All monitors and video cards are built to specific video graphic standards which determine resolution. The most common standards include: MDA, Hercules, CGA, EGA, VGA, and SVGA.

IBM introduced MDA in 1981 for its IBM PC. It boasts of a 720 x 350 resolution. However this standard supports only monochrome and can only display text without graphics. The IBM MDA video card also came with a parallel port for printer support. Although outdated, this standard was very popular in its day.

IBM introduced CGA at the same time as the MDA standard. This is the first color video standard. This standard has 16 colors available. In text mode all of the 16 can be displayed. In graphics mode two or four colors are available, depending upon the resolution. The most common resolution is 640 x 200, although this standard does support lower resolutions. The IBM XT PCs generally use this standard.

Hercules was the first high resolution monochrome standard. Introduced in 1982, it has a 720 x 348 resolution. It can display text and graphics. Since color was much more expensive than monochrome, most PC users settled for the Hercules standard.

EGA was introduced by IBM in 1984. It has 64 available colors, but can only display 16 at one time. It supports 640 x 350 resolution as well as lower resolutions. The IBM AT PCs use this standard.

VGA was introduced by IBM in 1986. It has 262,144 available colors, but can only support 256 at one time. It supports 640 x 480 resolution as well as lower resolutions. This is the one of the most common standards in use today.

SVGA came on the scene in 1988. Although not a specific standard, it refers to specific video cards and monitors that exceed the VGA standard. The resolutions can start at 800 x 600 and go up to 1600 x 1200. There are 16.7 million colors available, and all can be displayed at the same time! The VGA standard is also supported. SVGA is quickly becoming the most popular on the market today.

The older standards were designed to produce a digital signal while the newer standards produce an analog signal. You can't connect a VGA or SVGA monitor to the older type video cards (MDA, Hercules, CGA, or EGA). The signals are incompatible.

Finally, some monitors can support multiple video graphic standards. How do they do this? Each standard works at a certain frequency. These monitors are designed to support multiple frequencies. These are called multisync monitors.