Device of identifying host protocol and smart card including the same

An operating method of an integrated circuit card including a plurality of interface protocols and being configured to enable at least one of the plurality of interface protocols, the method comprising:

• receiving a status of at least one contact pad from a plurality of contact pads of the integrated circuit card connecting to a host, wherein the status of at least one contact pad is evaluated at a contact pad by sequentially connecting a plurality of pull-up resistors and a plurality of pull-down resistors having various resistance values to the contact pad;
• determining a host protocol is a MMC protocol if the status of the set of contact pads is in a low state;
• if the status of the set of contact pads is not in a low state, determining a voltage level of the host from the at least one contact pads;
• if the voltage level of the host is high, determining the host protocol to be a USB protocol,
• otherwise determining the host protocol to be a IC-USB protocol;
• enabling one of the plurality of interface protocols corresponding to the host protocol determined by the determining steps;
• and
• additionally determining whether the host protocol supports an ISO 7816 protocol by evaluating whether a different contact pad that is not in the at least one contact pads is in a clocking state.