Graupner SUMD/HOTT Notes
For SUMD (preferred protocol) make sure the receiver is setup in the radio as SUMD OF #no channels and connected to the external radio connector (spektrum connector). Use 5V from another pin or use the Telemetry Connector with 5v from the DIMU serial port.
The #no channels can be anything between 6 and 18 channels, for a MX20 set the number on 12. This will make a setting of SUMDOF12. The SUM signal on HoTT receivers will always be connected to channel 8.