to describe the dynamic behavior of a system. ASN.1 Abstract Syntax Notation One. An ISO standard to describe data types that can be used within SDL. TTCN-3 Testing and Test Control Notation version 3. A testing language standardized by ITU-T and written by ETSI. Unified Modeling Language A generic modeling notation. A profile has been standardized based on SDL. See also Specification (technical standard) Specification language Ivar Jacobson References External links ITU Languages and general software aspects for telecommunication systems SDL Forum Society List of SDL tools Formal specification languages ITU-T recommendations Diagrams Software modeling language Telecommunication protocols