 scanning. Computer monitors do not interlace a signal to deal with flicker because their inherent frame rate of 60 fps and above is fast enough to fool the human eye. Unfortunately, this difference in scan rate creates an incompatibility between computer and TV monitors. Computers and television systems differ in resolution, too. Again, resolution describes the number of horizontal and vertical pixels a monitor can display. The most commonly used formats in computing are 640-by-480 pixels (VGA) and 1,024- by-768 pixels (SVGA). SVGA can be extended to accommodate larger monitors, with 1,280-by-1,024 pixels (1.3 million pixels per screen). In television systems, resolutions are either 525 vertical lines (NTSC) or 625 lines (PAL and SECAM). However, viewers do not see all the 525 NTSC scan lines on a television monitor because 42 of them are blanked during vertical retrace, which leaves 483 visible lines. The horizontal resolution of an NTSC video image depends upon the quality of the signal and monitor and generally ranges from about 300-450 dots per horizontal scan line. Consequently, the image quality of a picture displayed computer monitor will always be better than that displayed on a television monitor. To display a computer-generated image on a television monitor, a scan converter required. Scan converters also convert from composite to component video. With composite video, color is encoded using YIQ where the Y component describes luminance (a weighted average of the red, green and blue primaries of the image) and the I and Q components provide chrominance (color) information. VGA and SVGA monitors use a color encoding method called YUV in which luminance (Y) is stored separately from the chrominance (U and V). Video Communications: The Whole Picture CONNECTING To THE NETWORK Video communication facilities should be located close to the network interface (demarc). This keeps cabling costs down, simplifies troubleshooting, and eliminates the need for line drivers to regenerate a digital signal over extended