We have a 2811 with CME on with 12.4.15 code on and two ISDN BRI lines. The problem we are experiencing is that outgoing calls are intermitantly working. This is not due to load as I'm the only one on these lines. I can use all four lines if I'm really lucky. What is strange though is that I can type in the number and hit dial and it IMMEDIATELY starts ringing. It does this sometime even when the BRIs are shut??? It doesn't give an enganged tone or anything, I get a sound like it's ringing on the other side. Then other times I hear a bit of delay and then I can see the call go out. Any thoughts, please. This is driving me nuts.