Getting video and audio into and out of computers has gotten a lot simpler thanks to digital technologies such as FireWire and USB. But with every newfangled port there's a new type of connector to become familiar with and new adapters to buy. The following is a lexicon of connectors and their typical uses.
Adapters
These allow you to connect plugs or jacks of one sort to plugs or jacks of another. Radio Shack is a good place to begin collecting adapters of all sorts. Ideally, have multiple adapters for every possible senario-male-to-female, female-to-female, mono-to-stereo, and so on.
BNC
The BNC (Bayonette-Neill-Conselman) is a more professional video connector. The female is barrel-shaped. It's good to have BNC male-to-BNC male and BNC-to-RCA adapters in your tool kit. You never know when a VCR will have BNC jacks instead of RCA jacks.
IEEE 1394
This connector is known by many names, commonly FireWire (originally an Apple trademark). Sony calls it iLink. IEEE 1394 is fast-at 400 Mbps (megabits per second) it has 30 times more bandwidth than USB. A new version, just released, runs at 800 Mpbs. FireWire is also hot plugable (devices can be exchanged while the computer is on) and supports up to 63 devices and cable lengths up to 14 feet. There are two types of FireWire connectors, 4-pin (shown at left) and 6-pin (right). You'll find 4-pin connectors on camcorders, whereas the 6-pin connectors are usually found on FireWire hard drives and on computers' FireWire ports. The two extra pins on 6-pin FireWire connectors are used to send power to the device. Keep a 6-pin-to-6-pin cable and 6-pin-to-4-pin cable handy.
Jacks
The term for female connectors.
S-Video
Also called mini-DINs, these multi-pin connectors are found on most prosumer video cameras. In an S-Video (a.k.a. Y/C ) signal, the video brightness (Y) and color (C) information are carried on separate connections, making it cleaner than a composite video signal. By the way, DIN stands for Duetsches Institut fur Normung (German Institute of Standards).
Miniplugs and Minijacks
These are used for headphones in cassette players, MP3 players, and CD players. Minijacks are used as audio inputs, speaker outputs on most computers, and external microphone inputs on camcorders. Inexpensive mono phonic and stereo microphones also use these miniplug connectors. Note there are two different sized mini connectors: 3.5 mm and 2.5 mm. The difference is next to impossible to spot visually, and they aren't compatible. The 3.5 mm variety is what you'll most often encounter in audio connections. The 2.5 mm variety is found on some ear phone connectors.
Most camcorders come with angled 3.5 mm miniplug-to-RCA plug adapters for right and left audio channels and a composite video signal.
Plugs
The term for male connectors.
Phone (or Phono) Plugs
Also called 1/4-inch plugs, these are used to connect electric guitars and keyboards to musical instrument amplifiers and mixers. They come in both mono and stereo configurations, and use a tip-ring wiring configuration where the tip is hot and the ring is ground. The stereo version (pictured) has two rings, and was once the connector of choice on many pairs of headphones. Have adapters handy to convert these. Only Radio Shack resists calling them "phono" plugs.
RCA
RCAs are used for VCR video audio in and out; to connect old Apple II computers to their monitors; and to hook up laser disc outputs to a TV set. You'll also find them on all sorts of consumer audio gear as both external audio inputs and audio outputs. In some cases, you'll find RCA connectors used for speaker outputs. Be careful not to plug a speaker output into an audio input-the mismatch in signal strength can damage your equipment.
You'll notice stereo RCA cables use separate wires for left, right, and video channels. Their connectors are generally color-coded red for right, white for left, and yellow for video. Note: the video signal carried over wires terminated in RCA connectors on consumer electronics equipment is known as "composite" video, wherein the brightness and color information of a video signal are combined on the same channel. It's used on most all consumer video equipment. Note: They call RCA connectors "phono" connectors at Radio Shack.
RF, "F" Connectors, or Coaxial
These connectors go by many names and live behind VCRs and TVs, as they're the connectors used for cable television connections. Be careful not to bend the little pin in the middle.
USB (Universal Serial Bus)
Offers transfers rates of up to 12 megabytes per second, more than 50 times old serial ports (and 12,000 times older style buses). Keystrokes, printer data, video, still photographs, and more can be moved through USB connections.
XLR
Also called Cannon connectors after the company (ITT-Cannon) that invented them, these three-pin connectors are used to carry balanced audio signals (where two pins carry alternating current that's 180-degrees out of phase and the other is wired to ground, a design that rejects noise and electromagnetic interference). Balanced audio is the type of signal output from most professional sound reinforcement equipment, including microphones. XLR connectors are also used to terminate some professional format digital audio connections.
Hall Davidson (hall@cccd.edu) is executive director of educational services and telecommunications at KOCE-TV in California. He has received numerous awards, including an Emmy for Best Instructional Series.
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