PURPOSE: To measure or command any station from a certain station by applying data measuring ability and storage ability in an accident time or a current state to the all stations.

CONSTITUTION: Each station has the ability to decode the storage and command of the data and to operate conforming to the command and transmitting and receiving ability. When the command to collect the total data from a No.1 station to a No.5 station in to the No.1 station is issued, the No.2 station is accessed from the No.1, and the reception of the command of the total data requests is transmitted. The No.2 accesses the No.3, and the command of the total data requests is transmitted. In the same way as above, the command of the total data requests is transmitted to the last No.5. The No.5 transmits the total data stored into a memory to the No.4. The No.4 stores the data to the memory, and transmits it to the No.3 together with the data of the No.4. In the same way as above, the data of the No.5 4, 3 and 2 are transmitted to the No.1. Thus, when the command of the total data requests is issued to the final station at the beginning and the transmission is started, only the data are sent and the command is not sent.