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The Dreamcast VGA Box (also known generally as a DC VGA adapter or DC VGA cable) is an accessory for Sega's Dreamcast video game console that allows it to connect to a video display such as a computer monitor or an HDTV set through a VGA port. Because the Dreamcast hardware can produce a VGA-compatible video signal natively, this connection provides improved picture quality compared to standard composite video or S-Video connections, along with support for progressive scan video. Sega released the original VGA Box as an official accessory, but many third-party versions were also produced and sold worldwide in various form factors. Most games for the Dreamcast are VGA-compatible, while various workarounds exist to enable VGA output from many of the games that do not feature official support. ==Functionality== When pins 6 and 7 on the Dreamcast's A/V out port are connected to the ground pin (such as when a VGA box is connected to the console and externally switched to VGA mode), the Dreamcast system internally switches to VGA mode,〔(【引用サイトリンク】title=Dreamcast VGA box schematic )〕〔(【引用サイトリンク】title=Dreamcast AV Connector )〕 displaying a 640x480p60 image (progressive scan, at a standard EDTV resolution) in RGBHV at 31 kHz, which allows it to connect to a computer monitor or EDTV/HDTV set with a VGA input. The official VGA Box consists of a rectangular black plastic case, bearing a VGA out port and a 3.5 mm minijack for stereo audio output on one side, and an A/V output jack breakout panel (S-Video, composite, and RCA stereo audio jacks) on the other, for switching output either to a typical computer monitor and speakers/headphones or to a typical TV. Most third-party versions are functionally identical to Sega's model besides cosmetic differences, but some simplified designs lack the additional A/V breakout and output switch. These units can only be used for VGA and audio output. Some of these designs are streamlined to the point that no extra housing is required beyond the cable jacket and the connectors; such units are described generically as DC VGA cables. One enhanced model, the ''Performance''-branded VGA Adapter for Dreamcast produced by InterAct, additionally features a VGA input port and stereo minijack input for PC video and audio pass-through, with automatic source switching when the Dreamcast system is powered on and off.〔(【引用サイトリンク】title=Performance VGA Adapter - IGN )〕〔(【引用サイトリンク】title=Every Performance VGA Adapter Question Answered - IGN )〕〔(【引用サイトリンク】title=Madness Gameware DC-VGA Adapter - IGN )〕〔(【引用サイトリンク】title=CNN - Review: Performance VGA Adapter )〕 This enables a computer or other daisy-chained video game console with VGA output to remain connected to the same monitor and speakers as the Dreamcast simultaneously, without swapping cables or using additional switches for both VGA video and 3.5 mm stereo minijack audio. It is also possible to modify a Dreamcast to add the same VGA functionality to the console itself, obviating the need for a standalone VGA box.〔(【引用サイトリンク】title=Sega Dreamcast VGA mod )〕〔(【引用サイトリンク】title=Dreamcast internal VGA )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dreamcast VGA」の詳細全文を読む スポンサード リンク
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