Abstract: An underground marker and methodology for locating the same is discussed. The marker has a tuned circuit and an energy storage device. The marker also has a transponder that is coupled to the tuned circuit. When the tuned circuit receives electromagnetic energy at its tuned frequency, the tuned circuit resonates and provides power to the energy storage device, which in turn powers a transponder. The transponder has a memory containing a coded signal. The transponder transmits this coded signal using the tuned circuit. The transponder alters the impedance of the tuned circuit in accordance with the coded pattern. In this manner, an addressable underground marker can be used to locate particular types of buried structures. Nonaddressable markers can be used to locate addressable markers by providing a reference point for searches.

Abstract: The marker has a housing, an inner member and a tuned circuit. The housing has a spherical cavity therein. The inner member is located inside of the housing cavity and is rotatable therein. The tuned circuit has an inductance in the form of a coil as well as a capacitance. The tuned circuit is tuned to a particular frequency. A weight is coupled with the inner member and is eccentrically located within the spherical cavity. The eccentrically located weight seeks the lowest portion of the housing cavity. Thus, when the marker is manipulated so as to disorient the tuned circuit, the weight will rotate the inner member back to its stable position so as to properly orient the tuned circuit coil.

Abstract: A passive electrical marker has tuned circuits, each of which includes a coil and a capacitance. The tuned circuits are oriented with respect to each other in a predetermined arrangement so as to provide a broader spatial response. A foamed core inside of the tuned circuits maintains the tuned circuits in their respective orientations and protects the tuned circuits from mechanical shock. A shell or housing around the foamed tuned circuits provides environmental protection to the tuned circuits. The tuned circuits can be foamed together in a mold and then placed into the housing. Alternatively, the tuned circuits can be foamed together inside of a housing, which housing maintains the orientations between the tuned circuits during foaming. As still another alternative, the housing can be applied to the outside of the foamed tuned circuits as a coating.

Abstract: A digital telephone circuit is transferred from an old line to a new line. Before the transfer, a first stage delay circuit is inserted, wherein the delay of the data is incrementally adjusted to match the delay of a data control element. The data control element is then inserted in series with the data on the old line. The data control element incrementally adjust the delay and amplitude of the data on the old line to match that of the data on the new line. The incremental adjustments to delay and amplitude are within the specifications of the circuit, so as to minimize interruptions to the circuit. Interruptions are also minimized when the circuit is transferred to the new line. The data control element also introduces variations into the data at an upstream location. These are detected at a downstream location and are used for testing and communication purposes. The variations are removed from the data at the downstream end.

Abstract: A probe for use in sampling signals from a pair of telephone wires has two conductors that are separated from each other by an insulating material such as a circuit board. Each of the conductors has an overall size and has plural nonconductive interstices therein so as to reduce the capacitance of the probe. In one embodiment, each of the conductors is shaped like a comb having conductive strips. Each of the conductors could alternatively be shaped in a zig zag manner. The telephone wires are oriented parallel to the strips so as to enhance coupling therebetween. The probe can have plural channels thereon, such as two conductors on each side of the insulating material. The strips of one conductor are located in the gaps of the other conductor which on the same side of the insulating material. The probe can reduce common mode noise by being balanced. A grounded guard trace on each side of the insulating material snubs homogeneous electric fields.

Abstract: A passive marker is placed adjacent to a structure in order to locate that structure after burial. The marker has a tuned circuit arrangement contained within a housing. The tuned circuit arrangement has plural tuned circuits that are oriented substantially orthogonally to each other. A multidirectional response pattern is produced by the tuned circuit arrangement, which pattern is broader than the directional response pattern of a single tuned circuit. The housing is divided into two hemispheres for ease of assembly. Each hemisphere has channels formed therein for receiving the respective tuned circuits. The channels can be formed by the exterior wall of the housing, interior walls of the housing, or in an interior spherical mandrel.

Abstract: In a jack that receives a "make with break" plug or jack, there is provided a "make without break" plug. The jack has a circuit with a set of contacts that are normally closed. The circuit is opened by displacing one of the contacts out of contact with the other contact. With the make without break plug, only a minimal displacement of the jack contacts occurs. The plug minimizes the displacement of the jack contacts by limiting the physical size of the plug. A preferred embodiment utilizes a reduced radius to form a notch in the plug. This notch receives the jack contacts with little or no displacement of these contacts. Another technique used to minimize the displacement of the jack contacts is to limit the amount of force exerted by the plug against the jack contacts. The plug itself is provided with displaceable and pliant contacts. Less force is required to displace the plug contacts than is required to displace the jack contacts.

Abstract: Resistive faults are analyzed on a conductor in a telephone line by first charging the conductor to an initial voltage. The conductor is allowed to float for a finite amount of time, allowing some of the charge on the conductor to leak through any resistive fault. Then, the voltage of the conductor is measured and compared to the initial voltage. Loss of voltage indicates a resistive fault. This information can be used to provide an indication of the accuracy of a capacitance measurement and can be used to correct the capacitance measurement to account for the error due to the resistive fault.

Abstract: The invention provides methods of communication between two locations along a cable where the only metallic conductor available is grounded at numerous points along its length, which methods utilize a "distributed earth referenced carrier system" and wherein a first transceiver is electrically coupled to the metallic conductor at a first location and a second transceiver is electrically coupled to the metallic conductor at a second location.