Hello Simon, the baud rate is set in the app to 9600. my problem with the new app version is that I can not connect to Teensy when I select the correct com port. I still try to understand what the problem is. somehow i wonder that it looks like that this problem is only on my end. even when i run a vm on win10, i have exactly the same issue. anyway, I will post an update once i have some news on this. br Martin

minor update: when I try to save the config, i get an error in console: (ar4-py37) PS C:\........\Annin Robotics\AR4 HMI interface source> python .\AR4.py Exception in Tkinter callback Traceback (most recent call last): File "C:\.....\anaconda3\envs\ar4-py37\lib\tkinter\__init__.py", line 1705, in __call__ return self.func(*args) File ".\AR4.py", line 4262, in SaveAndApplyCalibration toolFrame() File ".\AR4.py", line 4012, in toolFrame ser.write(command.encode()) NameError: name 'ser' is not defined note about the windows exe app: when i run the exe version, only a small window starts and the curser spins but the main app is not started.