A Power over Ethernet (PoE) Powered Device (60) is described herein that includes an auxiliary processor (62) that negotiates a power level with a PoE Power Sourcing Equipment using a first link layer (650), means for holding the PoE Powered Device in a low power state, and a second link layer (50) that allows the main processor to communicate over the Ethernet.

A loudspeaker system is provided herein comprising: a digital transmitter adapted to store, retrieve, and transmit digital messages over a network cable using an audio over internet protocol (AoIP), and wherein the transmitted digital messages are individually addressable using an IP address, and wherein the transmitted digital messages contain digital audio messages and digital command and control messages; an endpoint enclosure adapted to have a unique IP address pre-assigned to it such that the endpoint enclosure is adapted to receive the transmitted digital messages addressed to it and extract the digital audio messages and the digital command and control messages from the transmitted and received digital messages, and wherein the endpoint enclosure comprises additional circuitry adapted to extract the digital audio messages from the received digital messages and power from the network cable, and generate an electrical audio signal from the extracted digital audio messages; an “N” position switch adapted to receive the electrical audio signal from the additional circuitry and output the same on one or more of “N” output ports based on the position of the switch; and a first set of loudspeakers adapted to receive the electrical audio signal and broadcast the same as an acoustic audio signal.

Emergency power control systems enable Power-over-Ethernet (PoE) devices to be powered by primary and emergency power sources.

A power receiving device includes a connector configured to be connected to a power feeding device; a power source configured to receive a power supply from the power feeding device via the connector; and a controller configured to perform a predetermined process before a power supply stopping time in response to receiving a preliminary notification of power supply stopping from the power feeding device via the connector.

In an embodiment, a powered device (PD) interface circuit includes a lower priority PD and a higher priority PD. The lower priority PD is configured to receive, and to couple to a power supply onboard a subsystem, a first power signal from first power source equipment (PSE). And the higher priority PD is configured to receive a second power signal from second PSE, to couple the second power signal to the power supply, and to prevent the lower priority PD from coupling the first power signal to the power supply while the higher priority PD is coupling the second power signal to the power supply. That is, such a PD interface circuit is configured to impart a respective priority to each PD such that if two or more PDs receive power from respective PSEs, then the interface circuit enables only the PD having the higher priority to couple a corresponding PSE power signal to the power supply onboard the subsystem.

A first network device is connectable via electrical lines to a power supply and to other subscribers of a network for transmitting audio and/or image information. It has an input terminal connectable to the power supply, an output terminal connectable to a second network device, and signals and operating voltage are transmitted via the terminals using four layers. Equipment processes the signals received via the lines and the operating voltage in the first network device by receiving and/or retrieving or processing information relating to a maximally available PoE supply input on the input and receiving, or retrieving and or processing information relating to a power intake required at least by the second network device received and/or retrieved and/or further processed by the second network device. A tester is connected to the equipment for checking whether the supply input at the input is sufficient for the first and second network devices.

An integrated system is described. This integrated system includes: a radio node that communicates using a cellular-telephone communication protocol; and an access point that communicates using an IEEE 802.11 communication protocol. Moreover, the integrated system includes a housing between the radio node and the access point, where the housing provides mechanical coupling and electrical coupling between the radio node and the access point, and the housing provides electrical power and data to the access point from the radio node. For example, the housing may provide the electrical power and the data using a PoE cable. In some embodiments, the radio node dynamically modifies the electrical power provided to the access point or receives, from a controller, an instruction specifying the electrical power to be provided to the access point.

A photovoltaic system and a communication method therefor. The communication method includes: each slave sends a report signal to a host, and monitors a response signal of the host; and if the at least one slave receives the response signal, the corresponding slave executes a corresponding action on the basis of the response signal. Therefore, communication between the host and each slave is achieved in a mode that each slave actively sends the report signal, the host is prevented from adopting a roll call query mode, and occupation of bus resources by the host is reduced.

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.

Control device for PoE system having multiple power source devices comprises power supply state code generator in connection with the power source devices to convert a power supply state signal into a serial power supply state code; plural control circuits to generate power consumption control signals corresponding to said power supply state code by reference to a power supply to power consumption look-up-table, to control the ON/OFF of plural port switches; a signal bus connecting the power supply state code generator and the control circuits.