PURPOSE: To facilitate the input setting of set data to a transmission unit and to prevent erroneous set data from being set to the transmission unit by performing a transfer by the transmission signal of the set data stored in the transmission unit.

CONSTITUTION: A setting can be performed by transmitting the set data of a set transmission unit 1 to an operation unit 5, storing it and transmitting the set data from this operation unit 5 to an unset transmission unit 1a. Namely, the transfer by the transmission signal of the set data can be performed and the setting of the transmission unit 1a can be easily performed. If the set data stored in the transmission unit 1 is made to be stored by being transmitted to the operation unit 5 at the time of the maintenance of the transmission unit 1, the set data stored in the operation unit 5 can be restored by being transmitted to the transmission unit 1 even if the storage of the transmission unit 1 is reset and the reinput of set data can be prevented.