Patent ID: 7869458

Claim:
A relay connection unit comprising: reception connectors to which a plurality of insertion connectors of communication lines can respectively be connected; a branch connection unit that branch-connects the communication lines through the reception connectors so as to divide the reception connectors into a plurality of groups; a plurality of vehicle-mounted LAN communication units each connected to the corresponding group of the reception connectors through the branch connection unit, and configured to transmit/receive messages; and a relay processing unit that relays an incoming message received through one of the vehicle-mounted LAN communication units to another of the vehicle-mounted LAN communication units in accordance with a relaying destination, wherein the branch connection unit is a matrix circuit in which switching circuits are arranged in lines between first conductors connected to the reception connectors and second conductors connected to the vehicle-mounted LAN communication units, the switching circuits being configurable to pass/block electrical signals bi-directionally.