Video vs Audio Cables
Video and audio cables are so named because they carry video and audio signals from a source device like a player or camera to a destination like speakers, TV, or a recording device. In most cases there is really no difference between the cables as the only difference is the signal that they actually carry. A good example of this is the RCA cable. The RCA cable is typically composed of 3 cables that would carry 1 for video and 2 for audio (left and right channels). The three cables can be easily swapped without compromising performance.
There are certain cables that carry both audio and video in the same cable. The most prominent is HDMI. It is a very recent standard that is capable of carrying HD quality video as well as multiple channels of high fidelity audio. Aside from the two types of signals, HDMI also allocates a channel for inter-device communication; allowing all connected devices to communicate with each other and be controlled through one remote.
There are also cables that can only carry one type of signal and cannot be used for the other. The first example would be DVI for video. DVI is largely used with computers and is compatible with HDMI sans the audio and communications channels. For audio, there is the TRS jack, more popularly known as the 3.5mm headphone jack. We also have the optical link, commonly known as S/PDIF or TOSLINK, which carries audio in a digital and lossless format. These cables can only carry either audio or video but not the other type.
Choosing the right cable to interconnect your devices can be a difficult task as you would want the best possible cable for both audio and video. If your devices support HDMI, it is the best that you can get. It is digital so it is lossless, and you would only need one cable between two devices so clutter is kept to a minimum. If HDMI is not supported, a combination of digital via DVI and S/PDIF is the next best choice. The number of cables is increased but quality is kept to a maximum. As a last resort, analog can be used via RCA can be used. Compatibility should not be a problem as all devices have RCA or component jacks in them.
Summary:
1.Audio and video cables are basically the same they just differ on the signal they carry
2.Some cables can carry both audio and video
3.Some cables can only carry either video or audio