(American National Standards Institute, New York, www.ansi.org) A membership organization founded in 1918 that coordinates the development of U.S. voluntary national standards in both the private and public sectors. It is the U.S. member body to ISO and IEC. Information technology standards pertain to programming languages, EDI, telecommunications and physical properties of diskettes, cartridges and magnetic tapes.

Cardioid microphones are uni-directional microphones that pick up sound mostly in the direction you point them.

Short for charge-coupled device, an instrument whose semiconductors are connected so that the output of one serves as the input of the next. Digital cameras, video cameras, and optical scanners all use CCD arrays.

An acronym for Digital Cable Ready.

(Digital Light Processing) A data projection technology from TI that produces clear, readable images on screens in lit rooms. DLP is used in all ends of the projection spectrum, from data projectors that weigh only a few pounds to 60" rear-projection TVs to electronic cinema projectors for movie theaters. The technology uses a Digital Micromirror Device (DMD), a chip with 400,000 to more than two million light switches that cancel or reflect light. Microelectromechanical mirrors, each 16 micrometers square, are built on top of a CMOS memory chip.

A standard for high-quality digital audio that is used for the sound portion of video stored in digital format, especially videos stored on DVD-ROMs. Dolby® Digital delivers 6 channels in the so called "5:1" configuration: left, right, and center screen channels, separate left and right sounds, and a subwoofer channel. This is sometimes called surround sound or 3D sound.

(Digital Single Lens Reflex) A digital still image camera that uses a single lens reflex (SLR) mechanism.

The digital visual interface or digital video interface (DVI) is a video connector designed to maximize the visual quality of digital display devices such as flat panel LCD computer monitors and digital projectors. It was developed by an industry consortium, the Digital Display Working Group (DDWG).

A high-speed serial bus developed by Apple and Texas Instruments that allows for the connection of up to 63 devices. It is widely used for downloading video from digital camcorders to the computer. Also known as the IEEE 1394 standard, the i.Link connector and the High Performance Serial Bus (HPSB), the first version of FireWire supported 100, 200 and 400 Mbits/sec transfer rates and a distance of 4.5 meters between devices.

IEEE 1394b provides 800, 1,600 and 3,200 Mbps speeds, increases cable distance to 100 meters and can use glass or plastic fiber and Cat 5 Ethernet cable. FireWire 800 was the first implementation of 1394b and became available in 2003. Backward compatible with FireWire 400, earlier devices run at the lower speed.

FireWire supports hot swapping, multiple speeds on the same bus and isochronous data transfer, which guarantees bandwidth for multimedia operations.

A very thin display screen used in portable computers and televisions. Nearly all modern flat panel displays use LCD technologies. Most LCD screens are backlit to make them easier to read in bright environments.

An adjustment to the light intensity (brightness) of a scanner, monitor or printer in order to match the output more closely to the original image. A gamma correction imposes the complement of the "tone curve" in order to flatten the line and bring the gamma closer to the ideal 1.0.

HDCP (High-bandwidth Digital Content Protection) is a specification (http://www.digital-cp.com/data/HDCPSpecificationRev1_1.pdf) developed by Intel Corporation to "protect" digital audio and video content as it travels across Digital Visual Interface (DVI) or High Definition Multimedia Interface (HDMI) connections. The HDCP specification is proprietary and implementation of HDCP requires a license. It is a form of Digital rights management.

(High-Definition Multimedia Interface) A digital point-to-point interface for audio and video signals from HDMI Licensing, LLC, trademarked both as an acronym logo and full text name. Like DVI, HDMI is mostly based on Silicon Image's TMDS technology and is backward compatible with DVI. Introduced in 2002 by the HDMI consortium (Hitachi, Philips, Matsushita, Silicon Image, Sony, Thomson and Toshiba), HDMI was designed as a common interface for devices from set-top boxes to digital TVs. It supports 165 megapixels per second, which is nearly 5 Gbps and more than sufficient for high-definition DTV at its highest resolution.

