电子专业英语part课件.pptVIP

ISDN is rapidly growing in popularity and is widely accepted in industry as the way to access multimedia over a network. Although it is still expensive when compared to a standard line, it is still cheaper than an ATM connection. ISDN在工业上被广泛接受为网络上访问多媒体的主 要方法。和标准线路相比，它偏贵，但比不转移模式便宜很 多。 access standard line ATM: ATM (Asynchronous Transfer Mode ) is a method of communication which can be used as the basis for both WAN (Wide Area Network ) and LAN technologies. It is being developed by a forum of over 300 companies. ATM was designed to allow the transmission of different types of information such as data, video, voice, simultaneously. 异步转移模式：是一种既可以用于广域网又可以用于局域网的通信方 法。 它可实现：同时传输数据、视频、语音等各种类型的信息。 异步转移模式：ATM (Asynchronous Transfer Mode ) 广域网：WAN (Wide Area Network ) 局域网：Local Area Network (LAN) This means a dedicated bandwidth for each connection, and flexible access speeds. When a connection to send data is set up, the sender specifies various attributes, such as the type and speed of the call. Information sent via ATM is divided into fixed length cell, consisting of a header and the actual data. The ATM Forum can be found at: http: ///. ATM的设计要实现每个连接享有独立的带宽和灵活的访问速度。在 建立发送数据的连接时，发送端指定各种属性，通过ATM发送的信息被分 成一些固定长度的信元，信元包含信元头和具体数据。具体可查阅相关论坛。 access speed ATM Forum Fiber Distributed Data Interface Integrated Services Digital Network multimedia application Asynchronous Transfer Mode local area network Wide Area Network standard leased line dedicated bandwidth random time interval twisted pair 综合业务数字网 分布式光纤数据接口 随机时间间隔 标准租用线 局域网 广域网 独立带宽 双绞线 多媒体应用软件 异步传模式 Exercise: Unit 17 Optical Communications 光纤通信 A main indicator technological advancement of optical communications in the past 30 years is the annual growth in transmission capacity, which is physically reflected in the progress made three aspects: the optical appliance, multiple multiplexing modes and novel optical network protocols. 过去30年光纤通信技术发展的主要标志是传输容量的逐年增长， 这主要是表现在三个方面：光器件、多种复用模式和新颖的光网络协 议