A system is disclosed including a docking mechanism and mobile device having a resident client application are used to establish a network connection between the mobile device and a local area network such as an enterprise Private Branch Exchange (PBX). Once docked, the client application, a mobile unified communication integrated dialer (MUCID), is able to be used to select between carrying a communications call over a land line (through the PBX system) or a mobile telephone line (through a cellular communication network). User mobility is provided by allowing a docked mobile device to be undocked after transfer of an active call being carried over the PBX onto the mobile device. Communications protocols are provided between the MUCID and the docking station.