Quote Originally Posted by Daniel Browning View Post
I would check the case manufacturer's manual. It could be related to a water cooling system of some sort, more than the typical "two holes for tubes".

Another possibility: I've seen things like you describe for firewire, MIDI, serial ports, etc. They come with a cable that goes to the correct spot on the motherboard. It's possible that your case didn't come with them because so few people ever need them, and perhaps they are an optional accessory available for purchase.
Daniel, I believe you are correct. I just talked to a guy who has an older machine, and he looked inside of it. Sure enough, down near the bottom of the case, in the rear, was a small card. Attached to it was a small cable that went to the mother board. It was an audio output card of some type.

Thanks everyone for the replies.

Alan