Abstract: A computer-executable method for diagnosing trouble causes in telephone cable segments when trouble data are available only for entire cables is presented. This method diagnoses problems in the components of processes when the component location of process problems is not known. It gives a statistical relationship between component attributes and process problem rates, to facilitate assessment and improvement of policies about the process. This method may be used for diagnosing systematic problems in segments of telephone cable connections of given central offices.

Abstract: A method and apparatus (12-20, 32) for automatically locating faults in a network of signal carriers (cables) utilises an interrogation waveform which is pulse-like in form and receives composite reflected signals from the carriers which are a time distributed collection of individual reflections. These are sampled and compared using the function of an adaptive filter (52) to minimise the difference signal. The difference signals are analysed to determine significant points of departure which identify the fault location which is then represented as a distance value.

Abstract: A transmission line for carrying digital signals is provided with auxiliary line drivers at the receiver end, which are used in combination with the data line driver at the transmitting end to apply a sequence of sets of test voltages onto the line. The voltage resulting at the receiver input is used to detect open signal conductors and/or shorts in the receiver.

Abstract: With DC constant current applied to an end of one of transparent electrodes by a constant current application terminal, a voltage is measured at an end of a transparent electrode adjacent to the foregoing electrode by a voltage detection terminal, while a common electrode is earthed by applying a brush earth terminal thereto in the vicinity of the foregoing transparent electrode. If the transparent electrode is broken, the DC constant current application circuit detects a voltage saturation state, whereas if the transparent electrode is short-circuited, the DC voltage detection circuit detects variation in the foregoing voltage. A short-circuiting/wire breakage memory circuit stores the detected irregularity of the voltage as defect information, and either wire breakage or short-circuiting is detected on the basis of the defect information.

Abstract: In a device for detecting the abnormality of a wire harness or a power supply device for a motor vehicle, a temperature fuse which blows out when a temperature exceeds a certain value is arranged within or adjacently to a wire harness. By detecting the presence or absence of break of the temperature fuse, abnormality of the wire harness is detected. Thus, deterioration of the wire harness due to rare short can be avoided.

Abstract: A parallel data bus tester is particularly applicable to SCSI type buses, and uses a plurality of comparator circuits to simultaneously examine the voltages present on the conductors of a bus cable. For twisted pair type conductors, the tester uses a high reference voltage, which is compared to the high voltage conductor of each pair, and a low reference voltage, which is compared to the low voltage conductor of each pair. The reference voltages are adjustable, and allow each reference voltage to be swept through the expected voltage range for its respective conductors. As the level of a reference voltage crosses that of a conductor voltage being examined, a comparator that receives the reference voltage and conductor voltage changes output state. This output is used to drive a corresponding LED assigned to the conductor in question. Thus, as the reference voltage, which is compared to each of its corresponding conductor voltages (i.e.

Abstract: In circuit tester apparatus using one or more carrier elements, each carrier element having one or more first electrical connectors, the combination comprising one or more base sections, one or more second electrical connectors carried by the section or sections and positioned to interfit the one or more first electrical connectors when the element or elements are assembled to the section or sections, at least two of the multiple base sections located for bridging thereof by at least one carrier element. Carrier elements may comprise adapter cards.

Abstract: A conductor tester including two contour-identical parts of a main unit and a remote unit is used to test and indicate present condition of conductors. Both the main and the remote units are formed at two ends with high and low raised portions that are provided with fastening means for the two units to detachably connect to each other to form a compact unit. The high and low raised portions are provided at side walls with notches that are electrically connected to internal circuits of the main and the remote units, and at inner walls between the high and low raised portions with light-emitting diodes.

Abstract: A cable testing system comprises a network tester connected to a multi-line test coupler, which includes a plurality of output cables connected to a patch panel. A terminator is also connected to the patch panel to selectively test lines by engaging wall outlets etc., with the terminator. With this system it is not necessary to connect the tester to each individual line thereby saving considerable time and expense.

