| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmission system employing a star coupler for the connection between a station side unit and a subscriber unit that can quickly and effectively recover communication on the occurrence of a fault in an optical transmission line. SOLUTION: Optical transmission lines of an active system and a standby system including the star coupler 30 are used to interconnect the station side unit 10 and a plurality of the subscriber side units 20, and on the occurrence of a fault of a multiplex block optical fiber 40A, all the subscriber units select the standby system optical transmission line, and on the occurrence of a fault in a branch block optical fiber 41A-i, a concerned subscriber unit selects the standby system optical transmission line, and the station side unit selects a reception channel of the active system or the standby system in the unit of channels in response to the fault occurrence location. |
