To reduce the power consumption of a transmitter when circuits with different operating power supplies are isolated in terms of direct current and a signal is transmitted among the circuits.
An interface 2C, having a photocoupler that isolates circuits in terms of direct current is provided between a control section operated by a commercial power supply and a line side circuit operated by a station power supply, the interface 2C is provided with AND gates 31-33, each signal sent from the line side to the control section is given to photocouplers pc1-pc3 for each prescribed time, which provide an output to the control section. Furthermore, the interface 2C is provided with latch circuits 34, 35 and signals from photocouplers pc5-pc8 are allocated to either of latch circuits 33, 35 and outputted to the line side so as to reduce the number of photocouplers in the interface 2C.
TOYODA TAKAAKI
MUROI JUNICHI
SATO ISAO
