Abstract: Messages on controller area network (CAN) buses are communicated over subsea links. Repeaters couple CAN buses to each end of a subsea link. The subsea link may be, for example, a twisted pair or a single wire with a sea ground. The repeater detects a direction of transmission, that is, whether a signal began on the CAN bus coupled to the repeater or on the subsea link coupled to the repeater. Signals from the CAN bus are conditionally transmitted to the subsea link depending on the detected direction of transmission. Signals from the subsea link are conditionally transmitted to the CAN bus depending on the detected direction of transmission. The repeater can operate at the physical layer without analyzing contents of the CAN bus communications.

Abstract: Distortions of both amplitude and phase along a transmission line are compensated for by a trace canceller inserted between a transmitter and a receiver. The trace canceller has an equalizer that compensates for a trace length between the transmitter and the trace canceller. A variable gain amplifier between the equalizer and an output buffer has its gain controlled by an automatic gain control circuit that compares low-frequency swings of the input and output of the trace canceller. The gain of the variable gain amplifier is reduced to prevent the output buffer from saturating and clipping peak voltages on its output. Thus both the variable gain amplifier and the output buffer remain in the linear region. Training pulses from the transmitter are passed through the trace canceller without clipping of peak voltages, allowing the transmitter and receiver to adjust transmission parameters to best match the transmission line.

Abstract: Herein disclosed is a communication apparatus to be operative in combination with first and second external devices for respectively producing first and second information, comprising: first information receiving means for receiving the first information from the first external device; communication performing means for performing a communication with the second external device by receiving the second information from the second external device and producing an exchange information to be transmitted to the second external device and; controlling means for controlling the communication performing means by assuming two different operational states including a first operational state to allow the communication performing means to be operable to perform the communication with the second external device and a second operational state to allow the communication performing means to be inoperable to perform the communication with the second external device, the controlling means being adapted to selectively assume th

Abstract: A power over Ethernet controller comprising: control circuitry; at least one temperature sensor operatively connected to the control circuitry; and a plurality of electronically controlled switches responsive to the control circuit, each of the electronically controlled switches enabling power to a respective port and having associated therewith inrush current limiting functionality, the control circuit being operative to input at least one temperature indication from the at least one temperature sensor; operate at least one of the plurality of electronically controlled switches thereby enabling power to a first port; and delay a time period dependent on the at least one temperature indication, whereby operation of a second of the plurality of electronically controlled switches to enable power to a second port is permitted only after the delayed time period.

Abstract: Method for transmitting charging signals via a data transmission path using resonance phenomena The invention provides a method for transmitting charging signals, in which an electrical resonance effect is provided, with an output current (100) being emitted from a line current driver device (202), which output current (100) is passed through a data path filter block (201), which has a data transmission path unit (122) and a matching filter unit (123), to a line impedance (102), and the matching filter unit (123) and the data transmission path unit (122) are set such that an electrical resonance effect occurs, which leads to a voltage peak occurring in a line voltage level (101).

Abstract: A remote power feeding method allowing efficient remote power feeding into a network termination device in the event of a commercial power failure at a subscriber site is disclosed. When the commercial power failure occurs, a power failure signal is transmitted from the subscriber-side network termination device to the central office-side line termination device. The central office-side line termination device, when receiving the power failure signal, starts DC power feeding to the subscriber-side network termination device via the subscriber line. During the power failure, only voice communication is permitted using previously selected good channels.

Abstract: A method is provided for communicating on an equipment network. According to the method, a message is sent from a sending equipment unit to a receiving equipment unit as a signal having a nominal power. Whenever the signal is amplified by an intermediate equipment unit through which the signal passes, the message is modified to indicate that the signal has been amplified by the intermediate equipment unit. Also provided is a first equipment unit for connection to an equipment network.

Abstract: A system and method for remotely powering an Ethernet network repeater through an attachment unit interface (AUI) between the repeater and a remote personal computer (“PC”) or workstation. The AUI includes logic circuitry to detect when the Ethernet is supporting a transmit signal and a receive signal. Associated with the AUI is a DC to DC converter which receives, remotely through the AUI interface, a DC voltage from the PC or workstation and converts the DC voltage into working voltages for the remote repeater.

Abstract: An isolated, high impedance, DC current source is provided from a readily available AC type source. The DC current source includes an isolating transformer which receives the AC source signal and provides an isolated AC voltage signal therefrom, a resonant low pass filter which is tuned to the frequency of the AC type source and which takes the AC isolated voltage signal and generates therefrom an AC current source signal, and a rectifier which rectifies the AC current source signal to provide a DC current source signal. A voltage limiting clamp is preferably coupled to the rectifier in order to limit the output voltage to a desired level. The resonant low pass filter is preferably comprised of two substantially equally valued inductors coupled to respective poles of the secondary winding of the isolating transformer, and a capacitor which is coupled to both of the inductors.

Abstract: A system of impedance matching is provided to match the total impedance of the cable system to the total impedance of the powered elements such as the repeaters. The source impedance of the power supplies may be considered as part of the cable impedance. By matching impedances, the source voltage for driving the electronics is advantageously minimized.

Abstract: A telephone includes a speech network for transmitting an outgoing voice signal and receiving an incoming voice signal from a remote telephone. The speech network is not supplied with power from a telephone exchange through a telephone line but supplied with a separate power supply. To interrupt the power supply from the telephone exchange, a transformer is interposed between the speech network and the telephone line. A ringer circuit and a dialer circuit are connected to the primary side of the transformer. Because the power supplied to the speech network does not fluctuate, the circuit design of the speech network can be readily performed using inexpensive circuit components.

