I just had an issue where the the phone on the first extension showed a "Layer 1 Link Error" which caused us to not be able to establish a line out, it would say "BUSY - All lines are busy". We could still ring internal extensions.

I could ping the SIP trunk server from my PC OK.

After I rebooted the router and the SV9100 switch, all was fine.

I'm just wondering if anyone has experienced this or knows what could have caused it?

Thanks