A VoIP telephone provides basic VoIP capabilities, such as those defined by SIP, with an onboard communications engine that presents a user interface at a display. More complex communications capabilities are provided by interfacing the telephone with an information handling system and driving the user interface of the telephone with a UC application executing on the information handling system. For example, the telephone has an LCD that presents a number pad or basic telephone number list for interaction with the communications engine; however, UC application drives a user interface with greater processing power and storage available from the information handling system, such as an address book or communication actions not supported by the communications engine.