@metamaarten Thanks for the tip. That was indeed the case. After flashing it with CodeLoadBC95HB.bat (available here in software: https://docs.t-mobile.nl/s/Huvmz5cSzciPtlv) I was getting proper output at 9600 bouw at the main tx/rx pins.
Unfortunately, @ericbarten is also right, there is a BC95-B5 on the board,m wich is not going to work in europe, BC95-B8 is required, so I guess it’s back to the drawing board for me…