Old age is creeping in on me.... I don't know how I missed this last night.
What line cards are you using, and what is your source of dial tone? Comcast box, Voip adapter, copper POTS line?
These cable company phone boxes and Voip adapters use metallic ringing, where the ringing voltage is applied between tip and ring. 400D cards are looking for grounded ringing, where ringing voltage is between ring and ground.
If you've got a 400D card that's pre-issue 15, you're going to have a no ring-up condition. Those cards only work with grounded ringing. Even my copper POTS line won't work with pre-15 D cards anymore. If you can get hold of an Issue 15 400D card, or an ITT 400E, or any of the later 400G/H cards, try that. Might be your issue.