HDMI is expected to provide a single-cable solution that replaces a variety of different cable types used in home theater systems, including stereo and multi-channel audio, component video and S-video. HDMI is electrically identical with DVI (single link), but uses a smaller 19-pin connector and dedicates an additional pin to the Consumer Electronics Control (CEC) channel for device control. Although HDMI has its own enhanced protocols that also support audio and auxiliary data packets, an HDMI source can detect a DVI device on the other end and switch to the DVI protocol. HDMI-to-DVI cables are available for DVI-based equipment. For more information, visit www.hdmi.org.

Short for High-Definition Television, a new type of television that provides much better resolution than current televisions based on the NTSC standard. There are a number of competing HDTV standards, which is one reason that the new technology has not been widely implemented. All of the standards support a wider screen than NTSC and roughly twice the resolution. To pump this additional data through the narrow TV channels, images are digitized and then compressed before they are transmitted and then decompressed when they reach the TV.

See FireWire®

Lavalier microphones, commonly referred to as lav mics, are tiny mics that you clip onto a person's shirt or lapel to record their voice. Lavalier microphones often have their own power source - usually a single AA battery (microphones that need a power source are called "condenser" mics).

Short for liquid crystal display, a type of display used in digital watches, many portable computers, and televisions. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

Monochrome LCD images usually appear as blue or dark gray images on top of a grayish-white background. Color LCD displays use two basic techniques for producing color: Passive matrix is the less expensive of the two technologies. The other technology, called thin film transistor (TFT) or active-matrix, produces color images that are as sharp as traditional CRT displays, but the technology is expensive. Recent passive-matrix displays using new CSTN and DSTN technologies produce sharp colors rivaling active-matrix displays.

A unit of measurement of the amount of brightness that comes from a light source. The standard lumen rating of a data projector is the average of photometer readings at several points on a full white image on the screen.

Technically, lumens measure "luminous flux." A wax candle generates 13 lumens; a 100 watt bulb generates 1,200. The lumen rating is a critical specification when choosing a data projector. In a darkened room, 500 lumens may be ample; however, in a conference room with normal lighting, 1,000 lumens would be better. In a room with bright daylight, 2,000 lumens is preferred.

Short for National Television System Committee. The NTSC is responsible for setting television and video standards in the United States (in Europe and the rest of the world, the dominant television standards are PAL and SECAM). The NTSC standard for television defines a composite video signal with a refresh rate of 60 half-frames (interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors.

The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.

Short for Phase Alternating Line, the dominant television standard in Europe. The United States uses a different standard, NTSC. Whereas NTSC delivers 525 lines of resolution at 60 half-frames per second, PAL delivers 625 lines at 50 half-frames per second. Many video adapters that enable computer monitors to be used as television screens support both NTSC and PAL signals.

(PIX [picture] ELement) Generally, the smallest addressable unit on a display screen or bitmapped image. Screens are rated by their number of horizontal and vertical pixels; for example, 1024x768 means 1024 pixels are displayed in each row, and there are 768 rows (lines). Likewise, bitmapped images are sized in pixels: a 350x250 image has 350 pixels across and 250 down.

A type of flat-panel display that works by sandwiching a neon/xenon gas mixture between two sealed glass plates with parallel electrodes deposited on their surfaces. The plates are sealed so that the electrodes form right angles, creating pixels. When a voltage pulse passes between two electrodes, the gas breaks down and produces weakly ionized plasma, which emits UV radiation. The UV radiation activates color phosphors and visible light is emitted from each pixel.

Today, Plasma displays are becoming more and more popular. Compared to conventional CRT displays, plasma displays are about one-tenth the thickness--around 4'', and one-sixth the weight--under 67 pounds for a 40" display. They use over 16 million colors and have a 160 degree-viewing angle.

Refers to the sharpness and clarity of an image. The term is most often used to describe monitors, printers, and bit-mapped graphic images. In the case of dot-matrix and laser printers, the resolution indicates the number of dots per inch. For example, a 300-dpi (dots per inch) printer is one that is capable of printing 300 distinct dots in a line 1 inch long. This means it can print 90,000 dots per square inch.

For graphics monitors, the screen resolution signifies the number of dots (pixels) on the entire screen. For example, a 640-by-480 pixel screen is capable of displaying 640 distinct dots on each of 480 lines, or about 300,000 pixels. This translates into different dpi measurements depending on the size of the screen. For example, a 15-inch VGA monitor (640x480) displays about 50 dots per inch.

