Mr. 120 wasn't exactly correct.

7018 AC rods are both AC and DC. In fact, technically a standard 7018 is supposed to be able to weld with AC. I have, and the flux is a little sticky with Ac, but it works.
6011 Rods are DC and AC. They aren't picky.
The 200DX will run every rod that I can think of except 6010, and it's possible to get an arc, but the stability is not good with it.