Abstract: In one embodiment, a system for coupling communications signals to an underground medium-voltage power line includes a medium-voltage power line, a ground conductor, one or more ferrites, and a low-voltage communications line. The medium-voltage power line includes a center phase conductor and a concentric neutral conductor. The ground conductor couples the concentric neutral conductor to a ground connection. The one or more ferrites substantially surround at least a portion of the ground conductor. The low-voltage communications line includes a first conductor and a second conductor. The first conductor is coupled to the ground conductor between the one or more ferrites and the concentric neutral conductor. And the second conductor is coupled to the ground conductor between the one or more ferrites and the ground connection.

Abstract: In one embodiment, a device for coupling communications signals onto a medium-voltage power line includes a first connector, a second connector and one or more components. The first connector is adapted to couple to a low-voltage communications line. The second connector is adapted to couple to a surge arrester. The one or more components are operable to substantially match the impedances between the surge arrester and the low-voltage communications line.

Abstract: In one embodiment, a system for coupling a communications signal to a medium-voltage power line includes a surge arrester electrically coupled to a medium-voltage power line and a disconnect device electrically coupled to the surge arrester. The disconnect device is electrically coupled in parallel with a communications device and has a resistance of at least one thousand ohms and a capacitance between one picofarad and twelve picofarads. Furthermore, the disconnect device is electrically coupled to a ground without the use of ferrites.

Abstract: In one embodiment, a system for coupling communications signals onto a medium-voltage power line includes a metal oxide varistor, a disconnect device and a capacitor. The metal oxide varistor is electrically coupled to the medium voltage power line. The disconnect device includes a resistor in parallel with an air gap and is electrically coupled in series between the metal oxide varistor and a communications device. The capacitor is electrically coupled to the metal oxide varistor and the communications device in parallel with the disconnect device.

Abstract: In one embodiment, a device for enabling communications signals over a medium voltage power line includes a first modem, a second modem, a third modem, and one or more switches. The first modem is electrically coupled to a medium voltage power line and is adapted to receive communications signals from the medium voltage power line. The second modem is electrically coupled to the medium voltage power line and is adapted to transmit communications signals to the medium voltage power line. The third modem is electrically coupled to a low voltage power line and is adapted to transmit communications signals to the low voltage power line. The one or more switches are coupled to the first modem, the second modem, and the third modem, and they are operable to transfer communications signals between two or more of the first modem, the second modem, and the third modem.

Abstract: A system for testing a communication path for digital subscriber line (DSL) signals includes a loop management device coupled in the communication path between a DSL access multiplexer (DSLAM) and a DSL modem located at a customer premises. The system also includes a remote test interface coupled in the communication path between the loop management device and the DSL modem. The loop management device and the remote test interface communicate using voice-band signals transmitted over the communication path and collaboratively test the communication path.

Abstract: Controlled activation of a message-waiting light of a telephone unit of a PBX system, that is coupled over a two-wire link to a foreign exchange subscriber circuit terminating a digital communication link, is carried out by hardware and software modifications to each of FXO and FXS channel units at opposite ends of the digital communication link. These modifications are effective to rob redundant signalling bits of extended superframe format time division multiplexed digital communication signals to transport a prescribed request code, that instructs the FXS circuit to generate a message-waiting light driving signal on the tip-ring pair to the message-waiting phone.