X20/X20S and Ethos v1.0.11 User Manual
Tap on Options:
Options
Telemetry 25mW: Checkbox to limit telemetry power to 25mW (normally 100mW),
possibly required if for example servos experience interference from RF being sent
close to them.
High PWM Speed: Checkbox to enable a 7ms PWM update rate (vs 20ms standard).
Ensure that your servos can handle this update rate.
Port: Allows selection of the SmartPort on the receiver to use either S.Port, F.Port
or the F.Port2(FBUS) protocol. The F.Port protocol was developed with the
Betaflight team to integrate the separate SBUS and S.Port signals. F.Port2(FBUS)
also enables one Host device to communicate with several Slave devices on the
same line. For more information about the port protocol, please refer to the
protocol explanation on the official FrSky website.