FrSky telemetry

If you are not a developer: Use the user guide:

The frsky_telemetry app emulates a FrSky sensor hub (FSH-01) by periodically sending data packets on the specified UART device. The serial ports wiring page shows the mapping between NuttX /dev/ttyS_ and UART ports.

Supported data

The app currently sends the following data back to the transmitter:

  • Every 200ms:
    • acceleration values (X-Y-Z)
    • barometer altitude (vario)
    • temperature
    • battery voltage & current
  • Every second:
    • course
    • latitude
    • longitude
    • ground speed
    • altitude (GPS)
    • remaining battery level
  • Every five seconds:
    • GPS date & time


This guide expects you to use one of the older "D" receivers which support connecting the FSH-01 sensor hub. Connecting the PX4 to one of the new Smart Port (S.Port) receivers is untested and may or may not be possible.

A TTL-to-RS232-converter is required to connect a FrSky receiver to a PX4FMU UART.

A ready-made D4R-II telemetry cable for Pixhawk is available from Craft and Theory.


The following diagram shows the wiring required to connect a D4R-II receiver using a FrSky FUL-1 converter. It is however possible to use any other RS232-converter.


usage: frsky_telemetry start [-d <devicename>]
       frsky_telemetry stop
       frsky_telemetry status

Pixhawk (version 1 and 2)

To start the frsky_telemetry app on the Pixhawk SERIAL5 on startup, create a file called /etc/extras.txt on your SD card with the following contents:

# Start FrSky telemetry on SERIAL4 (ttyS6, designated "SERIAL4/5" on the case)
frsky_telemetry start -d /dev/ttyS6


For the older PX4 FMU module, please use UART5 on startup, create a file called /etc/extras.txt on your SD card with the following contents:

# Start FrSky telemetry on UART5 (ttyS2)
frsky_telemetry start -d /dev/ttyS2


The frsky_telemetry app has been developed using a FrSky Taranis transmitter but should be compatible to every transmitter supporting the display of FrSky telemetry data.

It is recommended to use a recent OpenTX firmware on your transmitter. You can then use the “Telemetry” page of the model setup to adjust the displayed telemetry data fields to your needs.

Please refer to the corresponding section in the OpenTX user manual for details.

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