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1080i
1080i (pronounced "ten eighty eye") is shorthand name for a category of video modes. The number 1080 stands for 1,080 lines of vertical resolution, while the letter i stands for interlaced or non-progressive scan. 1080i is considered to be an HDTV video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels and a frame resolution of 1920 × 1080 or exactly 2,073,600 pixels.
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1080p
1080p (pronounced "ten eighty pee") is the shorthand name for a category of display resolutions. The number 1080 represents 1,080 lines of vertical resolution, while the letter p stands for progressive scan (meaning the image is not interlaced). 1080p is considered an HDTV video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or exactly 2,073,600 pixels. The frame rate in hertz can be either implied by the context or specified after the letter p (such as 1080p30, meaning 30 frames per second).
1080p is sometimes referred to in marketing materials as "Full High-Definition" or "Full HD". Although 2K/4K digital cinema technology is commercially available, and ultra-high definition video is in the research phase, 1080p and 1080i are currently the highest-resolution formats widely used for broadcasting and consumer distribution of video content.
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10-Base2
Short for 10 Megabit, baseband, 200 Meters. Refers to an older Ethernet standard that used RG-58 Thinnet coaxial to network computers in a daisy-chain topology. This system is antiquated.
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10-BaseT
Short for 10 Megabit, baseband, Twisted pair. An upgrade to Ethernet from 10-Base2, it switched from the coaxial daisy-chain method to using a star topology running over twisted pair cable. This allowed for greater flexibility and reliability. Still used today, although the speeds have increased.
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100-BaseT
Short for 100 Megabit, baseband, Twisted pair. See 10-BaseT. An upgrade that increased the speed from 10 Megabits per second (Mbps) to 100 Mbps.
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13W3
DB13W3 (also known simply as 13W3) is a particular style of D-subminiature connector commonly used as an analog video interface connector that was used primarily on Sun Microsystems, Silicon Graphics and IBM RISC workstations, as well as some displays from Apple Computer, NeXT Computer and Intergraph Corporation .

The 13W3 connector is no longer used with modern displays, which have generally moved on to VGA or DVI connectors. The DB13W3 connector is also used by some 3Com SuperStack Ethernet switches to carry DC power.
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16:9
Widescreen aspect ratio used for a video display. The display measured is 16 units wide for every 9 units tall. This creates a rectangular viewing area that better represents a movie theater screen.
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4:3
Standard aspect ratio used for a video display. The display measured is 4 units wide for every 3 units tall. This creates an almost square viewing area. Standard TV’s and computer monitors use a 4:3 aspect ratio.
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5.1
A type of surround sound with 5 distinct sound channels and a LFE (low-frequency effects) channel: Center, Front Left, Front Right, Rear Left, and Rear Right. The .1 refers to the LFE channel, which is so named because it only reproduces the lower 1/10 of the sound frequency (the deep bass tones) of the other channels. Each channel requires a separate speaker. Dolby and DTS both offer 5.1 Surround technologies.
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6.1
The same as 5.1, with the addition of a Rear Center channel.
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7.1
The same as 5.1, with the addition of a Left Rear Center channel, and a Right Rear Center Channel. In a 7.1 setup, the Rear Left and Rear Right of the 5.1 setup are pushed a bit forward to create a more rounded shape to the sound field.
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A

A/V
Stands for Audio/Video. Refers to a system that generates both sound (audio) and picture (video).
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ADC
Short for Apple Display Connector, ADC is a proprietary modification of the DVI connector that combines analog and digital video signals, USB, and power all in one cable. Apple used ADC for its LCD-based Apple Cinema Displays and their final CRT displays, before deciding to use standard DVI connectors on later models.
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Adapter
Something that adapts; an adapter is used to change one connector type to another.  Typically an adapter refers to a passive adaptation; i.e. a simple physical change in the connection. The signal is not affected. If the signal is changed, it is more appropriate to use the term "Converter".
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Analog
A type of signal transmission with an infinite number of values within a specific wavelength. Transmitting and storing analog information requires a great deal of bandwidth and resources. Also, because the values are not discreet, analog signals are more susceptible to interference. However, they are less so to signal loss and often the signal of choice for long distance applications.
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Analog Video
The original video recording method that stores continuous waves of red, green and blue intensities. In analog video, the number of rows is fixed. There are no real columns, and the maximum detail is determined by the frequency response of the analog system. Analog video contains the luminance (brightness) and chrominance (color) of the image, which may be carried in separate channels, as in component video (YPbPr) and S-Video, or combined in one channel, as in composite video and RF connector. Digital video signal formats with higher quality have been adopted and gradually replacing analog video, including serial digital interface (SDI), Firewire (IEEE1394), DVI and HDMI.
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Aspect Ratio
A relationship in a display between the width and height. See 16:9, 4:3. Aspect ratio is an important consideration when choosing a home theater display.
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ATA
Advanced Technology Attachment. ATA is a parallel storage interface technology for disk drives and removable media like CD-ROM drives. It was the first technology to integrate the controller onto the drive itself, called IDE or Integrated Device Electronics. Because of this, ATA is also called IDE. However, because many other drive technologies also utilize IDE it is more proper to use the term ATA.

ATA supports two drives per channel, one designated as master and one designated as slave. ATA uses a 40-pin ribbon cable which can be bulky and cumbersome to work with, and is one of the things that lead to the development of SATA. After SATA was released, ATA is now more commonly referred to as PATA for Parallel ATA. ATA has evolved over the years to remain viable by increasing the speed of the bus. Typically ATA will be listed with the speed it supports, such as ATA/66, ATA/100, or ATA/133 for 66, 100, and 133 MB/s respectively.
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AWG
Stands for American Wire Gauge.  A measurement of the size or thickness of a wire.  The larger the number, the thinner the wire.  This standard was developed from a series of measuring gauges made in the 1850s by a Rhode Island manufacturer named Brown & Sharpe.
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B

Banana Plug
A single pin connector that bulges in the middle (like a banana), used for joining wires to equipment, primarily for speaker connections. A (male) Banana Plug connects to a (female) Banana Jack.
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Bandwidth
A measure of the amount of data that can be transmitted in a fixed amount of time. Digital signals are measured in bits per second (bps), whereas analog signals are measured in cycles per second, or Hertz (Hz).
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Baud Rate
The number of symbol changes (signaling events) made to the transmission medium per second using a digitally modulated signal. Used to refer to the number of bits per second when only one bit is sent per clock cycle. 300 baud = 300 bits per second (bps). Today, most transmission systems are capable of sending more than one bit per clock cycle, so the term bps (bits per second) is used instead.
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Bi-Directional
Refers to a parallel printer interface that sends data in two directions; both from the computer to the printer, and from the printer to the computer. Bi-directional signals are used to increase transmission speed, and to allow the printer to report status information such as ink levels or error messages.
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Bit
Binary Digit – The smallest unit of digital information. A bit represents a single value, usually a 1 or a 0. Bits are usually arranged into more meaningful values by combining them into larger units. See Byte.
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BNC
A type of connector that uses a twist and lock type of retention. No one knows what BNC stands for, but there are several theories, including British Naval Connector, Bayonet Nut Connector, and Bayonet Neill Concelman (named for the alleged creators of the connector). Of the three, the latter seems to be the most feasible. BNC connectors terminate to coaxial cable and are commonly used with video and radio communication equipment, and also older Ethernet networks.
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Booster
An electronic device used to increase the power of a signal. The booster has one or more inputs, and one or more outputs. The signals coming in are gathered, given a power boost, and sent to the output. Boosters are used to send signals a greater distance than they could reasonably travel on their own. Booster also refers to a component of an audio/video system that collects line-level signals, processes them, boosts them, and sends the high-level signal to the target destination.
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Broadband
A method of communication in which a signal is transmitted by being impressed to a higher frequency carrier wave. This allows more data to be carried for a longer distance.
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Bulk
Used to refer to cable or items that are purchased in large amounts. Bulk cable is cable sold in a large roll, typically in 100 ft or higher increments. Bulk cable can also refer to raw, unfinished cable (a cable with no connectors).
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Byte
8 bits combined into a logical unit. A byte typically represents a single character in a computer system such as the letter "A" or the number "4".
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C

