Glossary of Consumer Electronics
5.1 Surround Sound
Alternate Names: Dolby Digital, 5.1, Dolby AC-3
A common way of describing standard Dolby Digital surround sound. The numbers stand for five separate "channels" of sound information, each playing through its own separate speaker, plus a sixth channel (speaker) just for the low bass, called a subwoofer (this is the ".1"). Three of the six speakers of a 5.1 surround sound setup go to the left, center, and right of the TV screen; while a left surround and right surround speaker go to the rear or sides of the listening area.
6.1 Channel Surround
Alternate Names: Dolby Digital EX, Dolby 6.1
An extension of 5.1 Dolby Digital surround sound that uses a sixth full-range speaker in the center rear of the surround field. The sound information for this extra channel is recorded into the source content, and played back by an AV receiver that offers this feature. Content that has been recorded with 6.1 sound is compatible with conventional 5.1 channel Dolby Digital surround sound systems. DVDs and other software with Dolby Digital EX soundtracks have a digital "flag" that alerts your AV receiver that there is a sixth channel. If your system has been set up for 6.1 playback, the extra channel is played. If your system doesn't have the optional sixth channel, the system plays the software in 5.1 format.
7.1 Channel Surround
An extension of 6.1 Dolby Digital EX surround sound that uses 2 extra center speakers in the rear of the surround field, which results in a total of 7 separate sound channels and an eighth channel just for the low-bass speaker, the subwoofer (hence, 7.1). Like 6.1 Dolby Digital EX, 7.1 software is backward compatible with standard 5.1 Dolby Digital systems.
AC Power Connector
Stands for Alternating Current; this is a way of describing the electrical power that come out of a home's walls. When you connect a device to AC power, you're giving it electricity so that it can be turned on and off.
AC Conditioner
Alternate Names: Power cable, power plug, AC connector
A device that lets you plug in electrical components like TVs, receivers and DVD players, and regulates the electrical current from the wall that feeds them, thus providing a stable source of non-fluctuating power. AC conditioners can make components perform better and last longer.
AC Power Strip
A device that plugs into an AC electrical wall outlet and allows multiple electrical components to be "plugged in" at the same time. Some AC power strips have additional features, such as protection against power surges and dips that typically happen as AC power fluctuates in the home.
AC Surge Protector
A device plugs into an AC wall outlet, and lets you plug in multiple components like TVs and DVD players. The surge protector prevents damage to these components in the event of a power "surge" that might occur due to a nearby lightning strike or other electrical anomaly.
Access Card
A physical, card-like object that is used by some components like cable TV and satellite receivers, to authorize or bill a user account.
AM Antenna
AM antennas are specifically designed to receive signals from conventional AM (Amplitude Modulation) radio broadcasts. AM radio is typically monaural (non-stereo) and offers lower sound fidelity than stereo FM (Frequency Modulation) radio. AM broadcasts are transmitted at frequencies between 535 kHz and 1,605 kHz.
AM Radio
A component, or feature of a component, that receives conventional AM (Amplitude Modulation) radio broadcasts. When the component has amplification and a speaker built in, it is called an AM radio. If the component is only capable of receiving AM broadcasts, and not able to play them back without other equipment, it is called an AM tuner. Stand-along AM radios or tuners are relatively rare; this capability is usually built into combination AM-FM tuners or radios.
AM-FM Antenna
An AM-FM antenna provides reception of conventional (analog) radio broadcast signals. AM and FM radio broadcasts work with different frequencies; an AM-FM antenna is able to receive both. Antennas can reside indoors or outdoors, and range from simple T-shaped wires called "dipole antennas" to elaborate roof- mounted outdoor antennas.
Analog
From the word "analogy" — analog technology is the opposite of digital technology. A good example of the difference between analog and digital would be an old style clock with minute and second hands, versus a digital clock. One is a "representation" — analogy — of something (time), while the other is a precise description of the same thing. In the consumer electronics world, analog technologies are those that use traditional methods of receiving, recording and/or reproducing content or communications. Examples include VCRs, cassette tapes and NTSC (standard) cable and TV broadcasts, as opposed to digital devices, like DVD players and HDTVs.
Analog Cable Box
A set-top box designed to receive analog video content delivered by a local cable TV (CATV) provider. A single wire from the provider comes into the home and feeds the box, which then sends analog video and audio signals to your components, such as an AV receiver.
Antenna
An accessory device designed to receive broadcast signals that are sent through the air. Antennas are usually designed for a specific type of reception, such as TV, conventional and satellite radio, etc., though some antennas are capable of receiving more than one type of broadcast signal. Antennas come in both indoor and outdoor models, as well as models designed for cars and portable devices.
Aspect Ratio
The shape of a video picture, which is described as the ratio of width to height for an image or screen. Traditional analog TVs use a square-ish 4:3 ratio (4 units of measurement wide by 3 units of measurements high). Most digital televisions are shaped in the wider 16:9 aspect ratio.
ATSC
Stands for Advanced Television Standards Committee, a body that was formed to establish technical standards for the U.S. digital television system.
Audio Power Amplifier
A component that accepts processed audio signals and then electrically amplifies them for delivery to loudspeakers. Power amplifiers come in numerous configurations, and can appear both as a stand-alone component and as an integrated device when combined with a preamplifier (called an "integrated" amplifier). When the power amplifier is built into the same box as a preamplifier and a tuner, it is called an AV receiver. Whether built into an AV receiver or as a separate component, power amplifiers vary in the number of "channels" of sound that they can power. A two-channel power amplifier is stereo, five, six and even seven-channel power amplifiers are common for surround sound.
AV Preamplifier
A device that accepts digital and analog video and audio signals from source components like DVD players and satellite receivers; decodes and processes them, and then distributes them to other components for eventual playback. Essentially, an AV preamplifier is the same as an AV receiver, except without the audio power amplification capabilities. Also known as the AV Preamp-Processor or "pre-pro", the AV preamp is a standalone component most often seen in costlier, high-end systems.
AV Receiver
The Audio Video receiver typically serves as the central component of a home theater system. The AV receiver accepts audio and video signals through various jacks and ports from source components like DVD players and set-top boxes. Once these signals are connected to the receiver, they are processed and amplified, and then output to audio and video display devices, such as speakers and TV monitors. At minimum, the AV receiver is a one-box combination of an audio/video preamplifier, an audio amplifier, and a tuner for radio reception. Oftentimes they will have additional digital processing functions to enhance video and audio signals. AV receivers vary in the number of audio channels they can reproduce. Virtually all AV receivers are capable of 5.1 channel Dolby Digital sound; some are capable of even more channels.
