The invention is capable of performing flexible constructing design and system design together with coercive control under various circumstances. The invention comprises a connection interface (22) which is able to be connected with a communication network (25), performs control according to an request from an outside machine (26) of the communication network (25) to enable a signal line (Ls) to transmit a coercive control request signal, which requests a remote monitoring control system coercive control transfered to a coercive control state, to a transmission unit (10).