Printers, monitors, scanners, and other I/O devices are often classified as high resolution, medium resolution, or low resolution. The actual resolution ranges for each of these grades is constantly shifting as the technology improves.

(Single Lens Reflex) A camera that uses the same lens for viewing and shooting. A mirror reflects the image from the lens to the viewfinder. When the shutter button is pressed, the mirror flips out of the way and the shutter opens to expose the film.

A speaker that reproduces the lower end of the audio spectrum. A subwoofer system may include a crossover circuit which switches frequencies at approximately 100Hz and under to the subwoofer, while passing the rest of the signal to the main speakers.

Unlike front, center and surround channels, where speaker placement is critical to the listener, subwoofers are non-directional and can be located anywhere in the room.

Short for Super VGA, a set of graphics standards designed to offer greater resolution than VGA. SVGA supports 800 x 600 resolution, or 480,000 pixels.

The SVGA standard supports a palette of 16 million colors, but the number of colors that can be displayed simultaneously is limited by the amount of video memory installed in a system. One SVGA system might display only 256 simultaneous colors while another displays the entire palette of 16 million colors. The SVGA standards are developed by a consortium of monitor and graphics manufacturers called VESA.

(Super-VHS) A VHS recording and playback system that increased resolution from 240 to 400 lines and used a higher-quality cassette. S-VHS introduced the S-video interface, which separated the luma from the color (see S-video).

Introduced in the mid 1980s, there is little noticeable difference between VHS and S-VHS when taping programs off-the-air. However, if the source material is higher quality (camcorder, satellite, etc.), S-VHS recordings are visibly superior. S-VHS VCRs also play regular VHS tapes, and S-VHS-ET (Expansion Technology) machines are able to record S-VHS content on regular VHS tapes.

Short for Super-Video, a technology for transmitting video signals over a cable by dividing the video information into two separate signals: one for color (chrominance), and the other for brightness (luminance). When sent to a television, this produces sharper images than composite video , where the video information is transmitted as a single signal over one wire. This is because televisions are designed to display separate Luminance (Y) and Chrominance (C) signals. (The terms Y/C video and S-Video are the same.)

Computer monitors, on the other hand, are designed for RGB signals. Most digital video devices, such as digital cameras and game machines, produce video in RGB format. The images look best, therefore, when output on a computer monitor. When output on a television, however, they look better in S-Video format than in composite format.

To use S-Video, the device sending the signals must support S-Video output and the device receiving the signals must have an S-Video input jack. Then you need a special S-Video cable to connect the two devices.

A small loudspeaker designed to reproduce high-pitched sounds in a high-fidelity audio system.

Abbreviation of video graphics array, a graphics display system for PCs developed by IBM. VGA has become one of the de facto standards for PCs. In text mode, VGA systems provide a resolution of 720 by 400 pixels. In graphics mode, the resolution is either 640 by 480 (with 16 colors) or 320 by 200 (with 256 colors). The total palette of colors is 262,144.

Unlike earlier graphics standards for PCs -- MDA, CGA, and EGA -- VGA uses analog signals rather than digital signals. Consequently, a monitor designed for one of the older standards will not be able to use VGA.

Since its introduction in 1987, several other standards have been developed that offer greater resolution and more colors (see SVGA , 8514/A graphics standard, and XGA), but VGA remains the lowest common denominator. All PCs made today support VGA, and possibly some other more advanced standard.

(Video Home System) A half-inch, analog videocassette recorder (VCR) format introduced by JVC in 1976 to compete with Sony's Betamax, introduced a year earlier. During the 1980s, VHS overtook the Beta format and became the standard for consumer entertainment as well as by industry for training and product promotions. S-VHS (Super VHS) was a subsequent format that increased resolution from 240 to 400 lines, but was not widely used by consumers. In 2002, sales of VHS players were superseded by DVD players for the first time.

Large loudspeaker designed primarily to reproduce low frequency audio signals.

Short for extended graphics array, a high-resolution graphics standard introduced by IBM in 1990. XGA was designed to replace the older 8514/A video standard. It provides the same resolutions (640 by 480 or 1024 by 768 pixels), but supports more simultaneous colors (65 thousand compared to 8514/A's 256 colors). In addition, XGA allows monitors to be non-interlaced