Abstract: A digital communication interface for downloading software for upgrading the functionality of a telephone craftsperson's butt-in test set is configured to be powered externally by respectively different voltages ported from the host computer and the test set. Digital communication connectivity for software upgrade signals sourced from the host computer for delivery to the control processor of the test set, and for communication signals sourced from the test set for delivery to the host computer, is effected by a pair of opto-isolators which provide signal integrity isolation between the respectively different parameters of the host computer and the test set.

Abstract: 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.

Abstract: A portable, hand-held ‘test tag’ device enables a test unit to conduct a wireline connection verification test, in order to determine connectivity of a subscriber metallic wireline pair from a point of access by the test unit to a ‘test tag’ point of entry location along the metallic wireline pair. The ‘test tag’ includes a controllable termination circuit and a port coupled to one or more lead connects, that enable a craftsperson to connect the test tag to the metallic wireline pair. The controllable termination circuit includes a prescribed resistance that is configured such that, for a first applied line voltage, the test unit will observe characteristics of the metallic line pair terminated with a low resistance termination, whereas for a second line voltage, the test unit will observe characteristics of the metallic line pair terminated with a high resistance termination.

Abstract: A digital signal processor-based test set is configured and programmed to enable a craftsperson to monitor, receive and process signals of a variety of formats that may be present on a line under test, including user feature analog modem signals. Such user feature signals may include caller-identification signals, visual message waiting indicator signals, and analog display services interface signals. The test set employs a signal processing routine that operates in two modes: 1- terminal mode—in which the test set functions in the place of customer premises equipment (CPE); and 2- line monitor mode—in which the test set is connected to the line under test and monitors data signals being transmitted to and received from an existing CPE. In both modes the test set has the ability to not only display the data being sent to and from the CPE, but also parametric information about the data.

Abstract: A test interface adapter allows a line-conditioning or test device, such as a direct access test unit (DATU), that is normally interfaced with a standard central office switch via a no-test trunk, to be coupled to and communicate with the respective ports of a test interface of a non-standard central office switch that is not equipped with a no test trunk, so that conditioning and/or testing of subscriber telephone lines served by such non-standard central office switch may be carried out. When so installed, the interface adapter of the present invention is operative to map signals at first interface ports, to which the non-standard central office switch is connected, to second interface ports to which the line conditioning/test device (e.g DATU) is connected, and vice versa.

Abstract: A test interface adapter allows a line-conditioning or test device, such as a direct access test unit (DATU), that is normally interfaced with a standard central office switch via a no-test trunk, to be coupled to and communicate with the respective ports of a test interface of a non-standard central office switch that is not equipped with a no test trunk, so that conditioning and/or testing of subscriber telephone lines served by such non-standard central office switch may be carried out. When so installed, the interface adapter of the present invention is operative to map signals at first interface ports, to which the non-standard central office switch is connected, to second interface ports to which the line conditioning/test device (e.g DATU) is connected, and vice versa.

Abstract: The possibility of corrupting digital data traffic carried by a data line (powered or unpowered), by the connection of a telephone test set to the data line is effectively prevented by augmenting the telephone test set with a mechanism that prevents the test set from asserting an OFF-HOOK condition on the line, unless it has been determined that each of two conditions are satisfied. These conditions are: 1- that no digital data traffic is being carried by the line; and 2- that the electrical voltage condition of the line satisfies a prescribed minimum voltage level criterion. If either of these conditions is not satisfied, a switch circuit installed in the test set's connection path to the line is maintained in a default, open condition, so that it is effectively impossible for the line to be presented with an OFF-HOOK condition through operation of the test set. This default condition remains in effect until both criterion are fulfilled.