Harris Corporation

Wayne K Wong

Robert B Walance

Thomas W Durston

John R Nelson

Tim G Godfrey

Steven R Coffelt

Theodore E Chavannes

Gregory J Pettit

James D Eckman

Dean L Benjamin

George D Fleitz

A test system automatically locates impedance mismatched, energy reflection discontinuities (e.g., bridged taps) along a wireline communication link, by coupling a linearly stepped sinusoidal waveform to a measurement location of the wireline link. The applied waveform propagates down the link and is reflected back from the energy reflection discontinuities. A line monitoring receiver coupled to the measurement location samples the response of the line to the swept waveform. A response processor executes a frequency domain reflectometry algorithm to analyze the frequency response of the wireline to the stepped frequency waveform. It then generates an output representative of distances from the measurement location to the bridged taps.

Detection of bridged taps by frequency domain reflectometry

To prevent entry of contaminants into a craft unit, each of a telephone signal connector (RJ11 jack) and DIN-type digital signalling link connector is replaced with a sealed, multi-pin plug/receptacle type connector which integrates the routing of both telephone communication signals and digital communication signals between the craft unit and an external device. When stored in a storage and battery-charging station, the craft unit is maintained in a communication-ready state, by providing each of the battery-charging holder and the portable craft unit with an additional multi-pin interconnect arrangement, that contains a charging path for the craft unit's internal battery, and a multi-pin signalling path. This multi-pin interconnect arrangement contains both a set of communication signalling pins and a set of terminal pins through which the internal battery of the portable craft unit is charged. Within a receiving cup-like portion of the storage and battery charging unit, a plurality of male connector pins are nested in a compact linear arrangement to engage a corresponding set of female connector terminals supported within the portable craft unit.

Battery charging and signalling interconnect arrangement for craftsperson's

Corruption of communication signals on a telephone line by the direct (low impedance) interfacing of test equiupment to the line is precluded by a protective interlock circuit, which prevents the test set from seizing the line if data traffic is present. The interlock circuit is coupled between the line circuit to be accessed and the test equipment, and includes a multiple band frequency detector, which monitors the line for signals lying within (in and out-of-audio) frequency bands. Should the detector identify any traffic within its sensitivity range (out of the audio band) during the interval of a timing pulse produced by the closure of a switch, the logic level applied to combinational logic will change state and prevent the generation of a test set enabling signal. The test set enabling signal is normally coupled to a `line-seize` transistor circuit within the test set, so that, without this enabling signal, the test set is effectively locked-out from the line and data cannot be corrupted. Should the frequency detector not have produced an out of audio band detection signal after the expiration of the timing pulse, the combinational logic circuit and an associated flip-flop generate an output signal for enabling the test equipment to seize the line. The flip-flop remains set and the logic level of the output signal is maintained until the line is no longer seized by the test equipment.

Interlock circuit for preventing corruption of telephone line signals

The telephone line test capability of a craftsperson's test set is supplemented by communication/interface circuitry which carries out data communications with a host central office control processor, and contains memory for storing (task assignment) information downloaded from the central office control processor. This task assignment information stored in the test set-communications unit may be coupled from the unit to an associated printer for providing a hard copy of service assignment information to the field technician. In addition to printing out the downloaded task assignment information, the printer unit contains a charging circuit which charges a rechargeable battery in the handset for powering its internal circuitry. During off-duty hours, the test set may be connected to a home dispatch unit installed in the craftsperson's home and through which the handset is coupled to a telephone link for providing off-duty communications with the central office processor without technician intervention. The home dispatch unit also contains a battery charging circuit through which the test set's internal battery is charged when the test set is coupled to the dispatch unit and communications between the central office and the test set-communication unit are not taking place.

Test set communication/interface system

Growing community of inventors

Camarillo, CA, United States of America

Wayne K Wong