I really appreciate your help, but I don't think I can point the finger just to cell phones. None of this happened before the system upgrade. People called into the old SVMi16 all the time and there was never an issue with dialing extensions. The PRI is unchanged and they still even have the same desk phones - Falcon 18-button. There has to be something different in the DTMF timing on the SVMi20. I guess the best thing to do would be to fire up the old SVMi16 and compare settings