Asus T3-P5945GC - Manual (Page 47)

4-8 Chapter 4: Motherboard Info
5. Optical drive audio connector (4-pin CD)
These connectors allow you to receive stereo audio input from sound
sources such as a CD-ROM, TV tuner, or MPEG card.
R
P5L13L
P5L13L Internal Audio Connector
CD
(black)
Right Audio Channel
Left Audio Channel
Ground
Ground