A data network has at least three line branches connected via a common star node to distribute message signals from one of the line branches onto the other line branches, wherein connected to at least one of the line branches is at least one bus-user device is configured to generate in a corresponding transmit mode by a corresponding transmit unit at least one of the message signals, wherein in the corresponding bus-user device, the transmit unit has a current source circuit which, in generating the message signal (16), is configured to inject an electric current into electrical lines of the line branch to which the bus-user device is connected, and via the current source circuit the lines are connected to an internal impedance value of the current source circuit that in transmit mode is constantly greater than 10 times the value of the characteristic impedance, for example greater than 500 Ohms.

In one or more embodiments, a system includes a plurality of network devices comprising a plurality of ports, a power bus connecting the network devices, wherein power is shared between the network devices over the power bus, and a controller for identifying available power and allocating power to the ports. The ports include a plurality of PSE (Power Sourcing Equipment) PoE (Power over Ethernet) ports each operable to transmit power to a device connected to one of the PSE PoE ports, a plurality of PD (Powered Device) PoE ports each operable to receive power from a device connected to one of the PD PoE ports, and a plurality of bi-directional PoE ports each configurable to operate as a PSE PoE port to transmit power to a device connected to one of the bi-directional PoE ports or as a PD PoE port to receive power from the connected device.

One embodiment is directed a powered device that comprises a connector to connect a multi-conductor cable to the powered device and device circuits partitioned into a first partition and a second partition. The powered device is configured to receive power from a first cable circuit and a second cable circuit provided over the multi-conductor cable. The powered device is configured to separately power the first partition using power received from the first cable circuit and power the second partition using power received from the second cable circuit and to power isolate the first cable circuit from the second cable circuit. The powered device further comprises at least one isolation device coupled to the first partition and the second partition and configured to enable information to be communicated between the first partition and the second partition. Other embodiments are disclosed.

A low voltage drive circuit includes a transmit digital to analog circuit that converts transmit digital data into analog outbound data by: generating a DC component; generating a first oscillation at a first frequency; generating a second oscillation at the first frequency; and outputting the first oscillation or the second oscillation on a bit-by-bit basis in accordance with the transmit digital data to produce an oscillating component, wherein the DC component is combined with the oscillating component to produce the analog outbound data, and wherein the oscillating component and the DC component are combined to produce the analog outbound data. A drive sense circuit drives an analog transmit signal onto a bus, wherein the analog outbound data is represented within the analog transmit signal as variances in loading of the bus at the first frequency and wherein analog inbound data is represented within an analog receive signal as variances in loading of the bus at a second frequency.

A control device for controlling at least one LED module includes: a power supply module arranged to receive power over Ethernet to generate a first supply power; and an illumination controlling module coupled to the power supply module for receiving a communication signal from the Ethernet to generate a serial bus signal to control an illumination of the at least one LED module; wherein the illumination controlling module is powered by the first supply power.

One aspect provides a power sourcing equipment controller for providing power to a powered device using power-over-Ethernet (PoE). The power sourcing equipment includes a voltage-output logic block to output a sequence of voltage signals, the voltage signals comprising at least a detection signal and a classification signal; a current-measurement logic block to measure current provided responsive to the voltage signals; a backoff-time-determination logic block to determine a backoff time in response to the current-measurement logic block detecting the provided current exceeding a predetermined threshold, the backoff time being determined based on an amount of time needed for discharging an internal capacitor associated with the powered device; and a timing logic block to cause the voltage-output logic block to delay the output of a next sequence of voltage signals based on the determined backoff time, thereby facilitating powering up of a device compliant with a different PoE standard.

A measuring assembly with at least two measuring devices and a higher-level unit, characterized in that the measuring assembly further has a network distributor, wherein the measuring devices are connected to the network distributor via a two-wire Ethernet connection, the measuring devices are fully supplied with power via the two-wire Ethernet connection, and the network distributor is connected to the higher-level unit with an Ethernet connection.

A sensor device may include an environmental sensor configured to sense an environmental parameter and generate a signal representative thereof, a single pair ethernet (SPE) interface configured to cooperate with an SPE link, and a controller provided in communication with the environmental sensor and the SPE interface. The controller may be configured to receive the signal representative of the sensed environmental parameter and to control the SPE interface to generate at least one ethernet frame including data indicative of the sensed environmental parameter for transmission over the SPE link. The controller may be further configured to automatically configure communication with a remote server over the SPE link via the SPE interface.

Techniques are provided for detecting a fault across a pair of lines. Pulse power is applied across the pair of lines. The pulse power comprises alternating pulse on-time intervals and pulse off-time intervals. During a pulse off-time interval, a resistor is connected across the pair of lines and then disconnected when a voltage across the pair of lines reaches a first droop percentage in a first period of time. After disconnecting the resistor, it is determined whether the voltage across the pair of lines droops at least a second droop percentage within a second period of time that begins after the first period of time. Occurrence of a line-to-line fault across the pair of lines is determined when the voltage across the pair of lines droops by at least the second droop percentage or more within the second period of time.

An in-vehicle communication system includes a first relay apparatus installed in a first area of a vehicle, and a second relay apparatus installed in a second area and are connected via a communication main line. A main control apparatus and an auxiliary control apparatus are connected to the first relay apparatus and a controlled apparatus is connected to the second relay apparatus, each connected via a communication branch line. The first input apparatus is installed in the first area and inputs information to the main control apparatus and the auxiliary control apparatus. The second input apparatus is installed in the second area and inputs information to the main control apparatus and the auxiliary control apparatus via the first relay apparatus and the second relay apparatus. The first relay apparatus and the controlled apparatus communicate via an auxiliary communication line provided into both the first area and the second area.