aux input in factory headunit
 

hi,
i have a 2006 mazda 3 and i want to connect an external MP3 player to the factory head unit,
i've seen 3 connectors in the back of the head unit,one for power and speakers,one for the display,and the third for external player.
i need to know what is the layout of this connector in order to connect it an audio cable for the MP3 player.
thanx