Like all my other posts, this post has a huge n00b disclaimer. I know very little about AV equipment and have only become interested in the past week.

That being said, please try to answer my question in the most layman terms possible, however feel free to elaborate using jargon that I should be picking up. Thanks.

So my question is basically, what is RS-232 & IP?? What does it do? How does it work? How does it vary from IR input? What devices feature it? Why is it not known in the mainstream to n00bs like me? How usable is it (how difficult)? Feel free to answer your own questions as my understanding is as superficial as can be.