Meriachee, upgrade which part, I'm getting a little confused, there is the AP, the link converter and the C80. Should I just hook them up and see if it works? It would be great to have the C80 and EV100 work together.
If you want to use the EV100 with the C80, you need the ITC5, Part Number E22158. (and you need enough of the right type of cable to connect the whole works up too. You CANNOT splice this stuff unless you know what you're doing). The Ray support site lists the latest software revision for the ITC5 as 1.21. You can't upgrade the ITC5 with the C80, so you need to be sure that as part of the purchase, you specify that it has to be at revision 1.21.
That's where you are at today. There is another, somewhat grey consideration: Your C80, assuming it is a "classic" C series, as listed on the Ray site, will, at some point, possibly now, be deficient in some features. Some of those features may be directly attributable to what you want to do, or how you envision the system operating. Even the most current stuff can be a royal pain to upgrade. I bought an "a" series plotter for that very reason, and cannot get the bootloader code in my p70 to come newer than 1.04, and it will NOT talk properly with the patched network for a wind track. But I'll shut up now before I say something I'll regret.
You might consider a newer plotter, some of them have both networks embedded, and you would then be at a level to upgrade the EV and the plotter when Monday morning's firmware is released. In the meantime, spend a few minutes in the support section of the Ray pages and read about the software upgrades. They do list functions, features, and upgrades, so you can make a reasonably educated choice as to upgrade or not. The new LighthouseII code does have a whole bunch of cool tactical toys for the racecourse.
Hope it helps.
Networks are you friend when they work.