This International Standard establishes a common framework data structure for unambiguous identification in RTTT/ITS systems. It excludes any physical aspects such as interfaces. It is neither frequency- nor air interface protocol-specific. Data elements that form part of transmission or storage protocols such as headers, frame markers and checksums are thus excluded. The specifications for protecting against changes, classifying and qualifying security aspects of the data structure elements are not included within this International Standard. The principles of data element structure and description determined in ISO/IEC 8824, ISO/IEC 8825-1 and ISO/IEC 8825-2 have been adopted to provide an interoperable architecture within a standard framework according to guidelines from ISO/TC 204 and CEN/TC 278. This International Standard defines data structures based on the ISO/IEC 8824-1 ASN.1 UNIVERSAL CLASS types that may be directly IMPORTED to other application standards that would need only subsets of the full APPLICATION CLASS types. These UNIVERSAL CLASS and APPLICATION CLASS types are uniquely defined as an ASN.1 module in Annex B. This module may be directly linked into an application data definition. This International Standard defines default encoding for simple AVI/AEI applications where no other relevant application standard exists. This definition forms Clause 4.