Right now Romo pretty much knows what plays are called, he hears the QB's audible's, the center's calls etc, and tells the fans what play is coming. That won't last forever, the farther he gets away from the game, the less he'll be able to do that as offensive systems change.
I've seen bits and pieces of what he does in comparison to Gruden, and Gruden does not go into depth of detail like Romo currently does.