Hi,
I appreciate all your help,

I am not sure if my tech did the process of eliminarion with 1st the EXP unit and then the dtib, but I certainly will pass that to him. There is an inskinVM. The system is fine until the EXP unit is plug in. There are 6 co lines there is 1 additional CO board in the main processor;There is only 1 dtib in the expansion. Not sure if he used etrace, but the problem is sporadic sometimes the extension will forward to VM after 4 rings and sometimes, it just doesn't???? Big mystery, But I will have him check those items individually, I'm sure he may have, but who knows...

Thanks for your great help, more than Vodavi has ever given LOL

Lorena