Banana Plug
A plug used at the ends of speaker cables to connect speakers to an amplifier or receiver. The bowed plug looks something like a banana, hence the name. Banana plugs create a secure, high quality connection for speakers, and are usually seen in costlier equipment and systems. Because the plugs are relatively large, they are rarely seen in compact components or systems.
Bandwidth
A term used to describe the amount of digital data (ones and zeroes) that moves from one place to another. The more data, the greater the bandwidth needed. Bandwidth is expressed as a measure of capacity and speed, such as Megabits per second (Mbps).
Bluetooth
A low-power wireless technology that can send and receive digital information over a short-range wireless network. Already popular for cell phones, Bluetooth is beginning to appear in other consumer electronics products, such as camcorders and audio systems.
Blu-ray Player
A component capable of playing high-definition video discs in the Blu-ray format. Blu-Ray is capable of playing and outputting true 1080p HDTV content. To get all the benefits of Blu-Ray quality, an HDMI connection is mandatory. Lower quality connections will pass signals, but not at the highest quality. Blu-ray players can also play standard DVD discs and most recordable DVD discs.
BNC
A type of connection usually associated with professional video and audio equipment. It uses a twist-turn (bayonet) style plug that locks onto a BNC jack for an extremely secure connection. In the consumer A/V world, BNC connections are unusual, occasionally seen on high-end video projectors.
Bose Link
A proprietary connection used by Bose to expand Bose Lifestyle systems into multiple rooms. It's a special cable with a miniature multi-pin DIN plug at the end, and is designed only for Bose equipment.
Cable Box
A set-top box designed to receive analog or digital video content delivered by a local cable TV (CATV) provider. A single wire from the provider comes into the home and feeds the box, which then sends analog video and audio signals to your components, such as an AV receiver. See Analog Cable Box or Digital Cable Box.
CableCARD
A security card that some digital cable customers must obtain in order to view high-definition scrambled programming and premium services from their cable provider. In essence, the CableCARD serves most of the same function as a cable set-top box receiver. Instead of being a separate, outboard component, the CableCARD slips into another device — typically a TV — and delivers authorizations for content delivery from the cable provider.
Camcorder
A portable device that's a combination of a camera and a video recorder, hence the word "camcorder." Most of today's camcorders are digital; many record video onto small digital cassettes called DV (Digital Video) cassettes, while other record footage onto an internal hard drive or a miniature, recordable DVD disc. Camcorders are often connected to full AV systems to enjoy big-screen picture and full stereo audio.
Cassette Deck
A component that can play back (and usually record) analog cassette tapes in the Compact Cassette format. Players may be either stereo or mono; there are no cassettes recorded in surround sound. Some recorders are capable of recording sound continuously on both sides of a cassette tape, while others require manual intervention to turn the tape over to record on the second cassette side.
CATV Coax Cable
A connection that sends a combined analog or digital video and audio stream from a cable TV provider through a coaxial wire to the cable TV (CATV) set top box. The cable itself is usually terminated with a screw-on plug and jack system called an "F" connector. The source wire from the cable company comes into the home and gets connected to the cable TV set-top box. The set-top box then feeds the audio and video streams to other AV components through dedicated video and audio (or combined) connections.
CD player
An audio-only device designed to play optical discs in the Compact Disc (CD) format. Discs are inserted into the player and read by a laser. The signal may then be sent in pure digital form to an AV receiver for digital-to-analog decoding, or the CD player may perform this function itself, outputting analog stereo audio signals to an AV receiver. CD players are available in either single-disc or multi-disc styles.
CD Recorder
A component capable of recording audio content onto a CD-compatible optical disc, as well as being able to play back these discs. Two types of CD recordings exist, and most CD recorders are capable of both. A CD-R (Recordable) disc is "written" once with content and then becomes permanent. A CD-RW is a re-writable disc that can be recorded and re-recorded many times. All CD-R discs are theoretically capable of playing in any CD player, though some older machines have trouble with these discs. CD-RW discs can only be played in a player capable of playing CD-RW, and incompatibilities between players are more common in this format.
Center Channel Speaker
A speaker dedicated to the center (dialog) channel of a home theater's surround sound system. The center channel speaker is often identical (in terms of drivers and specifications) to the left and right main (front) speakers.
CL Rated
Alternate Names:CF Cards, CF Type I Card
CL rated cables are specifically made for in-wall installation and have been flame tested for safety and building code compliance.
Coaxial Cable
Coaxial ("coax") wires come in different types for different uses. The word "coaxial" actually refers to the design of the cable, rather than its use. A coaxial cable typically has two conductors, one in the center of the cable, and another in the outer portion; both are insulated. When connected, both conductors make the desired contact. Coaxial cable is used to bring signals from a cable TV or satellite TV provider into the home. A different type of coaxial cable is used for digital audio connections.
Compact Flash
A small chip with flash memory storage, typically used to store media like digital photographs and music. Type I Compact Flash cards are 3.3mm thick, which is thinner than the later 5mm Type II card. Data can be written and re-written to a Compact Flash card hundreds of thousands of times. Storage capacity can now extend to 64 gigabytes, though more typical sizes range from 500 megabytes to 4 gigabytes.
Component Video
A type of signal format where the video has been separated into its base elements (components) of brightness, color and synchronization, for high signal purity and performance between devices. A component video connection typically uses three plugs and jacks, which are color coded green, blue and red. These jacks are often confusingly described; one common way of labeling them is Y-Pb-Pr, and another is Y-Cb-Cr. In consumer equipment, the difference is largely academic, and both of these component video connections are compatible with each other. Component video connections, which are analog, can provide outstanding quality, though not as good as what is possible with digital connections like HDMI.
Composite Video
An analog video connection that combines all the color, brightness and timing information needed to pass video images into a single wire. Because all the signals are mixed together, the connection is called "composite". Composite video cables are always terminated with an RCA-type (inner pin, outer collar) plug. The image quality through this cable is at the low end of the totem pole, not as clear as either S-Video, component video or HDMI. However, since it is the oldest of the consumer video connection types, and therefore the most compatible with the most devices, it is still seen even on modern video gear.
