ISO/TS 10303-421:2005 specifies the application module for Functional data and schematic representation. The following are within the scope of ISO/TS 10303-421:2005: the classification, structure, properties and identification of products, activities, documents, organisations and people; The structure of products includes both composition and connection relationships. A composition relationship can be either physical or functional. Similarly a functional relationship can be either physical or functional. Types or classes of relationship are defined in a Reference Data Library. The type of a relationship indicates whether it is functional or physical. schematic diagrams that presents the classification, structure, properties and identification of products, activities, documents, organisations and people by the relative position of symbols; associations between symbols on a schematic diagram and the things that the symbols represent.