Abstract: A probe is made to contact one end of the test wiring of a circuit board 32, with a head 52 electrostatically coupled to the other end of said wiring. A pulse-like DC voltage is supplied from a signal source 46, and, simultaneously with a switch section SWp turning on, the maximum voltage is applied to the test wiring. If a detection signal is below a specified value, then a computer 44 will read it as “open” or “shorting”. Further, a tip 52a of the head 52 is associated with the circuit board 32 only through an insulating sheet 33, so that the tip 52a is kept away from each pad of a pad section 38 on the board at a fixed distance (equivalent to the thickness of insulating sheet 33). Thus, continuity testing may be performed in a non-contact manner by moving head 52 only in X and Y directions without movement in the Z-direction.

Abstract: Device for identifying multiple two-conductor alarm wires originating from a common location but terminating at individual remote locations. This device is utilized at the common location by connecting a plurality of test leads and common leads to wires to be identified. User then visits the remote locations where alarm wires connected to test leads and common leads are suspected to terminate. Device emits frequency pulses along connected wires. Using an inductance amplifier probe user can locate and verify that the wire at the remote location is indeed connected to the device. If necessary the user can find the wire it buried within the wall and when found, strip back insulation of the same terminating end of alarm wire and momentarily join the two conductors together. The result is a number of audible beeps sounding from a piezoelectric transducer from the device letting user, who is at the remote location, know which test lead is connected to the wires that were momentarily joined together.

Abstract: A test system method for measurement of crosstalk in a multi-pair cable of the type used in local area networks. The system uses a far end signal generator at one end of the cable and a near end signal generator at the near end of the cable. For a far end crosstalk measurement, the far end test unit transmits a high frequency far end test signal and a lower frequency reference signal on one of the wire pairs of the cable. The near end test unit responds to the received reference signal to generate a near end test signal in phase coherency with the far end test signal. A far and crosstalk measurement analysis is then conducted using the received far end test signal, the near end test signal and a crosstalk signal induced by the far end test signal in one of the other wire pairs of the cable.

Abstract: A cable testing device apparatus has been developed so as to measure the NEXT and ELFEXT characteristics of a cable containing a plurality of twisted pairs. In particular, the present invention simultaneously provides each twisted pair within the cable with an electrical signal of equal magnitude and measuring the equivalent power sum output for each of the individual twisted pairs within the cable. Thus, a total of 25 measurements for each test are needed, for a total of 50 tests.

Abstract: In circuit tester apparatus using one or more carrier elements, each carrier element having one or more first electrical connectors, the combination comprising one or more base sections, one or more second electrical connectors carried by the section or sections and positioned to interfit the one or more first electrical connectors when the element or elements are assembled to the section or sections, at least two of the multiple base sections located for bridging thereof by at least one carrier element. Carrier elements may comprise adapter cards.

Abstract: A multiconductor continuity and intermittent fault analysis system that subjects the cable to controlled environmental stress stimuli, such as vibration at a plurality of frequencies simultaneously, during testing. Multiconductor cables used for the transmission of digital data and control signals include multiple individual conductors terminating at both ends in pins or sockets that are grouped together in a connector. Physical defects in these cables can be permanent, or they can be intermittent faults, such as temporary breaks or shorts caused by vibrational stress on the cables. By vibrating the cable under test and measuring continuity rapidly enough to detect short-term anomalies, even intermittent faults are located. A distributed processing embodiment disclosed uses a user interface unit such as a personal computer or personal digital assistant, a multiprocessor controlled control unit, and the dynamic stimulation unit.

Abstract: Method and apparatus for testing the video subsystem of a PC in a manufacturing environment. Hsync and Vsync signals from a VGA connector of the PC are input to first and second trigger inputs, respectively, of a monostable multivibrator (“MM”) of the test device to drive respective outputs thereof. In particular, the presence of Hsync at the first trigger input triggers the MM to output a positive pulse at a first output thereof; similarly, the presence of Vsync at the second trigger input triggers the MM to output a positive pulse at a second output thereof. Each of the first and second outputs is used to drive an LED, such that the presence of Hsync and/or Vsync results in the illumination of a corresponding LED.

