A computer’s DVI port for high-definition video output.
Computer graphics cards output high-definition video by default because standard definition is not clear enough to discern text and other information viewed on computer monitors. Different graphics cards use different output formats for high-definition video.
VGA ports are the oldest of these three types of graphics output. A VGA port is a trapezoidal 15-pin blue port with two screw holes on either side to hold the data cable to the port. Many HDTVs and computer monitors have a VGA port that allows them to connect directly to a computer.
DVI is replacing VGA as the standard computer monitor connection. DVI ports are rectangular and feature 24-pin holes, they also use two screw holes to hold the cable in place. Modifications of the basic DVI port can feature additional pins and prongs. A passive adapter makes DVI ports compatible with VGA cables and vice versa.
HDMI ports are used to transmit high-definition audio and video signals on the same channel. Many graphics cards are including HDMI ports in addition to VGA or DVI ports to facilitate the connection to HDTVs or home theaters. HDMI connectors are much smaller than DVI or VGA ports and do not use screws to hold the cable in place.