2) AUX IN= A socket for plugging in an audio source. Audio jacks are found on many types of audio equipment and musical instruments that accept external sound sources. In a car or truck, an audio jack, also called a "media jack" or "auxiliary (AUX) jack," is a mini-phone socket that connects any portable music player to the vehicle's amplifier and speakers. One end of a mini-phone cable plugs into the headphones socket of any CD, tape cassette or digital music player, and the other end plugs into the car's audio jack. An iPod can be hooked up in this manner as well, but there are also adapters designed strictly for the iPod (see MP3 car adapter and iPod car adapter). See jack and A/V ports.