All versions incorporate a top-loading slot for game cartridges, although the shape of the slot differs between regions to match the different shapes of the cartridges. The MULTI OUT connector (later used on the Nintendo 64 and GameCube) can output composite video, S-Video and RGB signals, as well as RF with an external RF modulator. Original versions additionally include a 28-pin expansion port under a small cover on the bottom of the unit and a standard RF output with channel selection switch on the back; the redesigned models output composite video only, requiring an external modulator for RF.