Harris Corporation

Joseph E Barron

Michael F Kennedy

Roy Lujan Soto

Onofrio Schillaci

Richard L Walsworth

Alex Knight

David W Keefe

Jeffrey W Hearsey

A device and method for testing a telephone circuit in which a caller takes advantage of available caller identification information to complete a ringback test without resort to potentially costly and overused toll trunks. The ringback test device is accessed by a caller (subscriber or craftsperson) who may not be aware of the telephone number from which he is calling when the caller completes a call to a telephone number assigned to the device. As the caller is accessing the test device, the test device detects the caller identification available between the first and second rings to identify the caller's telephone number, and answers the call after the second ring. The test device presents the telephone number to the caller, and the test device may thereafter be used to complete a ringback test to the identified telephone number. The caller ID information may also be display-formatted at the test device and provided to a caller's visual display.

Telephone ringback test device and method

A subscriber line circuit test and conditioning arrangement for use with a non-metallic (fiber optic) digital communication path-based digital communication network employs a single (basic rate ISDN) metallic channel unit (BMCU) installed at a site terminating the fiber optic communication path. A BMCU communicates with a central office test system using an auxiliary B-ISDN communication `test` channel portion (2B+D) channels of the time division multiplexed digital communication DS0 channels. Digital command and response signals are transported by the two ISDN bearer (B) channels and are coupled directly to tip and ring digital signal processors in the central office test system, without the need for intermediate digital-to-analog and analog-to-digital conversion by a metallic channel unit at a central office terminal, and that additionally performed by a central office terminal and central office switch. The data (D) channel is employed to conduct access, calibration and control communications with the metallic channel unit.

Arrangement for testing telephone subscriber line circuit via B-ISDN

A microprocessor-controlled voltage source selectively provides to a telephone line either a DC or an AC voltage, prescribed characteristics of which are programmably adjustable, enabling test equipment to controllably condition and test the line with essentially any desired line conditioning voltage or signal waveform. A digital-to-analog converter (DAC) provides an output voltage having an amplitude that is digitally programmable. This output voltage is available to be applied either directly or through controlled amplifier circuitry to the line. In order to generate an AC signal having both an adjustable amplitude and waveform characteristic, the output of the DAC sets the amplitude for a combination of signals from a plurality of squarewave generators having programmable frequency characteristics. The output of the combining unit is coupled to a switched capacitor filter which filters the controllably-interrupted, digitally-controllable output voltage, (e.g., removes odd harmonics from the fundamental frequency of the desired waveform) and an adjustable smoothing filter, which is coupled to the switched capacitor filter and removes the `stairstep` transitions in the waveform associated with the operation of the switched capacitor filter. The output of the smoothing filter is coupled to an output amplifier which amplifies the AC waveform output of the adjustable smoothing filter.

Programmable source for supplying controllably variable AC/DC voltage

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Newbury Park, CA, United States of America

Joseph E Barron