Abstract: The task of identifying the terminals to be interconnected and not interconnected, and whether connection is proper in a complex electrical system, such as at the main distribution frame of a telephone central office, is made possible while the system is in operation under power without adversely affecting its operation of being adversely effected. This is done by connecting the combination of a load impedance and a test voltage source across the test points and measuring the voltage across the load. If the measured voltage exceeds the test voltage, the load impedance is maintained at a high value. If it does not exceed the test voltage, the value of the impedance is reduced for the test. Thus, the test impedance is either greater or lesser than the impedance presented by the telephone system at the test terminals. The test results are interpreted in the view of whether the test terminals should or should not be connected when properly wired.

Abstract: An apparatus for locating electrical conductors and short circuits in AC and DC circuits is disclosed herein. The apparatus has leads for connecting across open circuit breaker or fuse box terminals. Current limiting resistors and transistors limit the current, if AC or converted to pulsated DC, to a value that is sufficiently high to be read on a clamp-on ammeter at any point in the circuit being tested. A first pulse generator intermittently interrupts the current through the current limiting means to create a momentary pulse of approximately 1/2 to 1 second duration at a frequency of approximately 3 to 5 seconds. A second pulse generator interrupts the current limiting means at approximately 225 cycles per second to provide a pulsating component in the momentary pulse for DC circuits. A clamp-on ammeter will indicate this pulse at all points in the circuit except at the short circuit, whether in a DC or AC circuit.

Abstract: A system for tracing electrical cables within a building utilizing in combination a pulsing electrical load and a standard clamp-on type ammeter. In operation the intermittent current flow can easily be detected and cables can readily be traced from outlet to circuit breaker. The novel pulsing electrical load draws current at a characteristic rate that is independent of the amount of current drawn, so that various load resistances can be used, to suit the circuit being traced. If desired, the standard clamp-on ammeter could be replaced by a detector designed for use with the pulsing load.

Abstract: The corresponding opposite end portions of wires at opposite ends of a multi-wire conductor are matched in accordance with this invention with the use of a direct current circuit tester in conjunction with a diode assembly. The diode assembly is connected to the wires at one end of the conductor and the direct current circuit tester is applied to the wires at the opposite end of the conductor according to a specified procedure to identify or match the corresponding opposite ends of the respective wires. The circuit tester comprises a pair of probes, a direct current power source, and indicator means all electrically connected and operable for indicating the presence of an electrically conductive path connected between the probes. A reversing switch is connected to the probes to permit reversing the polarity thereof, with the reversing switch including a handle portion positioned to facilitate readily actuating the reversing switch by someone using the circuit tester.

Abstract: An apparatus for tracing electrical power circuits by only one individual worker. A signal generator, which, when its source of power is interrupted, furnishes a signal to the electrical power line from which it derives that power and permits an electrician to test the lines at the main power distribution point. The line which indicates a signal shortly after being disconnected at the fuse box is the circuit being sought. The delayed signal is accomplished either by semiconductors or by delayed action relays.

Abstract: A verification technique which greatly simplifies and facilitates the tesg of the wiring of wrapped wire electronic boards. The technique contemplates continuity testing of each branch and discontinuity testing between successive branches. After a continuity test for one branch and a discontinuity test with the next succeeding branch, the two branches are then short-circuited. The procedure is repeated with each wired branch until all branches have been tested, whereupon the short-circuit wire may then be removed. The testing technique may be facilitated by utilizing a numerically controlled terminal locator in combination with a computer generated control tape. The technique also contemplates a visual check to verify that all pins on the board that are intended to be wired are indeed wired, and that all pins on the board which are not intended to be wired are indeed bare.

Abstract: Apparatus is described for detecting the presence of a variety of electrical faults in a multi-pair shielded cable from a junction box connected to the cable at one end and to a socket connected to the cable at the other end. The apparatus includes a first module which is adapted to be connected to the appropriate set of terminals of a main junction box connected to one end of the cable and a second module which is adapted to be connected to the socket at the other end of the cable. To use the apparatus each module is connected to its respective termination. The first module includes a battery, a termination and a plurality of light emitting diodes, resistors and switches arranged to give a visual indication of faults in the form of shorts between two wires in the cable, shorts between one wire in the cable and the grounding shield and continuity between a pair of wires in the cable.

