| 摘要 |
PURPOSE:To obtain a sufficient S/N in a terminal station without affecting a communication quality by sending a supervision control signal from the terminal station through an exclusive supervisory fiber, receiving the control signal by means of a bidirectional reproducing repeater circuit, driving a supervision control part, and returning a response signal including supervisory activity information to the terminal station. CONSTITUTION:When a terminal station (A) 1 sends a supervision control instruction 7 to an exclusive supervisory fiber 10, the instruction 7 is received by a bidirectional reproducing repeater circuit 9, guided to a supervision control part 4, demodulated, and aimed supervisory activity is executed. Further, for the information collected by the supervisory activity, a supervisory information medium signal transmitted from a terminal station (B) 2 is operated by a modulating part arranged in the supervision control part 4, it is modulated by the bidirectional reproducing repeater circuit 9, and returned through the exclusive supervisory fiber 10 to the terminal (A) 1 as the supervisory response signal 8. Thus, the expected S/N can be obtained without excercising an adverse effect on the communicating signal. |
