HALF DUPLEX CONTROL OPTICAL MODEM

摘要

PROBLEM TO BE SOLVED: To provide a half duplex control optical MODEM that excludes a noise fault in a transmission line and matches a full duplex optical transmission line with a system configuration condition of a half duplex transmission line in the case of long distance transmission between a peripheral device using the half duplex transmission for its system configuration condition and a computer. SOLUTION: In this half duplex control optical MODEM, a data signal S3x with a negative pulse received by a waveform shaping circuit 3b is outputted as a shaped data signal S11 from which the negative pulse is eliminated through 1st and 2nd waveform processing and the resulting signal is sent to a half duplex transmission line 101b as a normal data signal through an inverting circuit 2b and an input output buffer 1b. Furthermore, the shaped data signal S11 is given also to a signal control circuit 4d as a control signal and the signal control circuit 4b outputs a signal with a prescribed level on which a negative pulse is superimposed to match a system configuration condition of a half duplex transmission line and transmits the signal to a transmitter side.