are project is on designing a new type of computer sound system by finding out what sound cards are and what they do thruogh trouble shooting the sound card we will be able to know what to do.

Color Function

Pink Analog microphone input.

Light blue Analog line level input.

Lime green Analog line level output for the main stereo signal (front speakers or headphones).

Black Analog line level output for rear speakers.

Orange S/PDIF digital output (sometimes used as an analog line output for a center speaker instead)

http://en.wikipedia.org/wiki/Sound_cards#Connections