DVI D is an acronym which means Digital Video Interface Digital. Essentially it is a cable that connects two devices producing an output image on a screen.
The DVI connection is used on a variety of devices to produce better image quality. Commonly, you will see DVI cables on computer monitors, HDTVs and on LCD screens. DVI itself uses a mixture of both analogue and digital technologies. As a result there are 3 different types of DVI cables from which you may choose. DVI-D as you may have guessed supports digital output, DVI-A supports only analogue and DVI-I supports both digital and analogue transmissions, however, not simultaneously. You may choose to use any of the cables listed above depending on your immediate needs and the devices being used.
DVI Cables Explained
DVI-D as stated previously supports only digital connections. Once the device is able to allow a digital connection, that is, it is compatible with DVI-D or DVI-I, then the DVI-D connecting cable may be used. However, it may more beneficial to use the DVI-D cable because this means you will not run the risk of having compatibility issues should you be unable to properly initialize the digital connection with your DVI-I cable. Basically you will not need to tweak the settings you will be able to directly connect your cable to the two devices to access the digital output.
DVI-I consists of both a digital and analogue connections. You will not be able to use both digital and analogue transmissions at the same time; however, the cable has special sensors that allows it to pick up which signal it will use to communicate between the two devices. However, it should be noted that it may automatically choose analogue hence if you prefer to see your output as a digital image, it is best that you use DVI-D.
DVI-A is the form of DVI that supports analogue transmission, it is really a VGA cable with DVI connectors on either end. Thus many people prefer to use a VGA cable once their devices support it, mainly because it is cheaper. However, this may not be an option if one or two of your devices does not support a VGA connection.
DVI D Dual Link and Single Link Cables
DVI D cables come in two forms DVI D dual link and single link cables. Dual link is a more pricey version of DVI D because the technology is more advanced. It offers greater resolution, as much as WQXGA (2560 × 1600 @ 60 Hz), which is one of the best resolutions you will get on a monitor right now. However, the Dual link is not yet compatible with most computers in fact they are mainly used with the more high-end Dell monitors and Apple computers. Hence roughly around 10% of all computers support this type of cable.
Single link on the other hand offers comparatively lower resolution, the maximum amount being WUXGA(1920 x 1200@60 HZ) and is compatible with about 90% of most computer monitors including the first generation of HDTV monitors.
Either cable can be used however, because of the limitations, in terms of compatibility with the dual link cable, it is best to get a well made single link cable. Single link cables are sold at different prices based on quality. It is better to get a high quality dual link or single link cable especially if your devices are more than 10 feet apart.