Abstract: A library apparatus includes an accessor robot and a flat cable connected to the accessor robot. The flat cable has an outer check line and an inner check line each formed of a conductor. Breaks in each of the outer check line and the inner check line are detected to identify wear on the flat cable, and prevent sudden failure of the library apparatus.

Abstract: A device comprising of multiple quick connect/disconnect terminals used in conjunction with light emitting diodes connected to an integrated circuit using a single test probe, providing an efficient means when having to sort multiple conductors. The L.E.D's used in this device remain energized even after the test probe has been removed. This provides a useful alternative when having to sort multiple conductors within a particular wire bundle which may travel to a remote enclosure located away from it's origination point. Also this device is contained within a compact enclosure and operates from a small 9VDC power source, providing both convienence and safety to the panel assembler using this device.

Abstract: A detector and a variable signal generator are coupled so that one or more specific changes in the output of the detector will cause a change in the characteristics of the generated signal. This change in signal characteristics is non-transient, the change remaining in effect until such time that another change in the detector output causes another change in the signal characteristic. The system can provide remote-end positive wire identification with no additional instrumentation at the remote end. When this invention is embodied in an already existing piece of test equipment, such as a multimeter or time domain reflectometer, there need be no additional hardware instrumentation at either end.

Abstract: A method detects at least one property, such as cable length, of a multiconductor cable linked to a module by way of a logic and evaluation circuit within the module. The cable has at least one supply conductor connected by the module to a first potential and at least one signal conductor connected by the module to a second potential via a pull resistor. The supply conductor and the signal conductor will or will not be interconnected at the ends of the cable depending on whether given properties of the cable are present or not. The logic and evaluation circuit module detects the potential applied to the signal conductors and thereby determines the presence or absence of the cable properties to be determined.

Abstract: A method for determining the shielding effectiveness of a shielded and, particularly, permanently installed cabling path wherein the cabling path has an inside conductor connected via a patching cable at a first end to a transmitter which emits an electrical test signal. One pole of the transmitter output is applied to ground potential and the other pole is conductively connected to a patching cable. At a second end of the cabling path the shielding is applied to ground potential and conductively connected to the inside conductor via a terminating impedance. The shielding of the cabling path is connected to that pole of the transmitter output applied to ground potential. It is connected thereto by a return line which is connected to the first end of the cabling path at a differential current intensity of the currents flowing through the patching cable and the return line is converted into a measured value using a measuring device.

Abstract: A LAN tester 1 for carrying out a conduction test, a polarity test and an operation test of LAN wiring includes a power supply section (2) for supplying a power supply current to one of paired signal lines to be tested at one end thereof; a current detecting section (3) for detecting the current flowing through the other of the signal lines; a forward polarity detecting section (4) for detecting positive and negative pulses from positive and negative signal lines, respectively; a reverse polarity detecting section (5) for detecting negative and positive pulses; a first change-over switch (6) for operating the power supply section (2) and the current detecting section (3) in a conduction test mode and operating the forward polarity detecting section (4) and the reverse polarity detecting section (5) in a polarity test mode; and a second change-over switch (7) for realizing an operation test mode by connecting a connection terminal of a transmission signal line and a connection terminal of a reception signal li

Abstract: A method of improving fault current measurement accuracy on a power line is disclosed. A first sample is obtained from a first input channel. A current magnitude is calculated from the first sample. The current magnitude is compared to a possible current saturation value. If the current magnitude is less than the possible current saturation value, a second sample from a second input channel is obtained, and the current magnitude is recalculated from the second sample. Lastly, the current magnitude is scaled by a scale factor. Also disclosed is an apparatus for improving fault current measurement accuracy on electronic reclosure control.

Abstract: A circuit for performing a switching of a protection line between a common section and a channel section includes a common section and a channel section connected by signal lines. The common section has a working interface circuit and a protecting interface circuit. The channel section only has a working interface circuit. The working interface circuit of the common section is operably connected to the working interface circuit of the channel section by a working cable. The protecting interface circuit of the common section is connected to the working interface circuit of the channel section by a protecting cable. When a disconnection or a slip of the working cable occurs, a signal from the working interface circuit of the common section is transmitted and inputted into the protecting interface circuit via the protecting cable.

