A computer's audio ports link the computer's sound hardware with your speakers, microphone, headsets or other audio equipment. Every computer motherboard has at least a few basic audio ports built in, allowing you to connect stereo speakers and a microphone. Higher-end motherboards and computers with discrete audio cards include additional ports for connecting surround-sound speakers or external sound systems.
Analog Audio Ports
The basic audio port, usually labeled the "audio out," "line out" or "headphone" port supports up to two speakers plus a subwoofer. To connect a pair of stereo speakers or headphones, plug the audio cable into the green audio out port. If you have a mic, either standalone or built into a headset, connect its cable to the pink microphone port. If your audio ports don't have color coding, look for engraved icons of a microphone and pair of headphones to tell the two apart. Surround-sound speakers add additional color-coded cables that match up with the black and orange audio ports on some computers.
Digital Audio Ports
Some computers have one or two types of digital audio outputs, collectively known as S/PDIF, short for Sony/Philips Digital Interface. One type of digital port, rarely seen on computers, uses an RCA-style connector similar to the composite cables used with a DVD player. The more common digital audio port, Toslink -- Toshiba Link -- looks like a glowing red light. This light transmits audio data over a fiber-optic cable. Neither type of digital audio port can connect directly to a pair of speakers: Digital audio outputs are designed for hooking up an external amplifier, sound system or a digital-to-analog converter.