Hi Bart,
our software expects a Modbus RTU connection with either 19200 or 115200 baud with the DSE answering on either unit id 1 or 10. You can check the logs with tail -F /var/log/dbus-modbus-client.ttyUSB0/current | tai64nlocal. You might have to adjust the device to ttyUSB1 or ttyUSB2 etc., that depends on your system.
Good luck!