| 摘要 |
<p>PURPOSE:To make a seach for a fault by providing a repeater with the function of starting a PN(artificial random signal) sequence generating circuit when a signal from a prior-stage repeater is interrupted and the function of stopping a specific repeater from relay operating on detecting a control signal of specific repetitive cycles from a supervisory station. CONSTITUTION:When signals can not be sent out due to a fault of repeater R1k at the prior stage of repeater R1k+1 and optical fiber l between repeater R1k+1 and prior-stage repeater R1k is cut off, each repeater detects no received signal arriving to actuate PN sequence generating circuit 1 which generates a PN sequence of cycles characteristic to each trunk line. Then, PN sequence P is sent to the post-stage supervisory station M, which detects cycles of this PN sequence to judge repeater R1k+1 corresponding to the cycles, thereby identifying as a fault position an optical fiber extending to prior-stage repeater R1k or prior-stage repeater R1k.</p> |
