Maybe I didn't catch everything in your posts, but, do you have a network?
Before we can discuss installing an ethernet printer, we need to know if it has a network to work with. Since you are using Se, I will assume you don't have a router/switch, and will also assume you will be dissapointed with the plotters performance once it is connected.
Well, I looked tried to look at your <a href="http://www.gtcocalcomp.com/index.html">plotter specs</a>. Looks pretty serious. You might want to talk to them.