US 3,950,622 AGranted

Line fault locating system

AssigneeCulbertson Industries Inc.

InventorSteven C. Taylor

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Abstract

A method and means for fault testing the transmit and receive sections of repeaters which are connected in a pulse code modulation (PCM) transmission system, from a single end of said system, as described wherein testing between a first and second station is effectuated by sending between the first and second stations, a spaced trio pulse train with bipolar violations which are converted at the second station to a spaced trio pulse train without bipolar violations and then returned to the first station. When spaced trio bipolar signals are sent from the first to the second station, the second station converts these to a spaced trio bipolar signal pulse train with violations and sends these back to the first station. The testing circuits in the outgoing and incoming lines are only operative in the presence of a bipolar pulse train with violations.

Claims6

Dependent claims

In a PCM communication system where two lines extend between a first and second station and there are a plurality of repeaters in said line between said two stations which can receive and transmit signals in either direction, there being a fault locating cable pair extending between said two stations, to which all of said repeaters are coupled, a means for testing said repeaters for faults from one of said stations comprising

means at said one of said stations for generating a spaced three pulse bipolar pulse train having bipolar violation signals therein,
first and second circuit means each having an input and an output and comprising means for converting a spaced three pulse bipolar signal wavetrain having bipolar violations which is applied to its input into a spaced three pulse bipolar signal, wavetrain having no bipolar violations and for converting a spaced three pulse bipolar signal wavetrain having no bipolar violations which is applied to its input into a spaced three pulse bipolar signal wavetrain having bipolar violations,
means for connecting the input of said second of said circuit means at said second office location to receive signals from said transmission line and for connecting its output to said first transmission line to return signals back to said first office location,
means for applying the output of said pulse generating means at said first office location to said transmission line whereby a spaced three pulse bipolar pulse train with bipolar violations is transmitted between said first and second office locations, converted into a spaced three pulse bipolar wavetrain without bipolar violations by said second circuit means and then transmitted back to said first office location, whereby signals received at said first office location on said first cable pair may be monitored for determining the location of faulty repeaters in an outgoing direction,
means at said first office for applying the output of the pulse generating means to the input to said first circuit means, and
means for connecting the output of said first circuit means to said transmission line, whereby a spaced three pulse trio bipolar wavetrain without bipolar variations is transmitted between said first and second office locations and a spaced three pulse bipolar wavetrain with bipolar violations is transmitted between said second and first office locations, whereby signals on said fault locating pair may be monitored at said first office location for determining which of said repeaters is faulty in a return direction.

3 more elements

In a PCM communication system where only two lines extend between two stations and there are a plurality of repeaters in said lines between said two stations which can receive and transmit signals in either direction, there being a fault locating cable pair extending between said two stations, to which all of said repeaters are coupled,

a method for testing said repeaters between said first and second stations in both drections from said first station comprising
generating a spaced three pulse bipolar pulse train having bipolar violations thereon,
applying said pulse train to said transmission lines at said first station,
converting said spaced three pulse bipolar pulse train with bipolar violations into a spaced three pulse bipolar pulse train at said second station,
applying said spaced three pulse bipolar pulse train to said transmission line to be transmitted from said second station back to said first station,
monitoring the signals applied by said repeaters to said fault locating cable pair of said first station to determine which of said repeaters is faulty in a direction going from said first station to said second station,
converting said pulse train to a spaced three pulse bipolar signal train without violations at said first station,
applying said spaced three pulse bipolar signal train without violations at said first station to said transmission line to be transmitted to said second station,
converting the spaced three pulse bipolar pulse train without violations received at said second station to a spaced three pulse bipolar pulse train with bipolar violations,
applying said spaced three pulse bipolar pulse train with bipolar violations at said second station to said transmission lines to be transmitted back toward said first station, and
monitoring the signals received on said fault locating pair at said first station to determine which of the repeaters between said first and second stations have a fault in the return direction.

8 more elements

Dependencies are inferred from the claim text.