| Term |
Definition |
| V |
Volt. |
| VBR |
Variable Bit Rate - Traffic containing bursts but centered around an average bandwidth. VBR, divided into real-time (RT-VBR) and non-real-time (NRT-VBR) traffic requires the same service guarantees (that is delay, cell loss and timing) provided by CBR. |
| VBR-NRT |
Variable Bit Rate Non Real Time - One of the two VBR service types for transmitting traffic where timing information is not critical. Since this service type is delay tolerant, it is well suited for bursty traffic such as data communications. |
| VBR-RT |
Variable Bit Rate Real Time - One of the two VBR service types for transmitting traffic that depends on timing and control information. It is suitable for carrying delay sensitive traffic such as packetized video and audio. |
| VC |
Virtual Circuit - VC define a point-to-point connection between two nodes in a network. A single ATM cellcarries data that belongs to a single VC. |
| VCA |
Voltage Control Amplifier. |
| VCC |
Virtual Channel Connection - An end to end connection consisting of a concatenation of two or more Virtual Channels between two end points. VCCs may be bundled into a VPC. |
| VCF |
Voltage Control Filter. |
| VCI |
Virtual Channel Identifier - This is the label given to an ATM VC to identify it and determine its destination. The VCI is a 16-bit number that is included in the header of an ATM cell. |
| VCO |
Voltage Controlled Oscillator. |
| VCSEL |
Vertical Cavity Surface Emitting Laser. |
| VCXO |
Voltage Controlled Crystal Oscillator. |
| VDC |
Volts Direct Current. |
| VDD |
Virtual Device Driver. |
| VDLS |
Very high speed Digital Subscriber Lines. |
| VDMOS |
Vertical Double-diffused Metal Oxide Semiconductor. |
| VDN |
Virtual Data Network. |
| VDSL |
Very high bit rate Digital Subscriber Line - An ultra high-speed type of DSL that can deliver data communication at speeds up to 52 Mbps in close proximity to a central office. |
| VeDSL |
Voice-enabled DSL - A technique developed by Aware to deliver dedicated 64 kbps channels of voice over the DSL physical layer that does not require packetization of voice data into higher-layer protocols such as ATM and IP. |
| VF |
Voice Frequency. |
| VFC |
Voltage to Frequency Converter. |
| VFO |
Variable Frequency Oscillator. |
| VHF |
Very High Frequency - Transmission frequencies in the range 30 to 300 MHz. |
| Video on demand |
A pay-per-view television service in which a viewer can order a program from a menu and have it delivered instantly to the television set, typi-cally with the ability to pause, rewind, etc. |
| Video Signal |
A signal having the frequency range normally required to carry visual information. The range is 1 to 6 MHz. |
| VIO |
Virtual Input/Output. |
| Virtual Circuit |
A connection which "appears" and "performs" as if a physical connection exists between source and destination even if one does not. |
| Virtual Path (VP) |
A unidirectional logical connection between two ATM devices. |
| VLAN |
Virtual LAN - A network architecture which allows geographically distributed users to communicate as if they were on a single physical LAN by sharing a single broadcast and multicast domain. ATM forum LAN emulation supports VLANs. |
| VLF |
Very Low Frequency - The portion of the electromagnetic spectrum with frequencies between 3 and 30 KHz. |
| VMOS |
V-groove Metal Oxide Semiconductor. |
| VOA |
Video Over ATM - Specifications and standards to provide enhanced quality video services carried over an ATM network. |
| VoDSL |
Voice over DSL. Any technique that transports voice over the DSL physical layer protocol over a copper pair. This includes VeDSL as well as packetized solutions such as Voice over ATM over DSL and Voice over IP over ATM over DSL. |
| Voice Digitization |
The conversion of an analog voice signal into digital symbols for storage or for transmission. |
| Voice Frequency |
The range frequencies normally considered necessary for the effective transmission of human speech. Typically 300 to 3,400 hertz. |
| Voice Grade |
A term used for twisted-pair cable used in telephone systems to carry voice signals. |
| Voiceband |
A transmission service with a Bandwidth considered suitable for transmission of Audio signals. The frequency range is generally 300/500 to 3000 Hertz. |
| VoIP |
Voice Over Internet Protocol. |
| VPI |
Virtual Path Identifier - A virtual path determines the way an ATM cell should be routed. The VPI is an 8-bit (in UNI) or 12-bit (in NNI) number that is included in the header of an ATM cell. |
| VRAM |
Video Random Access Memory. |
| VTAM |
Virtual Telecommunications Access Method. |
| VTOA |
Voice and Telephony over ATM - ATM forum group developing standards for voice trunking, signaling, and N-ISDN interworking. |
| VVMOS |
Vertical V-groove Metal Oxide Semiconductor. |
| VXO |
Variable crystal Oscilator. |
