Abstract: Apparatus and methods for testing multiconductor data cables. A test connector having plural elements is engaged with one connector of the data cable, and a test signal is applied to a preselected common element of the test connector. The test signal is conducted through one conductor of the data cable to a connector on a breakout box and terminals on the breakout box are interconnected with one another while the presence or absence of the test signal at elements of the test connector other than the common element is detected.

Abstract: A circuit tester provides an indication of open circuit faults of individual conductors in cables. An oscillator circuit in the tesster includes a capacitance as an internal part of the circuit. Test probes connect conductor pairs to the oscillator circuit, thus changing the effective capacitance of the circuit. This changes the frequency output of the oscillator in accordance with the length of the conductors. Test indications may include a low pass filter and an audio circuit, or a circuit to convert frequency to a voltage or digitalized output. The tester may be used with automated test equipment.

Abstract: Test apparatus for evaluation of multiconductor cable assemblies inlcude plural diverse indicators for each dedicated conductor pair and is responsive to single operator input to selectively drive the indicators for indication of proper cable assembly condition, conductor shorts, open assembly condition, and connection polarity reversal per assembly pair.

Abstract: A thermal printer with a fault detection circuit for detecting faults in heating elements of the printer includes a print head containing heating elements and a heating circuit for each heating element and a power supply for supplying power to the heating elements. Power is supplied to the print head either directly through one terminal of the power supply or indirectly, during a test mode, through a fault detection circuit which is also connected to the print head. The fault detection circuit includes a constant voltage source, preferably formed of series-connected diodes, through which power flows to the print head. Current passing through the constant voltage source activates a photocoupler having an output the voltage of which determines whether a current is or is not flowing into the print head. A CPU which controls overall operations in the printer monitors the photocoupler and selects either a normal printing mode or a print head test mode.

Abstract: A test module incorporating a unique diagnostic circuit for monitoring the magnitude of electrical parameters existing between an electrical driver such as the electronic control module (ECM) of an automotive vehicle and an electrical load in the vehicle's electrical system. The circuit employs a visual indicator connected to a point adjacent the driver to provide a visual signal when the voltage at the point of connection lies within a predetermined range with respect to electrical ground. An additional visual indicator, separate from the first, is connected to a point adjacent to the electrical load, and provides a visual signal when the voltage at its point of connection lies within a predetermined range with respect to electrical ground. A third visual indicator is connected between the driver and load, and provides a visual signal in response to current flowing between the driver and load.