In-vehicle communication system

An in-vehicle communication system comprising:

• a plurality of communication buses mounted in a vehicle;
• a plurality of communication devices connected to any one of the plurality of communication buses;
• a relay device for relaying information among different communication buses;
• and
• a power supply control device for respectively performing power supply control of one or a plurality of in-vehicle devices being connected;
• wherein:
• one communication device of the plurality of communication devices transmits/receives an information group including one or more pieces of information to one communication bus of the plurality of communication buses, and
• the relay device comprises:
• a plurality of communication parts respectively connected to the plurality of communication buses;
• a communication control part for transmitting/receiving the information group transmitted from each communication device through the plurality of communication parts;
• a storage part in which a power supply state table indicative of power supply states in which said one or a plurality of in-vehicle devices are to be under each vehicle state is stored in a rewritable manner, for each of a plurality of vehicle states predetermined in the vehicle;
• an extracting part for extracting information required for power supply control of said one or a plurality of in-vehicle devices respectively from information groups received via different communication buses among the plurality of communication buses;
• a specifying part for specifying a vehicle state based on the information extracted by the extracting part;
• a determining part for determining a power supply state of one or a plurality of in-vehicle devices, based on a vehicle state specified by the specifying part and the power supply state table stored in the storage part;
• a creating part for creating control information for providing an instruction of a power supply state determined by the determining part;
• and
• a transmitting part for transmitting control information created by the creating part to the power supply control device.