Abstract: In an ISDN communications system, a remote station power detector circuit comprises a capacitor connected between center taps of transformers on the receive and transmit pairs of conductors. The capacitor stores energy delivered from a central DC power source. Two serially-connected opto-couplers form a discharge path for the capacitor. The first opto-coupler is periodically driven on to partially complete the discharge path. If the capacitor charge exceeds a predetermined minimum, the second opto-coupler will then be driven on, providing a logic level output usable by the remote station. Power consumption is minimized by the use of large resistors in series with the capacitor while reliable power detection is achieved by detecting accumulated charge on the capacitor. Dielectric isolation is provided through the use of opto-coupler circuits.

Abstract: An improved transformer-less electronic isolating transformer is obtained with an output subcircuit that outputs a controlled current rather than voltage. Specifically, the improved hybrid comprises an output drive subcircuit that receives an ac signal and creates a corresponding current that is passed to the line that supports two way communication. The subcircuit not only converts the applied voltage to current but includes means for effecting gain. Signals arriving to the hybrid from the line are applied directly to a near-end echo circuit that is also responsive to the signal applied to the output drive subcircuit. Both the input of the output drive subcircuit and the output of the near-end echo subcircuit are isolated with opto-isolators that employ photodiodes in their photo-voltaic mode.

Abstract: A transmission line between terminals of a three-terminal station is branched by a branching unit and power is transmitted between the terminals of the three-terminal station and a power feed system in the transmission line including: a switch for switching a power feed line feeding power to a repeater between a both-end power feed mode and a single-end power feed mode; and connection holding means for holding a power feed connection state without change upon an occurrence of a failure.

Abstract: In a circuit arrangement for automatic connection of a remote feed current path of a remote feed loop fed from both sides for electrical loads with direct current series feed, a parallel circuit of a first four-terminal network comprising two feed outputs and a second four-terminal network containing a connecting two-terminal network, controllable by current sensors, is provided for the acquisition of a feed output per remote feed current path, this being undertaken by way of diode current branches. The circuit arrangement can advantageously be employed for the remote feed of regenerators and communications transmission links.

Abstract: When a transmitter sends information signals time multiplexed in a single channel over a coaxial cable to a receiver, the expense necessary for synchronizing the demultiplexing operations to the multiplexing operations at the transmitter and for supplying the current necessary to energize the receiver is reduced by impressing or interposing pulses on or into the multiplex signal at the transmitter for synchronization and current supply at the receiver. 12 V pulses are transmitted at low impedance either as frame pulses at the beginning or at the end of a signal pulse frame of the multiplex signal or supplementarily as clock pulses between successive signal samples in the multiplex signal.

Abstract: A dataset apparatus is powered by voltages extracted from electrical signals passing between the data terminal apparatus and the dataset by circuits comprising a capacitor and diode combination. The transmitter of the dataset includes capacitance isolation of the signal from the transmission lines by applying an oscillated voltage and an inverted oscillated voltage dependent upon the signal to capacitors in a first circuit to charge the capacitors through a diode whereby the oscillating voltage causes the capacitors to discharge through a second path formed by further diodes to charge a pair of capacitors coupled across the transmission lines. A second circuit of similar impedance to the first charges the capacitors to the opposite polarity. The arrangement can handle high common mode voltages on the transmission lines.

Abstract: The telephone amplifier of an audio transmission circuit comprises a class-B output stage as a result of which the required supply current of this amplifier is considerably lower than with prior art telephone amplifiers. A distorting voltage produced by the current signal in the supply current of the glass-B output stage does not affect the output signal of the telephone amplifier because the input stage and the output stage each comprise their own setting circuits which produce mutually independent setting voltages.

Abstract: A circuit arrangement comprises two feed circuits which are connectible to a load with mutually opposite polarity. The circuit arrangement avoids mechanical contacts in the load circuit, at least with respect to one feed circuit. This is achieved in that switches, provided for the activation at at least one of the feed circuits, are disposed outside of the output circuit and in that a transistor is disposed between such a feed circuit and the load, this transistor being conductive given an activated feed circuit and being inhibited given a deactivated feed circuit. The circuit arrangement can advantageously be employed in remote feed devices of communications transmission device for the purpose of optionally feeding a remote feed section with a remote feed current or with a fault locating voltage.

Abstract: A subscriber line interface circuit is provided for a telephone system for interconnecting a two-wire telephone channel with a four-wire telephone channel. The circuit includes a pair of power amplifiers employing complementary circuitry and being coupled in complementary fashion to the two-wire channel so as to provide for both DC electrical excitation to the two-wire channel, as well as providing for an impedance match over the voice frequency spectrum, thereby reducing power dissipation while improving the coupling of voice and/or data signals. The presence of any noise on power line is rejected by use of transistor biasing circuits and by use of feedback circuitry. Both resistive and capacitive feedback branches are provided for the impedance matching.

Abstract: An electronic hybrid circuit for coupling a two-wire communication path to a four-wire communication path includes amplifier circuits having a reactive feedback path such that the output impedance of each amplifier is approximately zero ohms at DC and is a predetermined value at audio frequencies. The amplifiers are arranged to provide battery and voice signal injection on the two-wire path. Serially connected diodes provide protection from lightning.