I have some routers 1751 with an analog line backup, when the line is up, the router sended a message with a trace back code. I tried to decoded it with several cisco tools but I couldnt do it.
The software release that Iam using is 12.2.(4)T3
The messaje is the next:
Sep 25 17:35:11: %LINK-3-UPDOWN: Interface Async5, changed state to down
Sep