Spektrum SPM1200 - Manual (Page 9)

Receiver Channel Usage
Port 1 – Battery and telemetry options
Port 2 – CH1 Steering
Port 3 – CH2 Throttle
Port 4 – CH3 Auxiliary channel or personal transponder
Note: Align the servo leads so the black wire is towards
the outside edge of the receiver case.
Channel Assignments
9
Auxiliary
Throttle
Steering
Battery
Bind Button
LED Indicator