I have a similiar issue with a small twist.
I have a couple of Bell POTS lines, and a few VOIP lines that come into the DVX-2000MS system. The Bell POTS lines go directly to the the DVG-3104MS. The VOIP lines go through a VOIP to POTS convertor from the service provider.
When I plug in an analog phone into the VOIP to POTS convertor, I always get the caller id displayed on the analog phone. When this same line is plugged into the DVG-3104MS, the caller ID does NOT work in the DVX-2000MS system.
The weird part that the Bell POTS lines that go into the DVG-3104MS have the caller ID working perfectly on the DVX-2000MS system. Why would they not be the same?
I've looked a the settings behind the scenes, in the DVG-3104MS :9999 but with no success. Can anyone help?