Compression
A way of reducing the amount of data present in digital content, so that the content becomes easier to move from place to place. In audio, MP3 is a popular compression technique; even HDTV uses compression to manage the huge amount of data that high-definition video requires. Compression can be either "lossy" (i.e., some data is removed during the process) or lossless (no data is lost during compression). The amount of compression varies by the type of content, and sometimes can be controlled by the end user.
Crossover
A function that divides an audio signal into parts above and below a particular frequency called the "crossover point." The reason for the crossover is so that particular portions of the audio spectrum can be assigned to the components that can best play them. For example, a home theater setup that includes speakers and a subwoofer might use the crossover to assign only bass frequencies to the subwoofer, while any sound "above" this crossover point is fed to the other speakers. Crossovers reside in both loudspeakers and in AV receivers; setting proper crossover points in the receiver setup ensures the best balance of bass, midrange and treble sound from the speaker system.
CRT
Stands for cathode ray tube, and describes the traditional glass picture tubes that have been used in analog TVs since their inception. Televisions based on CRT technology are increasingly rare, and usually seen in smaller screen sizes. In larger screen sizes, they have been supplanted by newer display technologies, such as plasma, LCD and DLP.
Digital Audio Coaxial Cable
A digital cable used to send digital audio signals from a source component (like a DVD or CD player) to an audio playback component, such as an A/V receiver. Coaxial refers to the cable design and not the connection technology, which unfortunately results in some confusion with other TV and networking cables that use a coaxial design. For digital audio applications, coaxial cables are more economical than optical cables (which perform the same function) and are capable of the same high-quality performance. Digital audio coaxial cables are always terminated with RCA-type plugs.
Digital Cable Box
Alternate Names: D-Sub, S-Subminiature
A set-top box designed to receive digital video content delivered by a local cable TV (CATV) provider. A single coaxial wire comes into the home to feed the box, which then sends digital video and audio signals to processing components, such as an AV receiver. Because the signals are digital, copy protection can be controlled by the CATV provider. Digital cable boxes are capable of delivering all common digital television (DTV) formats, including HDTV.
DLP TV
Alternate Names: D-Sub, D-Subminiature
A TV with technology based on the Digital Light Processing (DLP) imaging engine invented by Texas Instruments. In this method, a lamp assembly bounces light of an array of millions of tiny mirrors, which open and close in real time to produce red, green and blue colors. In combination, these produce full-color images. DLP TVs are not flat like LCD and plasma TVs; they appear as either rear-screen projection TVs or front-projection video projectors. Screen sizes are usually large for this format, beginning at 40 inches and extending to as large as 80 inches. DLP sets are capable of excellent quality, though like LCD and plasma, they are subject to certain picture artifacts, depending on the quality of the set.
Dolby Digital
A digital audio format found on many DVDs and HDTV broadcasts that provides up to six channels of audio: left, right, center, left surround, right surround and a low frequency effects (subwoofer) channel. There are numerous variations on Dolby Digital that may include more than six channels, but the five speakers plus a subwoofer (referred to as "5.1") is the standard.
D-VCR
A short-lived digital VCR format pioneered by Matsushita that recorded digital video content (including HDTV) on special digital VHS (Video Home Standard) tapes. The format brought to market was called D-VHS and enjoyed a brief spurt of niche popularity. Despite its considerable technical capabilities, this format has become largely obsolete.
DVD Audio Player
Alternate Names: DVD-A Player
A DVD player that has additional circuitry that can decode discs recorded in the DVD-Audio (DVD-A) high resolution audio format. These discs require hardware that is specifically capable of playing them; they will not play in a DVD player that does not have DVD-A playback capabilities. The DVD-A format is primarily audio-based, but also features video and photographic content, so connection to both video and audio processors are necessary for playback. The connection ports for DVD-A are a group of five separate analog cables, terminated in RCA-type plugs. These copy-protected signals conform to the 5.1 audio connection protocol, which is to say a separate wire for left, center, right, left surround, right surround and subwoofer channels.
DVD Player
A source component capable of playing discs formatted in one or more of the standard Digital Versatile Disc (DVD) video formats. DVD players can typically play numerous types of discs, including CD discs, DVD-ROM data discs and photo discs. They are required to play DVD-V (DVD-Video) discs (movies, etc.) at a minimum. DVD players appear in both single and multi-disc models. They are typically capable of passing both interlaced and progressive-scan video signals; in the latter case, the video connection protocol must be component video or better. Other common connections for DVD players include S-Video and composite video (both analog), and HDMI for digital video and audio transmission. Digital audio output connections, such as optical or coaxial digital, are also featured in virtually all players. For connection to older or simpler gear, analog connections are usually also provided on most DVD players.
DVD Recorder
A digital audio component capable of recording video content onto a DVD-compatible disc, as well as being able to play back these discs. There are actually four types of recordable DVD discs. There are "write-once" discs, and also re-writable discs that can be re-recorded many times. Both exist in two formats, one called DVD-R ('dash" R) and one called DVD+R ("plus" R); there are also DVD-RW and DVD+RW recorders. The two formats are only slightly different, but are actually incompatible. In real terms however, the incompatibility is moot, as most DVD recorders will record either format, and most DVD players will play discs recorded in either format. DVD recorders can appear as single-disc or multi-disc units, and also integrated within other components, such as a DVR, for making archival DVD discs of recorded content.
DVI Connector
Stands for Digital Visual Interface — a pure digital connection between video devices, providing a fast transfer rate, high quality image and no quality loss. This connection comes in two types: A single link version that is capable of 1920x1080 resolution and a dual link that has greater bandwidth and can provide resolution of 2048x1536. Dual-link cables are backward compatible with single link connections. For most consumer electronics, DVI connections have been superseded by HDMI connections, which have physically smaller plugs and can pass audio as well as video, which DVI can not. However, HDMI is backward compatible with DVI, through the use of a simple plug adapter.
DVR
Alternate Names:PVR
Stands for Digital Video Recorder, a stand-alone or integrated component that accepts video content from broadcast or pre-recorded sources, and is able to digitize the content onto a hard disk. The advantages of a DVR over previous video recording systems like VCRs are numerous, including instant access, menu selections for content, the ability to "rewind" live TV, and simplified electronic program guides that make it easy to find wanted content and schedule wanted recordings. DVRs get fed their video content through a variety of video connection protocols, and pass their signals through conventional audio and video conventional connections to a receiver or a TV.
