Abstract: The length of an electrical cable is measured from only one of its ends, even though much of the cable may not be visible and its remote end may not be accessible. The ends of a conductor pair are selected to serve as contacts for a test capacitor. A reference capacitor having known capacitance value, and the test capacitor, are alternately inserted into an oscillator circuit while measuring the oscillator frequency. The two oscillator frequencies are compared to provide a ratio, which is then mathematically combined with a number indicative of the capacitance per unit length of the cable so as to produce an output number representing cable length.

Abstract: A pocket-size hand-held testing tool is provided for testing the operation of telephone lines and tracing the location of electric wires, including a sound signal channel with an output speaker, a dial tone detection circuit for detecting a dial tone on a telephone line, a probe for capacitively receiving a signal from a particular wire in a bundled wire cable to identify that wire as one to which a tracing signal is being applied at the other end of the cable, and a momentary switch normally connecting the dial tone detection circuit into communication with the sound signal channel but manually depressable to instead selectively switch the probe into communication with the sound signal channel while disconnecting the dial tone detection circuit from it.

Abstract: An electrical test kit for testing a telephone line from the terminals at the customer's end of the line includes a circuit for testing line continuity without falsely indicating to the voltage source that a telephone call has been answered, a push-button selection switch and a parallel pair of light-emitting diodes connected in reverse polarity relative to each other for determining polarity of the telephone line, and test pads in parallel with the continuity test circuit for permitting the attachment of a voltmeter so as to determine the magnitude of the internal resistance of the telephone line.

Abstract: An electrical connector utilizing a circuit board assembly for providing straight-through electrical interconnection of data line pairs between two jacks, and for providing breakout terminals. The layout of the electrical connector is such that common mode rejection is improved and cross-talk between data line pairs is minimized. The electrical connector has a circuit board with conductors located on both the bottom and top surfaces of the circuit board. The conductors are serially coupled to test pads to form a straight-through connection between pin openings located at opposite ends of the circuit board. The test pads are located so that the pads representing data line pairs are adjacent one another. Location of the test pads allows the conductors representing data line pairs to be located in a close parallel relationship for at least part of the way along the circuit board.