| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical network system which has a protective function and comprises low-cost communication nodes. <P>SOLUTION: In the optical network system, an optical transmission device 101 has at least one optical transmitter 111 and one optical receiver 121, and sending and receiving optical signals to and from a counter node. A switching device 201 sends an optical signal from the transmitter 111 to an signal-sending transmission path 301, and an optical signal from a signal-receiving transmission path 302 to the receiver 121 when both transmission paths 301, 302 have no faults. On the other hand, the switching device 201 changes the connection of transmission paths to send an optical signal from the transmitter 111 to the signal-receiving transmission path 302 when a fault occurs on the signal-sending transmission path 301, while changing the connection so as to enable an optical signal that is to be received at the receiver 121 to come in through the signal-sending transmission path 301 when an fault occurs on the signal-receiving transmission path 302. <P>COPYRIGHT: (C)2004,JPO |
