An abstract syntax is a description of a data structure that is independent of hardware structures and transmission methods. The abstract syntax links two corresponding application instances in the source and target systems.
The syntax describes which data types and values are used, how they are to be structured and exchanged. Since these structures are usually very complex, a language for describing abstract syntax was developed and standardized by the International Standards Organization( ISO) under the name Abstract Syntax Notation One( ASN.1).
The International Telecommunication Union( ITU) has standardized abstract syntax under X.409, X.208 and X.209, and the International Standards Organization (ISO) under standards 8824 and 8825.