Selecting the right DVI connector can be confusing at times due to the many different formats being used today. This tutorial will hopefully help to clear up any potential confusion you might have on which connector type to purchase. We have also included a section to describe why the DVI video format was adopted and what its advantages are over previous video formats.

DVI Formats
DVI connectors use a digital RGB transmission format which sends out TMDS (transition minimized differential signal) video signals. This preserves the image quality while providing high-speed transmission of the video signal. All DVI formats use the same basic connector, but in some cases the connector may not use all of the connection pins depending on the DVI output video type. The DVI connector has three primary design formats, depending on which signals the video processor outputs:

DVI Format	Link Type	Link Speed	Color Depth/Pixel	Connector Layout
DVI-I	Dual	350MHz	24 bit
DVI-I	Single	165MHz	24 bit
DVI-D	Dual	350MHz	24 bit
DVI-D	Single	165MHz	24 bit
DVI-A	Single	165MHz	24 bit

DVI Advantages
Digital Visual Interface (DVI) format is a video interface standard designed to maximize the visual quality of digital display devices; such as high-end computer video cards and display monitors, flat panel LCD displays, and digital projectors. The Digital Display Working Group (DDWG), http://www.ddwg.org,an industry consortium comprised of all the primary video system manufacturers, defined the DVI output standards that were designed primarily for carrying uncompressed digital video data to larger higher resolution video displays. The DVI format is partially compatible with the HDMI standard which allows for conversions between video formats.

The DVI interface uses an all digital signal output protocol where the desired brightness of each pixel is transmitted from the video processor to a DVI compatible video monitor as binary data. The displays are driven at their native resolution where it reads each number and applies a specific brightness value to the desired output pixel. This allows each pixel in the output buffer of the source device to correspond directly to one specific pixel on the display. This differs from systems using analog signals since the appearance of each pixel in an analog system may be affected by adjacent pixels. The DVI format is also less sensitive to electrical noise and electromagnetic interference than analog formats greatly reducing or eliminating potential video distortion.

Single link connectors are the most common type DVI connector used. DVI transmission is based on the RGB ratio design. A single link DVI video transmission is cabable of handling up to 165MHz signals at 8 bits per color type (red, green and blue), providing each pixel with 24 bits of color depth. Dual link DVI connectors add a second set of color data paths allowing video signals up to 350MHz in bandwidth while maintaining the 24 bit color depth. This is accomplished by adding an additional six pins in the center of the dual link DVI connector.

DVI systems are also capable of transmitting data to the display monitor at greater speed than previous display standards, such as VGA and SVGA. As the analog source for a VGA or SVGA system transmits each horizontal line of the image, it varies its output voltage to represent the desired brightness. In a CRT device, this is used to vary the intensity of the scanning beam as it moves across the screen. However, this becomes a limitation when using digital displays with analog signals. When the source is also a digital device, such as a computer, this can lead to distortion of the video signal.

The DVI connectors contain slotted pins at a 45 degree angle to pass the native digital video signals along. The angled slotted pins provide two advantages. Their larger slotted design creates greater surface contact with the female connector terminals and the angled slotted pins help keep the connection fully seated in the female connector reducing the potential for interference and noise.

DVI connectors are also designed to incorporate pins to interface to legacy analog video systems which use a VGA or SVGA format standard. This design feature was included in standard in order to make the DVI standard a universal video output format. Allowing either an analog or digital video signal to be handled by the same DVI-I connector. The DVI format allow is compatible with the DFP output format.

DVI is the only widespread video standard that includes both analog and digital transmission options in the same connector. This allows this digital video format to be be to be used over a wide array of video formats.