DVI I
An implementation of the Digital Visual Interface that can pass both digital and analog signals over a single cable. A DVI-D male connector will connect/transmit with a DVI-I female connector, but the DVI-D female connector will not connect/transmit with a DVI-I male.
EDTV
Alternate Names: DVI Analog
Enhanced Definition Television is the middle-level quality of DTV pictures, better than SDTV (standard definition), but not as good as HDTV (high definition). The typical resolution for an EDTV display would be 480p, the same resolution as progressive-scan pictures from a DVD player.
Ethernet Connector
A connection used for a variety of networking applications, primarily for connections between PCs, routers, gateways and bridges that connect users to the Internet. Increasingly, consumer electronics devices such as satellite receivers, DVRs AV receivers and game consoles are also including Ethernet Connectors to connect them to the Internet.
F Connector
Alternate Names:RF Connector
A coaxial-type cable connection where the plug features a center wire strand and a screw-on grounding collar. The collar surrounding the center strand, or pin, is often threaded for a secure screw-on connection, but slide-on collars without threading are common as well. This connection is often used for both analog signals (such as analog cable TV) and digital connections (such as satellite TV).
FM Antenna
FM antennas are specifically designed to receive signals from conventional FM (Frequency Modulation) radio broadcasts. FM radio is typically stereo and higher fidelity than AM (Amplitude Modulation) radio, though not as good as CD-quality audio. FM broadcasts are transmitted at frequencies between 88 MHz and 108 MHz.
FM Ratio
An analog audio source component that receives conventional FM (Frequency Modulation) radio broadcasts. When the component has amplification and a speaker (or speakers) built in, it is called an FM radio. If the component contains only the receiving device, and must pass along its signals to another device to be heard, it is called an FM tuner. FM tuners often include the ability to receive AM broadcasts as well as FM. They are unable to receive satellite radio broadcasts or the new HD Radio broadcasts. FM radios and tuners are capable of stereo audio, and sometimes even surround sound, though this is rare. When an FM tuner is built into the same box as an audio-video preamplifier and an audio power amplifier, it is called an AV receiver.
Game Console
A device designed for playback of interactive video games, which are available as optical discs, as game "cartridges" or via the Internet as a "networked" game. This device connects to an AV system or TV set and allows one or more players to compete against the games or against each other. The market is divided among several key brands, with software that is incompatible with each other. The Microsoft Xbox and Sony's PlayStation are market leaders, with home and portable models by Nintendo and Sega also available. More advanced consoles allow players to compete with other players from around the world via the Internet. Game consoles often represent state of the art capabilities in video and audio performance, and connect to other AV gear (receivers, etc) through conventional digital and analog connections.
HD-DVD
A now-discontinued (though still available) disc player capable of playing content presented in the high-definition video format. HD-DVD disc players are backward-compatible with most DVD disc formats, but are incompatible with the competing Blu-ray format, unless the player is a multi-format machine capable of playing both. HD-DVD is capable of playing and outputting true 1080p HDTV content. To get all the benefits of HD-DVD quality, an HDMI connection is mandatory. Lower quality connections will pass signals, but not at the highest quality.
HDMI
HDMI (High Definition Multimedia Interface) is a digital connection offering signal purity that represents the current state of the art. It passes audio, video and control signals, including digital rights management (DRM) through the HDCP (High Definition Content Protection) protocol. HDMI supports uncompressed video resolutions of 1080p and beyond, and also supports up to 8 audio channels with extended audio fidelity far beyond today's CD and DVD sound. HDMI connections for audio-video equipment terminate in a single small plug, and there is also an HDMI Mini connector for smaller devices like camcorders and digital cameras. Through the use of a cable adapter, an HDMI video stream can be made compatible with a DVI connection, if your equipment uses it.
HDTV
A digital, high-definition television capable of presenting video content in one or more of the high-definition (HDTV) versions of the DTV (Digital Television) standards. At minimum, an HDTV must be able to play 720p HDTV signals (see Resolutions), though many of them have higher resolutions, such as 1080i and 1080p. In strict terms, an HDTV set must incorporate a tuner capable of receiving HDTV channels as defined by the Advanced Television Systems Committee (ATSC). If there is no tuner, but the set can still display HDTV, it is called an HDTV monitor, rather than an HDTV TV. HDTV sets can play lower resolutions (SDTV standard definition and EDTV enhanced definition) as well, and also can convert standard analog broadcasts to digital presentation.
Home Theater Package
Alternate Names:Home Theater Speaker System
A grouped complement of speakers capable of producing standard 5.1 Dolby Digital surround sound. While the speakers may vary in size, these systems consist of at least a left, center and right front speaker; two speakers for left and right surround, and a subwoofer for the low-frequency ".1" bass channel. In many cases the subwoofer will incorporate its own internal amplification, but passive, non-powered subwoofers are also common, and require amplification from the AV receiver or audio amplifier.
HTIB
The HTIB – Home Theater In A Box – is a packaged system consisting of 5.1 speakers and a central component capable of audio-video processing and usually (though not always) DVD disc playback. The electronics are often the same as an AV receiver, sometimes with a DVD player built in. The concept behind these systems is simplicity; the consumer connects the speakers to the receiver and the receiver to a TV (not included) and gets an easy, inexpensive home theater solution.
IEEE 1394
Alternate Names:Firewire, iLink
A connection capable of carrying digital video or audio signals at 400mpbs of throughput. The connection is not fast enough for full-bandwidth, uncompressed HDTV transmission, therefore it is used mostly for lower-demand video applications, such as camcorders, and for audio applications, which are less bandwidth-intensive than video. There are two sizes of 1394 plugs and jacks; one with 4 pins and a second with 6 pins. There are cables that terminate in 4-pin at each end, 6-pin at each end, or 4 on one end and 6 on the other. These are all interoperable, and plug sizes can be altered by an adapter.
IEEE 802.11b
Most commonly known as "Wi-Fi," 802.11b is a wireless local-area networking standard. Many PC and networked home entertainment devices use 802.11b, which is capable of speeds up to 10Mbps.
IEEE 802.11g
A more evolved and faster version of the Wi-Fi local-area networking standard, offering speeds up to 54Mbps, 802.11g is backward-compatible with older 802.11b wireless devices.
