Good question about the transfer. Have not tried that but will. No problem with internal calls. Did route inbound calls to an analog set on the third call the problem showed itself. Checked pbx during this call and the status was "talkg". The outside caller was hearing ringback but we could hear the outside person talking to a person with them. Telling the other person " why are they not answering". The carrier gets their logs for every call I submit to them and claim they have good setup and connect messages form the pri.