Analog rca cables use these connectors -- red for the right stereo channel and white or black for the left.

© iStockphoto/MartinDegryse

Video Cables

The most common type of video cable is called composite video. A composite video cable consists of one yellow RCA connector that's usually bundled with red and white RCA analog audio cables. It's called composite video because all of the video information -- color, brightness and sync -- is composited, or squeezed, onto one cable. Composite video cables were designed for older TVs and have a maximum resolution of 330 lines. They're fine for watching VHS tapes on the old TV in the basement, but if you have a newer television, or an HDTV, composite video cables simply won't cut it.

S-video cables are a step up from composite video with a maximum resolution of 400 lines. You will recognize an S-video cable by its circular, nine-pin connector. S-video separates color information from picture information, resulting in a crisper image. Although S-video jacks are found on a lot of TVs, DVD players and home theater receivers, the cable's initial popularity was quickly eclipsed by component video.

Component video cables consist of three RCA connectors colored red, green and blue. With component video, not only is color separated from picture, but the color portion is split into two separate signals. The result is a super-sharp image with deep color saturation. Component video cables are ideal for connecting high-definition video components like Blu-ray players and HDTVs. Most home theater receivers come with several sets of component video jacks.

DVI (digital video interface) cables were designed specifically for use with HDTVs and other high-definition video components. They have large, 18-pin connectors that look like computer cables. DVI cables offer the exact same image quality as component video cables, except that DVI comes with a built-in copy protection protocol called HDCP (High-bandwidth Digital Content Protection). Critics of DVI claim the built-in copy protection mechanism causes compatibility problems with certain devices.

Lastly, we'll look at three kinds of cable that carry both audio and video signals.

Audio/Video Cables

There are a handful of cables that transmit both audio and video signals. For years, coaxial video cables were one of the only choices for connecting video components. Coaxial video cables have that famous one-pin connector, sometimes called a stinger, that can either be pushed or screwed into place. Coaxial video cables are now mostly confined to outside connections, such as satellite TV or cable TV lines that come through the wall. A single coaxial cable carries both video and audio signals.

HDMI cables are an updated version of DVI. HDMI cables were also designed for use with HD components, but their connector is much slimmer, like a large USB cable. HDMI also includes HDCP copy protection. Manufacturers of HDMI cables tend to advertise their product as the only choice for connecting HD video components, but that's not true. DVI cables work equally well. However, if you're using an analog TV, all three work equally well.

In Europe and the UK, the most popular dual-purpose cable is called SCART (Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs). SCART cables have fat, 21-pin connectors. In Europe, SCART cables do the work of RCA analog audio cables as well as composite, s-video and component video cables, but they can't carry high-bandwidth digital video or audio signals, such as those necessary for high-definition TVs. HDMI is the preferred cable in Europe for HD components.

FireWire, or IEEE 1394, cables are mostly associated with connecting devices to computers, but a few high-end home theater receivers and HDTVs now come with FireWire ports. FireWire is capable of carrying compressed MPEG-2 video and digital audio. You might use a FireWire cable to connect a digital video camera directly to your home theater system to show off some unedited footage.

To sum up, here are the cables that you would use for some common home entertainment systems.

Home stereo system (CD changer, stereo receiver, speakers):

• Lower-end: If you're playing regular CDs or MP3s, you'll only need RCA analog audio cables and speaker wire.

• Higher-end: If you want crisper digital audio, go for optical or digital coaxial cables and thicker speaker wire.

• Highest-end: If you want the unparalleled sound of DVD-audio in full surround sound, you'll need special DVD-audio cables and 12-gauge speaker wire.

Home theater system (Blu-ray player, DVD player or VCR, video game console, home theater receiver, TV, speakers):

Home theater system (Blu-ray player, DVD player or VCR, video game console, home theater receiver, TV, speakers):

• Lower-end: If you have an older standard-definition TV and mostly use your system to watch regular DVDs or VHS tapes, then you'll do fine with a composite video cable bundled with RCA analog audio cables.

• Higher-end: For a newer standard-definition TV, you should really upgrade to component video cables. RCA cables will still do fine for audio.

• Highest-end: Once you enter the world of high definition, you'll need to use either component video cables or one of the two copy-protected options: DVI or HDMI. You'll also want to invest in thick-gauge speaker cable to make the most of your surround-sound system.