To provide an interface 1 for transmitting and receiving a signal between data terminal equipment 6 and a driver device 5 while electrically insulating those devices capable of realizing miniaturization and weight reduction without making it necessary to provide any battery or external power source, and realizing power saving, heating reduction, and noise reduction.
When data terminal equipment 6 and a driver device 5 use, for example, RS-232C as communication specifications, a signal power to be applied to the TXD of an RS-232C terminal 51 of the driver device 5 is used for the lighting of an LED 13 for transmitting an instruction signal from the driver device 5 to the data terminal equipment 6 in this interface 1. Then, when a data signal from the data terminal equipment 6 is received by the driver device 5, a signal power to be applied between the TXD and DTR of the RS-232C terminal 51 is used as a power for operating a photo-transistor 18 and an LSI 20 for a receiving circuit.
TAKAHASHI YUKIO
TAKAHASHI KOICHI
