Abstract: A transmitting circuit is connected to a communication line and configured to transmit a primary signal, being a current signal, to the communication line by changing a current flowing from a transmission unit via the communication line. A receiving circuit is configured to receive a secondary signal which is generated by converting the primary signal transmitted from the transmitting circuit to a voltage signal by a current/voltage converter provided between the transmission unit and the communication line. Specifically, the primary signal, being a current signal transmitted from a communication terminal, is converted to the secondary signal being a voltage signal by the current/voltage converter. As a result, communication can be performed even when the impedance of the communication line is reduced, facilitating introduction of a communication system.

Abstract: A communication device 1 has a first protocol analysis section 11 that analyzes a status of a transmission signal Vs received at a transmission signal receiver 10. A transmission controller 14 determines a communication available period and a communication unavailable period based upon the analysis result. When the communication available period is determined, the transmission controller 14 allows a second protocol signal transmitter 12 to transmit a packet in accordance with a second protocol to a signal line Ls. With this result, it is possible to transmit a relatively large amount of data while suppressing noise influence caused by a varying condition of a carrier, in contrast to a prior system in which the transmission signal is superimposed only by a simple determination of the carrier condition. Thus, it is possible to share the signal line Ls with the time-division multiplexing transmission system and improve reliability of data transmission.

Abstract: A transmitting circuit is connected to a communication line and configured to transmit a primary signal, being a current signal, to the communication line by changing a current flowing from a transmission unit via the communication line. A receiving circuit is configured to receive a secondary signal which is generated by converting the primary signal transmitted from the transmitting circuit to a voltage signal by a current/voltage converter provided between the transmission unit and the communication line. Specifically, the primary signal, being a current signal transmitted from a communication terminal, is converted to the secondary signal being a voltage signal by the current/voltage converter. As a result, communication can be performed even when the impedance of the communication line is reduced, facilitating introduction of a communication system.

Abstract: A communication device 1 has a first protocol analysis section 11 that analyzes a status of a transmission signal Vs received at a transmission signal receiver 10. A transmission controller 14 determines a communication available period and a communication unavailable period based upon the analysis result. When the communication available period is determined, the transmission controller 14 allows a second protocol signal transmitter 12 to transmit a packet in accordance with a second protocol to a signal line Ls. With this result, it is possible to transmit a relatively large amount of data while suppressing noise influence caused by a varying condition of a carrier, in contrast to a prior system in which the transmission signal is superimposed only by a simple determination of the carrier condition. Thus, it is possible to share the signal line Ls with the time-division multiplexing transmission system and improve reliability of data transmission.

Abstract: A new network-adapted type protocol conversion connector with a function for converting the protocol for control signals sent and received between an indoor high-functional network laid in office buildings or dwelling houses and low-functional network-adapted appliances such as household electric appliance and facility, and an indoor communication network system using the connector. In the preferred embodiment, the protocol conversion connector comprises a primary connecting portion to be connected to the communication network laid indoors, a secondary connecting portion to be connected to a network-adapted appliance, a protocol conversion interface to convert the protocol for control signals sent and received between the communication network and the network-adapted appliance, and a feeder connecting portion to feed electric power to the network-adapted appliance to be connected to the secondary connecting portion.