| 摘要 |
PURPOSE:To provide the optical communication system by which the state of a standby system transmission line is monitored during its operation. CONSTITUTION:The optical communication system is formed such that an optical signal from a subscriber equipment 11 is fed to an active system station equipment 120 and a standby station equipment 121 through a star coupler 13 and the optical signal from the active system station equipment 120 and the standby station equipment 121 is fed to the subscriber equipment. The subscriber equipment and the station equipments are formed such that the subscriber equipment 11, upon the receipt of a standby system transmission line monitor instruction sent by the active system station equipment 120, sends a transmission signal transmission enable instruction to the standby station equipment 121, and the standby station equipment 121 receiving the instruction provides an output of information representing the state of the standby system transmission line to the active system station equipment 120 via the subscriber equipment 11. |
