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# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 


Value-Added Reseller (VAR)

Refers to distributors that also provide other services such as systems integration or network management.
Source: CableLabs, 9/25/2007  
Variable Bit Rate (VBR)

A type of telecommunications service characterized by a service bit rate specified by statistically expressed parameters that allow the bit rate to vary within defined limits.
Source: CableLabs, 9/25/2007  
VDSL

Very high-speed digital subscriber line that utilizes existing copper infrastructure of the telephone companies. VDSL offers video and data transmission rates up to 52 Mbps up to 2,700 feet. See also DSL.
Source: CableLabs, 9/25/2007  
Velocity of Propagation

Velocity of signal transmission. In free space, electromagnetic waves travel with the speed of light. In coaxial cables, this speed is reduced. Commonly expressed as percentage of the speed in free space.
Source: CableLabs, 9/25/2007  
Vertical Blanking Interval (VBI)

A portion of the television signal that does not contain visual data. In NTSC, the VBI are lines 1 through 21 in each field.
Source: CableLabs, 9/25/2007  
Very High Frequency (VHF)

Channels 2-13 (54-88 MHz and 174-216 MHz).
Source: CableLabs, 9/25/2007  
Very Small Aperture Terminal (VSAT)

Small earth stations with a satellite dish usually 4-6 feet in diameter used to receive high speed data transmissions; can also transmit slow-speed data.
Source: CableLabs, 9/25/2007  
Vestigial Sideband Transmission

A system of transmission wherein the sideband on one side of the carrier is transmitted only in part.
Source: CableLabs, 9/25/2007  
Video

A term pertaining to the bandwidth and spectrum of the signal which results from television scanning and which is used to produce a picture.
Source: CableLabs, 9/25/2007  
Video Band

The frequency band utilized to transmit a composite video signal.
Source: CableLabs, 9/25/2007  
Video Transmission

The original video signal before it is modulated and converted to radio-frequency and broadcast or cablecast. A home television set reconverts radio-frequencies to a video signal.
Source: CableLabs, 9/25/2007  
Video-on-Demand (VOD)

Allows the end-user subscriber to select at any time movies they wish to view from a large selection of titles and categories stored on a remote server. Service may also provide VCR functionality, (stop, pause, etc.) which allows the end-user subscriber to control the “play back” of the server from the remote control. Or a television service where viewers can select and watch video content for viewing at any time.
Source: CableLabs, 9/25/2007  
Videotape

Used to electronically record sight and sound for instant playback. Videotape comes in half-inch, three-quarters, one and two-inch widths and can be erased and re-recorded.
Source: CableLabs, 9/25/2007  
Videotape Recorder (VTR)

A device which allows the recording and playback of magnetic tape sound and picture recordings.
Source: CableLabs, 9/25/2007  
Videotex

The generic term used to refer to a two-way interactive system for the delivery of computer-generated data into the home, usually using the television set as a display device. Some of the more often used specific terms are “viewdata” for telephone-based systems (narrowband interactive systems); “wideband broadcast” or “cabletext” for systems utilizing a full video channel for information transmission; and “wideband two-way teletext” for systems which could be implemented over two-way cable television systems. In addition, hybrids and other transmission technologies, such as satellite, could be used for delivery of videotex services on a national scale.
Source: CableLabs, 9/25/2007  
Viewers Per Viewing Household (VPVH)

A demographic percentage which indicates how many persons per 100 or per 1,000 households are viewing. For example, a VPVH of 80 K2-11 means that for every 100 households viewing, there are an estimated 80 children ages 2 to 11.
Source: CableLabs, 9/25/2007  
Violence Chip (V-Chip)

A term used to describe a microchip which will permit parental control over rated television programs.
Source: CableLabs, 9/25/2007  
Virtual Ccircuit

This term refers to a predefined path through a network that provides a connection-oriented session between two applications.
Source: CableLabs, 9/25/2007  
Virtual Channel (VC)

The communication channel that provides for the sequential unidirectional transport of ATM cells.
Source: CableLabs, 9/25/2007  
Virtual Channel Table (VCT)

Data declared as part of the Service Information standard defined by SCTE.
Source: CableLabs, 9/25/2007  
Virtual Private Network (VPN)

A term that is applied to either voice or data networking. In essence, a VPN is a portion of a public network that has been logically partitioned for private use.
Source: CableLabs, 9/25/2007  
Voice Activation Detection (VAD)

Allows a data network carrying voice traffic to detect the absence of audio and conserve bandwidth by preventing the transmission of “silent packets” over the network. Most conversations include about 50% silence. VAD is also called “silence suppression”.
Source: CableLabs, 9/25/2007  
Voice-over-Internet Protocol (VoIP)

VoIP services are a provision of voice telephony via the use of packet-switched networks running Internet Protocol (IP) networks rather than traditional circuit switching. CableLabs has developed the PacketCable specifications for the delivery of IP-based multimedia services, including voice services, over the DOCSIS 1.1 access network.
Source: CableLabs, 9/25/2007  
Voice-Over-Net (VON)

A term that refers to various sets of technologies that are used to enable voice applications across the Internet.
Source: CableLabs, 9/25/2007  

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z