VGA cables come in a wide variety of lengths and quality. Although no authority sets any special requirements for VGA cable kinds, manufacturers use different production options and marketing slogans in an attempt to define their cables. As a consumer, select VGA cables solely based on the resolution specifications quoted by the manufacturer.
VGA Signals
VGA produces five signals to connect from a computer, video game console or home entertainment device to an HDTV or computer monitor. Three signals carry discrete level information for each of the primary video colors of red, green and blue. Two others carry information for vertical and horizontal synchronization. The 15-pin connector also provides four control functions for information to return to the signal source from the monitor. Manufacturers produce VGA cables in different lengths, but the higher the resolution of the signal, the shorter distance it can travel.
VGA Resolutions
Developed in 1987, VGA had an original resolution of 640 by 480 pixels. Improvements over the years have increased resolution in incremental stages, with different letter designations ending in "GA." Today, all resolutions fall under the general heading of VGA, and can be identified either by their letter designations or the actual resolution specifications. Examples include XGA at 1,024 by 768 pixels, SXGA at 1,280 by 1024 pixels, WSXGA at 1,680 by 1,040 and the highest, WQUXGA, at 3,840 by 2,400. The pixel designation tells the number of individual dots the signal can illuminate on a viewing screen.
Manufacturing Differences
Cable lengths make critical differences for VGA. A foot-long cable could use 15 straight wires without twisting any pairs or using internal coaxial cables; however, such a cable would have problems at three feet. To extend the length and improve resolution specifications, manufactures use coaxial cables for the five signals with varying sizes of center conductors, types and number of shields, and an assortment of insulating materials between center conductor and shield. All manufacturing options work together with complex considerations determining the actual usable resolutions. No single factor can determine cable quality.
Resolution Specifications
A reliable VGA cable should have a label identifying the resolutions it can carry for its designed length. The specifications could be in the letter designations, the actual resolution numbers or both. Avoid cables that don't identify resolutions exactly or only use marketing terms such as "extra shielding," "22-gauge wires," "high-resolution," "high-performance" or "gold-plated connectors." These terms may not be relevant to the resolution you send over the cable. Check your owner's manual for the signal resolution specifications of your equipment.