同步数字系统：synchronous digital hierarchy

国际标准：international standard

信号格式：signal format

网络节点接口：network node interface

支路信号：tributary signals

数字交叉连接：digital cross-connection

网络管理：network management

网络维护：network maintenance

网络运营者：network operators

传输速率：transmission rate

支路映射：tributary mapping

灵活性：flexibility

用户业务：subscriber services

覆盖层：overlay levels

制造商：manufacturer

同步传输帧：synchronous transmission frame

线路终端复用器：line terminal multiplexer

分插复用器：add-drop multiplexer

再生中继器：regenerator

灵敏度：sensitivity

虚容器：virtual container

成帧字节：framing bytes

段开销：section overhead

端到端传输：end-to-end transmission

误码监视：error monitoring

信号处理节点：signal processing nodes

净负荷：payload

指针：pointer

同步传输系统：synchronous transmission system

覆盖NNI 的标准：the standard covering the NNI

国际标准接口：the international standard interface

直接同步复用：direct synchronous multiplexing

灵活的通信联网：flexible telecommunication networking

点对点的传输技术：point-to-point transmission technology

先进的网络管理：advanced network management

不同厂家提供的设备：the equipment supplied by different manufacturers

提供的灵活性：the flexibility provided by SDH

同步复用设备的运营者：operator of synchronous multiplexers

电信联网：telecommunication networking

支路信号：tributary signals

维护能力：maintenance capabilities

统一的电信网络基础结构：unified telecommunication network infrastructure

组件：building blocks

终端复用器：terminal multiplexer

贯通方式：through-mode fashion

同步数字交叉链接：synchronous DXC

可变带宽：varying bandwidth

各个支路信号：individual tributary signals

传输系统：transport system

光载体：optical carrier

二维图形：2-dimensional map

传输次序：the order of transmission