Many software packages are "modular". That is you can buy only the modules you need and leave the rest on the table. Good companies use this feature as a selling point, but the bad guys use it to rip you off! Don't get cheated. If you're looking at a modular system, be sure that you are getting all of the functions that you think you're getting. One of my users tells a story about buying such a system. He paid about $1000.00 for the original package, then he discovered that various functions did not work. When he called for technical support ("Oh, I'm so sorry. I thought you understood that you'd need these modules, too."), he learned that he needed another module or two. By the time he'd gotten to a usable system, he'd purchased another $1000.00 in additional modules.
110vac is not modular. When you buy it you get everything.