| 摘要 |
PROBLEM TO BE SOLVED: To obtain a redundancy optical access system with a function for always performing self-monitoring of normality of a backup interface board and an optical switch for connecting the backup interface board to an optical transmission path in standby when redundant structure of N:1 is adopted in a PON system. SOLUTION: The backup interface board 6 drive at least a light emitting element to perform a transmitting operation in the standby. The optical switch 7 having 1×(n+1) ports transmits output light of the backup interface board 6 from one port on the non-switching side to a port # (N+1) on the switching side. A self-monitoring circuit 8 monitors the normality of the backup interface board 6 and the optical switch 7 from presence/absence, a level and quality, etc. of optical signal transmitted to the port #(N+1) on the switching circuit and when a failure is detected, informs a controller 9 of the failure. Maintenance such as exchange of a backup system is preliminarily performed before the failure occurs in an active system. COPYRIGHT: (C)2008,JPO&INPIT
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