Video Cables Buyer's Guide

Video cables can have a profound effect on the quality of the images you view on your monitor or television. Because they transmit the electric signals from a video source, such as a DVD player or your cable box, to your television screen, you need to make sure your signal is carried by the right cable in order to achieve optimal image quality.

Here are a few questions to ask before buying video cables.

What kind of signal are you transmitting?

There are two main types of video signals: analog and digital. Depending on the capabilities of your entertainment system, you’ll need to match the cable you purchase with the type of signals your system is able to transmit. Digital image and sound have revolutionized home entertainment with consistently high-quality signal transmission. Depending on how old your equipment is, there’s a chance your system might be able to transmit analog signals. Analog signals are more susceptible than digital to degradation by interference and noise, so you need to make sure you have high-quality analog cables in order to preserve their integrity.

What’s the quality of the signal you’re transmitting?

Screen resolution, determined by the number of scan lines on your screen, is the main way to measure video quality. These scan lines are comprised of thousands of pixels. Higher resolutions have more scan lines and thus a greater number of pixels, which provide sharper images.

Whether your picture is interlaced or progressive also helps determine video signal quality. An interlaced picture only generates half of a TV’s scan lines, skipping over every other one. The result is 30 full frames per second. Progressive picture, in contrast, generates all scan lines, providing 60 full frames of video per second and therefore a smoother, clearer image.

Here are the standard signal resolutions (“i” indicates interlaced, while “p” refers to progressive):

• 240i – low res signal used in standard VCRs
• 480i – standard resolution for analog signals and non-progressive DVD players
• 480p – resolution for digital, non-HDTV signals and progressive-scan DVD players
• 720i, 720p and 1080i – possible HDTV signal resolution
• 1080p – highest HDTV resolution

You need to make sure the cables you use are compatible with the signal quality your system can transmit.

What cable length do you need?

Measure the distance between your system’s components before purchasing cables. You don’t want to wind up with cables that are either too long or too short – they need to be just right. If they’re too long, you could have reduced video quality. Cables that are too short won’t be able to connect your components. Use cables with some slack in case you ever need to move your components around.

Different types of cables have better capabilities at different lengths. HDMI cables, for instance, are best up to about 50 feet for standard high definition, though the shorter they are, the better the signal. For S-Video, the safest length for quality signal transmission is up to 150 feet. If you need to increase this, there’s a device available called an S-video Balun, which converts S-Video channels to and from CAT-5. CAT-5 cable, which is less expensive than S-Video, can be run up to 500 feet while still producing a very good signal.  DVI cables work best between 1 and 9 meters, though repeaters and other devices can be used to increase this length.

You could also run any of these cables using an amp in order to increase their signal power over a longer distance.

Cable Types

Here are the main types of cables you’re likely to encounter:

• Composite RCA video cables
• HDMI
• Component video
• DVI
• VGA
• BNC (component)
• M1
• S-Video
• Category 5 (Cat 5)
• SMART/Whiteboard cables

 

Composite RCA video cables

These cables transmit a 480i signal, making them useful for analog signals, but not the best for high-definition signals. Composite cables, which often have a yellow connector head, usually come combined with a pair of analog audio cables, which have red and white connector heads. These cables are commonly provided with your video components, but are best for older VCRs, TVs and other gear.

HDMI

HDMI cables are designed to deliver the highest quality video to your receiver – high definition. High-definition audio and video is becoming more and more popular, meaning more systems require these cables.

These cables deliver both audio and video to your television or computer monitor via a single, convenient cable. Designed with a 19-pin connector, they transfer digital audio and video through the components of your home entertainment system, offering the crispest, clearest images. These cables also carry up to eight channels of audio for surround sound and an incredibly realistic and cinematic experience.

As this technology is continually evolving, make sure the cable you purchase meets the HDMI standards of the equipment you’re connecting.

DVI

DVI transmits high-definition video signals – but not audio – generally only to your computer monitor these days, as HDMI has almost entirely replaced DVI ports on televisions. However, some TVs can still connect to DVI. If there’s a DVI port in both your computer and TV, it will allow you to hook up your TV as a second computer monitor. There are also adapters on the market to convert your computer’s DVI signal to HDMI on your TV.

Component video

These are the most advanced non-digital cables available. They separate video into three signals for superior images. Though designed primarily for analog connections, they’re also able to transmit high-definition signals up to 1080p and are a good go-to when HDMI cables aren’t an option.

