To operate a handy terminal equipment by connecting the same handy terminals to respective plural transmission stations.

Concerning this handy terminal, when operating various kinds of equipment of plant facilities, handy terminal equipment 3 is connected to a transmission station 2i to which the target equipment is connected so that the ID symbol of the transmission station, to which the handy terminal is connected, is identified and corresponding to this identified transmission station, the operation picture of equipment to be operated at that transmission station can be automatically prepared. Therefore, even when the common handy terminal is connected to any transmission station, the equipment can be operated by generating the operation picture corresponding to the transmission station, one handy terminal 3 is connected to a lot of respective transmission stations 21, 22, 23... and the equipment, of which the operation is allocated to every transmission station, can be freely operated.