现代通信和网络技术及产品词汇(英文).doc

现代通信和网络技术及产品词汇(英文) 词 汇 表 术语 定义 Access Line The physical telecommunications circuit connecting an end user location with the serving central office in a local network environment. Also called the local loop or last mile. See also Local Loop. Access Network That portion of a public-switched network that connects access nodes to individual subscribers. The access network today is predominantly passive twisted pair copper wiring Access Nodes Points on the edge of the access network that concentrate individual access lines into a smaller number of feeder lines. Access nodes may also perform various forms of protocol conversion. Typical access nodes are DLC systems concentrating individual voice lines to T-1lines, cellular antenna sites, PBXs, and ONUs. Access Rate The transmission speed of the physical access circuit between the end user location and the local network. This is generally measured in bits per second; also called Access Speed. Adapter See Adapter Card. Adapter Card Circuit board or other hardware that provides the physical interface to a communications network; an electronics board installed in a computer which provides network communication capabilities to and from that computer; a card that connects the DTE to the network. Also called a Network Interface Card. See also Data Termination Equipment and Network Interface Card. ADSL Forum The organization developing and defining xDSL standards, including those affecting ADSL, SDSL, HDSL, and VDSL. Members participate in committees to vote on ADSL specifications; auditing members receive marketing and technical documentation. ADSL Transmission Unit - Central Office The ADSL modem or line card that physically terminates an ADSL connection at the telephone service providers serving central office. ADSL Transmission Unit - Remote The ADSL modem or PC card that physically terminates an ADSL connection at the end users location. Always On Current dial-up services require the user to make a