Abstract: There are two coaxial cable test instruments, of which a primary instrument provides a rump circuit having a battery, a first electric signal device and two probes in series-connection with each other, of which the probes are in the form of the central conductor and surrounding shield parts of a typical coaxial cable connector. The other or secondary instrument provides a second electric signal device which is connected with two further probes in the form of the central conductor and surrounding shield parts of another coaxial cable connector. To test a cable component for a short-circuit, the primary instrument is connected with one of the end connectors of the cable. If the first signal device, for instance a light bulb, then lights up on closure of the rump circuit via the short-circuit bridge between the central conductor and surrounding shield of the cable, the lighted bulb will clearly indicate the short circuit in the cable.

Abstract: A portable diagnostic device for checking electrical signalling systems of school buses and/or tractor trailers. The device has several receptacles for connection to a corresponding receptacle or pin connector of a school bus and most types of trailers. One electrical circuit includes switches for energizing individual signalling or illumination circuits of the trailer individually, and indicating lamps for annunciating circuit operability. Another electrical circuit includes switches for energizing individual signalling or illumination circuits of the school bus individually, and indicating lamps for annunciating circuit operability. The device, which is contained on a wheeled cart, has its own power supply and circuit overcurrent protective devices, and is thus independent of a school bus and a tractor, both of which normally generate the signals. The device enables a shop to perform a safety check for many varieties of school buses and trailers.

Abstract: A multiplexed audio-video signal transmission system has a camera-equipped intercom which produces a balanced audio-video signal. A twisted pair-wire connected to the intercom transmits a multiplexed signal of audio signal, video signal modulated to a frequency band not overlapping the audio signal frequency, and DC power. The audio signal and video signal are carried in the pair-wire in opposite phase in a balanced condition, and the DC power is carried between the pair-wire. A relay device is inserted in the pair-wire to refine the video signal. Main line branching device and door branching device are provided to branch out the multiplexed signal to a television equipped control unit 17.

Abstract: An apparatus for detecting a trouble location in a wire harness can easily detect a location of any trouble such as breakage or short circuit in electric wires in a wire harness and in particular can detect the trouble location by way of a simple structure utilizing a portion with a shield function. In the detecting apparatus, a pulse signal is transmitted in electric wires (2) in a wire harness (1), in which a trouble location is to be detected, and in a sensing line juxtaposed along the electric wires (2) at their ends. A measuring device (20) receives a reflected wave from a transmitted wave and measures a difference in time between the transmitted wave and the reflected wave. A distance from a transmitting end point to a trouble location point is determined in accordance with the difference in time and a signal propagation velocity. Each electric wire (2) in the wire harness (1) is a single wire having no splice portion and a shielded wire having a conductive shield sheath (10).

Abstract: A communication line identification apparatus and method which automates the identification of communication line is engaged with a particular adapter within a communications system. A communication transducer (140) is mounted on a connector (122) of the communication line (118). The communication transducer (140) contains identification information for the communication line (118). Mounted near the adapter (114) which engages the connector (122), is an adapter transducer (138) which receives the identification information from the communications transducer (140). This identification information is transmitted to a system controller which provides the communication systems operator with the information about which communication line is connected to which adapter.

Abstract: An electrical cable containing two or more twisted pairs of wires and having terminals at one end connected to corresponding wires is tested for possible mis-pairing of an assumed wire pair. At that end of the cable, all terminals except the two for the assumed wire pair are connected to ground. A test signal is then applied to a first terminal for the assumed wire pair, and at the same time a measurement is made of a response signal received at the second terminal for the assumed wire pair. The test signal is a time-varying signal. The strength of the response signal is compared to the test signal to establish whether the assumed pair of wires are in fact wound to each other.

