Abstract: A relay device may include a plurality of communication circuits and a state control portion. The relay device may relay the data among a plurality of buses, each of which connecting one or more nodes. The plurality of communication circuits may perform transmission and reception of the data, and transition among a plurality of states including a transmission enabled state and a transmission disabled state. The plurality of communication circuits may be connected to the plurality of buses in one to one manner. The state control portion may cause a specific communication circuit to transition from the transmission enabled state to the transmission disabled state when a relay transition time has elapsed from an occurrence of predetermined event. The specific communication circuit may represent at least one of the plurality of communication circuits to which at least one of the plurality of buses connecting the specific node is connected.

Abstract: A relay device may include a plurality of communication circuits and a state control portion. The relay device may relay the data among a plurality of buses, each of which connecting one or more nodes. The plurality of communication circuits may perform transmission and reception of the data, and transition among a plurality of states including a transmission enabled state and a transmission disabled state. The plurality of communication circuits may be connected to the plurality of buses in one to one manner. The state control portion may cause a specific communication circuit to transition from the transmission enabled state to the transmission disabled state when a relay transition time has elapsed from an occurrence of predetermined event. The specific communication circuit may represent at least one of the plurality of communication circuits to which at least one of the plurality of buses connecting the specific node is connected.

Abstract: In a case that a gateway unit connected with multiple networks receives mode managing data indicating an operating mode from a first network, the gateway unit sends mode managing data formed based on the received mode managing data only to control units and a gateway unit connected with a second network excluding the first network. This prevents both the gateways units from repeatedly exchanging mode managing data indicating a normal operating mode. Each control unit thereby rapidly transfers to a low power consumption mode when being able to operate in the low power consumption mode.

Abstract: A data relay unit capable of relaying data communication between first and second networks interchanging different structures of data, a gateway (GW) and a method are provided. An identifier is assigned to transmission data and reception data exchanged in a GW unit. A data conversion section specifies a conversion process using reception data for generating transmission data for each transmission data piece identified by an identifier and uses a conversion table to store conversion processes. The data conversion section can generate intended transmission data based on an identifier of the transmission data to be transmitted by selecting and executing a necessary conversion process from the conversion table. Even when a method of generating transmission data is added or changed, it is only necessary to add or change a conversion process in the conversion table.

Abstract: In a case that a gateway unit connected with multiple networks receives mode managing data indicating an operating mode from a first network, the gateway unit sends mode managing data formed based on the received mode managing data only to control units and a gateway unit connected with a second network excluding the first network. This prevents both the gateways units from repeatedly exchanging mode managing data indicating a normal operating mode. Each control unit thereby rapidly transfers to a low power consumption mode when being able to operate in the low power consumption mode.