Abstract: A card device for performing high-speed wireless data communication faster and more stable than a wireless data communication via an existing USB interface and UART serial bus interface is provided, including an antenna for transmitting and receiving a RF signal, a RF signal converter for converting the RF signal received by the antenna into a baseband signal and converting an internal data signal into an RF signal, and a mobile communication modem for outputting the internal data signal to the RF signal converter, receiving the baseband signal from the RF signal converter, checking whether a dual port RAM is accessible, and performing a data transmission/receiving operation with the dual port RAM when the dual port RAM is accessible. The dual port RAM has two ports connected respectively to the mobile communication modem and a PCMCIA interface and interfaces a data transmission/receiving operation between the mobile communication modem and the PCMCIA interface.