Hi, I tested sounddiver on the rest of my setup and realised that there are other problems: Oberheim Matrix1000: sounddiver receives data but cannot send properly, the Matrix wont recognise any messages. Again it seems that one byte is missing: the checksum byte. Peavey PC-1600 is working good! (no checksum used in this adaptation...) Oberheim Microwave XT is also doing good. So my guess is that any bank manager Adaptation using a checksum will fail...