本书针对通信软件的特点,介绍了几种适用于通信软件需求分析阶段和设计阶段的形式化语言,包括通用建模语言UML,消息跟踪语言MSC和规格说明与描述语言SDL,重点介绍了在电信领域得到广泛应用的SDL语言.并以设计一个微型交换机软件为例,说明如何运用这些形式化语言进行通信软件的需求分析,概要设计和详细设计。-The book for the characteristics of communication software, introduced several applied to communication software requirements analysis stage and design stage of the formal language, including the Universal Modeling Language UML, message tracking language MSC and specifications and descr iption language SDL, highlighted in the the field of telecommunications has been widely used SDL language. and to the design of a micro-switch software as an example to show how to use these formal language for communication software needs analysis, outline design and detailed design.