ORDER WIRE SYSTEM FOR RING CONSTITUTION

摘要

PURPOSE:To ensure voice talking between stations and to improve the operation and maintenance of a network by switching an order wire line when a fault takes place in an optical transmission line between stations. CONSTITUTION:When a fault takes place in a transmission line, a control section 180 of a transmitter-receiver (100-1 to 100-n) adjacent to the transmission line detects it and a switch section 170 of the transmitter-receiver is set OFF. Then a control section 180 of the other transmitter-receiver (100-1 to 100-n) adjacent to the transmission line having the fault detects it and outputs a signal with an analog frequency in response to a dial number of a destination to transmitters-receivers (100-1 to 100-n) adjacent to the transmission line and not in use so far. Then the control section 180 of the transmitter-receiver (100-1 to 100-n) adjacent to the transmission line not in use receives the signal with the analog frequency corresponding to the dial number to turn on the switch section of the same transmitter-receiver (100-1 to 100-n).