I've called Crutchfield, and supposedly the guy looked in the manual for the DE985 and didn't see if there was a way to assign the optical digital inputs. I just looked it up, and evidently my DVD player does coaxial digital output (I don't have my DVD player with me for the summer).

But I have a question, which is better, optical or coaxial? I would have thought optical, but maybe that's me being attracted to shiny things