A friend, Private Pilot, with whom I fly on occasion and I were talking about the NWA overflight. He wondered why the Minneappolis controller didn't call the aircraft on the last frequency they had been given by Denver. When I told him that each ATC facility has only its own frequencies he was somewhat incredulous. He believes, and claims that every facility has tranceivers similar to those in the aircraft that can transmit and receive on the entire aviation spectrum. Unless things have changed in the last several years, I am pretty sure that this is incorrect. Is it?