Abstract: A system for determining if there is a break in the shield or a compromise in the shielding effectiveness of coaxial cable plant by inducing a reference test signal onto the sheath or outer conductor of a coaxial cable. Concurrent testing is done with a digital sampling receiver for the presence of some of the induced reference signal on the inner or center conductor of the cable. The test current may be introduced directly onto the coax's sheath by magnetically coupling with a split ferrite core, or it may be applied indirectly by inducing the current onto a conductor, such as a grounding wire, that attaches to the coaxial cable. The test signal on the center conductor may be received back at the headend, or it may be received near the injection point by breaking the coaxial cable, or by connecting a probe to the center conductor. The invention may employ ranging to determine the distance to the shield break.

Abstract: A method for determining whether a circuit under test is open is presented. A digital-to-analog converter is dithered to generate a known signal. This known signal is summed with an external attenuation signal which is brought into the system from a probe on the circuit under test. This summation is then measured by an analog-to-digital converter (ADC). If the known signal is not attenuated by the probe (i.e., the ADC measures essentially the known signal), we can conclude that the circuit is open.

Abstract: Frequency domain reflectometer and method of determining severity of faults in a transmission line are disclosed. The reflectometer compensates for attenuation effects in the transmission line when determining severity of faults. In general, the reflectometer applies a sweep signal to the transmission line in order to obtain a reflected sweep response signal. Then, the reflectometer obtains a sweep response spectrum from the reflected sweep response signal. The reflected sweep response signal includes a plurality of spectral peaks which represent the frequency components of the reflected sweep response signal. Then, the reflectometer determines a first attenuation compensation factor for a first spectral peak of the reflected sweep response spectrum.

Abstract: The invention relates to a method of detecting a shielding defect of a shielded cable mounted in a building which defines between an instrument and the shielding of the cable, a first stray capacitance; the method steps are:placing measurement apparatus in such a manner as to define a second stray capacitance between itself and the building;injecting a high frequency signal into the shielding of the cable, by means of the measurement apparatus, the signal circulating back to the apparatus via the first and second stray capacitances; andmeasuring on the core of the cable, a signal that appears by radiation due to the injection of the high frequency signal, and representative of a defect in the shielding of the cable.

Abstract: A current flowing through the automotive battery and the battery voltage are measured by the battery current measuring means and the battery voltage measuring means. The battery is connected to a plurality of wiring harnesses which in turn connect to a plurality of loads. Data on normal resistance values between the battery and the wiring harnesses as produced by each of the loads being activated are stored and held in the load current data holding means. When the resistance value comparison means determines that the resistance value between the battery and the wiring harnesses calculated by the resistance value calculating means does not agree with the data of normal resistance values between the battery and the wiring harnesses held by the load resistance data holding means and produced by each of the loads being activated, it is decided that abnormal currents are flowing through the wiring harnesses.

Abstract: An apparatus for determining when a synthetic fiber cable for an elevator is ready for replacement is disclosed. The apparatus includes at least one voltage detection unit for detecting a voltage in at least one carbon fiber of the synthetic fiber cable and at least one threshold device for determining when the detected voltage exceeds a predetermined voltage threshold. The detected voltage is dependent upon the integrity of the portion of the synthetic cable and exceeding the predetermined voltage threshold is indicative of a failure of the at least one portion of the synthetic cable. The apparatus also includes a device for disabling the elevator when a predetermined number of the at least one threshold device determine that the at least one carbon fiber of the synthetic fiber cable has failed. The synthetic fiber cable includes a plurality of strand layers and at least one carbon fiber, each strand layer including a plurality of strands of synthetic fibers, such as aramide.

Abstract: A pulse-based local area network (LAN) cable test instrument provides a measurement of the cross-talk characteristic of a LAN patch cord as a function of frequency in order to evaluate its relative performance and workmanship of assembly. A LAN cable test instrument applies a test signal in the form of narrow pulses to a selected transmission line of a LAN patch cord while the cross-talk response induced in another transmission line in the same LAN patch cord is measured and stored as a time record in digital memory. The near-end and far-end pulse responses are separated in the time record, leaving only the near-end pulse response. The LAN cable test instrument analyzes the near-end pulse response by performing a discrete Fourier transform on the time record to provide cross-talk versus frequency information. The same test may then be performed on the far-end end of the patch cord to obtain a complete test of the quality of workmanship at both ends of the patch cable.

