PURPOSE: To make it possible to move an instruction means to an optional position equipped with a telephone line by forming the instruction means independently of a center control part and allowing the instruction means to send an instruction to the center control part through the telephone line.

CONSTITUTION: A system control part 300 receives and inputs data from a display operation part 306 or a telephone set 313 through telephone lines 319, 321, 322. When the received data are those received from the operation part 306, whether the data are those to be outputted to a control output part 304 or not is decided. When the data are the those to be outputted to the output part 304, the control data are outputted to the output part 304. Then a data signal is inputted from a sensor input part 305. When a change is generated in the sensor signal, sensor data are outputted from a communication part 303 to the operation part 306. When the received data are those received directly through the telephone line 321, dial data receiving processing is executed.