The calculation programs of the German Research Association for Gears and Transmissions were developed at the leading German instituts and are able to calculate nearly all aspects of a gear unit. For the automatic data exchange between these programs a standardized interface was created. Based on the standard ISO 10303 ‘STEP’ [1] a product model for gear units was developed at the Gear Research Centre (FZG) of the Technical University of Munich to realize a central data base. Meanwhile this product model is published as VDMA guideline 23900 [2]. A converter program enables the connection to the FVA programs. Additionally this converter program includes a data interface to CAD systems.