Boy is that a awkwardly worded sentence or what.

"Requires compatible display card and Macintosh IIsi NuBus Adapter card or display adapter."

This is how I read that sentence

Requires (Display Card ^ NuBus Adapter) v (display adapter).

So what is this display adapter of which they speak?

--edit Well never mind, if I had scrolled down a little it explains what the display adapter is.