This project has been realised for company D. Reinhardt GmbH in Solms, Germany. The adapter interface various route guidance systems (PNA) to car radio systems.
Up to now it might happen, that the car driver missed to hear an announcement of the PNA because of listening radio or CD. To solve that problem, the adapter mutes the audio signal of the radio and amplifies the message of the PNA by switching it to the front loud speakers simultaneous.
The system could be used also for blue tooth mobile phone applications, if the PNA assist that function.