| 摘要 |
PURPOSE:To monitor a standby transmission line at all times even when the optical transmission line between an office device and a star coupler has in-use and standby redundant constitution by sending and receiving light signals which are different in wavelength by an in-use system and a standby system between the office device and a subscriber device and detecting a fault. CONSTITUTION:This system is equipped with a system-0 office device 1-1, a system-1 office device 1-2, and (n) (n: natural number) subscriber devices 2-1 to 2-n; and one-terminal sides of optical transmission lines 5-1 and 5-2, and 9-1 to 9-n are connected to the input/output terminals of the office devices 1-1 and 1-2 and subscriber devices 2-1 to 2-n, and the other-end sides are mutually connected by the star coupler 3. Then monitor signal transmitting and receiving circuits 8 which send and receive monitor signals are installed between the office devices 1-1 and 1-2 and at least one of the subscriber devices. Then the office devices 1-1 and 1-2 and the optical transmission lines 5-1 and 5-2 connected thereto have the two redundant constitutions and the monitor signals are different in wavelength by the two optical transmission lines 5-1 and 5-2 of the redundant constitutions. |
