What is dvi port, how to use dvi port?

DVI, Digital Visual Interface, is a video interface standard designed to provide very high visual quality on digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an industry consortium, the DDWG, Digital Display Working Group, to replace the "legacy analog technology" VGA connector standard. It is designed for carrying uncompressed digital video data to a display. It is partially compatible with the HDMI, High-Definition Multimedia Interface, standard in digital mode (DVI-D), and VGA in analog mode (DVI-A).

The DVI interface uses a digital protocol in which the desired illumination of pixels is transmitted as binary data. When the display is driven at its native resolution, it will read each number and apply that brightness to the appropriate pixel. In this way, each pixel in the output buffer of the source device corresponds directly to one pixel in the display device, whereas with an analog signal, the appearance of each pixel may be affected by its adjacent pixels and also the electrical noise and other forms of analog distortion.

The DVI connector has pins to pass the DVI-native digital video signals. If dual-link systems used, additional pins are needed for the second set of data signals.

Besides providing the digital signals, the DVI connector includes pins giving the same analog signals found on a VGA connector, allowing a VGA monitor to be connected with a simple plug adapter. This feature was included in order to make DVI universal, as it allows either type of monitor. analog or digital, to be operated from the same connector.

Depending on which signals it implements, the DVI connector on a device has one of four names as follows:

DVI-D (digital only) 
DVI-A (analog only) 
DVI-I (integrated, digital & analog) 
M1-DA (integrated, digital, analog & USB)