I'm having a problem with humming on just one port (port 7) on my TA308. Additionally, the cordless phone I was using on that port just stopped working. I tried another cordless and it doesn't work either. It's like that port had something weird happen. I have cross-talk between my CO lines, but I'm not sure that's related. Does this all seem to add up to needing repair of my TA308?

If it's something that just happened out of the blue or over night then yes, I would say you need to send the unit in.

You could always try defaulting the system and reprogramming but it sounds like that unit took a power surge or lightning hit.