DVI - Digital Visual Interface

The push is on to make displays digital, whether they’re legacy CRTs (Cathode Ray Tubes) or newer LCDs (Liquid Crystal Displays)—because a digital monitor provides both excellent picture quality and higher transfer bandwidths.

There are three main types of digital video interfaces: P&D, DFP, and DVI. P&D (Plug & Display, also known as EVC), the earliest of these technologies, supports both digital and analogue RGB connections and is now used primarily on projectors. DFP ( Digital Flat-Panel Port) was the first digital-only connector on displays and graphics cards; it’s being phased out.

There are several types of connectors: DVI-D, DVI-I, DVI-A, DFP, and EVC.

• DVI-D is a digital-only connector for use between a digital video source and monitors. DVI-D eliminates analog conversion and improves the display. It can be used when one or both connections are DVI-D.
• DVI-A (analog) is used to carry a DVI signal from a computer to an analog VGA device, such as a display. If one or both of your connections are DVI-A, use this cable. If one connection is DVI and the other is VGA HD15, you need a cable or adapter with both connectors.
• DVI-I (integrated) supports both digital and analog RGB connections. It can transmit either a digital-to-digital signals or an analog-to-analog signal. It is used by some manufacturers on products instead of separate analog and digital connectors. If both connectors are DVI-I, you can use any DVI cable, but a DVI-I is recommended.
• DFP (Digital Flat Panel) was an early digital-only connector used on some displays.
• EVC (also known as P&D, for Plug & Display), another older connector, handles digital and analog connections.

DVI-D, Single-Link	DVI-I, Single-Link	DVI-A
DVI-D, Dual-Link	DVI-I, Dual-Link	DFP

All these standards are based on transition-minimised differential signalling (TMDS). In a typical single-line digital signal, voltage is raised to a high level and decreased to a low level to create transitions that convey data. TMDS uses a pair of signal wires to minimise the number of transitions needed to transfer data. When one wire goes to a high-voltage state, the other goes to a low-voltage state. This balance increases the data-transfer rate and improves accuracy.

Learn more:
HDMI - The digital interface to combine HD video, multichannel audio and more.