CAC
Common Access Card (CAC) is a United States Department of Defense (DoD) smart card issued as standard identification for active-duty military personnel. CAC is used as a general identification card as well as for authentication to enable access to DoD computers, networks, and certain DoD facilities. It also serves as an identification card under the Geneva Conventions. CAC enables encrypting and cryptographically signing email, facilitating the use of PKI authentication tools, and establishes an authoritative process for the use of identity credentials.
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CAT-5/5e Cable, or Category 5/5e Cable
A twisted pair cable type designed for high signal integrity. Many such cables are unshielded but some are shielded. Category 5 has been superseded by the Category 5e specification. This type of cable is often used in structured cabling for computer networks such as Ethernet, and is also used to carry many other signals such as KVM, A/V and USB.  Category 5 cable includes four twisted pairs in a single cable jacket. This use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and other pairs (this latter form of interference is called crosstalk). It is most commonly used for Ethernet networks and extender systems. CAT- 5 cable typically has three twists per inch of each twisted pair of 24 gauge copper wires within the cable.
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CAT-6 Cable, or Category 6 Cable
A cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. CAT-6 features more stringent specifications for crosstalk and system noise. The cable standard provides performance of up to 250 MHz and is suitable for 10BASE-T / 100BASE-TX and 1000BASE-T (Gigabit Ethernet). It is expected to suit the 10GBASE-T (10Gigabit Ethernet) standard, although with limitations on length if unshielded CAT- 6 cable is used. The cable contains four twisted copper wire pairs, just like earlier copper cable standards. CAT-6 is sometimes made with 23 gauge wire, but may be made with 22 to 24 AWG gauge wire, so long as the cable meets the specified testing standards. When used as a patch cable, CAT-6 is normally terminated with modular connectors referred to as "RJ45" electrical connectors.
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CAT-7 Cable, or Category 7 Cable
A cable standard for Ethernet and other interconnect technologies that can be made to be backwards compatible with traditional CAT-5 and CAT-6 Ethernet cable. CAT-7 features even more strict specifications for crosstalk and system noise than CAT-6. To achieve this, shielding has been added for individual wire pairs and the cable as a whole. The CAT-7 cable standard has been created to allow 10 gigabit Ethernet over 100 m of copper cabling. The cable contains four twisted copper wire pairs, just like the earlier standards. CAT-7 can be terminated either with RJ45 compatible electrical connectors which incorporate the RJ45 standard or with TERA connectors. When combined with GG-45 or TERA connectors, CAT-7 cable is rated for transmission frequencies of up to 600 MHz.
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CATV
Cable Television. Refers to equipment or technologies used to transmit, receive, or carry cable television signals. CATV cables typically use the F-type connector terminated to 75 Ohm coaxial cable.
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CCTV
Closed-Circuit Television. A system where video (and sometimes audio) is directly transmitted to specific users and not broadcast to the general public. Most often used for security systems.
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Cladding
Material that surrounds the core of an optical fiber. It blocks the light from "leaking" out of the core, causing the transmitted light to travel down the core.
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Client
A computer on a network. A client is a computer or application that relies on a server to perform some operation. See Client/Server.
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Client/Server
A network architecture which dedicates each computer on the network as a client or a server. Clients rely on servers for resources, such as files, devices, and even processing power. Client/Server architectures are typically more expensive and complex, but they have distinct advantages over peer-to-peer networks. Having files in a central location, for example, makes them easier for all the clients to access and makes it easier for them to be archived. Putting shared devices on a server (such as printers) saves cost by allowing multiple clients to share that single device. Running applications for a central server saves costs because the client machines do not have to be as powerful as the server machine.
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Coax, or Coaxial
A type of cable composed of a center conductor inside a metal tube or shield. A dielectric material separates the center conductor from the shield, which is covered by an insulating jacket. Coaxial is a popular cable for video because it is highly resistance to signal loss and interference, and can carry a large amount of bandwidth.
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Component Video
One of the highest quality types of analog video signals, commonly used for Hi-Definition Television (HDTV). Component video separates the signal into three elements or components; the luminance or picture signal, and two color signals. The three signals are carried on their own conductor, so Component video cables are three cables with RCA or BNC connectors colored Red, Green, and Blue.
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Composite Video
The lowest common denominator video signal, found on virtually all consumer grade video hardware today. Composite Video combines all the picture information into a single signal. The connector type used is RCA, and it is typically colored Yellow.
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Console
A set of peripherals that allow accessing and controlling a computer, typically consisting of a monitor, a keyboard and a mouse.
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Converter
A device that converts a signal from one type to another type. If the only change is in the physical connection type, it is more appropriate to use the term "Adapter".
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Coupler
A special type of adapter used to join two cables together that have the same connector type. For example, if you have two six-foot cables you can use a coupler to join them together to get a twelve-foot cable.
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Crimp
A type of pin to conductor termination method. Crimp pins have little teeth or flanges that are pressed or pinched into the conductor to make electrical contact.
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Crimp Tool
A tool used to affix a crimp pin or connector housing to the conductors in a cable.
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Crosstalk
A problem that occurs in a cable by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect (interference) in another circuit or channel.
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CRT
Cathode Ray Tube (CRT) is a vacuum tube containing an electron gun (a source of electrons) and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, used to form images in the form of light emitted from the fluorescent screen. CRT is used (among other applications) as a video display for televisions and computer monitors. The CRT uses an evacuated glass envelope which is large, deep, heavy, and relatively fragile. Display technologies without these disadvantages, such as flat plasma screens, liquid crystal displays (LCD), DLP, OLED displays have replaced CRTs in many applications and are becoming increasingly common as costs decline.
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Current
The flow of electricity through a wire or circuit. Measured in Amperes.
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D

DB (db)
Used as a prefix for d-shaped connectors, such as the db-9 or db25. Short form of D-Sub.
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DC
Direct Current. An electric current flowing in one direction only and substantially constant in value. Electric batteries use DC.
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DDC
Short form for Display Data Channel. It is a VESA standard for communication between a monitor and a video adapter. DDC is what enables plug and play connection between a computer's video gard and a monitor. Using DDC, a monitor can inform the video card about its properties, such as maximum resolution and color depth (i.e. supported resolutions, manufacturer, phosphor/filter type, display size, luninance data and in the case of digital panels - pixel mapping). The video card can then use this information to ensure that the user is presented with valid options for configuring the display.
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DDWG
Digital Display Working Group (DDWG) - an industry consortium which is the creator of the DVI specification.
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Decibel (dB)
Logarithmic scale measuring the intensity of sound (the sound pressure level); a 10 decibel (dB) increase represents in a doubling of sound level. Also used as the unit of measure for attenuation.
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Device Driver
A piece of software that acts as a translator between the computer and the device allowing the two to communicate.
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Digital Audio
Audio signals that are converted to a digital format. Digital audio provides a cleaner signal because it is immune to interference and provides a more accurate representation of the source material. The digital format also allows a tremendous amount of information to be sent over a single cable, such as a complete 5.1 surround presentation.
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Digital Coaxial
Digital audio over a 75 Ohm coaxial S/PDIF cable.
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Digital Optical
Digital audio over a thin glass or plastic fiber optic cable. Digital optical has a length limitation of about 5 meters. Also called Toslink.
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Digital Signage
A form of out-of-home advertising in which content and messages displayed on an electronic screen, or digital sign, can be changed without modification to the physical sign, typically with the goal of delivering targeted messages to specific locations at specific times. Digital signs may be scrolling message boards, LCD or plasma display panels, electronic billboards, projection screens, or other emerging display types like living surfaces or Organic LED screens (OLEDs) that can be controlled electronically using a computer or other devices, allowing individuals or groups to remotely change and control their content.
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DIN
Stands for Deutsches Institut für Normung, or German Institute for Standardization, a manufacturing industry standards group.  DIN refers to a round connector with pins arranged in a circular fashion, and is commonly used for keyboards, MIDI instruments, and other devices.  See also Mini-DIN.
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DisplayPort
A digital display interface standard put forth by the Video Electronics Standards Association (VESA) since 2006. It defines a royalty-free, digital audio/video interconnect, intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system.

