| 摘要 |
PURPOSE:To prevent retinopathy even when an optical fiber is inadvertently observed and to restart communication automatically when a line fault is recovered by using an output of an electrooptical converter into a pilot light of a low output when the line fault takes place. CONSTITUTION:A control means 50 upon the receipt of an input light interrupt signal from an optical signal detection means 40 via a line 60 outputs an output of an electrooptic converter 10 as a pilot light of a low output. When the fault is restored and the optical signal detection means 40 detects a pilot light of a low output, the transmission of an optical input interrupt signal is stopped and the control means 50 restores the output of the electrooptic converter 10 to a normal output. Thus, even when an optical fiber is observed directly and inadvertently, no retinas fault takes place and the communication is automatically restarted when the line fault is recovered. |
