This paper introduces a case study of a driver terminal product family. The terminals are used for fare collection in public transportation. The case study applies the QADA architectural design and analysis method in documenting and evaluating the portability and maintainability of existing architecture. During this case study it was found out how to improve the architectural descriptions of the QADA method for better quality evaluation support. In addition, evaluation revealed risky points of architecture that were improved with separation, compression and abstraction.