[abhishekh]

Older drives used to come with a audio jack and audio output pins on the rear along with play fwd/rew buttons on CDROM drives to play audio cds. Now the newer drives do not have a play button. Then whats the use of the audio output pins?

[Sharky]

If you turn off digital output in your OS, the sound is played through that.

[Smith6612]

It is best if you use digital, as if you are doing something like ripping a CD to your hard drive, you may pick up noise from your system, plus you'll be removing digital error correction.

[kkenny]

And sometimes it's more easy to imput the headphones into the front of your computer than reaching all the way to the back.

Interesting problem really :O
(Do they still have volume controls on the newer CDROMs?)