A portable terminal includes a jack interface for connecting an audio device thereto, a converter for converting an impedance of each of the poles, that correspond to a LEFT, RIGHT channel, and MIDDLE channel of a plug of an audio device, connected to the jack interface, to a voltage value in order to deliver the respective voltage values, a first comparator for comparing the voltage value, converted from the impedance of the pole corresponding to the LEFT channel, a second comparator for comparing the voltage value, converted from the impedance of the pole corresponding to the RIGHT channel, a third comparator for comparing the voltage value, converted from the impedance of the pole that corresponds to the MIDDLE channel, and a controller for recognizing the type of audio device connected to the jack interface based on a combination of the comparison results supplied from the first to third comparators, respectively.