| 摘要 |
PURPOSE:To make it possible to transmit signals through two transmission lines and to prevent the titled device from being operated erroneously due to noises by a method wherein a control device and a device to be controlled both of which are separated from each other are so arranged that they have no common potential. CONSTITUTION:A command signal transmitting and receiving section 1 on the side of the control device and a plurality of operation signal transmitting and receiving sections 2 on the side of the air conditioner are connected through the two signal transmitting lines 3 and 4 and the sections 2 themselves are connected parallel to one another. The command signal transmitting and receiving section 1 includes a reference voltage supply terminal 111, switching elements 112, 120- 122, resistors 113, 114, 117, switching diodes 119, 126, a signal reversing inverter circuit 123, a signal receiving terminal 124, a signal transmission switching signal input terminal 125 and a transmitting signal input terminal 127 while the operation signal transmitting and receiving section 2 includes photo-couplers 221, 222, reverse flow preventive diodes 227, 228, a switching element 232, a reference voltage supply terminal 230, resistors 229, 231, a signal receiving terminal 234 and a transmitting signal input terminal 233. |
