Video cables can be an alphabet soup of confusing acronyms, and with so many of them out there the differences can be easily lost. The RGB cable, commonly known as a component video cable, is one of many ways to get video from your playback device to your TV. While it's fallen out of popularity recently, you may still have some devices that support it.
An RGB cable is actually made up of three separate cables that are bound together, each one carrying one of the primary colors used to create a video picture -- red, green and blue. Combining these three colors in the right proportion can create any color the human eye can perceive. The cable uses a standard, RCA or phono style plug and is capable of transmitting an analog, high-definition signal. An HDTV uses an analog to digital converter to translate this signal into a digital format the TV can display, which can introduce artifacts into the picture. While this makes RGB cables a less than ideal choice with modern HDTVs, some legacy devices do not support any type of output other than RGB, so you can still get an HD picture even though it may not be of the highest quality possible.