In a node communicably coupled to alternative nodes through a bus, a transmitting unit receives first designation information from an alternative node. When the first designation information designates the node, the transmitting unit successively transmits, on the bus, the first designation information and data. When a request of an active communication occurs in the node, a request unit determines whether to receive a former part of the first identification information indicative of start timing of an active communication mode on the bus. When determining to receive the former part of the first identification information, the request unit transmits, on the bus, collision information at a timing that allows the collision information to collide with a latter part of the first identification information, resulting in rewrite of the first identification information based on bus arbitration, and transmits second designation information meeting the request of the active communication.