In order to enable switching control over power-feeding paths even in the event of a ground fault or an open fault in a power-feeding path, the submarine branching unit is provided with: a switching circuit which switches multiple power-feeding paths formed among a first through a third power-receiving ports; a control circuit which receives power from a power-feeding path formed between the first power-receiving port and the second power-receiving port and controls the switching circuit; and a connection circuit which connects the control circuit between the third power-receiving port and a sea-earth when no power is supplied to the control circuit from the power-feeding path formed between the first power-receiving port and the second power-receiving port.

Systems, methods and devices for a coaxial cable transmission system. A power supply receives a primary power signal from a power source. The power supply generates a switched direct current power signal from the primary power signal. A power gateway receives the switched direct current power signal over a coaxial cable from the power supply. The power gateway generates a secondary power signal from the switched direct current power signal. A load device receives the secondary power signal from the power gateway. In some implementations, the power supply generates the switched direct current power signal at a positive direct current voltage level for a first part of a time period and at a negative direct current voltage level for a second part of the time period.

Systems, methods and devices for a coaxial cable transmission system. A power supply receives a primary power signal from a power source. The power supply generates a switched direct current power signal from the primary power signal. A power gateway receives the switched direct current power signal over a coaxial cable from the power supply. The power gateway generates a secondary power signal from the switched direct current power signal. A load device receives the secondary power signal from the power gateway. In some implementations, the power supply generates the switched direct current power signal at a positive direct current voltage level for a first part of a time period and at a negative direct current voltage level for a second part of the time period.

The present invention is provided with: a first contact in a first relay connected to a circuit to be grounded; a resistor which is connected between the first contact and the earth, and which suppresses the flow of electric current to the first contact when the first contact is closed; a second contact in a second relay connected in parallel to the resistor; and an interlocking control means which inhibits opening of the first contact in a closed state when the second contact is opened, and which inhibits closing of the first contact in an open state when the second contact is closed.

To be able to check, from a remote location, a switching result of a power supply route, this communication system comprises: a plurality of terminal stations which each have a function of supplying power to a power supply path; a branching device which switches the power supply route, which includes a power supply path; and a monitoring device which, in response to one of the plurality of terminal stations transmitting to the branching device a switching signal specifying the power supply route, compares the voltages of the power supplied to the power supply paths respectively observed by the plurality of terminal stations, before and after transmission of the switching signal, and which, with the compared power supply voltages each having fluctuated by a first threshold or more, determines a switching result of the power supply route in the branching device.

To be able to check, from a remote location, a switching result of a power supply route, this communication system comprises: a plurality of terminal stations which each have a function of supplying power to a power supply path; a branching device which switches the power supply route, which includes a power supply path; and a monitoring device which, in response to one of the plurality of terminal stations transmitting to the branching device a switching signal specifying the power supply route, compares the voltages of the power supplied to the power supply paths respectively observed by the plurality of terminal stations, before and after transmission of the switching signal, and which, with the compared power supply voltages each having fluctuated by a first threshold or more, determines a switching result of the power supply route in the branching device.

A node of a radio frequency waveguide system can include a waveguide interface, a signal splitter, a power rectifier and conditioner, a communication filter, and a network processor. The waveguide interface is configured to communicate through a waveguide in the radio frequency waveguide system. The signal splitter is configured to split a radio frequency transmission received at the waveguide interface between a power path and a communications path within the node. The power rectifier and conditioner are configured to produce a conditioned power signal based on power received through the power path. The communication filter of the communications path is configured to produce a filtered communication signal. The network processor is powered by the conditioned power signal and configured to extract encoded information from the filtered communication signal.

A node of a radio frequency waveguide system can include a waveguide interface, a signal splitter, a power rectifier and conditioner, a communication filter, and a network processor. The waveguide interface is configured to communicate through a waveguide in the radio frequency waveguide system. The signal splitter is configured to split a radio frequency transmission received at the waveguide interface between a power path and a communications path within the node. The power rectifier and conditioner are configured to produce a conditioned power signal based on power received through the power path. The communication filter of the communications path is configured to produce a filtered communication signal. The network processor is powered by the conditioned power signal and configured to extract encoded information from the filtered communication signal.

In one embodiment, a switched amplifier is provided to amplify a data transmission. The switched amplifier may use a control signal that is received via a control signal channel in a transmission cable. Also, the switched amplifier may detect signal power to determine whether the data transmission is received at one of a first port and a second port. Data transmissions via the data transmission channel occur in a first direction and a second direction in a same frequency range in a time division multiplex (TDD) mode. Also, the control signal and data transmission are diverted from the transmission cable that transmits a type of signal different from the control signal and the data transmission. The switched amplifier is controlled based on the control signal or the signal power detected. The amplified signal is diverted in the first direction or the second direction via the data transmission channel back to the transmission cable.

In one embodiment, a switched amplifier is provided to amplify a data transmission. The switched amplifier may use a control signal that is received via a control signal channel in a transmission cable. Also, the switched amplifier may detect signal power to determine whether the data transmission is received at one of a first port and a second port. Data transmissions via the data transmission channel occur in a first direction and a second direction in a same frequency range in a time division multiplex (TDD) mode. Also, the control signal and data transmission are diverted from the transmission cable that transmits a type of signal different from the control signal and the data transmission. The switched amplifier is controlled based on the control signal or the signal power detected. The amplified signal is diverted in the first direction or the second direction via the data transmission channel back to the transmission cable.