CD-IN
Alternatively
referred to as the optical drive audio connector, the CD-IN is a
four-pin connector found on a computer motherboard or sound card that connects an optical drives audio to the motherboard or sound
card audio. In the picture to the right, the top black four-pin connector is an
example of what this connector looks like on a computer motherboard.An example of how this connector could be used is connecting the four pin wire from the back of a CD-ROM drive to the connection on the motherboard, allowing the user to listen to an audio CD.
Also see: CD definitions