DisplayPort's simplified construction and plug-and-play design provides ease of use to consumers and installers. One cable can be used to carry both analog and digital video, offering a viable alternative to VGA and opening up future expandability. Rounding out DisplayPort's advantages is support for both the proprietary 40-bit HDCP, and a new 128-bit scheme called DPCP which is freely licensed and certain to accelerate the viewing of protected content in the consumer marketplace.
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Dolby Digital
The first implementation of Surround Sound that is encoded to a digital signal. See 5.1. Dolby Digital is widely available and is the de facto standard on DVD's today. Named for the company that invented the technology, Dolby Laboratories.
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Driver
See Device Driver.
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DRM
Digital Rights Management (DRM) is an umbrella term that refers to access control technologies used by publishers and other copyright holders to limit usage of digital media or devices. DRM can also refer to restrictions associated with specific instances of digital works or devices. The term is often confused with copy protection and technical protection measures, which refer to specific technologies that control or restrict the use and access of digital content on electronic devices. Such technologies act as components of a complete rights-management system design.
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DSL
Digital Subscriber Line. A type of broadband internet service that is carried over standard phone lines. DSL can typically provide speeds up to 1.5 Mbps, which is over 30 times greater than standard dial-up speeds.
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D-Sub (D-subminiature)
Refers to the shape (d) and size (sub or subminiature) of the connector. D-sub (db) connectors are the most common type of connector used on computers and electronics equipment.
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Duplex (Duplex Cable)
A cable assembly with two separate cable paths, usually one transmit and one receive. Typically used in reference to fiber cables.
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DVD
Digital Versatile Disc. A 5-inch optical disk that stores audio and video information. It is currently the most popular format for storing movies.
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DVI
Digital Visual Interface (DVI) is a video interface standard designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an industry consortium, the Digital Display Working Group (DDWG). It is designed for carrying uncompressed digital video data to a display. It is partially compatible with the High-Definition Multimedia Interface (HDMI) standard in digital mode (DVI-D).
As well as digital signals, the DVI connector includes pins providing the same analog signals found on a VGA connector, allowing a VGA monitor to be connected with a simple plug adapter. This feature was included in order to make DVI universal, as it allows either type of monitor (analog or digital) to be operated from the same connector.
The DVI connector on a device is therefore given one of three names, depending on which signals it implements:
DVI-D (digital only)
DVI-A (analog only)
DVI-I (digital & analog)
The connector also includes provision for a second data link for high resolution displays, though many devices do not implement this. In those that do, the connector is sometimes referred to as DVI-DL (dual link).
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DVI – Dual Link
Dual link DVI describes the use of all 24 pins of the DVI connector to achieve mega high video resolutions up to 3840 x 2400.
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DVI – Single Link
Single link DVI describes the standard use of DVI, capable of resolutions up to 1920 x 1200.
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E

EDID
Extended Display Identification Data (EDID) is a VESA standard data format that contains basic information about a monitor and its capabilities, including vendor information, maximum image size, color characteristics, factory pre-set timings, frequency range limits, and character strings for the monitor name and serial number.
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EMI
Electromagnetic Interference. Any electronic device gives off an electrical field when it is operating. EMI is when the electrical field of one device interferes with the electrical field of another device. EMI is bad for a signal going through a cable as it can corrupt the signal, so to prevent EMI in a cable, a shield is used. Conversely, the shield also prevents the signal going through the wire from causing EMI in other devices.
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Enclosure
A box or cabinet that holds electronic components.
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Ethernet
A network architecture and set of standards defined by the IEEE as the 802.3 specification. Ethernet is the standard way that computers get on the Internet and communicate with each other today. Ethernet has evolved over the years from bulky systems that only ran at 10 Mbps (megabits per second) to small fast systems that run at over 1 Gigabit (1000 Mbps). The most common cable used with Ethernet is the Cat5 patch cable, which uses the RJ-45 modular connector, but fiber optic cables can also be used.
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Extender
A device that extends an original signal or extends the capability of controlling an original device to a remote (extended) location, typically using standard CAT-5 (5. 5e, 6, or 7) cable(s).  An Extender typically consists of two (2) components: A (local) transmitter that connects to the source, and a (remote) receiver that resides at the extended location connecting to the target.  The Transmitter and the Receiver are typically connected over a distance with a CAT-5 cable.  Extenders may include:
Audio Extender – Extending speakers.
Component Extender – Extending component video to a remote display.
DVI Extender – Extending DVI video to a remote display.
HDMI Extender – Extending HDMI signals to a remote HDTV display.
KVM Extender – Extending a computer console consisting of a Keyboard, Video-monitor, and Mouse.
PS/2 Extender – Extending PS/2 peripherals (keyboard and mouse).
RS232 Extender – Extending RS232 devices such as touch-screens.
USB Extender – Extending USB devices such as cameras.
Video Extender – Extending a video signal to a remote display.
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F

F-Connector (F-Type Connector)
A round, inside-threaded, barrel connector used with coaxial cable and common for CATV use.
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Fiber Optic
A type of conductor made of a fine thread of plastic or glass used to carry a signal that consists of pulses of light. Fiber Optic cables are capable of much greater bandwidth capacity than standard electrical cables, and can also go much greater distances without signal degradation.
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FireWire
FireWire is Apple Inc.'s brand name for the IEEE 1394 interface (although the 1394 standard also defines a backplane interface). It is also known as i.Link (Sony's name). It is a personal computer (and digital audio/digital video) serial bus interface standard, offering high-speed communications and isochronous real-time data services. IEEE 1394 has been adopted as the High Definition Audio-Video Network Alliance (HANA) standard connection interface for A/V (audio/visual) component communication and control.

Almost all modern digital camcorders have included this connection since 1995. Many computers intended for home or professional audio/video use have built-in FireWire ports including all Apple, Sony laptop computers and most Dell and HP models currently produced. FireWire was used with initial models of Apple's iPod, but later models eliminated FireWire support in favor of USB due to space constraints and for wider compatibility.

4-pin IEEE 1394a-2000 FireWire connectors are typically found on camcorders and other digital A/V equipment.
6-pin IEEE 1394a FireWire 400 connectors are typically found on PCs (Apple especially) and disk systems.
9-pin IEEE 1394b FireWire 800 connectors (typically found on Apple computers) allow interconnection to older 1394a systems in 'bilingual mode' (4- or 6-pin using an appropriate adapter-cable).
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Flat Ribbon
A type of cable named for its shape. The conductors are bonded together and laid flat in a ribbon-like configuration. Flat ribbon cables are commonly used for connection of internal computer peripherals. They are also designated by their number of conductors, such as 40-pin flat ribbon (40 conductors) or 50-pin flat ribbon (50 conductors). The type of connector used on a flat ribbon cable is typically the IDC.
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Frequency
The measure of the number of complete electrical cycles that occur within a specific period of time. Frequency is measured is Hertz (Hz), or cycles per second. See bandwidth.
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Frequency Rate
The number of times a display can paint its screen with a complete image.
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Front Projection
A type of display that uses a CRT projected onto a large screen mounted to the wall or hanging from the ceiling. This is the type of system a movie theater uses.
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Full HD
Full HD, also referred to as full HDTV, ultra-HD, true HDTV, and 1080p, is a television (TV) display technology that surpasses the video quality and sharpness of the original high-definition television (HDTV) technology, providing an image resolution of 1920 by 1080 pixels with progressive scanning, at a frame-rate of 60 frames per second (60Hz).
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G

Gauge
See AWG.
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Gender
Refers to the orientation of the contacts on a connector as male or female. Male connectors typically have pins, and are called plugs.  Female connectors typically have sockets, and are called jacks.
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Gender Changer
A special type of adapter that simply changes the gender from male to female, or vice versa. Gender changers can also be used as couplers.
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Gigabit
1000 Megabits, or 1 billion bits per second.
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H

