Abstract: 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.

Abstract: A region to store authentication commands to perform authentication between a data carrier and a reader/writer device is divided into at least three areas, and as for the three areas, a first authentication command is stored in a first area, a second authentication command is stored in a second area, and a third authentication command is stored in a third area, and security levels can be selected depending on a command of an inquiry signal (41) transmitted from a reader/writer device (10), and thereby selection of the security level suitable for circumstances can be realized by a simple constitution.

Abstract: Both RF communication and contact serial communication can be performed with the use of: communication protocol storage unit for storing a communication protocol for performing communication with an external communication apparatus; a coil terminal section provided with two coil terminals for performing communication with the external communication apparatus with an RF signal; a contact communication terminal section provided with a first communication terminal, a second communication terminal, a power supply voltage terminal and a ground terminal as contact communication terminals for performing contact communication with the external communication apparatus; and connection control unit for causing the power supply voltage terminal and a power supply of an internal switch circuit to be in contact or non-contact with each other depending on the level of voltage applied to the first and second communication terminals.

Abstract: A region to store authentication commands to perform authentication between a data carrier and a reader/writer device is divided into at least three areas, and as for the three areas, a first authentication command is stored in a first area, a second authentication command is stored in a second area, and a third authentication command is stored in a third area, and security levels can be selected depending on a command of an inquiry signal (41) transmitted from a reader/writer device (10), and thereby selection of the security level suitable for circumstances can be realized by a simple constitution.

Abstract: 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.

Abstract: Both of a proximity communication command in order to perform proximity communication with a reader/writer device and a vicinity communication command in order to perform vicinity communication with the reader/writer device are held in a command holding unit, and in the case when being inquired from the reader/writer device by using the proximity communication command, a response signal is generated by using the proximity communication command, and in the case when being inquired from the reader/writer device by using the vicinity communication command, the response signal is generated by using the vicinity communication command, resulting that both of the proximity communication and the vicinity communication can be performed depending on a usage mode.

Abstract: Both RF communication and contact serial communication can be performed with the use of: communication protocol storage unit for storing a communication protocol for performing communication with an external communication apparatus; a coil terminal section provided with two coil terminals for performing communication with the external communication apparatus with an RF signal; a contact communication terminal section provided with a first communication terminal, a second communication terminal, a power supply voltage terminal and a ground terminal as contact communication terminals for performing contact communication with the external communication apparatus; and connection control unit for causing the power supply voltage terminal and the power supply of the internal circuit to be in contact or non-contact with each other depending on the level of voltage applied to the first and second communication terminals.

Abstract: A plurality of small loop antenna cells 61, 62 and 63 are magnetically coupled to an antenna coil 8 of a non-contact type data carrier 3. In the plurality of small loop antenna cells, the directions of the magnetic moments of the signals transmitted to the non-contact type data carrier 3 are opposite to each other, the sum of the magnetic moments generated from all the small loop antenna cells 61 to 63 is zero and a conductor forming a short ring pattern 67 is provided collectively for the plurality of small loop antenna cells. Thus, imbalance caused between the small loop antenna cells 61 to 63 can be compensated for by the short ring pattern 67.

Abstract: A data carrier system is provided including: a main apparatus including a first control unit for outputting a first signal and a first coil unit having at least a transmission coil for transmitting the first signal; a tuner circuit unit having a tuner circuit being tuned with the frequency of the first signal, the tuner circuit having a tuning coil disposed facing the transmission coil of the first coil unit; and a tag including a second coil unit having at least a reception coil and a second control unit for performing a predetermined control operation in accordance with the first signal transmitted from the main apparatus and received by the reception coil of the second coil unit.