A personal communications system includes an interface unit which transmits calls received on a mobile wireless phone to one or more hard-wired telephones. In one embodiment, the interface unit includes a connector which mates with a voice communications port of a wireless device, which may be a cell phone, web-enabled phone, personal digital assistant adapted for wireless communications, or a so-called pocket PC. When a call is received by the wireless device, a processor automatically sends the call to a hard-wired telephone through the connector. In another embodiment, the interface unit is equipped to receive multiple wireless devices, and calls from each device are managed to prevent calls from two or more of the devices from being sent to the hard-wired telephone at the same time. This system thereby advantageously allows a use only one telephone number to satisfy all his personal communications needs. This translates into significant cost savings to the user in terms of end-of-the-month bills and increased convenience to all concerned. In another embodiment, a removable recording medium stores information (e.g., a user's telephone number) for activating the wireless communications device to receive or place calls through a wireless service provider. The wireless communications device may be integrated, for example, into a hard-wired telephone, wireless device, an appliance, a television, or a car. In another embodiment, a cell phone is programmed to automatically configure, and re-configure, itself to operate using cell phone numbers of different users.