DVI (Digital Visual Interface) is a specification created by the Digital Display Working Group (DDWG) to accommodate analog and digital monitors with a single connector. There are three different DVI configurations: DVI-A, designed for analog signals, DVI-D, designed for digital signals, and DVI-I (integrated), designed for both analog and digital signals.
Using a DVI connector and port, a digital signal that is sent to an analog monitor is converted into an analog signal. If the monitor is a digital monitor, such as a flat panel display, no conversion is necessary. Many monitors now include a DVI connection and many video adapters include a DVI port along with, or instead of, the traditional 15-pin Video Graphics Array (VGA) port.