My SciAtl 4200HD cable box has these settings Upconvert-1, upconvert-2, passthru, fixed. The passthru and fixed I figured out. But I called my cable company and they could not explain the difference with cvt-1 v.s. cvt-2. It looks to me like the better picture results from letting the cable box upconvert for the TV ; either cvt1 or 2 look about the same but better than passthru.