Recognition of audio device in portable terminal

A portable terminal comprising:

• 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 channel, a RIGHT channel, and a MIDDLE channel of a plug of an audio device, connected to said 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 that corresponds to the LEFT channel of the plug among the voltage values delivered from said converter, with a reference voltage to deliver the result of the comparison;
• a second comparator for comparing the voltage value, converted from the impedance of the pole that corresponds to the RIGHT channel of the plug among the voltage values delivered from said converter, with the reference value to deliver the result of the comparison;
• a third comparator for comparing the voltage value, converted from the impedance of the pole that corresponds to the MIDDLE channel of the plug among the voltage values delivered from said converter, with the reference value to deliver the result of the comparison;
• and
• a controller for recognizing the type of the audio device connected to said jack interface based on a combination of the comparison results supplied from said first to third comparators, respectively.