When VGA (Video Graphics Array) was introduced by IBM® in 1987 for PC video display, it was a huge improvement over the earlier EGA DB9 connector. VGA, the basic format, supports resolutions up to 640 x 480 with 256 colors. You can find it on many video cards and computer monitors.

SVGA (Super VGA), EGA, and later formats continued the drive to provide ever-sharper images and greater color depth. Plus, over the years, VESA standards have brought structure and interoperability to a market that was becoming a mixture of often incompatible SVGA graphics cards.

Later formats supported even higher resolutions—oftentimes, rivaling those of digital 1080i and 1080p displays. These later formats include SXGA (1280 x 1024), UXGA (1600 x 1200) and WUXGA (1920 x 1200).

Other analog video connectors:

Composite video—Typically presented as a yellow RCA connector, the analog Composite interface has been the standard interface for consumer TV equipment. As its name suggests, Composite video has the luminance (black and white), chrominance (color) and sync pulses combined in one signal.

S-Video—Also called Y/C video, S-Video was introduced to overcome some shortfalls associated with Composite video. It’s a less encoded video format, transmitting color (C) and luminance (Y) information separately to produce a sharper image.

Component video—This YCbCr connector separates the signal more than S-Video for less interference and improved video. In addition to Y (luminance) signals, it transmits color information as two signals: B-Y (Blue minus luminance, also called Cb or Pb) and R-Y (Red minus luminance, also called Cr or Pr).

Go Long! Alternatives to analog video cable extension

Extending video long distances isn’t often possible or practical using standard VGA or coax cabling. With Composite, Component, and other analog video cabling, frequency losses result in deteriorated video quality. Generally, with these cables, the shorter distance the better.

Extenders that extend analog video over UTP copper or fiber optic cable solve this problem, enabling you to use backbone or horizontal wiring for your long-distance extensions. Depending on the extender model, video input can be VGA, Component, S-Video, Composite, or BNC coax. They’re a great alternative to using analog video or coax cables, which often can’t be easily pulled through tight conduits and can be more difficult to terminate. What’s really nice is, in most buildings, copper or fiber cabling is already installed to service data communications.

Fiber-based extenders provide higher bandwidth and interference-free extensions at distances much farther than copper-type CATx extenders. But there’s the matter of cost. CATx extenders that use cabling and connectors cost considerably less than fiber cabling components.

Another thing to consider: Coax- or VGA-cabled extension installations usually require a separate RS-232 or other line for transmitting the control signal for the display—yet another cable to fit into the conduit. CATx cable, however, delivers both the video and control signals through a single transmission medium.

But what if you have long runs of coax installed? An extender like the MediaCento RF that uses low-cost RF cabling to broadcast video to remote HDTV screens may be the answer. Supporting both VGA and Component video source input, the MediaCentro RF encodes and modulates signals for single-channel RF transmission over existing coax wiring. The QAM tuner at the screen enables the reception of the high-definition MediaCentro RF channel, so no set-up box or other piece of hardware is required.

Resources

Buyer’s Guide: Analog Extenders