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 an extremely high-quality image. In doing so, 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 visually as wisted at an angle. This design is referred to as an LFH (low force helix) connector, insuring by way of frictional force of the pins, that a good contact with the mating connector is constant. DVI connectors use thumbscrews for retention and are very reliable. 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 Connector

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 hannels� that can carry more than 10 Gbps of digital video information. A dual-link cable is backwards-compatible with single-link applications. The vast majority of DVI applications will use this DVI-D dual-link cable connection.

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 originally designed to carry both digital and analog signals, in complete form. 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.