There is a closed thread that has the exact same problem I am having, Cisco 7841 IP phone has fast busy as soon as digit is dialed. The thread referenced indicates the solution “was missing the version number at the top of my Dialplan”. What version number are they referring to and how is the version number tagged in xml in the dialplan.xml file? I’ve looked for examples and can’t find any. Unfortunately the dialplan.xml referenced in the thread is missing.