Home A/V Connections: What Plugs In Where?

Back in The Good Ol’ Days, putting together a home theater system was relatively simple – you plugged in your TV set and you watched it and you were happy. The closest things were to confusing was figuring out if you could get away with just using rabbit ears, or if you were going to have to shell out for an antenna. 
These days, your average home theater has all kinds of crazy holes you can shove cords into in order to enhance your viewing experience. Even worse, it’s a television, stereo receiver, DVD player, DVR, MP3 player, home theater PC… and that’s just the tip of the iceberg. This gives people lots of options, but figuring out which connection is going to provide the best level of quality, or which cable you need to connect two devices, can be maddening. This guide will help to cut through the cord chaos and confusion.

 

 

Video Cables

Coaxial

This is your most basic of cables. They’ve been connecting televisions to antennas for decades now. If you have a pair of rabbit ears, they’re connected to your TV with a coaxial cable. It sends the video feed along with audio, so it’s overall not of the highest quality. If you want a high-end audio visual system, you should generally avoid these like the plague. The major exception to that statement involves over-the-air high definition programming (yes, you can really watch free HD programming over-the-air!) -- OTA HDTV antennas often use a coaxial connector to join the antenna to your TV or cable box.

 

Composite Video

Composite video uses an RCA cable. RCA cables are named for the RCA Corporation, which used the cable to hook up mono phonographs to amplifiers in the early 40s. That’s right, one of the prime connectors of your state-of-the-art A/V system is WWII-era technology. Composite video is the yellow RCA plug that is usually paired up with the red and white audio plugs that deliver audio (which we’ll discuss in the audio section). The colors are standard identifiers so if you have an RCA cable with only one connector and its color is yellow, it carries a video signal. If you can avoid using composite video, do so. It’s better than coaxial, but it’s still sending the entire video feed through one cable because the signal is compressed, which means some loss of visual information. Composite video is a standard-definition video signal and will not transmit high-definition television. VHS tapes are encoded in composite video format natively.

 

S-Video

The S-Video socket looks a little like a mushroom in a circle. The male connection has four pins and a larger ground pin. It’s superior to the composite video cable, because it splits the video feed into two signals, luma and chroma. It only carries video signals, so you’re still going to have to have to run additional cabling to carry your audio signals. Although it is superior to composite video, S-video also can’t provide HD-quality video. Many VHS VCRs use either S-video or composite connectors to deliver video to your TV.

 

Component Video

If you aren’t careful, it’s easy to confuse component video with composite, since they both use RCA-type connectors. In fact, you can use cables created for composite video with component video devices with no problem. The difference is that component video splits the video feed into three separate parts. You can tell them apart from a composite feed because of the different colors of the connectors -- green, blue and red -- and because there are often the letters Y, Pb and Pr underneath them. Component video is capable of delivering a high definition video feed, but it is not uncommon to find HDTVs that do not support the highest-quality 1080p high-def signal over component video (instead supporting up to 720p over component even while supporting 1080p over HDMI). DVDs are encoded natively in component video format. As with S-video you will need additional cables to handle the audio delivery in your home theater setup.

 

VGA

VGA stands for Video Graphics Array. It’s the same type of cable with 15-pin connectors you find in older or less expensive computer monitors. Introduced by IBM in the late 1980's, the VGA standard became adopted by a majority of PC clone manufacturers, came into widespread use, and still remains the lowest common denominator resolution standard that computer hardware will support before any device-specific drivers are loaded. VGA cables can now provide high-def video, but in analog, not digital, format. Nevertheless, many newer LCD and Plasma HDTVs provide a VGA input in order to accomodate connections from your computer.

 

DVI

DVI stands for Digital Video Interface. It’s the same cable you’ll find in newer computer monitors, projectors, and many HDTVs. Developed by an industry consortium, the DDWG or Digital Display Working Group, the DVI standard was designed for carrying uncompressed video information to a display. This is the good stuff. It provides a clean, digital video signal. If your devices support DVI connections, you're better off taking advantage of it as opposed to using composite, component, S-video or VGA.

There are actually several types of DVI connections you may run into, the two most common of which are Single Link DVI-I and DVI-D. DVI-I stands for DVI-Integrated, which supports both digital and analog transmissions. DVI-D stands for DVI-Digital and carries only digital signals. The DVI-I male connector has 4 extra pins above and below the long flat pin that carry an analog signal. It is possible to plug a male DVI-D connector into a female DVI-I receptacle, so if your LCD monitor or HDTV only has a DVI-D connector and your computer, receiver or set-top box has a DVI-I female input, the devices should still be compatible.

 

Audio

Analog stereo

These are the cables with red and white RCA plugs that are often paired with the yellow composite video cable. They are only capable of handling two channels of audio at a time (left and right speakers, typically), so don’t expect to achieve advanced 5.1 surround sound out of this type of cabling. The most common way to connect a portable media device such as an iPod or Zune to your home audio or theater setup is to use a 1/8-inch mini-jack to stereo RCA cable. Many VHS and DVD players output audio from stereo RCA to RCA, and many more modern components still offer RCA outputs and inputs as a "lowest common denomintor" audio standard to accomodate a wide range of older devices.

 

Digital TOSLINK

These connections are fiber optic cables that send audio as beams of light instead of electricity. This helps eliminate distortions in the sound. If your television or stereo receiver has holes in it that glow red, this is the cord you use. Although it is just one cable, it is capable of delivering 6.1 surround sound and certain kinds of 7.1 surround sound. You may hear this type of audio technology also referred to as S/PDIF audio, which stands for Sony/Philips Digital Interconnect Format (the two companies primarily responsible for designing the format). S/PDIF is really a standard protocol describing how to transmit digital audio information between devices, and cables and devices that conform to the S/PDIF standard can use either TOSLINK cables or coaxial cables with RCA connectors, which we'll talk about in the next section.

 

Digital coaxial

Even though digital coax uses the same type of RCA connectors that basic old stereo audio uses, these types of cables actually carry higher-fidelity digital audio information. The plugs are often colored something other than red or white to distinguish them from the typically red and white connectors of analog RCA cabling. Just like TOSLINK cables, these cables and the devices that support them are using the S/PDIF standard for transmitting digital audio. Digital coax or TOSLINK cabling will often be used with home theater receivers that support Dolby Digital or DTS Surround Sound.

 

Audio and Video

HDMI

High Definition Multimedia Interface cables are the current gold standard of A/V cables. Not only can they provide perfect, uncompressed digital high-definition images at 1080p and 7.1 surround sound, they do it all with one cable. That means a high quality digital video and audio connection between your components as well as far fewer wires hanging out the back of your home theater. If you can use it, do so.

The HDMI standard is actually derived from the DVI standard, so some backwards compatibility between the two technologies exists. You will find DVI to HDMI cables on the market that will allow the connection of devices with DVI-only output to HDTVs, projectors and A/V receivers with HDMI inputs. Because DVI does not transmit audio signals, however, you'll require additional audio cabling if you're using a DVI to HDMI cable to transmit video in your home theater setup.

[Guide co-authored with contributor Jeremy Goldstone]