HD15
Or HD-15 - See VGA.
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HDBaseT
HDBaseT is a consumer electronic (CE) connectivity technology optimized for long-distance multimedia distribution, transmitting HD video, audio, Ethernet, power and control signals over a single CAT-5/6a cable (up to 100m/328ft) with RJ45 connectors.
HDBaseT supports Full HD uncompressed video, 100BaseT Ethernet, and control signals including IR, CEC, and RS-232. Up to 100W of power can be extended over HDBaseT, to power remote devices.
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HDCP
High-bandwidth Digital Content Protection (HDCP) is a form of Digital Rights Management (DRM) developed by Intel Corporation to control digital audio and video content as it travels across Digital Visual Interface (DVI) or High-Definition Multimedia Interface (HDMI) connections. The specification is proprietary, and creating an implementation of HDCP requires a license. HDCP is used with HDTV signals over DVI and HDMI connections and on D-Theater D-VHS recordings to prevent unauthorized duplication of copy written material.
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HDMI
The High-Definition Multimedia Interface (HDMI) is a licensable all-digital audio/video interface capable of transmitting uncompressed streams. HDMI provides an interface between any compatible digital audio/video source, such as a set-top box, a DVD player, a PC, a video game console, or an A/V receiver and a compatible digital audio and/or video monitor, such as a digital television (DTV).
The High-Definition Multi-media Interface (HDMI) is an industry-supported, uncompressed, all-digital audio/video interface. HDMI provides an interface between any compatible digital audio/video source, such as a set-top box, DVD player, and A/V receiver and a compatible digital audio and/or video monitor, such as a digital television (DTV).
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HDMI 1.3
With the advent of Blu-ray Disc and HD-DVD, HDMI version 1.3 includes improvements in both audio and video capability.

• Higher speed: Although all previous versions of HDMI have had more than enough bandwidth to support all current HDTV formats, including full, uncompressed 1080p signals, HDMI 1.3 increases its single-link bandwidth to 340 MHz (10.2 Gbps) to support the demands of future HD display devices, such as higher resolutions, Deep Color and high frame rates. In addition, built into the HDMI 1.3 specification is the technical foundation that will let future versions of HDMI reach significantly higher speeds.
• Deep Color: HDMI 1.3 supports 10-bit, 12-bit and 16-bit (RGB or YCbCr) color depths, up from the 8-bit depths in previous versions of the HDMI specification, for stunning rendering of over one billion colors in unprecedented detail.
• Broader color space: HDMI 1.3 adds support for "x.v.Color™" (which is the consumer name describing the IEC 61966-2-4 xvYCC color standard), which removes current color space limitations and enables the display of any color viewable by the human eye.
• New mini connector: With small portable devices such as HD camcorders and still cameras demanding seamless connectivity to HDTVs, HDMI 1.3 offers a new, smaller form factor connector option.
• Lip Sync: Because consumer electronics devices are using increasingly complex digital signal processing to enhance the clarity and detail of the content, synchronization of video and audio in user devices has become a greater challenge and could potentially require complex end-user adjustments. HDMI 1.3 incorporates automatic audio synching capabilities that allows devices to perform this synchronization automatically with total accuracy.
• New HD lossless audio formats: In addition to HDMI’s current ability to support high-bandwidth uncompressed digital audio and all currently-available compressed formats (such as Dolby® Digital and DTS®), HDMI 1.3 adds additional support for new lossless compressed digital audio formats Dolby TrueHD and DTS-HD Master Audio™.

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HDMI 1.4
HDMI version 1.4 adds practical enhancements for HDMI connectivity.

• HDMI Ethernet Channel - The HDMI 1.4 specification adds a data channel to the HDMI connection, enabling high-speed, bi-directional communication. Connected devices that include this feature can send and receive data via 100 Mb/sec Ethernet, making them instantly ready for any IP-based application. The HDMI Ethernet Channel allows internet-enabled HDMI devices to share an internet connection via the HDMI link, with no need for a separate Ethernet cable. It also provides the connection platform that will allow HDMI-enabled components to share content between devices.
• Audio Return Channel - The new specification adds an audio channel that will reduce the number of cables required to deliver audio “upstream” from a TV to an A/V receiver for processing and playback. In cases where a TV features an internal content source, such as a built-in tuner or DVD player, the Audio Return Channel allows the TV to send audio data upstream to the A/V receiver via the HDMI cable, eliminating the need for an extra cable.
• 3D - The 1.4 version of the specification defines common 3D formats and resolutions for HDMI-enabled devices, enabling 3D gaming and other 3D video applications. The specification standardizes the input/output portion of the home 3D system, facilitating 3D resolutions up to dual-stream 1080p.
• 4K Resolution Support - The new specification enables HDMI devices to support extremely high HD resolutions, effectively four times the resolution of a 1080p device. Support for 4K allows the HDMI interface to transmit digital content at the same resolution as the state-of-the-art Digital Cinema systems used in many movie theaters.
• Expanded Support For Color Spaces - HDMI now supports color spaces designed specifically for digital still cameras, enabling more accurate color rendering when viewing digital photos. By supporting sYCC601, Adobe®RGB, and Adobe®YCC601, HDMI display devices are capable of displaying more accurate, life-like colors when connected to a digital camera.
• HDMI Micro Connector (Type D) - The HDMI Micro Connector is a significantly smaller 19-pin HDMI connector supporting up to 1080p resolutions for portable devices such as cell phones, portable media players, and digital cameras. This new connector is approximately 50% smaller than the size of the existing HDMI Mini connector.
• Automotive Connection System (Type E) - The Automotive Connection System is a cabling specification designed to be used for in-vehicle HD content distribution. The HDMI 1.4 specification provides a solution designed to meet the rigors and environmental issues commonly found in automobiles, such as heat, vibration and noise. Using the Automotive Connection System, car manufacturers now have a viable solution for HD distribution within a vehicle.

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HDTV
High-Definition Television. The high-resolution subset of our DTV system. The ATSC defines HDTV as a 16:9 image with twice the horizontal and vertical resolution of our existing system, accompanied by 5.1 channels of Dolby Digital audio. The CEA defines HDTV as an image with 720 progressive or 1080 interlaced active (top to bottom) scan lines. 1280:720p and 1920:1080i are typically accepted as high-definition scan rates.
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Home Theater
A term used to describe an audio/video system designed to bring a movie theater experience into the home by the use of  a large screen television and surround sound.
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Hot-Swap
The act or process of removing and replacing an electronic peripheral or component from a device without first powering down the device.
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Hub
A device used to connect multiple computers or peripherals together so that they may be shared. A hub is typically a boxed shaped device with several ports on it. Each device to be shared plugs into one of the ports. Hubs are common in Ethernet, USB and FireWire applications.
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I

IDC
Insulation Displacement Connector. A special type of crimp connector. IDC works by piercing or pushing aside the insulator on a wire so that the connector pins can make contact with the conductor material . IDC connectors are typically pre-loaded with the pins. They are commonly used with flat ribbon cables.
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IDE
Integrated Device Electronics. Refers to a hard drive or storage disk where the controller is integrated to the drive itself.
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IEEE
Institute for Electrical and Electronics Engineers, pronounced I-triple-E. A body of engineers, students, and scientists that develop and govern standards for the computer and electronics industry.
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IEEE-1284
A set of standards set by IEEE in 1994 to upgrade the aging parallel interface. It defined a set of protocols to enable bi-directional communication between the computer and the peripheral, improving speed and functionality.
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IEEE-1394
The technology known as IEEE-1394 High Performance Serial Bus, or simply 1394. Developed by Apple in the 1980s is a versatile, high-speed, and low-cost method of interconnecting personal computer peripherals and consumer electronics devices. See FireWire. Similar to USB, but with a few distinct differences. First, FireWire is a peer-to-peer technology, so no host is needed; devices can connect directly together. Second, FireWire is faster with speeds up to 800Mbps (called 1394b, or FireWire800). Even when running at speeds comparable to USB (such as the common 400 Mbps mode) FireWire is able to achieve higher sustained bandwidth throughput due to more intelligent logic circuits. Therefore, FireWire is a much more common interface for Digital Video (DV). Sony has adapted the trade name of i-Link for it’s implementation of the IEEE-1394 technology. 
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Impedance
Impedance is a measure of how much a component or wire resists the flow of current through it. It is calculated by adding together the electrical properties of resistance and reactance. Because impedance affects the flow of current, it is important for a cable to maintain a constant impedance from one end to the other. Because impedance is a derivative of resistance, it is measured in Ohms.
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Interlaced
A type of video display where the image is drawn in an alternating pattern. The odd lines are drawn first, and then the even lines are drawn. See also, progressive. On a typical display, this alternating pattern occurs 30 times a second, so it can cause the display to flicker. Interlaced video was developed so that only half an image has to be transmitted at a time, saving bandwidth. Standard televisions are interlaced. Most computer monitors and HDTV’s are non-interlaced.
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IP
Internet Protocol (IP) is the principal communications protocol used for relaying datagrams (also known as network packets) across an internetwork using the Internet Protocol Suite responsible for routing packets across network boundaries. It is the primary protocol that establishes the Internet.

IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering datagrams from the source host to the destination host solely based on the addresses. For this purpose, IP defines datagram structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram source and destination.

Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced in 1974, the other being the connection-oriented Transmission Control Protocol (TCP). The Internet Protocol Suite is therefore often referred to as TCP/IP.

Internet Protocol is responsible for addressing hosts and routing datagrams (packets) from a source host to the destination host across one or more IP networks. For this purpose the Internet Protocol defines an addressing system that has two functions: identifying hosts and providing a logical location service. This is accomplished by defining standard datagrams and a standard addressing system.
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ISP
Internet Service Provider. A company or organization that provides Internet connections to individuals or companies.
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J

Jacket
The outer covering of a cable. The jacket material is typically a type of PVC (Poly-vinyl Chloride). Some jackets are made with FEP (Fluorinated Ethylene Propylene) or other Teflon derivatives when a plenum-rated version of a cable is needed.
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Jumper
In cable or adapter, a jumper is a small wire or solder joint that fuses two or more conductors into one. Many times jumps are needed to fulfill the signal requirements of a particular cable’s pinout.
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K

KVM
An abbreviation for Keyboard, Video, Mouse.
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KVM Drawer
A sliding drawer consisting of a computer console (keyboard, video monitor and mouse) that is designed to be installed in a computer rack. A KVM Drawer typically features a folding flat-panel monitor, hence allowing the device to occupy minimal height (when folded closed) in the rack.
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KVM over IP
Keyboard/Video/Mouse (KVM) switches or gateways that allow remote user(s) over an IP connection (via LAN, WAN or Internet) to access and control computer(s) and server(s) through their keyboard, video and mouse ports operating a remote computer, as if the user was locally (and physically) connected to the controlled computer. A KVM over IP switch provides the same functionality as a (non-IP) KVM switch, only that the user – instead of using a console connected to the KVM switch – is using a computer which is physically far away from the KVM over IP switch. The KVM over IP switch is connected to the network and the remote user gains access to it over the network (using an IP connection).  A KVM over IP gateway provides a similar remote (over IP) access, but typically gets connected to a (non-IP) KVM switch, thus serving as an IP gateway to a non-IP KVM switch. Both KVM over IP switches and gateways typically provide connections for a local console (keyboard, mouse, monitor) as well, to allow access to a local user in the same physical location. Smaller KVM over IP Gateways are designed to access only one computer/server over IP and typically don't offer local access.
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KVM Switch
A KVM switch (with KVM being an abbreviation for Keyboard, Video, Mouse) is a hardware device that allows a user to control multiple computers from a single console (keyboard, video monitor and mouse).  USB KVM switches have also added the ability to share USB devices and speakers with multiple computers.

Some KVM switches allow more than one console to be connected to the switch, offering multi-user capability so that a few users can access and control different computers connected to the KVM switch at the same time.
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KVMA
An abbreviation for Keyboard, Video, Mouse, Audio. Typically used to define a KVM switch that also supports audio, allowing many computers to be connected to (and controlled by) one set of monitor, keyboard, mouse, speakers and sometimes a microphone as well.
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KVMP
An abbreviation for Keyboard, Video, Mouse, Peripherals. Typically used to define a KVM switch that has a built-in USB hub, allowing all connected computers to share USB peripherals such as printer, camera, external hard drive, etc.
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L

LAN
Local Area Network. Refers to a computer network or segment of a network that is confined to a single physical space, such as a building or group of buildings (such as a campus). Multiple LAN’s can be connected together via telephone lines, radio waves, or the Internet. See WAN (Wide Area Network).
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LCD
Liquid Crystal Display. A type of display that consists of a layer of liquid crystals sandwiched between two layers of glass. As an electrical current is applied to the crystals, they change their shape allowing more or less light to shine through. LCD displays are popular because they are bright, sharp, thin, and lightweight. They are most commonly used on laptop computers.
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LCD Console
Also known as 'LCD Console Drawer/Tray' or 'KVM LCD Console' - LCD Console is a rack-mounted all-in-one computer console with an LCD display.

A thin (typically no more than 1U - 1.75" high), rugged tray/drawer constructed of metal that gets rack-mounted in an IT equipment rack so that - when not in use - it occupies minimal space in the rack.  The rack-mount tray has a handle at the front, allowing the 'drawer' to slide and be pulled out for use.  Once pulled out - the top portion of the sliding drawer gets lifted up on hinges, exposing a built-in LCD screen which displays the video from the connected computer. The bottom portion of the drawer consists of a built-in keyboard and a pointing device (touch-pad or track-ball), for interaction with the connected computer.

An LCD Console gets connected to the video, keyboard and mouse ports of one computer, or can have an integrated KVM switch, allowing the user to use the console to interact with many computers connected to the switch. Some models feature an integrated KVM-over-IP switch.

Some LCD Consoles feature a sliding mechanism for the LCD screen which is separate than the sliding mechanism for the keyboard/mouse, allowing only the screen to be visible (while the keyboard/mouse tray is 'tucked in'. This feature is useful for monitoring purposes, also allowing a rack's see-thru front door to be closed while the monitor is still visible.
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LED
Light Emitting Diode. A circuit that emits light when an electrical current is applied to it.
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LFE
Low Frequency Effects. The .1 in 5.1, it is the audio channel that carries only low frequency information of 80 Hz and below (the deep bass sounds).
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Luminance
The brightness and darkness (black and white) portion of a video signal. Also called "Y".
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M

Matrix Switch
A device that allows controlling (or viewing) multiple devices connected to its ports from multiple consoles or screens.  The switch provides the user with the ability to switch between ports, routing the control (or view) of any port to any one of the controlling (or viewing) consoles. Matrix switches are typically used for video applications (with computers or with home-theater HDTV), allowing custom routing of multiple sources to multiple destinations.
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Media Player
A term typically used in reference to digital signage to describe computer software for playing back multimedia files. Most software media players support an array of media formats, including both audio and video files.
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MHL
Mobile High-Definition Link (MHL) is a proposed industry standard for a mobile audio/video interface for directly connecting mobile phones and other portable consumer electronics devices to high-definition televisions (HDTVs) and displays. The MHL standard features a single cable with a low pin-count interface able to support up to 1080p high-definition (HD) video, 192khz digital audio sound quality, and 7.1 channel surround sound, while simultaneously charging the connected device.
MHL is being developed by the MHL Consortium, a consortium of developers of mobile devices including Nokia, Sony, Samsung, and Toshiba.
Main features include:
• The HDTV provides power to the connected device.
• Uses a single, thin cable to connect the mobile device to the HDTV.
• The HDTV remote will control the connected device with guaranteed mixed manufacturer interoperability CEC.
• 1080p uncompressed HD video.
• 7.1 surround sound uncompressed audio.
• Supports High-bandwidth Digital Content Protection (HDCP).
• MHL is connection agnostic, i.e., not tied to a specific type of hardware connector.
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Mini DisplayPort
Mini DisplayPort is a miniaturized version of the DisplayPort interface. First publicly announced by Apple on October 14, 2008, it is used in revisions of the MacBook notebooks, Mac desktops and Apple Cinema Display.

Mini DisplayPort is capable of driving resolutions up to 2560x1600, commonly used with 30-inch displays. With a suitable adapter, Mini DisplayPort may be used to drive displays with a VGA or DVI interface.

