Most cell phones now have some sort of an audio jack, which allows you to listen to your uploaded MP3 audio files without disturbing other individuals around you. With this audio connection you are also able to send the music to outside devices, including an audio mixer. Although you do need an adaptor cable, the actual connection process only takes a moment or two to complete.
Plug the 3.5mm end of the cable into the headphone jack on your cell phone. Without a headphone jack you are unable to connect the cell phone to an audio mixing board.
Plug the quarter inch end of the cable into one of the "Line-In" ports on the audio mixer.
Power on the cell phone and the audio mixer. Select the audio track on the cell phone and press "Play." The audio now runs through the audio mixer and into any connected speaker system.