Dual interface radio frequency chip and dual interface method thereby

The invention 13.56MHz RFID (Radio Frequency IDentification) relates to the RF chip (Chip) for, particularly the RF chip according to the present invention the host (Host) on the smart card (Smart Card) and a portable device to be mounted on a personal digital assistant interface, a CPU, a smart card and an external RF reader (reader), respectively (interface) dual (dual) and having an interface function, a user password from the host CPU that; a (PIN Personal Identification Number) input, compared with the smart card password to provide a dual interface RF chip and a dual interface method using the same that enable and then performs user authentication, the external RF reader and the smart card to change the communication mode to communicate. A personal digital assistant, smart cards, dual interface, RF chip, RF reader