Abstract: Impedance of a power system adapted for operation at a predetermined line frequency is measured by providing a test signal of frequency different from the predetermined line frequency by an increment significantly less than the predetermined line frequency to provide an impedance measurement signal representative of the impedance of the power system at the test frequency. The impedance measurement signal is processed to provide a line impedance signal representative of the power system impedance at the predetermined line frequency.

Abstract: An apparatus for testing the racks and installation wiring of telephone switch equipment takes the form of a module capable of insertion into the various slots of a particular rack configuration. The module includes a circuit board which terminates in a connector suitable for interconnection with a particular telephone switch system, and which receives a continuity testing subassembly useful in performing the desired testing. To this end, selected contacts (or pins) of the connector are coupled with a light emitting diode (LED) and a biasing circuit for operating the LED responsive to connection of the biasing circuit to ground. Each LED, and the biasing circuit, is provided with a suitable operating voltage which can either be derived from the rack which is being tested or a battery which is resident in the test apparatus.

Abstract: A field bus system may be used in which transmission ability of the system can be maintained even if communication error occurs due to noises or failure of a transmission line. The system can be easily shifted at a lower cost from a conventional system to the field bus system without degrading the high reliability thereof. The transmission line is constituted by a multiple-cable transmission line having at least three transmission cables. An external power supply supplies power to field devices through a pair of transmission cables of the multiple-cable transmission line. The field devices are connected to the transmission cables through a transmission line switching unit constituted by a plurality of rectifier elements, so that the field devices are supplied with current flowing in one predetermined direction when any of the pairs of transmission cables is selected.

Abstract: A latching tester for testing continuity of wires in a system has an array of pin electronics cells, where each pin cell couples a signal to a row sense line and a column sense line when a change in current flow through a pin occurs; apparatus for detecting the signal on the row sense line; and apparatus for detecting the signal on the column sense line. The array of pin electronics cells may also operate as a capacitively coupled neural network, where a signal coupled onto the row and column lines from a stimulus line varies with the load on each pin of the pin electronics cells. An alternate mode of operation permits stimulus of the network and attached loads, and generation of a signature based upon the response of the network to the stimulus, as observed on the row and column sense lines. In yet another mode of operation, the tester may serve to recognize particular signals.

Abstract: An efficient method for calculating Power Sum cross-talk loss is provided. Cross-talk loss measurements may include near-end cross-talk (NEXT) loss, far-end cross-talk (FEXT) loss, multiple disturber NEXT (MD NEXT) loss, and multiple disturber FEXT (MD FEXT) loss. Pair-to-Pair cross-talk loss responses are collected between a given wire pair and all the other wire pairs of concern, with each pair-to-pair cross-talk loss measurement having a number of frequency data points corresponding to the frequencies of interest. The pair-to-pair cross-talk loss response having the lowest positive value for a particular frequency data point is first selected as the baseline cross-talk loss response. The effects of each of the remaining pair-to-pair cross-talk loss responses on the baseline cross-talk loss response are then accounted for by applying power sum contribution values obtained from a look-up table.

Abstract: A probe card tester for detecting defects occurring as a result of integrated circuit processing of a substrate having a plurality of space to conductors with a contact at each end of each conductor, includes: a probe card tester including a set of parallel resistors for connecting at least one in parallel with each conductor and a set of series resistors for connecting together the ends of the conductors to form a series resistance and a number of probe elements, one corresponding to each end of each conductor, for interconnecting the parallel and series resistors with the conductors for detecting defects bridging the conductors.

