Wiring a receiver (RX) to a RadioMaster NEXUS-XR or original NEXUS flight controller depends heavily on the model you are using and the type of receiver protocol.

The NEXUS-XR features an internal ExpressLRS (ELRS) receiver, meaning no external RX wiring is required for most setups. However, if you are using an external receiver or the original NEXUS (which does not have a built-in RX), wiring it is straightforward.

1. Wiring an External Receiver

You can connect an external receiver (such as an RP3-H, Spektrum, or Futaba) to any of the dedicated ports on the side of the unit (Port A, B, C, or the DSM port).

Using Port A, B, or C (CRSF / S.BUS):

Use a standard 4-pin JST-GH cable to wire your receiver:
  • Pin 1 (TX pin): Signal (e.g., Yellow/Orange wire)
  • Pin 2 (RX pin): Telemetry / SmartPort
  • Pin 3 (V or 5V): Power (Red wire)
  • Pin 4 (G or GND): Ground (Black/Brown wire)

Using the DSM / SBUS Port:DSM Port:

Outputs clean 3.3V power (perfect for DSM satellites).SBUS Port: Typically mapped to UART1 and handles S.BUS signals.

2. Wiring ESC Throttle & Telemetry

Proper wiring of the ESC (Electronic Speed Controller) is crucial for accurate throttle and telemetry data:ESC Port: Plug the 3-wire throttle lead into the ESC pin header on the unit.RPM Wire: The individual RPM signal wire (often yellow) from your ESC plugs into the RPM pin.ESC Telemetry: Plug the telemetry signal wire (or a single-wire connection) into the TLM pin header.

Power (High Voltage ESC): The positive (+) pins on the Nexus pass direct voltage from your ESC. Ensure your BEC voltage matches the limits of your servos (up to 12V).

3. Software Configuration in Rotorflight

After wiring, you must configure the software so the flight controller can read the receiver:Connect the unit via USB to your PC and open the Rotorflight Configurator.Open the Ports tab.Enable the Serial Rx toggle for the UART corresponding to the port you used (e.g., UART 4 for Port A, UART 6 for Port B, or UART 2 for the TLM port).Navigate to the Receiver tab and select the correct Receiver Provider (e.g., TBS CRSF for ELRS/Crossfire receivers, or SRXL2/F.Port for others)