IEEE 802.11n
Not yet officially ratified as a standard, 802.11n is being designed as an even faster version of the popular Wi-Fi protocols, capable of at least double and possibly as much as six times as fast as 802.11g. Numerous companies have started marketing products in advance of the specification being finalized. These are called "pre-802.11n".
Infrared (IR)
A transmission medium used mainly for remote controls. It works by emitting pulses of light that are too low for the eye to perceive, but can be "read" by electronic devices. IR technology is long-established for remote controls, but suffers from drawbacks; it can only work with a clear line of sight from one component to another, and it has limited range. IR remotes will likely be replaced in the not-distant future by remote controls that use RF (radio frequency) technology.
Intelligent Stick
A compact flash memory drive that is compatible with a standard USB port, but with a smaller form factor than conventional USB flash drives. Storage capabilities range from 64MB - 1GB.
Interlaced Scan
A method of creating video images by dividing a frame of picture information into two "fields," and combining them at a rate fast enough so that the eye perceives fluid motion. In interlaced scanning, the number of vertical lines that make up a TV picture are divided into odd and even; one field of video contains the odd lines, the other contains the even lines. When they are "interlaced", the odd and even lines are flashed in sequence and result in fluid pictures. The opposite of interlaced scan is progressive scan.
Laser Disc Player
An early analog, disc-based format for home theater software that used 12-inch two-sided discs. Two types of disc recordings were marketed – a CAV (Constant Angular Velocity) recording, which featured increased playing time of one hour per disc side; and CLV (Constant Linear Velocity), which offered less playing time per side, but more interactivity features, thanks to a frame-by-frame storage method. Introduced in the 1980s, laserdisc was the highest standard of home video quality until the advent of DVD in 1997. The laserdisc format is now largely obsolete, though some home theater fans still own hardware and software.
LCD TV
Alternate Names: IEEE 1394, Firewire, iLink
A type of TV or video monitor using a Liquid Crystal Display (LCD) technology to produce pictures. The form factor for this type of TV is typically "flat", but there are LCD TVs based on rear and front projection technologies as well. LCD TVs are always digital and capable of DTV playback, though not always capable of true HDTV playback. LCD TVs are "fixed pixel" displays, meaning that they have a native resolution, and all incoming content is up- or down-converted to fit that resolution. LCD TVs are typically equipped with a variety of audio and video connections, with HDMI being the preferred hookup.
Line Level
A relatively low signal level (typically in the 0.5 - 5 volt range) that is used by most audio and audio/video source components. It is not the same as other common signal levels, like microphone level and speaker level, and components must make adaptations to properly play line level signals.
Memory Stick Duo
Alternate Name:MS Duo
A variation of Memory Stick flash storage that features higher capacities (up to 8 GB) and faster data transfer rates than conventional Memory Sticks. Generally compatible through an adapter with any device that accepts a conventional Memory Stick, but not with some older devices.
Memory Stick Micro
Alternate Names: MS Micro
A miniaturized variation of Memory Stick flash storage, about the size of a fingernail, designed for compact portable devices. With an adapter (often supplied), it can be read by the other larger Memory Stick Drives.
Micro Drive
A miniature, 1-inch hard disk designed to fit in a Compact Flash Type II slot, with storage capacities of up to 8 GB and potentially more. Relatively uncommon in consumer electronics devices.
Micro SD
Alternate Names: MS Duo
A miniature format for removable flash memory cards, used mainly in mobile telephones, but also in portable audio players and video game consoles. Storage capacity can range up to 8 GB, and adapters can allow a microSD card to be used in devices intended for SD cards.
Mini Disc Recorder
Alternate Names: MS Micro
An early technology for compressed digital audio recording pioneered by Sony in the 1990s. Available in both portable and home components, MiniDisc uses a small plastic shell containing a magnetic recording medium for audio storage. The compression scheme, called ATRAC, is effective and still in use, but incompatible with the much more popular MP3 format for compressed audio files.
Mini Jack
Alternate Names: MS Micro
A miniature 3.5mm jack that typically accepts a stereo mini plug for 2-channel analog audio. Commonly seen on portable stereo audio devices, particularly as a headphone connection or audio line output.
MiniSD Card
A smaller version of the SD (Secure Digital) flash memory card, and a larger version of the Micro SD card, used as storage for portable devices such as digital cameras, cell phones and MP3 players. Has a typical capacity of up to 4 GB, though they can range even higher.
MMCmicro Card
Alternate Names: Multimedia Micro Card
A miniaturized version of the MMC flash memory card, with which it is compatible, by way of an adapter. While this card looks very similar to a Micro SD card, the two are not compatible, due to a different pin output configuration.
Micro SD Card
A miniature format for removable flash memory cards, used mainly in mobile telephones, but also in portable audio players and video game consoles. Storage capcity can range up to 8 GB, and adapters can allow a microSD card to be used in devices intended for SD cards.
Mono Mini Connection
A monaural audio-only analog connection that uses a 1/8-inch plug and jack. Most often seen in portable dictation recorders and other small personal devices. Relatively uncommon, in comparison to the similarly-sized stereo mini audio connection.
Mono Phono Connection
A monaural, audio-only analog connection that uses an RCA-type plug with a center pin and outer collar. Mostly seen as the monaural connection between a subwoofer and an AV receiver or amplifier, though it is also encountered in older equipment, such as non-stereo VCRs.
MP3 Player
Alternate Names: Mini Stereo Jack, Headphone Jack, Mini Phone Jack
Generic term for a digital audio player or audio server capable of playing compressed audio files, typically in the standard MP3 format. MP3 players are most often seen as portable devices, but home audio servers that can deliver these files are growing in popularity. While the MP3 format is a standard, there is significant deviation in the actual players and their ability to play all types of digital audio files. As a pertinent example, the popular Apple iPod uses a different file format called AAC (Advanced Audio Coding), which is incompatible with MP3. Portable players can connect to a home AV system, usually through a mini stereo connection (1/8" plug); home based units connect to AV systems through conventional analog or digital audio connections.
Mu Card
A miniature flash memory storage card based on an open standard and royalty-free manufacturing specifications, thereby making them less costly than SD memory cards, which are functionally similar, but incompatible. Other types and sizes of MMC flash memory cards use this same, open standard Mu Card technology.
Multimedia Card
Alternate Names:MMC
An older flash memory card standard, about the size of a postage stamp. They have been more or less superseded by newer and smaller flash memory cards with greater capacities, but can be used in most devices that support SD cards.
