Presentation of the history of the ISYBAU interface and presentation of optimized quality assurance measures as part of a BVBS initiative. Many special features of drainage can in principle be transferred using this interface, but in some cases there are no binding specifications and considerable scope for interpretation. As part of a BVBS working group, several software companies have agreed on specific procedures and content for quality assurance in data exchange. This will ensure even better quality of interaction between different solutions in the future.