Architecture for a communications system enabling a user to provision a telephone at a new location without network administrative pre-configuring. An input component (e.g., keypad) receives a numeric extension and PIN. The extension is a telephone extension of the user and the PIN can be administratively assigned. A location component provides location information of an enterprise communications server to the telephone based on the extension. The telephone uses the location information to send messages to the enterprise communications server. A registration component registers the telephone with the enterprise communications server based on the numeric extension. A telephony address is returned to the telephone. An authentication component authenticates the telephone based on the PIN. Upon authentication, the extension is assigned to the telephone, and telephone communications can be sent and received from that location.