Abstract: Systems and methods for detecting ground faults in a power transmission circuit powering a load. The system includes a common mode union that is connected to a positive terminal of a power supply and a negative terminal of the power supply. The power supply may be a bifurcated symmetrical power source. A power supply symmetry circuit is connected to the common mode union and a offset threshold comparator circuit is connected to the power supply symmetry circuit. The offset threshold comparator circuit is configured to compare a signal from the power supply symmetry circuit to a threshold voltage value and generate a ground-fault signal indicating a ground fault when the signal from the power supply symmetry circuit exceeds a threshold voltage value. A local load control circuit is connected to the offset threshold comparator circuit and configured to receive a signal from the offset threshold comparator circuit.

Abstract: A durable touch screen assembly including a display screen for projecting images to a viewer; an optically clear, flexible touch sensor through which the images are projected; an optically clear, flexible substrate positioned between the electronic display screen and the flexible touch sensor; a space between the flexible substrate and the electronic display screen sufficient to enable the substrate and the touch sensor to flex; and a durable polycarbonate protective layer at least about 0.01 inch thick attached in front of the touch sensor substantially free of intervening features that would impair visibility.

Abstract: A system for optimizing the transmission of power through multiple conductors from a remote power source to a local communications device including: (a) a controller for the power source and for incrementally increasing the output voltage during a transmission resistance detection protocol; (b) a first voltage detection circuit for detecting a predetermined minimum voltage received by the detection circuit and for placing a load across the conductors when that minimum voltage is received; (c) a second voltage detection circuit for detecting a predetermined maximum voltage received by that detection circuit and for removing the load from across the conductors at that time; (d) voltage and current measuring devices to measure the transmission current and the output voltage of the power source when the predetermined maximum voltage is received; and (e) memory for storing the measured voltage, measured current and the predetermined maximum voltage for use by the controller.

Abstract: Embodiments are described that include a “front end” device located remotely from a local telephone location. The front end filters DC and AC current on a telephone line to separate these signals and passes a DC current through a low resistance Low Pass Filter without traditional resistance or current limiting means. The front end also provides signaling capability isolated from the DC and audio channels by a High Pass Filter. Some embodiments also include a “back end” unit located near a local telephone location. The “back end” unit filters the DC and AC currents into at least two DC current streams. One of the DC current streams provides sufficient current to power a local telephone. The other stream(s) provides current sufficient to power an auxiliary device. The “back end” device may also provide signaling isolated from the DC and audio channels that is complementary to the “front end” signaling.

Abstract: Embodiments are described that include a “front end” device located remotely from a local telephone location. The front end filters DC and AC current on a telephone line to separate these signals and passes a DC current through a low resistance Low Pass Filter without traditional resistance or current limiting means. The front end also provides signaling capability isolated from the DC and audio channels by a High Pass Filter. Some embodiments also include a “back end” unit located near a local telephone location. The “back end” unit filters the DC and AC currents into at least two DC current streams. One of the DC current streams provides sufficient current to power a local telephone. The other stream(s) provides current sufficient to power an auxiliary device. The “back end” device may also provide signaling isolated from the DC and audio channels that is complementary to the “front end” signaling.