A system includes a subscriber identity module (SIM card and a communication circuit. The communication circuit communicates with an external device through a first wireless interface, and communicates with the SIM card through a second wireless interface. The SIM card includes a functional circuit core, an antenna and a transceiver connected to the functional circuit core and the antenna. The transceiver is configured to communicate a data signal between the functional circuit core and the communication circuit through the antenna, the communication circuit using the second wireless interface.