Standardized languages for telecommunication systems

In this paper, we give a survey of the most important ITU-T languages used in the system modeling and development process. We discuss the goals, the most important features, and the basic syntactic and semantic rules of the languages and notations. We compare the capabilities of the ITU-T languages and the OMG's Unified Modeling Language, considering the modeling and development aspects they support. At the end of the paper, we give an informative example to demonstrate the use of the languages during the different phases of the development process.