| 摘要 |
PURPOSE:To control a transmission optical level before data transmission is disabled and to attain normal data transmission by detecting a level of a received optical signal so as to output a transmission optical signal level control signal thereby adjusting the level of the transmission optical signal. CONSTITUTION:A transmission data signal 7a from a data processing unit 1a or the like is converted by an optical transmission control section 2a of such as an optical transmitter 5a into an optical signal and sent to an optical reception control section 4b of an optical transmitter 5b similar to the transmitter 5a via a star optical transmission line 13, converted into an electric signal and fed to a data processing unit 1b of the similar configuration to that of the processing unit 1a. The control section 4b gives a received optical signal to an optical level discrimination section 3b simultaneously, in which the optical level of the received optical signal is discriminated and the level adjustment optical control signal based on the optical level is outputted from the optical transmission control section 2b and fed to the optical reception control section 4b of the transmitter 5a. Then the level of the transmission optical signal is adjusted via the control section 2a and the transmission optical signal level is adjusted before the data transmission is disabled and normal data transmission is attained. |
