DVI (Digital Visual Interface) was developed by the industry body DDWG (the Data Display Working Group) to send digital information from a computer to a digital display, such as a flat-panel LCD monitor. DVI uses TMDS (transition minimized differential signaling) to transmit large amounts of digital data from the source to the display, resulting in a high-quality image. DVI technology successfully moved from the computer marketplace to the audio/video realm, and is now found on many high-end TVs, DVD players, and HDTV set-top boxes. DVI took a step forward with HDMI, which integrates audio and video into a more compact interface. The DVI interface uses a connector that resembles a DB-style connection. However, instead of round pins, the DVI connector uses flattened pins that appear “twisted” at an angle. This design is referred to as an LFH (low force helix) connector. The peculiar shape of the pin s ensures a good contact with the mating connector. DVI connectors use thumbscrews for retention. Most DVI connectors have 24 pins and a single larger, offset ground bar. These are called DVI-D interfaces, and carry a digital signal only. Some DVI connectors, called DVI-I, have four extra pins that surround the offset ground bar. A DVI-I interface is designed to carry both digital and analog signals.

DVI-D Dual-link  
 
This connector contains 24 pins, arranged in three horizontal rows of eight pins. To the side of this grouping of 24 pins is a wide, flat pin called a ground bar. A dual-link interface provides two TMDS links, or groups of data “channels” that can carry more than 10 Gbps of digital video information. A dual-link cable is backwards-compatible with single-link applications. The majority of DVI applications will use this DVI-D dual-link cable connection. Cables

DVI-D Single-link 
 
A single-link DVI connector has 18 pins. The male plug has them arranged in two groups of nine pins, with the flat ground bar off to one side. A single-link interface provides one TMDS link.

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DVI-I Dual-link 
 
This connector appears almost identical to the dual-link DVI-D connector except that it has an additional four pins that surround the flat offset ground bar. This is because the DVI-I interface was designed to carry both digital and analog signals. However, most DVI displays and video sources are DVI-D, and the female ports do not contain sockets to accept the four extra analog pins. As a result, DVI-I cables are limited to a narrow range of applications such as certain KVM switches. Also note that the offset ground bar on a DVI-I plug is larger than the one on a DVI-D plug. This means that a DVI-I connector cannot fit into a DVI-D socket simply by removing the four analog pins. Cables

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DVI-I Single-link  
 
This is similar to the dual-link DVI-I, but it carries only a single TMDS link. Cables

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DVI-A 
 
DVI-A is not an “official” standard according to the DDWG. Nevertheless, it is a connector type that allows a VGA device to connect to a DVI-I interface. For instance, the DVI output on a computer’s video card may be DVI-I and thus capable of supporting both digital and analog signals. In order to connect a VGA monitor, a cable or adapter with a DVI-A plug can be used to make the connection. A DVI-A connection has only the pins that carry analog signals loaded into the body of the connector. Cables

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HDMI  
 
HDMI stands for High Definition Multimedia Interface. This technology carries the same video information as DVI but adds the capacity for digital audio and control signals as well. The current version of HDMI carries one TMDS link of digital video. Found on many home-theater/consumer electronics devices, HDMI uses a 19-pin connector that is held in place by friction. This connector is technically described as a Type A HDMI connector. The Type B connector is larger (28 pins), but it is not currently used by any devices in the marketplace. HDMI and HDMI to DVI