Optical Digital Cable
Alternate Names:Toslink cable
A digital, fiber-optic connection used to send digital audio signals from a source component to an audio processor, such as an A/V receiver. Impervious to common household magnetic and RF interference, it offers excellent speed and bandwidth, though cables are usually more costly than coaxial cables that are used for the same purpose. In terms of performance, there is little if any discernable difference in sound between the two.
OTA Antenna
A device for receiving analog or digital signals that are broadcast over the air (OTA). The antenna receives the broadcasted signals and feeds them to either an AV processing device like an AV receiver, or directly into a TV monitor. OTA antennas are designed to work in specific frequency bands. The VHF (Very High Frequency) band is for U.S. TV channels 2-13, while the UHF (Ultra High Frequency) band is used for channels 14-83. Digital television broadcasts (DTV), including HDTV, is broadcast over the air using UHF frequencies. Some antennas are designed to receive from both bands. The OTA antenna may be used inside the home, or mounted outside the home.
PCM (Pulse Code Modulation)
A way of expressing digital data composed of "words," each made up of a number of ones and zeroes. The longer the "word," the more ones and zeroes, and therefore, the more data (i.e., better fidelity or resolution). In consumer electronics products, PCM is most often seen in home theater audio gear.
PCMCIA
Alternate Names:PC Card, PCMCIA Card
A credit-card sized peripheral that can be used for storage memory, PC applications or hardware functionalities, such as networking. More accurately and commonly called the PC Card, it comes in Type I, Type II and Type III sizes, which go from thinnest to thickest. Slots on PCs and other devices often accept any of the three types.
Phono Connector/Jack
Alternate Names:RCA connector
A common connection for numerous types of audio and video components. On the plug side, a metal tip is surrounded by a metal ring. The jack side (on the devices) consist of a central hole surrounded by a metal ring that the plug's ring fits over. This same type of plug and jack is used in analog audio and video connections and in some digital audio connections, where they are called digital coaxial connections.
Phonograph
Alternate Names:Turntable, LP player
Generic term for a playback device or system that can reproduce audio content from analog LP (long-playing) vinyl discs. This format was the standard for audio reproduction until the introduction of the CD in 1981; it has since begun a long slide toward obsolescence, though vinyl is popular with DJs and audiophiles still insist on the format's sonic superiority over the CD. Not every AV receiver or AV preamplifier has this special phono input, although outboard units are available that will allow hookup to a conventional AV system.
Pixel
Stands for picture element, the smallest bit of data in a video image. Most modern video displays have a fixed number of pixels that the screen can display at any given time. The more pixels, the more picture information, and hence, the more picture quality.
Plasma TV
A type of flat video display based on a technology where gasses enclosed inside a sealed glass apparatus are electrically "excited." As the gas is charged into a changing (plasma) state, light and color is produced. Plasma TVs have a flat screen, but not all flat screen TVs and monitors are plasmas, despite common and erroneous usage of the term. Plasma displays are always digital, and come in either full TV implementations (tuner and speakers built in) or as a stand-alone video monitor. Most plasmas are capable of HDTV reproduction.
Projector
More accurately called a "front projector", this device is essentially a TV without a box enclosure. The images are sent though an optical lens though the air to a screen surface, such as a blank wall or video projection screen. Video projectors can be based on several popular display technologies, with LCD and DLP topping the list. They are usually capable of HDTV reproduction, though not all models have enough resolution for these signals. While sometimes mounted to a ceiling or wall in a fixed position, many projectors are used as portables – the unit can be easily picked up and moved between locations.
Progressive Scan
The opposite of interlaced scan, a method that electronically draws the video picture in one complete pass, rather than the two odd and even passes of interlaced video.
PS2
Alternate Names:PS2, Mouse Port, Peripheral Port
A legacy mouse and keyboard connection consisting of 6-pin mini-DIN connectors. The female connectors are on the computer, the male connectors are on the cables that plug into the computer. PS2 connections have been largely superseded by newer technologies, such as USB.
RCA Connector
Alternate Names:Phono connector
A common connection for many types of audio and video components. On the plug side, a metal male tip is surrounded by a metal ring. The jack side (on the devices) consist of a central hole surrounded by a metal ring that the plug's ring fits over. This same type of plug and jack is used in analog audio and video connections and in some digital audio connections, where they are called Digital Coaxial connections.
Rear Projection TV
Alternate Names:RPTV
The big-screen rear-projection TV is essentially a video projector in a box. The light engine – DLP or LCD – produces images which are then bounced off an internal mirror, which then reflects them onto the rear of a light-gathering screen surface. Because the mirror and light engine both take up space, rear-projection TVs can't be flat like plasma or LCD direct-view sets. Consequently, they are losing popularity, and several manufacturers have already stopped making new models. Still, RPTV offers excellent value for the money in terms of performance and screen size.
Reduced Sized Multimedia Card
Alternate Names:RS-MMC
A reduced size (RS) version of the MMC flash memory storage card, with storage capacities typically ranging to 2 GB. The RS-MCC cards are about half the size of the original MMC cards, and are compatible when used with an adapter.
Resolution
The "sharpness" of a video or audio presentation. In video, this is expressed as the number of pixels used to create an image. In audio, resolution refers to a more complex brew of technical ideas, such as sampling rate and word length. Generally speaking, the more resolution that video or audio has, the better the quality.
RF Cable
A coaxial-type cable that carries picture and sound along a single wire, typically used for cable TV and satellite TV connections coming into the home. While it is possible to use RF cables to connect some devices to others, like DVD players to TVs, this connection should only be used when necessary, as other cable types provide better performance.
RGBHV
An video signal path where red, green and blue signals are accompanied by two separate, dedicated signals for picture synchronization; one for horizontal sync and one for vertical (hence RGBHV). An RGBHV connection may occur as a single cable terminated with a 15-pin plug, or through separate wires for red, green, blue, horizontal sync and vertical sync, terminated with either RCA-type or BNC connectors. This is mostly a connection for professionals, and rarely seen in mainstream consumer equipment.
RS-232
Alternate Names: RS-MMC
A connection sometimes seen on higher-end home electronics and custom-installed home theaters that is used for controlling devices. Mostly used by professionals.