Mini-DIN
A type of DIN connector that is smaller in diameter, with the pins arranged in rows rather than in a circular manner. The most common mini-DIN connectors are the 4-pin version used for S-Video, and the 6-pin version used for PS/2-style keyboards and mice.
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Molded or Molding
A method used to seal or encase a connector hood in a mold of plastic or rubber via an injection molding process. Molded hoods provide superior strain relief and an attractive appearance. Because the connector is sealed, it also prevents tampering. Most off-the-shelf PC cables are molded cables.
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Mono
A single channel, typically in reference to audio.
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Multi-Mode
A term used for a fiber optic cable with a core thick enough to carry multiple modes (beams) of light.
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N

NEMA Connectors
NEMA connectors are AC power plugs and receptacles used for mains electricity in North America and other countries that use the standards set by the U.S. National Electrical Manufacturers Association (NEMA). NEMA wiring devices are made in current ratings from 15 to 60 amperes, and electrical potential (voltage) ratings from 125 to 600 volts. Different combinations of contact blade widths, shapes, orientation, and dimensions give non-interchangeable connectors that are unique to a particular voltage, current capacity, and grounding system. NEMA 1 (two prong) and NEMA 5 (three prong) are used for commonplace domestic equipment; the others are for heavy duty or special purposes.

There are two basic classifications of NEMA device: straight-blade and locking. The straight-blade 5–15 and 5–20 are found nearly everywhere in countries using the NEMA standards, and are intended for supplying lighter-duty, general-purpose electrical devices. Twist-locking types are used for heavy industrial and commercial equipment, where increased protection against accidental disconnection is required. Numbers prefixed by L are curved-blade, twist-locking connectors; others are straight blade and non-locking.
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Network
A system of connected computers. The purpose of a network is so the connected computers can easily share data, peripherals, or printers. The most popular type of network today is Ethernet and, of course, the Internet.
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Node
A processing location on a network. A node can be a client, a server, or a device, such as a printer.
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Non-Interlaced
A type of video display where the image is drawn in an single pass, as opposed to interlaced. Because the image is drawn in a single pass, flicker is eliminated. Standard televisions are interlaced. Most computer monitors and HDTV’s are non-interlaced. See also, progressive.
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NTSC
National Television Systems Committee. Federal government agency that established the analog color television standard used in the United States. Delivers 525 lines of resolution at 60 half-frames per second.
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O

Ohm
The unit of measure of electrical resistance and impedance.
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P

PAL
Phase Alternating Line. Television broadcast standard developed in England and Germany and used in many countries throughout Europe. Delivers 625 lines of resolution at 50 half-frames per second.
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Parallel
Refers to a type of interface where the signal lines are running over multiple channels running parallel to each other. Think of parallel as a multi-lane highway for data. Common parallel interfaces are IEEE-1284, SCSI, and ATA. Parallel cables are typically thicker and larger because of the number of conductors necessary. Opposite of serial.
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PATA
Parallel ATA. Simply called ATA (or incorrectly IDE/EIDE) before SATA was introduced. The P was added to clearly distinguish the two technologies. See ATA, SATA.
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Patch Cable
Any cable used to patch or connect one device to another device. Most common in reference to Ethernet cables.
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Peripheral
A device that attaches to a computer. Common peripherals are printers, keyboards, mice, etc.
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Pinout, or Pinmap
The signal map of a cable. It shows how the signal conductors in the cable are arranged from one connector to the other. The pinout is what makes the signals flow correctly so the cable can work for its intended purpose. If the cable you are using does not have the correct pinout, data will not flow and your application will not work.
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Pixel
Picture element. The smallest component of a video display. Pixels are the individual dots that make up the image. The number of pixels is measured by the resolution of the display. The more pixels available, the sharper the image.
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Plasma Display, or Plasma TV, or Plasma Screen
A type of display that consists of a layer of plasma gas sandwiched between two layers of glass. As an electrical current is applied to the plasma it gives off energy which excites phosphors coated on the glass, producing an image. Plasma displays are bright, sharp, and thin.
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Plenum, or Plenum-Rated
A type of cable jacket with fire-rated properties typically made of Teflon or Teflon derivatives. The building codes in most localities require the use of fire-rated cables when they are run through the plenum spaces of a building to prevent the spread of fire or the release of toxic gases that can result from the burning of standard PVC materials. The plenum space is typically the open space between a drop ceiling and the roof, or the open space inside walls, for which the cable gets its name.
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Polarity
An electrical circuit has two sides; positive and negative. The polarity is which condition exists for a particular side. It is important to maintain polarity when connecting electrical circuits, or current will not flow. In some cases, it can damage the equipment.
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Port
On switches and telecommunication devices, a port (noun) is generally a specific place for being physically connected to some other device, usually with a socket and plug of some kind. On a KVM switch, for example, the number of ports determines the number of computers that get controlled through the switch.  On a video splitter, for example, the number of ports determines the number of displays the original video can be duplicated onto.
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Progressive
[Also known as Progressive Scanning] An HDTV resolution variant where each scan displays every line in the image raster sequentially from top to bottom (see 1080p).

Progressive scanning is considered superior to interlaced scanning for full-motion video displays, because there is less jitter, particularly for the portrayal of objects that move diagonally or vertically across the screen.  The improvement is especially noticeable for fast-moving images, typical of television and DVD programs.  Another advantage of progressive scanning is the fact that it is required for satisfactory video on TV sets that use micro displays, plasma displays, or liquid-crystal display (LCD) flat panels. The improved image quality afforded by full HDTV is well suited to the extra-large-screen displays used in home theater systems.
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Protocol
The language or format that is transmitted from one device to another. In order for two devices to communicate, they must be able to use the same protocol.
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PS/2
PS/2 connector is a 6-pin Mini-DIN connector used for connecting some keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9 RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design.

Original PS/2 connectors were typically black. Later the PC 97 standard introduced a color code: the keyboard port, and the plugs on compliant keyboards, were purple; mouse ports and plugs were green. Some vendors initially used a different color code, but today this code is still used on most PCs. The pinouts of the connectors are the same, but most computers will not recognize devices connected to the wrong port.
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Q

R

Rack
A metal frame or enclosure used to mount equipment.
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RCA
A type of connector primarily used for connecting audio and video equipment. It is a single pin connector with a surrounding shield ring that was developed by the company whose name it bears. Also called phono-plug, because the connector was originally develop for phonographs.
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Real VNC
See VNC.
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Rear Projection
A type of display that uses a CRT projected onto a mirror and reflected onto the back of a large screen. What most people think of when considering large screen or big screen TVs.
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Receiver
A component or an audio system that consists of an amplifier, pre-amplifier, signal processor, tuner, and junction point for the other components. The receiver is the heart of any audio/video or home theater system. Also used to define the collector end of a signal path.
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Refresh Rate
The number of times a display can paint its screen with a complete image, or the frequency with which a video image is refreshed, expressed as either frames per second (i.e. 60 fps) or as an equivalent frequency (i.e. 60Hz).  Faster refresh rates tend to render smoother motion sequences.

With computers, the refresh rate for each display depends on the video card used.  You can change the refresh rate in the display properties.  However, if you change the refresh rate to a setting that the display or video card cannot support, the display goes blank or the image becomes distorted.  It is recommended to consult the display and video card specifications (before changing the settings) to determine the supported refresh rates.

For computer use, an older refresh rate standard, developed by the Video Electronics Standards Association (VESA), was only 60Hz.  This refresh rate caused the display's image to flicker, causing eye fatigue and headaches in users.  A newer standard set the refresh rate to 75Hz. It is believed that 70Hz or higher eliminates the flicker.

Refresh rates for broadcast TV vary by region.  For example, European HD systems run at 50Hz.Back to Top

Resistance
The measure of the amount of opposition of a body or substance to the electrical current passing through it. The more resistance you have in a cable, the less current flows through the cable.
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Resolution
The measure of the number of pixels a display can produce. It is shown as the number of pixels (horizontal) by the number of lines (vertical). The higher the resolution, the more detailed the image.
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Retention
The mechanical anchor mechanism used to secure two connectors together. Typical retention methods are thumbscrews, squeeze latches, or friction fit.
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RFI
Radio Frequency Interference – A special type of EMI (electromagnetic interference) that is specific to transmitted fields within the radio frequency band, typically over 1Mhz. Whereas EMI is a by-product of electrical devices, RFI is typically a deliberate signal transmission such as a radio station, TV, cordless phone, etc. Because RFI is a type of EMI, is can be just as detrimental to the signals in a wire and may need to be shielded against.
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RJ45
RJ45 is a registered jack standard for a modular connector using 8 conductors, which specifies the physical male and female connectors as well as the pin assignments of the wires. The "RJ45" physical connector is standardized as the IEC 60603-7 8P8C modular connector with different "categories" of performance, commonly known as RJ45.

