Very weird problem here,
My UC500 unit powered off (loss of power), when it came back up none of my ip phones are able to get ip, config or register properly.
I tried resoring my config (in case config was wrong), but that didn't help and in the end I restored to factory default - but that didn't help either.
It will allocate IPs to the data pool (which I have since removed as my windows server does this on our network) but the phones cannot get an IP, so they never request tftp settings and thus never register.
I've unplugged everytnig from unit except a couple of phones.
Thanks in advance
After experimenting with stopping the cdp and vlans on the built-in ports. I discovered that during a test where I restored one of the fast ethernet ports to normal service with this command:
switchport voice vlan 100
the system reported "Vlan 100 does not exist, creating it" (or something like that anyway) and viola! Everything started working properly!
I have no idea what caused the issue - I'm just glad its working now!
If I can just get my 7970's out of their factory reset loops (looks like they are trying to upgrade to new loads, but are failing) - I'll be back to normal and a very happy chappy!