SACD Player
A digital audio component capable of playing special audio discs called Super Audio Compact Discs. Pioneered and advanced by Sony, SACD is capable of much higher audio resolution than conventional CD audio discs. The discs may be recorded in either stereo or surround sound, but both require the SACD player — conventional CD players will not play an SACD disc. The processing of SACD signals is performed in the player, and with few exceptions, the output from an SACD player to an AV receiver is sent over an analog 5.1 connection.
Satellite Coax Cable
A combined digital video and audio stream used by a DBS-type satellite dish (Direct TV, Dish) and sent down a coaxial wire to the satellite receiver set top box. The cable itself is usually terminated with an "F" connector, much in the style of an analog RF-type cable. The digital stream from this connection is only fed from the dish to the satellite receiver. The satellite receiver then decodes these signals and allows them to be passed on to other AV components, such as an AV receiver or TV display. This connection only appears on satellite TV systems and is provided at the time of satellite installation.
Satellite Set Top Box
Generic term for a component that decodes digital satellite TV content for delivery to an AV system. The satellite box is fed signals from a small DBS (Direct Broadcast Satellite) dish, mounted outside the home. The dish captures the satellite signals and passes them to the set-top box through a coaxial wire. The satellite content providers fall into two major camps of subscription-based program providers – DirecTV and Dish Network. The two are incompatible, and a receiver designed for one will not receive signals from the other.
SCART
An audio/video connector used in Europe, consisting of a 21 pin multi-connector that can carry two audio in and out channels, in and out video channels, RGB signals, ground and some additional control signals.
SDTV
Standard-Definition Television is a DTV format that roughly corresponds to the quality of today’s analog TVs, which is 480 lines scanned in the interlaced method, or 480i. SDTV is a lower-quality picture than EDTV or HDTV.
Secure Digital Card
Alternate NamesSD Card, Mini SD, Micro SD, HDSD
A miniature flash memory storage card popularly used in digital cameras, camcorders and audio players. SD stands for Secure Digital, and the cards can in fact protect content with digital rights management (DRM) although this isn't frequently used. Storage can extend to 8 GB, and progressively smaller versions are seen as the Mini SD and Micro SD.
Sirius Radio
A subscription-based digital radio service delivered by satellites and received in home, car and portable electronics through a specialized antenna. One of two satellite radio services available in the U.S., at the time of this writing, it is technologically incompatible with the competing XM satellite radio system, although the FCC has given the okay for the two companies to merge into one. Sirius radio requires a specialized hardware receiver. This connects through digital or analog connections to audio processing hardware, such as an AV receiver.
Spade Lug
A type of termination for wired speaker connections, so-named because the U-shaped metal terminal resembles a spade.
Speaker
Alternate Names:Loudspeaker
A "display" device for audio content; the last component in the audio chain. All audio from the rest of the components are finally resolved and output though the speakers, sometimes called loudspeakers. The speaker is essentially a "transducer" – a device that changes electrical energy into mechanical energy (vibration). These vibrations ultimately represent the sound we hear. Because it is difficult for any one speaker to effectively reproduce all the frequencies (vibrations) that the human ear can perceive, speakers are often divided into several "drivers" within one box. A speaker's "tweeter" is designed to reproduce high-frequency (treble) signals. A "woofer" is designed specifically for lower frequency (bass) signals. In many cases, one or more "mid-range" drivers handles frequencies below the tweeter's and above the woofer's. An internal component called a "crossover" determines which frequencies from the audio content will be fed to which speaker driver for output. Speakers are typically passive, meaning that they need external amplification to perform. Some speakers do include internal power, and subwoofers in particular – a speaker designed specifically for low bass – are often internally amplified. A single speaker is said to be monaural; two speakers create stereo (left and right) and 5.1 speakers are the norm for surround sound.
Speaker Bi-Wire
Alternate Names: SD Card, Mini SD, Micro SD, HDSD
A type of speaker connection with two conductors on one end (the side that goes into the amplifier) and four conductors on the speaker end. Not all speakers can accept this connection; in order to be bi-wired, each speaker must have two sets of connection terminals (two plus, two minus). The advantage to bi-wiring has been the subject of debate. Proponents claim that sending amplifier energy to different drivers separately (as bi-wiring does) results in more optimal performance. Bi-wiring can be accomplished with special bi-wires or with conventional speaker wire.
Speaker Wire
Speaker wires are two-conductor wires, with the plus and minus sides usually indicated on the insulating jacket that surrounds the copper wire. Speaker wires may terminate in numerous types of connectors, such as spade lugs, banana plugs, speaker pins, or even nothing at all, just bare wire. When connecting speaker wire from a speaker to an amplifier or receiver, plus must always be connected to plus and minus to minus.
Stereo Mini Connection
An analog stereo audio connection consisting of a single wire terminated in a 1/8-inch stereo mini plug. This connection is widely used in portable and personal electronics, particularly for headphone connections. Some home audio components have a line-level input jack that accepts this connection from devices such as MP3 players, but it is rarely used to connect full-sized home components. The exception is the headphone jack, where the stereo mini plug is popular enough to be called the new standard, having replaced the old standard, the larger stereo phone plug.
Stereo Phono Connection
Alternate Names:RCA connection, analog audio connection
An analog stereo audio connection typically consisting of two wires terminated with RCA-type plugs (center pin, outer collar) on each end. Plugs are typically color-coded for both the left and right channels of the stereo signal, red and white are common. Also called phono cables because of long-standing legacy use as an audio connection for phono turntables. Capable of potentially excellent audio quality, though in the vast majority of cases, not as good as pure digital audio connections such as optical, coaxial or HDMI.
Stereo Speaker Wire
While there is no such thing as a stereo speaker wire, speaker wires are necessary for stereo and surround sound. Speaker wires are two-conductor wires with a plus and a minus, and both sides of the wire are commonly terminated with a variety of plugs, spades and pins for connections between audio components and speakers. These terminations are optional, and many installations use bare wire as the termination. In a general sense, the rule is one speaker wire for each speaker, and even though the speaker wire may have two strands, they are both used to power just one speaker.
Sub Mini Connection
Alternate Names:>Sub Mini Plug, Sub Mini Jack
An extremely miniaturized 2.5mm plug and jack for analog audio, mainly used in personal and portable devices. It is seen in both mono and stereo versions, and can be used with a Mini connection by way of an inexpensive adapter.
Subwoofer Cable
A cable designed for connection between an A/V receiver and a subwoofer. This coaxial-type cable is essentially the same as a conventional analog audio cable, except that it is usually longer and often better insulated against interference.