Abstract: A method of improving fault current measurement accuracy on a power line is disclosed. A first sample is obtained from a first input channel. A current magnitude is calculated from the first sample. The current magnitude is compared to a possible current saturation value. If the current magnitude is less than the possible current saturation value, a second sample from a second input channel is obtained, and the current magnitude is recalculated from the second sample. Lastly, the current magnitude is scaled by a scale factor. Also disclosed is an apparatus for improving fault current measurement accuracy on electronic reclosure control.

Abstract: A pulse-based LAN cable test instrument that processes time-domain cross-talk measurement information in order to troubleshoot and quickly locate sources of cross-talk as a function of distance along the LAN cable system is provided. A pulse-response time record between a pair of transmission lines of the LAN cable system is first acquired. A series of steps to process the time-domain pulse response data in the time record are then performed to enhance the ability of the user to locate and troubleshoot the primary contributors to NEXT along any point of the LAN cable system. The pulse response data are first normalized as a function of distance from the LAN cable test instrument in order to compensate for losses along the LAN cable. Next, the pulse response data are integrated over the time record and the absolute value of the pulse response data is calculated to more clearly show the individual sources of cross-talk within the overall LAN cable pulse response.

Abstract: There is provided a system and method for locating faults in power distribution systems with complex topology, such as multi-phase urban networks (6), utilizing reliable time-delay techniques as well as a transponder (22) at a monitoring point to sense the arrival of the transient fault pulse and for transmitting a timing pulse a known time delay after sensing the arrival of the transient fault pulse and a calibration pulse a known time delay after transmitting the timing pulse. Installed along the power distribution system at key locations are receiver stations (4, 4a, 4b) capable of sensing the arrival of the transient fault pulse, timing pulse and calibration pulse and measuring the time intervals occurring between each. The location of the fault is then determined based on these timing intervals, known time delays and the known propagation velocity of the electric power cables in the power distribution system.

Abstract: A test instrument (50) for testing a cable (52), the test instrument having a main unit (54) and an interchangeable performance module (56). The main unit of the test instrument contains signal generators for generating AC and DC test signals. The AC test signals are generated as single-ended signals and applied to a pair selection switching array (76). The pair selection switching array switches the single-ended test signals to a plurality of lines (84a-84d) that couple to the performance module. The performance module is an interchangeable module having a plurality of balancing networks (baluns) (102a-102d) that are connected to the plurality of lines. Single-ended test signals applied to the baluns are converted into balanced signals and applied to a cable being tested. The performance module may be interchanged to allow the main unit to be connected to cables having various impedances and connectors.

Abstract: A multiconductor continuity and intermittent fault analysis system that sects the cable to controlled environmental stress stimuli, such a vibration at controlled frequencies, during testing. Multiconductor cables used for the transmission of digital data and control signals include multiple individual conductors terminating at both ends in pins or sockets that are grouped together in a connector. Physical defects in these cables can be permanent, or they can be intermittent faults, such as temporary breaks or shorts caused by vibrational stress on the cables. By vibrating the cable under test and measuring continuity rapidly enough to detect short-term anomalies, even intermittent faults are located.

Abstract: A protective grounding jumper cable tester basically includes a housing, a direct current power supply, a pair of jumper attachment terminals, a pair of test probe terminals, a current applying circuit connected between the direct current power supply and the pair of jumper attachment terminals for applying a direct current through a jumper cable attached between the jumper attachment terminals, and a resistance sensing circuit connected to the test probe terminals for sensing resistance to the flow of the direct current through the jumper cable by using a pair of test probes connected to the test probe terminals.

Abstract: An instrument and method for the troubleshooting and verification of copper-wire local area network (LAN) cable systems provides a series of resistance and capacitance measurements between all possible wire pairs using a pair of switch matrices and a software method for evaluating the measurements which are stored in a two-dimensional matrix. The stored measurements are evaluated against predetermined figures of merit and the decision pattern in matrix form is compared to that of a known good LAN cable system. Error messages responsive to mismatches are generated and presented to the operator via a user interface. Near-end cross talk (NEXT) isolation is evaluated using a mathematically calculated differential capacitance technique. Error messages are generated responsive to difference capacitance values larger than a figure of merit correlated to an acceptable level of NEXT isolation.