Alternatively called the optical drive audio connector, the CD-IN is a four-pin connector found on a computer’s motherboard or sound card that connects an optical drive’s audio. The picture shows a black four-pin connector and an example of what this connector looks like on a computer motherboard.

For example, CD-IN could connect the four-pin cable on the back of a CD-ROM drive to the corresponding audio connection on the motherboard, permitting direct playing of CD audio.

CD, CD terms

  • How to install a CD, DVD, or another disc drive.
  • CD-ROM help and support.