The 8P8C modular connector - commonly referred to as an RJ45 in the context of Ethernet and Category 5 cables - is a modular connector commonly used to terminate twisted pair and multiconductor flat cable. These connectors are commonly used for Ethernet over twisted pair and other applications involving unshielded twisted pair, shielded twisted pair, and multiconductor flat cable.

Electronics catalogs commonly advertise 8P8C modular connectors as "RJ45", but of course an installer can wire the jack to any pin-out or use it as part of a generic structured cabling system using RJ45 patch panels for both phone and data. Virtually all electronic equipment which uses an 8P8C connector will document it as an "RJ45" connector.
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Router
A router is a special type of Ethernet switch that provides a superior level of packet routing. A router perform the "traffic directing" functions on the Internet.

The most familiar type of routers are home and small office routers that simply pass data, such as web pages and email, between the home computers and the owner's cable or DSL modem, which connects to the Internet (ISP). However more sophisticated routers range from enterprise routers, which connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone..
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RS-232
Recommended Standard 232. This is the de facto standard for communication through PC serial ports. It can refer to cables and ports that support the RS232 standard.
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S

S/PDIF
Stands for Sony/Philips Digital Interconnect Format, the two companies being the primary designers of the S/PDIF format.  S/PDIF specifies a Data Link Layer protocol and choice of Physical Layer specifications for carrying digital audio signals between devices and stereo components.  A common use for the S/PDIF interface is to carry compressed digital audio, used to connect the output of a DVD player to a home theater receiver that supports Dolby Digital or DTS surround sound. Another common use is to carry uncompressed digital audio from a CD player to a receiver.
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SATA
Serial ATA, or Serial Advanced Technology Attachment. SATA is the latest evolution of the aging ATA storage technology interface. SATA advantages are speed (up to 150 MB/s currently), smaller and thinner cables and connectors, and lower power requirements. Opposite of PATA.
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Scaler
Scalers are add-on devices placed between the source and the display that enable the conversion of an input video signal from one format to a different resolution. Today more and more people want to use their main digital, high definition display with a variety of video sources, such as computers, DVD players, set-top boxes, gaming consoles and more. At their most basic level, home-theater scalers will accept any of these sources and properly convert them for pixel format compatibility with your main display.

Incoming video signals from different video sources (composite, component, HDMI) are converted to user-selectable output resolutions supporting any type of display, projector and monitor in all high definition resolutions up to 1920x1200 or 1080p.

Scalers can improve the quality of the image if the display has an inexpensive built-in scaler. This is done by outputting the video set to the native resolution of the display, bypassing its internal scaler. This ensures the best quality video possible.
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Scan Rate
The number of times a display can paint its screen with a complete image.
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SCSI
Small Computer System Interface. Pronounced "skuzzy". A set of standards designed for the connection of peripheral devices to computers. SCSI was ratified in 1986 (earlier versions date back to 1979) and has evolved much over the subsequent years to keep up with demands of speed and reliability. SCSI is a parallel bus interface that requires termination. The evolution over the years has created a large array of connectivity options for SCSI, and makes it one of the most confusing technologies to implement.
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SDI
Serial Digital Interface. A serial link standardized by ITU-R BT.656 and the Society of Motion Picture and Television Engineers (SMPTE). SDI transmits uncompressed digital video over 75-ohm coaxial cable within studios, and is seen on most professional video infrastructure equipment. The first revision of the standard, SMPTE 259M, was defined to carry digital representation of analog video such as NTSC and PAL over a serial interface and is more popularly known as standard-definition (SD) SDI. The data rate required to transmit SD SDI is 270 Mbps. With the advent of high-definition (HD) video standards such as 1080i and 720p, the interface was scaled to handle higher data rates of 1.485 Gbps. The 1.485-Gbps serial interface is commonly called the HD SDI interface and is defined by SMPTE 292M, using the same 75-ohm coaxial cable. Studios and other video production facilities have invested heavily on the hardware infrastructure for coaxial cable and have a vested interest in extending the life of their infrastructure. Fortunately, SMPTE recently ratified a new standard called SMPTE 424M that doubles the SDI data rates to 2.97 Gbps using the same 75-ohm coaxial cable. This new standard, also called 3-Gbps (3G)-SDI, enables higher resolution of picture quality required for 1080p and digital cinema.
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Serial
Refers to a type of interface where the signal lines are run over a single channel one bit at a time. Think of serial as a single-lane highway for data. Common serial interfaces are RS232, USB, and SATA. Serial cables are typically thinner and smaller because of the few number of conductors necessary. Opposite of parallel.
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Server
A computer or device on a network that manages applications or resources. Servers are powerful computers often dedicated to a singular task. Types of servers are: File servers – used to store, retrieve, and archive files; Print servers - manage one or more printers; Network servers - manage network traffic; and database or application servers – process one or more applications or programs. See Client/Server.
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Shield
Used in a cable to provide a protective layer of the signal conductors from EMI (Electro-Magnetic Interference) and RFI (Radio Frequency Interference). The shield works by providing a low-resistance path that collects the stray interference signals and grounds them to earth so that they do not get into the signal wires. There are two types of shields used in cables; a foil shield, and a braided shield. When both are used in a cable, it is called a double-shield, or foil and braid.
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Splitter
A device that takes one signal (from one source) and broadcasts (splits) it to many destinations at the same time – each destination receiving the same signal.  Splitters are typically used in video and audio/video distribution applications such as digital signage, or for distribution of HDTV to multiple screens.  Splitters typically support the target destinations being far away from the source, typically using CAT-5 cable as means of connecting the source to the destination.
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Subwoofer
A special form of speaker used to reproduce only the lower portion of the audible frequency spectrum usually from 80 Hz down to or below 20 Hz. See LFE.
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Surround Sound
Literally, surrounded by sound. A speaker setup that puts the listener in the center of a series of speakers so that sounds can be heard from any direction. Popular with home theater setups and cinemas. See 5.1, 6.1, 7.1.
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S-Video
The "middle of the road" video signal, found on most consumer grade video hardware today. S-Video separates the picture into two separate components, Chrominance and Luminance. This lets the video signal bypass the comb filter, which helps maintain signal integrity.  S-video typically uses a 4-pin mini-DIN connector.  Also known as S-VHS, or Super VHS, it was developed in the 80s by JVC as a response to attempts by Sony to corner the VCR market with their Beta technology.
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Switch
A device that allows controlling (or viewing) multiple devices connected to its ports from one console or screen.  The switch provides the user with the ability to switch from one port to another, thus controlling (or viewing) the device connected to that port, typically one port at a time.  A switch may be:
HDTV Switch – Connects multiple sources (DVD player, set-top box, etc.) to be viewed on one HDTV screen.
KVM Switch – Connects multiple computers to be controlled by one console (monitor, keyboard and mouse).
Serial-Console Switch – Connects multiple (networking) serial devices (routers, Ethernet Switches, etc.) to be controlled by one ("dumb") terminal.
Video Switch – Connects multiple video sources (computers or home-theater devices) to be displayed on one display.
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T

Termination
To end; to terminate a wire means to put a connector or connector pin on it. You are putting an end to the cable. In SCSI applications, it means you are putting an end to the SCSI chain by the use of a terminator.
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Terminator
A terminator is device used to end a signal chain, typically used for SCSI and older type of Ethernet such as 10-Base2. The terminator brings an abrupt end to the electrical signals moving down the cable. Without the terminator, the signals would hit the end of the cable and bounce back, causing interference and data corruption. Also, a cybernetic organism played by Arnold Schwarzenegger.
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Thunderbolt
Thunderbolt is an input/output (I/O) interface for connecting peripheral devices to a computer, supporting high-resolution displays and high-performance data devices through a single, compact port.

