DVI

The Digital Visual Interface or DVI is a video interface standard designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors. It is designed for carrying uncompressed digital video data to a display. The DVI interface uses a digital protocol in which the desired illumination of pixels is transmitted as binary data. DVI connectors are available in five models, differing in the way they handle analog or digital transfers. Video and monitor cards which are exclusively digital cannot be connected to analog, but can be connected to equipment that handles both analog and digital signals. The DVI standard also supports the Display Data Channel or DDC and the Extended Display Identification Data or EDID, which allows computers to communicate with different monitor extensions. DVI-I stands for "DVI-Integrated" and supports both digital and analog transfers, so it works with both digital and analog monitors. "DVI-D" stands for "DVI-Digital" and supports digital transfers only. A single DVI link consists of four twisted pairs of wire, i.e. red, green, blue, and clock to transmit 24 bits per pixel. The timing of the signal almost exactly matches that of an analog video signal. With a single DVI link, the largest resolution possible at 60 Hz is 2.75 mega-pixels. For practical purposes, this allows a maximum screen resolution at 60 Hz of 1915 x 1436 pixels (standard 4:3 ratio), 1854 x 1483 pixels (5:4 ratio) or 2098 x 1311 (widescreen 8:5 ratio). The DVI specification mandates a fixed single link maximum pixel clock frequency of 165 MHz, where all display modes that require less than this must use single link mode, and all those that require more must switch to dual link mode. The data pairs carry binary data at ten times the pixel clock reference frequency, for a maximum data rate of 1.65 Gbit/s x 3 data pairs for a single DVI link.

Like modern analog VGA connectors, the DVI connector includes pins for the display data channel (DDC). If a display supports both analog and digital signals in one input, each input can host a distinct EDID. The DVI connector usually contains pins to pass the DVI-native digital video signals. As well as digital signals, the DVI connector includes pins providing the same analog signals found on a VGA connector, allowing a VGA monitor to be connected with a simple plug adapter. DVI-D. The connector also includes provision for a second data link for high resolution displays, though many devices do not implement this. In those that do, the connector is sometimes referred to as DVI-DL or dual link. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so it is not possible to connect a male DVI-I to a female DVI-D by removing the 4 analog pins. It is possible, however, to connect a male DVI-D cable to a female DVI-I connector. Many flat panel LCD monitors have only the DVI-D connection so that a DVI-D male to DVI-D male cable will suffice when connecting the monitor to a computer's DVI-I female connector. DVI is the only widespread video standard that includes analog and digital transmission options in the same connector.[1]Some new DVD players, TV sets (including HDTV sets) and video projectors have DVI/HDCP connectors; these are physically the same as DVI connectors but transmit an encrypted signal using the HDCP protocol for copy protection. The DMS-59 connector is a way to combine two analog and two digital signals in one plug. M1-DA connectors are sometimes labeled as DVI-M1; they are used for the VESA Enhanced Video Connector and VESA Plug and Display schemes.