The ASAM standard has identified subsystems within automation and measuring systems as well as standard interfaces between these subsystems. One of these interfaces, called GDI (Generic Device Interface), defines the connection to measurement devices and intelligent subsystems. ASAM-GDI ensures the interoperability of real-time subsystems by separating the implementation code of device drivers and their interface descriptions, called DCD (Device Capability Description). DCD describes an object-like interface of procedural real-time components (device drivers) using the DCD language. In this paper it is shown how the DCD language and its constructs can be mapped to UML notation using the standard UML extension mechanisms. Advantages of modeling DCD using UML are numerous: uniform and standard graphical representation of device capabilities, improvement in DCD development, straightforward extension of DCD using UML notation, standard exchange text format of DCD documents using XMI (XML Metadata Interchange), etc. The definition of UML extensions for DCD contributes to the acceptance of the ASAM-GDI standard and simplifies the development of ASAMGDI tools in the future. It is also an example how similar constructs, i.e. blocks with inputs and outputs, can be specified using UML.