Thunderbolt combines PCI Express and DisplayPort into a serial data interface that can be carried over a single cable.

With PCI Express technology, you can use existing USB and FireWire peripherals — even connect to Gigabit Ethernet and Fiber Channel networks — using simple adapters.

Because Thunderbolt I/O is based on DisplayPort technology, any Mini DisplayPort display plugs right into the Thunderbolt port. Thunderbolt also supports DisplayPort, DVI, HDMI, and VGA displays through the use of existing adapters.

Thunderbolt was developed by Intel and brought to market with technical collaboration from Apple. It was introduced commercially on Apple's updated MacBook Pro lineup in February 2011, using the same connector as Mini DisplayPort.
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THX
Set of specifications and certifications designed by Lucasfilm to ensure optimum reproduction of movie sound and video in movie theaters and home theaters. Stands for Tomlinson Holman eXperience. Tom Holman was a Lucasfilm sound engineer.
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Topology
The shape or design abstract of a LAN or connected system. Three principle topologies are used; bus topology – all nodes are connected in a linear fashion to a single bus or backbone (also called a daisy-chain) ; star topology – all nodes are connected to a central point, typically a hub; and ring topology – all nodes are connected together in a closed loop.
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TOSLink
Stands for "Toshiba Link", and is Toshiba's brand name for optical digital audio cables. TOSLink is the most common type of digital optical connector. Comes in two types; a square shaped plug used on home theater equipment, and a mini-plug (similar to a headphone plug) used on handheld digital devices like mini-disc players.

Tuner
An electronic device used to receive coded signal transmissions and decode them into audio and video information.
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Twisted Pair
Two conductors twisted together. The purpose of twisted pair is to help reduce EMI/RFI interference by utilizing a principle called differential or balanced signaling. If the transmitting device does not utilize either of those methods, there is no technical advantage to using a twisted pair cable. CAT-5 cable, used for Ethernet, is the most famous type of twisted pair cable used today.
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U

"U"
A rack unit or "U" (less commonly, "RU") is a unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack or a 23-inch rack (The dimension refers to the width of the equipment mounting frame in the rack). One rack unit ("U") is 1.75 inches (44.45 mm) high.

The size of a piece of rack mounted equipment is frequently described as a number in "U". For example, one rack unit is often referred to as "1U", 2 rack units as "2U" and so on.
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Un-Twisted Pair
Opposite of Twisted Pair.
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USB 1.1
Universal Serial Bus (USB) is a serial bus standard to interface devices. A major component in the legacy-free PC, USB was designed to allow peripherals to be connected using a single standardized interface socket, to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). Other convenient features include powering low-consumption devices without the need for an external power supply and allowing some devices to be used without requiring individual device drivers to be installed.  USB 1.0 and 1.1 has a maximum bandwidth of 12 Mbps. Up to 127 peripheral devices can be attached to the bus.
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USB 2.0
Universial Serial Bus (USB) 2.0 is a complete overhaul of the Universal Serial Bus input/output bus protocol which allows much higher speeds than the older USB 1.1 standard did. The goal of the new serial bus is to broaden the range of external peripherals that can be used on a computer.
Hi-Speed USB 2.0 has a maximum bandwidth of 480 Mbps. Up to 127 peripheral devices can be attached to the bus, and USB 1.1 devices can plug into USB 2.0 ports. Fast devices can use the full bandwidth, while low-speed ones can use a 1.5 Mbps sub-channel.
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USB 3.0
USB 3.0 is the second major revision of the Universal Serial Bus (USB) standard for computer connectivity. First introduced in 2008, USB 3.0 adds a new transfer mode called "SuperSpeed," (distinguishable from USB 2.0 by either the blue color of the port or the initials SS) capable of transferring data at up to 5 Gbps - over 10 times faster than the 480 Gbps top speed of USB 2.0.

The USB 3.0 specification is similar to USB 2.0 but with many improvements and an alternative implementation. The changes in this specification make improvements in the following areas:

• Transfer speed – Added a new transfer type called Super Speed or SS – 5 Gbps (electrically it is more similar to PCIe Gen2 and SATA than USB 2.0) - 10x the data transfer rate of Hi-Speed USB 2.0.
• Increased bandwidth – Instead of one-way communication, USB 3.0 uses two unidirectional data paths: one to receive data and the other to transmit
• SuperSpeed USB 3.0 is a Sync-N-Go technology that minimizes user wait-time.
• Power management – SuperSpeed USB 3.0 will provide Optimized Power Efficiency.  No device polling and lower active and idle power requirements.
• Improved bus utilization – A new feature is added (using packets NRDY and ERDY) to let a device asynchronously notify the host of its readiness (no need of polling)
• SuperSpeed USB 3.0 is backwards compatible with USB 2.0. Devices interoperate with USB 2.0 platforms. Hosts support USB 2.0 legacy devices.

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USB Hub
A device that increases the number of USB ports on a computer, typically providing at least four Type A sockets for expansion. Like any other USB device, the hub plugs into a USB port on the computer and provides four or more USB ports for peripherals.

The peripherals themselves may also contain hubs. USB hubs are often used to extend ports to the top of the desk to make it more convenient to connect and remove external peripherals. For example, a monitor may have a built-in USB hub in order to provide a convenient desktop location for plugging in other devices.
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UTP
Unshielded Twisted Pair.
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V

VESA
Video Electronic Standards Association, a consortium of manufacturers formed to establish and maintain industry wide standards for video cards and monitors. VESA was instrumental in the introduction of the Super VGA and Extended VGA video graphics standards with a refresh rate of 70 Hz, minimizing flicker and helping to reduce user eyestrain and fatigue.
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VGA
Video Graphics Array (VGA) is an analog computer display standard first marketed in 1987 by IBM. It has been technologically outdated in the PC market for some time. VGA was the most recent graphical standard that the majority of manufacturers conformed to, making it the lowest common denominator that all PC graphics hardware supports before a device-specific driver is loaded into the computer. For example, the Microsoft Windows splash screen appears while the machine is still operating in VGA mode, which is the reason that this screen always appears in reduced resolution and color depth.

The term VGA is often used to refer to a resolution of 640×480, regardless of the hardware that produces the picture (even though this resolution is outdated in PC, in the pocket PC / PDA market it is currently becoming the standard). It may also refer to the 15-pin D-subminiature VGA connector which is still widely used to carry analog video signals of all resolutions.

A VGA connector is a three-row 15-pin connector. The 15-pin VGA connector is found on many video cards, computer monitors, and some high definition television sets.
VGA connector is also conventionally called RGB connector, D-sub 15, mini sub D15, mini D15, DB-15, HDB-15, HD-15 or HD15.
VGA connectors and cables carry analog component RGBHV (red, green, blue, horizontal sync, vertical sync) video signals, and VESA Display Data Channel (VESA DDC) data.
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VNC
[Also known as Real VNC] In computing, Virtual Network Computing (VNC) is a graphical desktop sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer.  It transmits the keyboard and mouse events from one computer to another, relaying the graphical screen updates back in the other direction, over a network.  Popular uses for this technology include remote technical support and accessing files on one's work computer from one's home computer, or vice versa.

VNC is platform-independent – a VNC viewer on one operating system may connect to a VNC server on the same or any other operating system.

There are a number of variants of VNC which offer their own particular functionality; e.g., some optimized for Microsoft Windows, or offering file transfer (not part of VNC proper), etc.  Many are compatible (without their added features) with VNC proper in the sense that a viewer of one flavor can connect with a server of another; others are based on VNC code but not compatible with standard VNC.

VNC and RFB are registered trademarks of RealVNC Ltd.
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W

WAN
Wide Area Network. Multiple LAN's connected together via telephone lines or radio waves. The Internet is a WAN.
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Widescreen
A display with a wider aspect ratio, typically 16 units wide for every 9 units high (16:9). Widescreen displays are popular because they more accurately represent the aspect ratio of a movie theater and present a better viewing experience.
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Wire Gauge
See AWG.
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X

Y

Z

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