LOOP ISLAND PROTECTION SYSTEM FOR SUBMARINE TRANSMISSION SYSTEM

摘要

PURPOSE:To realize a system that can prevent such a case where a submarine repeater cannot be controlled by both end offices on the land and is isolated. CONSTITUTION:A command transmitter 1 is provided at the end offices A and B on the land to transmit the commands to each submarine repeater in a fixed cycle for identification of the loop islands together with a command detector 2. If the detector 2 of a certain repeater does not detect the loop island identification commands received from the transmitters of both offices A and B while each repeater is receiving the loop-back commands from the offices A and B, the loop island state of the relevant repeater is recognized and the switch is reset to the loop backs L1 and L2 of the normal inputs Si1 and Si2 of the repeater. Then a timer 3 starts to count the time when the loop back instructions SV1 and SV2 are received by each repeater from the offices A and B and then produces the pulses at each fixed time to cancel the switch to the normal input loop back of its own repeater station.