WHAT ARE THE DVI FORMATS ?
There are three types of DVI connections: DVI-Digital, DVI-Analog, and DVI-Integrated (Digital & Analog)
DVI-D - True Digital Video
DVI-D cables are used for direct digital connections between source video (namely, video cards) and digital LCD (or rare CRT) monitors. This provides a faster, higher-quality image than with analog, due to the nature of the digital format. All video cards initially produce a digital video signal, which is converted into analog at the VGA output. The analog signal travels to the monitor and is re-converted back into a digital signal. DVI-D eliminates the analog conversion process and improves the connection between source and display.
DVI-A - High-Res Analog
DVI-A cables are used to carry a DVI signal to an analog display, such as a CRT monitor or an HDTV. Although some signal quality is lost from the digital to analog conversion, it still transmits a higher quality picture than standard VGA.
DVI-I - The Best of Both Worlds
DVI-I cables are integrated cables which are capable of transmitting either a digital-to-digital signal or an analog-to-analog signal. This makes it a more versatile cable, being usable in either digital or analog situations.
Like any other format, DVI digital and analog formats are non-interchangeable. This means that a DVI-D cable will not work on an analog system, nor a DVI-A on a digital system. To connect an analog source to a digital display, you'll need a VGA to DVI-D electronic convertor; to connect a digital output to an analog monitor, you'll need to use a DVI-D to VGA convertor.
Taken from here:
http://www.datapro.net/techinfo/dvi_info.html
