The data carrier has a communication protocol storage unit storing a communication protocol for communicating with an external communication device, an RF analogue receiver receiving an interrogation signal from the external communication device as an RF signal, a contact communication end terminal unit performing contact communication with the external communication device, a communication command controller controlling a command used in an RF communication protocol performed via said RF analogue receiver or a contact-type serial communication protocol performed via said contact communication end terminal unit, and a connection selector selectively connecting one of said RF analogue receiver and said contact communication end terminal unit with said communication command controller.