电信专业英英词典V（在线收听）

　　VAD

　　value-added distributor

　　VAN

　　value-added network

　　VAR

　　value-added reseller

　　VBR

　　variable bit rate

　　VCI

　　virtual circuit identifier

　　VCS

　　virtual circuit switch

　　Very Small Aperture Terminal (VSAT)

　　VSATs are earth terminals using small antennas (1.5 6 feet in diameter). This technology typically operates in the Ku band (11/14 GHz), and Ka band (20/30 GHz).

　　Video Conferencing

　　Video conferencing is the real-time, usually two-way transmission of voice and images between two or more locations. Today, both voice and video analog signals are digitized by video codices before transmission which can involve wide bandwidths. To conserve bandwidth, some systems employ "freeze frame," where a television screen is only "repainted" every few seconds. Codecs for higher quality full motion video attempt to minimize bandwidth requirements by taking advantage of intervals with relatively little motion (which require smaller bandwidths), and by trading off smooth motion tracking and picture resolution.

　　Virtual Private Networks (VPN)

　　VPNs are services using public network facilities augmented by network control point and service management system facilities wherein traffic is routed through the public network under computer control in a manner that makes VPN service indistinguishable from dedicated facilities based private networks. Customers can define, change and control network resources with the same or more flexibility as afforded by facilities based private networks.

　　VPI

　　virtual path identifier

　　VPN

　　virtual private network

　　VRU

　　voice response unit

　　VSAT

　　very small aperture terminal

　　Virtual Host - A Web site that includes a customized Domain Name and unique IP address to your home page, giving the appearance that you have your own server directly connected to the Internet.

　　VoIP  -  (Voice over Internet Protocol)  -  A technology used to transmit voice over a data network using Internet Protocol, such as the Internet or intranet networks.