GSD files: These shall be checked according to the functionality of the related device and the actual specification of the file. Additionally the GSD file may be processed through a dedicated checker tool (e.g. PROFINET XML Viewer or the GSD Checker tool) or by analyzing the XML content. In the case of PROFINET devices - which use an XML format - further tests are need to ensure that a file meets the XML schema requirements. FDT/DTM and EDD: Certification of FDT/DTM and EDDL are the responsibility of their respective organizations. Tool Calling Interface (TCI): No formal certification is required.