A Subscriber Identification Module (SIM) card enclosure is formed with an internal cavity adapted to receive a SIM card and a cellular transceiver. A wireless telephone is adapted for docking with the SIM card enclosure. A personal computer includes a docking receptacle for holding the SIM card enclosure and wireless telephone. The personal computer may communicate over a cellular telephone network when the SIM card enclosure is docked to the personal computer. The wireless telephone may conduct voice calls over a wireless link with the personal computer when the wireless telephone is undocked from both the personal computer and SIM card enclosure. The wireless telephone may communicate over a cellular telephone network when the SIM card enclosure is docked to the wireless telephone. Voice communications between the wireless telephone and personal computer may be conducted concurrently with data communications between the personal computer and the cellular telephone network.