Abstract: The corresponding opposite end portions of wires at opposite ends of a multi-wire conduit are matched in accordance with this invention with the use of a direct current circuit tester in conjunction with a plurality of diodes, one for each of the wires to be identified in the multi-wire conduit. The diodes have respective pairs of leads which are electrically connected in series in alternating polarity. The diodes are connected to the wires at one end of the conduit and the direct current circuit tester is applied to the wires at the opposite end of the conduit according to a specified procedure to identify or match the corresponding opposite ends of the respective wires.

Abstract: The individual conductors of a multiconductor cable are connected to a panel board for testing, without being separated from each other, by producing a very smooth end section of the cable, locating the positional coordinates of each conductor end in a computer memory and pressing a grid of wires that have been preconnected to the panel board against the cable section. Wires in the grid that do not center on one of the conductors are first pushed back under direction of a computer.

Abstract: A wiring harness in which each of a number of conductors is to have a first end connected at a first place and its other end connected to a respectively associated second place is produced by applying an initiating signal to one of the first places. All of the first places are examined in sequence and the sequencing is stopped when an initiating signal is found. An indication is provided at the second place which corresponds to the first place at which sequencing is stopped. Then, unless previously done, a conductor is connected with its first end at said first place and the other end of that conductor is connected to the corresponding second place whereupon the indication is terminated and the sequencial examination continues.That method may be practiced with an apparatus which is connected between all first places and second places and which "looks" at pairs of first and second places in sequence.

Abstract: A portable cable test set includes a master unit connected to one end of a cable made up of multiple wire pairs and a remote unit connected to the other end. The master unit generates a series of digital pulses, a pulse being applied to a first wire of each wire pair in a predetermined sequence. The remote unit interconnects the wire pair with a resistor of predetermined resistance which differs from every other resistor and which is much greater than the resistance of the wire pair undergoing testing. A corresponding resistor of like value is included in the master unit and receives the same pulse that is applied to the wire undergoing testing. A comparator in the master unit compares the magnitude of the pulse sent over the wire pair with the magnitude of the pulse sent through the reference resistance in the master unit and a sequencer applies the next pulse to the next wire and next corresponding resistance when the preceding pulse magnitudes are equivalent.

Abstract: A system for use in tracing and identifying each one of a group of AC circuits in a power distribution network without necessitating removal of power from live circuits and without adverse effect on normal circuit operation. A simulated load is adapted to be coupled to any specific one of the live circuits being traced within the power network, and is operative to provide a DC current in the particular circuit in addition to the normal AC current component. A test device is adapted to be coupled sequentially to each circuit breaker or other circuit protective device normally included in each branch circuit and uniquely identifies the circuit being traced by sensing a DC voltage drop solely across the small but finite resistance of the protective device within that circuit. Means are provided to protect the sensitive DC test apparatus from damage due to inadvertant contact with the high AC voltages present in the network.

Abstract: Apparatus is disclosed for testing a cable by connecting Zener diodes or similar acting structures between terminating contacts at one end of the cable and then selectively connecting a series connected DC voltage source and resistor between terminating contacts at the other end of the cable. The diodes introduce unique voltage drops which determine the current flowing from the voltage source. The magnitude of the current is indicative of the condition of the cable with respect to continuity, correct connections, and interconductor short circuits.

Abstract: This specification discloses a system comprising a source for selectively applying a test signal to a selected conductor at a first end of a cable and a detector having a plurality of input terminals for connection, respectively, to at least some of the conductors at the second end of the cable. The detector operates to perform individual comparisons of the amplitudes of the signals on its input terminals with the amplitude of a decreasing reference signal and to produce a signal after a predetermined number of such comparisons in excess of a predetermined value have occurred. This last-mentioned signal causes a display unit to indicate the input terminal on which appeared the signal that produced the last comparison in excess of the predetermined value.

Abstract: A telephone test and assignment bureau is provided with a telephone instrument interconnected with an automatic wire pair identification field unit. A telephone number to be verified is dialed on the instrument and a start button is illuminated when the connection is completed by the switching equipment. Pressing this button initiates the verification procedure, and the wire pair identification field unit sends an interrogate signal over the telephone line to the central office. A wire pair identification control unit is connected via shoes at the main distributing frame to the cable having the wire pair assigned to the telephone number dialed. When the interrogate signal is received by the wire pair identification control unit it sends an identifying code back over the same telephone line to identify which wire pair on the main distribution frame was selected by the switching equipment in response to the telephone number dialed.