriber lines. Measurements on the subscriber lines are used to predict which of the lines can carry signals used in high speed data services. The predictions are used in marketing select data transmission services.

Qualifying telephone lines for data transmission

A method and apparatus for pre-qualifying lines with respect to estimating the insertion loss of the line is presented. End-to-end insertion loss at high frequencies is estimated from measurements made at low frequencies through the voice switch at the central office of a telephone company. An AC voltage waveform is applied to the telephone line being tested. Real and imaginary components of the resultant waveform are measured. These measurements are captured and used to estimate the insertion loss of the telephone line at frequencies in the range of 40 kHz to 300 kHz.

Technique for estimation of a subscriber line insertion loss

The method assesses the suitability of customer telephone lines () for data transmission. The method includes selecting a telephone line having tip and ring wires by means of a computer () and switch (), and electrically connecting the tip and ring wires together at a test access () adjacent one end of the selected line to produce a common mode configuration. Single-ended electrical measurements are performed on the wires in the common mode configuration by a measurement unit () connected to the test access () to determine an electrical property of the wires from the measurements.

A method detects a fault in a subscriber line having two wires with separate input impedances. The method includes driving the subscriber line from one end with an alternating voltage, making one-ended electrical measurements on the driven liner and determining from the measurements a quantity proportional to the phase difference of the two input impedances. The method also includes identifying a fault in response to the phase difference having a signature associated with presence of a fault in the line.

Fault conditions affecting high speed data services

A method and automatic test system for determining qualification of a twisted pair transmission line to propagate data signals. The method includes measuring phase imbalance in the twisted pair transmission line. The phase imbalance is determined by resistance imbalance in the twisted pair transmission line. The resistance imbalance is determined by applying a common mode voltage to the twisted pair transmission line; and, determining phase imbalance in the twisted pair in response to the applied common mode voltage. The method includes applying a common mode voltage to the twisted pair transmission line; determining phase imbalance if the twisted pair in response to the applied common mode voltage; detecting a peak in the determined phase imbalance; determining a frequency of the detected peak; determining line qualification in accordance with the determined frequency. Methods are provided using series resistive imbalance and phase measurements to discover the type of imbalance existing on a twisted pair transmission line which is unable to support data transmissions. Methods are provided using series resistive imbalance and phase measurements to determine where an imbalance occurs as well as the magnitude of the imbalance.

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Swindon, United Kingdom

Roger Faulkner