OPTICAL FIBER CHANGEOVER CIRCUIT

摘要

PURPOSE:To increase the number of lines between branch lines and main lines without any fault by sending a control signal from a land station connected to the branch having no fault at the occurrence of the fault in the branch line so as to activate an optical fiber changeover switch connecting the main line and the faulty branch line thereby applying changeover of the faulty line at the fault of the branch line without giving effect on the normal line. CONSTITUTION:If a fault takes place in a branch B, a land station connected to a sound branch C generates a control signal, which is fed to a control circuit 105 via couplers 104, 103. The control circuit 105 activates an optical fiber changeover switch 101 connecting the main line A and the faulty branch B and turns the switch to the connection in broken lines from the connection in solid lines thereby controlling the switch to connect the main line A and the sound branch C. Thus, the faulty branch B is disconnected and the line increase between the sound branch C and the main line A is attained.