just added a 384i to my base. Not good with system yet. No ring on base cabinet but do have ringing voltage on 2nd shelf

The 384i requires a ringer generator. YOu will need to get a hardware manual to see how to properly hook this up to get ringing voltage.

The system does have a ring generator. The top shelf does work but the bottom cabinet does not have ringing current. I am leaning towards thinking it is a backplane problem. Thanks for the reply and anymore advice.

I would bet that the ringer power supply is not properly run. You will need a hardware manual for this and it shows how it's supposed to be wired in.