I have been playing my computer through home audio system for quite awhile and use to have a splitter so I could shift between computer speakers and audio system. Now I can't find what I did with it. When looking at the back of the Dell Dimension, I noticed what look like two outputs (at least they have the same symbol) along with the input/line in (I assume it is input since it has the microphone symbol). The supposed second audio output has no output though. So what is this? Thanks a lot.