Patent ID: 8705525

Claim:
A communication relay device for a train, mounted on a vehicle of a train having a vehicle formation including a plurality of vehicles, connected to an inter-vehicle communication path and to an in-vehicle communication path, and capable of relaying communications between communication terminals installed within own vehicle and communications between communication terminals installed in different vehicles, the communication relay device comprising: an inter-vehicle communication interface capable of transmitting and receiving a communication packet via the inter-vehicle communication path; an in-vehicle communication interface capable of transmitting and receiving a communication packet via the in-vehicle communication path; and an identification-information converting unit that converts, when vehicle identification information of a communication destination included in communication-destination identification information of a communication packet received from the in-vehicle communication path via the in-vehicle communication interface indicates other vehicle, vehicle identification information of a communication source, which is included in communication-source identification information of the communication packet and is vehicle identification information indicating own vehicle and used in common by each vehicle within the vehicle formation, into vehicle identification information for identifying a position of own vehicle within the vehicle formation, and then transmits the communication packet to the inter-vehicle communication path via the inter-vehicle communication interface, and converts, when vehicle identification information of a communication destination included in communication-destination identification information of a communication packet received from the inter-vehicle communication path via the inter-vehicle communication interface indicates own vehicle, the vehicle identification information of the communication destination into vehicle identification information indicating own vehicle and used in common by each vehicle within the vehicle formation and then transmits the communication packet to the in-vehicle communication path via the in-vehicle communication interface.