JPS6462929A - Repeater - Google Patents

Abstract

PURPOSE:To attain normal restoration after fault recovery in a short time, by selecting a synchronizing signal from a pre-stage as it is as an output in response to the detection output of a fault when a multi-stage repeater detects the fault of a means synchronizing with an input signal from the pre-stage. CONSTITUTION:An input signal 1 from the pre-stage is given to a frame synchronizing circuit 100 and a switching circuit 102 of a repeater 7. The frame synchronizing circuit 100 takes frame synchronization with the input signal 1 to extract a redundancy signal or an auxiliary signal and inserts an auxiliary signal 2. When no error exists in the circuit 100, the output 6 of the synchronizing circuit 100 is sent to the post-stage via a switching circuit 102. When a fault detection circuit 101 uses a monitoring signal 3 to detect the fault of the circuit 100, the switching signal 5 is sent to the switching circuit 102 to output the input signal 1 from the prestage to the post-stage as it is. When the fault is recovered, the state is restored into the initial state and the signal 6 is outputted (4) to the post-stage. Thus, the time of the frame synchronization in all repeaters at the restoration of fault is shortened.