An interface system capable of reducing or minimizing an electromagnetic interference. The interface system includes a serializing unit for receiving first data having a plurality of bits and second data having a plurality of bits, and for serially outputting the plurality of bits of the received first data and second data as 2 bits; a transmission circuit for generating 4 voltage levels in accordance with the 2 bits supplied from the serializing unit; a receiving circuit for recovering the 2 bits using the voltage levels supplied from the transmission circuit; and a deserializing unit for recovering the first data and the second data while sequentially storing the 2 bits supplied from the receiving circuit.