If you've ever hooked a CD player or DVD player to your TV, you likely used an RCA cable. A simple RCA cable has three color-coded plugs extending from one end of a cable that connects to three correspondingly colored jacks on the back of a TV, projector, or another output device. These cables carry audio and video signals from the component device to the output device (i.e. a television or speakers).Although an HDMI cable is a more modern way to connect devices, there are still plenty of opportunities to use RCA cables. An RCA cable can be used to connect a variety of audio and video devices, such as camcorders to TVs or stereos to speakers. Most high-end camcorders have all three RCA jacks, so the signal entering or leaving the camcorder goes through three separate channels — one video and two audio — resulting in a high-quality transfer.