Abstract: A system for transmitting data over power lines between a plurality of communication boxes, wherein each box is coupled to a neutral line such that at least one box can modulate data onto the neutral line and at least a second box can read modulated data off the neutral line. Accordingly, the system enables data to be transmitted over neutral lines, without requiring coupling to hot lines.

Abstract: Apparatus for remote detection of discharge on a power line, including a line sampler for obtaining samples of a signal on a power line; a high pass filter for identifying high frequency components of the signal, where the high frequency components are indicative of discharge within the signal; and a reporting unit for reporting identified components as a remote discharge.

Abstract: Communication apparatus, comprising: a network of power lines; and first, second and third transceivers, coupled to the network, the first transceiver being adapted to transmit a first signal over the network to the second transceiver within a selected frequency band at a transmission power level sufficiently strong that the first signal can be decoded by the second transceiver, but is attenuated sufficiently when it reaches the third transceiver so that the third transceiver can receive a second signal over the network in the selected frequency band substantially without interference by the first signal.

Abstract: A system for transmitting data over power lines between a plurality of communication boxes, wherein each box is coupled to a neutral line such that at least one box can modulate data onto the neutral line and at least a second box can read modulated data off the neutral line. Accordingly, the system enables data to be transmitted over neutral lines, without requiring coupling to hot lines.

Abstract: A method for communication over a network of power lines (34), including establishing a communication link within a selected frequency band over the network between a first transceiver (32B) coupled to the network and a second transceiver (32C) coupled to the network. The method further includes transmitting a first signal over the link from the first transceiver to the second transceiver at a transmission power level that is sufficiently strong that the signal can be decoded by the second transceiver, but is attenuated sufficiently when it reaches a third transceiver (32E) coupled to the network so that the third transceiver can receive a second signal over the network in the selected frequency band substantially without interference by the first signal.

Abstract: A method for communication over a network of power lines (34), including establishing a communication link within a selected frequency band over the network between a first transceiver (32B) coupled to the network and a second transceiver (32C) coupled to the network. The method further includes transmitting a first signal over the link from the first transceiver to the second transceiver at a transmission power level that is sufficiently strong that the signal can be decoded by the second transceiver, but is attenuated sufficiently when it reaches a third transceiver (32E) coupled to the network so that the third transceiver can receive a second signal over the network in the selected frequency band substantially without interference by the first signal.

Abstract: A method of transmitting data over lines of power line network comprising: inductively generating opposite polarity currents representing the data on first and second lines of a pair of lines of the network at a first location along the lines that propagate along the lines; and sensing the propagated currents at a second location along the lines.

Abstract: A method of transmitting data over lines of power line network comprising: inductively generating opposite polarity currents representing the data on first and second lines of a pair of lines of the network at a first location along the lines that propagate along the lines; and sensing the propagated currents at a second location along the lines.

Abstract: A method for communication over a network of power lines (34), including establishing a communication link within a selected frequency band over the network between a first transceiver (32B) coupled to the network and a second transceiver (32C) coupled to the network. The method further includes transmitting a first signal over the link from the first transceiver to the second transceiver at a transmission power level that is sufficiently strong that the signal can be decoded by the second transceiver, but is attenuated sufficiently when it reaches a third transceiver (32E) coupled to the network so that the third transceiver can receive a second signal over the network in the selected frequency band substantially without interference by the first signal.

Abstract: A management system for coin operated laundry machines at individual locations, the system including data transfer means at each machine, a hand held terminal for receiving and transmitting data, in which each machine includes a circuit board interconnecting coin collecting means and operational circuits, the circuit board having storage facilities for both operational parameters and coin auditing data, the hand held terminal having means for transmitting information serving to vary any of the operational parameters and for receiving data associated with coin collection.