SVGA
An analog or digital video signal stream called Super Video Graphics Array, calling for a resolution of 800 x 600 pixels. This type of RGB connection is typically connected with a 15-pin plug, and is most typically used in low-end video projectors and PC applications.
S-Video
Alternate Names:Y/C video
An analog video connection that sends color and brightness information through separate paths along a wire. By separating these signals, there's less interference between them than with a composite cable, hence potentially superior picture quality for an S-Video connection. This connection uses a miniature round, 4-pin DIN connector, and is sometimes called a Y/C cable, with Y representing brightness (luminance) and C representing color (chroma).
Toslink
Alternate Names:Optical Digital, Fiber Optic
A connection for a fiber optic wire, commonly used for digital audio applications, such as Dolby Digital and DTS. Developed by Toshiba (hence TOSlink), the connectors consist of a small snap-in port with a center pin. The cable's single conductor uses a special plastic fiber instead of copper, which eliminates the possibility of household interference with the signal. Toslink cables transmit light, which cannot be bent; therefore it is important to avoid bending or crimping the cable. See Optical Cable.
UHF Antenna
An antenna designed specifically for over the air broadcasts in the Ultra High Frequency range (UHF) of 300 MHz to 3 GHz. Over the air digital television (DTV) transmissions, including HDTV, are broadcast in this UHF range. UHF antennas come in both indoor and outdoor models, and are usually designed to receive from a relatively narrow directional radius. UHF broadcasts occupy channels 14-83 in the U.S.
UHF-VHF Antenna
An antenna designed for broadcast video reception that's capable of receiving both Ultra-High Frequencies of 300 MHz to 3 GHz (UHF) and Very High Frequencies of 30 MHz to 300 MHz (VHF). Because UHF and VHF waves are of such different frequencies, most combination antennas have separate receiving elements designed specifically for both signals. This type of antenna may have more than one type of connection, but the 75-ohm "F" type connector is most common. These antennas can either be used indoors (interior models) or outdoors, mounted on the roof or other high household position.
Upconversion
The process by which a lower resolution video source signal is digitally manipulated to play back more "comfortably" on a higher resolution display, with no further translation needed on the part of the TV (display). A typical example is an "upconverting" DVD player, which will take the 480 lines of picture information from a DVD and convert it to the native resolution of an HDTV set, which is higher than 480 lines. While this upconversion doesn't actually increase the number of lines sent from the DVD player, it lets the TV play back an image that it doesn't need any further processing. This can often lead to better final images.
VCR
An analog video recording device that stores content on magnetic tape housed in a protective plastic cassette, hence the Video Cassette Recorder (VCR). Now largely supplanted by other recording technologies such as DVRs and DVD recorders, VCRs were the first popular home video recording devices. Originally seen in two competing formats – Beta by Sony and VHS by Matsushita – the VHS format became the standard and makes up most of the user base of existing VCR products.
VGA
An analog or digital video stream based on the Video Graphics Array standard introduced by IBM in the late 1980s. It calls for a resolution of 640 x 480, and has largely been superseded by more extended display techniques, such as SVGA and XVGA. An RGB connection is typically terminated with a 15-pin connector, though other types of connections are used for this protocol, such as separate leads terminated with RCA-type plugs, one each for red, green and blue signals, and sometimes with extra leads for synchronization signals.
VHF Antenna
An antenna designed specifically for over the air broadcasts in the Very High Frequency range (VHF) of 30 MHz to 300 MHz. Conventional over-the-air analog TV transmissions are broadcast in this VHF range, which is usually expressed as channels 2-13 on a television set.
VPORT
A connection specifically designed for the Microsoft Xbox game console, which allows component video and stereo audio (analog) from an Xbox to travel over a single wire to the TV or AV receiver. The connection port is physically similar to the Xbox multi-connector, and an accessory connection block on the cable allows the user to connect a special optical cable for digital audio to a receiver.
Wire
Alternate Names:Cable, Cord
An elongated strand of a conducting material, usually metal or strands of metal, that carry electricity or communications signals. Wires may contain a single conductor or several, and may be made of various metals, as well as plastic fiber. Wire is always insulated with plastic, rubber or other materials to protect users and the signal. Wires may be terminated by one or more of many different types of connectors, depending on usage. Signals may degrade over the length of long wires, depending on their type.
XD Card
The "extreme digital" (XD) Card is flash memory card used mainly in digital cameras. Developed by Olympus and Fujifilm and available through numerous brands, the miniature cards (about the size of a fingernail) have capacities of up to 2GB. Their main advantage is physical size, but because newer technologies have matched or exceeded XD in terms of size, storage and cost, the format is falling behind in the marketplace.
XM Connector
A type of plug-in connection used for XM satellite radio systems. A round collar surrounds a center pin on the plug end of the wire, which slides into the jack end on the device with no turning or threading. An XM-type connector generally works with the competing Sirius satellite radio system and its antennas.
XM Radio
Alternate Names: Y-C Connector
A subscription-based digital radio service delivered by satellites and received in home, car and portable electronics through a specialized antenna. One of two satellite radio services available in the U.S., it is technologically incompatible with the competing Sirius satellite radio system, although the FCC has given the go-ahead for these companies to merge into one. XM radio requires a specialized hardware receiver. This connects through digital or analog protocols to audio processing hardware, such as an AV receiver.
XVGA
Also known as XGA, XVGA (Extended Video Graphics Array) is an analog or digital video stream capable of resolution of 1024 x 768; better than SVGA or VGA, but backward-compatible with both of them.
Y-Cr-Cb
A high quality video connection that passes digital component video signals. Y-Cr-Cb (also sometimes written as Y-Cb-Cr) represents images through a combination of brightness information and two color "difference" signals. In Y-Cb-Cr, the Y is the brightness (luma), Cb is the color blue minus luma (B-Y), and Cr is the color red minus luma (R-Y). This connection typically terminates in a three-plug array, color coded into red, blue and green (for the luma signal). See Component Video.
Y-Pr-Pb
Y-Pb-Pr is an analog version of component video in the Y-Cb-Cr color space. The two are equivalent in terms of function, and are often interchangeably labeled, but Y-Pb-Pr is designed for use in analog systems whereas Y-Cb-Cr is intended for digital video. This connection typically terminates in a three-plug array, color coded into red, blue and green (for the luma signal). See Component Video.
