What are all of these cables and which one does what? - Part 1

The picture to the left does a good bang-up job of depicting what most people see in their mind when thinking about the mess of wires behind all of their audiovisual equipment. Just trying to figure out which cable goes where and what each one does can be a gruelling thought for most folks. The good news however is that all of the plugs on today's residential equipment are all color coded to match the wire you’re trying to plug in. Keep in mind color coding may not apply if you are purchasing some high end or custom cables but is always present on the equipment ports. Let’s take a look at each type of cable from the worst to best quality.

There are two different types video of signals that need to be understood before we continue. Analog is the first and most common type of signal used today. Analog video is made up of 5 key components "Red, Green, Blue, Horizontal and Vertical Sync." I will refer to this as RGBHV for the rest of my post. The second type "Digital" is gaining more popularity every day with HDMI and DVI cables.


ANALOG Video

RF Cable: This is the most common type of cable that plugs directly into your television when hooking up basic CableTV and uses an F-Connector. It has the worst picture, sound quality and has all 5 signals "RGBHV" compressed onto one wire including left and right audio. As a video signal is compressed the quality of the picture will always go down. This cable and connector type is also used to hook up internet cable modems and digital cable boxes. The cable and connector looks the same but for these two applications there is a completely different signal being carried so don’t confuse it with the video in your home theater.

Composite Cable: This cable uses an RCA connector and is always yellow in color. It also has RGBHV compressed onto a single cable but the stereo audio has been taken out. The same connector is used for several different signal types but yellow is the only color used for composite video. The plug on the back of your equipment will also be yellow.

S-Video: This connector usually has no color coding other then black but is the only connector that looks like this used in home theaters. S-Video is less compressed and the "RGBHV" signal is broken up between two wires. Keep in mind a cable can only be called a cable if it has more then one wire inside of it. It could have two wires or it could have twenty-four wires and still be called a cable.




Component Video: Uses the same RCA connector as composite video and due to the name can be easily confused. Component video in a home theater setting is what I would recommend using at the bare minimum. Try not to use any of the ones before this unless you are out of input jacks and are forced to. Component video has RGBHV split up onto three wires instead of two. The red wire carries the red portion of the picture, blue is on blue and green is on green. The "HV" portion of the "RGBHV" signal is compressed onto the green wire and this is why you can plug in green by itself and still get a picture. If you were to plug in red or blue alone nothing will show up. This cable can support high definition at 720p but should not be used for 1080p. If you plan to use 1080p be sure to use the HDMI cable further down.

VGA aka RGBHV: The blue VGA cable is used by most if not all personal computers and carries each of the RGBHV portions on separate wires inside the cable. No compression takes place on this cable and should be used whenever possible if you have to use an analog signal. The only place you will find this connector in a home theater is directly on the back of your TV if it is supported. The connectors standard color code is blue for both connectors and equipment ports. The thickness of this cable type is very important depending on its length and the resolution setting of the computer. Newer computers have very high resolutions "1680x1050" vs older resolutions such as "800x600." The resolution tells you how many dots are on the screen in a matrix format. Multiply 800 by 600 to get 480,000 which is the total amount of dots available to create the detail of an image. Make sure to get a thicker cable if you’re using a higher resolution "1280x720" and for long lengths "30 feet or more".


Digital Video

DVI Cable: Is replacing VGA in the computer world for personal computers and is gaining popularity. Once again this is a completely uncompressed video signal but since it is digital it will either work or it won't. A digital signal doesn't degrade quite the same as an analogue signal and the picture is better / far more reliable. If your equipment supports this type of cable always use it over VGA when possible. The downside is the limitation on the length of your cable vs the cost to overcome it. A good point to note is to never buy "Monster" anything for digital cables. You can buy a more affordable 25 foot DVI cable and get the exact same picture quality. Like I said "Digital either works or it doesn't." I wouldn't recommend buying the cheapest cable you can find as you still want it to be well made as far as reliability goes but there is no need to pay double for "Monster" cables when there is little to know added benefit.

HDMI Cable Is replacing component as the new standard in high definition home theater systems. HDMI like DVI is also a completely uncompressed digital signal but also carries audio as well. DVI for the most part doesn't carry audio but I have heard some new hardware is starting to support this feature. HDMI has the same distance limitations as DVI and they are very compatible with one another. If your laptop has an HDMI output but your monitor has a DVI port you don't need to worry. You are able to buy a cable with HDMI on one end and DVI on the opposite. They also sell tiny converters that you can pop onto the end of either type to get the connector you need.

Stay tuned for the second half of this post tomorrow and I will cover the different analog and digital cables for audio.