VGA

An analog video connector that transmits component video signals, this is the oldest type of standard cable for your PC. It’s mostly used to hook up your monitor to a PC. Each VGA cable has a large rectangular connector head on each end. Within the connector is a trapezoid-shaped plug with 15 small pins as well as a screw connection. If you have an LCD HD set with a VGA port, you also might be able to connect your computer to your TV in order to use the latter as a monitor.

M1

M1 cables, which can carry both digital and analog signals, are used to connect your projector to its video source. They’re able to connect to either VGA or DVI inputs.

S-Video

These cables transmit video signals and divide them into two separate channels: one for color and one for brightness. This results in sharper images sent to your television.  As TVs are designed to display luminance and chrominance signals separately, S-Video is much better than using a composite cable, which transmits just a single signal over one wire.

Cat 5

This Ethernet network cable consists of four pairs of twisted copper wires. They come in two varieties: solid and stranded.  Solid Cat 5 cables are better for longer distances and work best in scenarios with fixed wiring configurations, like office buildings. Stranded Cat 5 cables are best for shorter lengths, especially systems that are less permanent and require movable cables.

SMART/Whiteboard cables

Most SMART boards use USB cables to connect and draw power from your computer, so you can project presentations, documents, websites and more as you view them on your PC. However, if you’re connecting a SMART board to a projector, you’re going to need a VGA cable.

Cables Specs

Here are a few other factors to consider when shopping for video cables:

• Shielding
• Connector types
• Supported transfer speed

Shielding

Your cables are shielded to protect the signal from interferences that could degrade the video quality. The shielding keeps interference from reaching the conductor.

There are three main types of shielding:

• Braided shield
• Spiral-wrapped or serve shield
• Foil shield

Braided shield
Shielding often comes in the form of a wired braid. Small wire strands are braided to surround and protect the center conductor’s insulator. Since this type of shielding is flexible and durable, it’s great for handling the wear and tear of live performances on stage. These cables are best used for microphones and instruments.

Spiral-wrapped shield
Also known as a serve shield, this protection is formed by wrapping a flat strip of wire strands around the center conductor in a spiral. It’s more flexible than a braided shield, but not as strong. These shields are also slightly less resistant to interference than other shielding types available but generally less expensive than braided shields.

Foil shield
These mylar-backed aluminum tubes have a copper wire connected at each end. Though inexpensive and effective at transmitting signals, they’re also fragile and prone to damage. For that reason, they’re best used in more permanent installations.

Cable Connectors

Cables are used to connect your various components. Cables consist of at least one protruding pin, though some connectors have several and are designated as either male or female.

Here are a few common types of connectors:

• RCA
• VGA
• F-type
• BNC
• S-Video
• USB

RCA

RCA connectors are usually a pair of wires that are molded together. The ends of these wires, however, are separate and usually come with red and white connecting heads (though sometimes you’ll see a black, rather than white, connector). These connectors have a central pin approximately 2mm long, which is surrounded by an outer shell. Designed for ease and convenience, it takes mere seconds to plug them into your electronic devices. They can handle a wide range of frequencies and power.

VGA

Used to hook up your monitor to your computer, each VGA cable has a large rectangular connector head at each end. Each connector has both 15 small pins and screw connections.

F-type

Seen on coaxial cables, these are often used for cable and satellite TV and off-air antennas. Its round connector has the conductor protruding from the center and usually screws into place.

BNC

These round plugs with a bayonet-style locking system are used on coaxial cables. They’re incredibly secure once connected and are great for limiting impedance.  Typically, they’re used for professional and high-end video systems, and are commonly used with closed-circuit television and surveillance cameras.

S-Video

This 4-pin connector has its pins arranged in two rows and uses a keying block to ensure it’s always inserted properly. S-Video connectors transmit two signals only – luminance and chrominance – and the other two pins are used for signal-ground connections.

USB

USBs are commonplace among digital, computer connections. They have type A or type B connectors on one end and are used to plug audio and video gear into your computer.

Supported Transfer Speed

Also known as bandwidth, this refers to how quickly signals are transmitted via the cable you’re using. Measured in bits per second (bps), signals transmitted from the video source to the receiver (monitor, television, etc.) are referred to as “downstream,” while signals going the opposite are referred to as “upstream.” Each cable has a different capacity. The higher the bandwidth your cable can handle, the better the quality of signal.