Running different MAVLink protocol version on different TELEMx port independently

Hello everyone,

I got one small issue regarding MAVLink telemetry function between Holybro pixhawk 4 and Radiolink AT10II RC transmitter. I think this is a general problem for many people which their RC telemetry only can understand MAVLink version 1.
Here below is my current configuration data.

  1. QGroundControl v4.0.5
  2. Holybro pixhawk 4 with PX4 Pro V1.10.1 stable release
  3. a Radiolink PRM-03 telemetry module connected at TELEM1 port, the other end of PRM-03 connected to R12DS RC receiver. So, I want my quad’s GPS and Yaw/Roll/Pitch, etc. information will display in my RC transmitter LCD display.
  4. a pair of radio telemetry, one connected at TELEM2 port of pixhawk 4 and the other connected to USB port of my laptop.
    This was working fine before QGroundControl software and pixhawk 4 firmware upgraded to latest version, v4.0.5 and V1.10.1 respectively. It still working if QGC connects to FC through USB directly.
    But, my RC transmitter stop updating realtime GPS and above mentioned information when if the QGC connected with FC through radio telemetry.
    After spent some time on this problem, I realized it was due to that the QGC and FC are communicating with each other using MAVLink 2 protocol, MAV_PROTO_VER=0, and this forces all telemetry ports bond at version 2, but the RC telemetry only understands version 1. If I set MAV_PROTP_VER=1 which set all telemetry always using version 1, my RC transmitter will show my quad’s GPS information.

So, I am wandering if it is possible to tune PX4 in pixhawk 4 so that each telemetry port can run different MAVLink version independently. Maybe this is already implemented but just QGC does not expose the option to us, If anyone know how to do it please advise.
If it is not possible now, maybe the develop team can consider it for future release.

Anyhow thank you very much for reading.


Edward Su

1 Like


Have a similar issue where Mavlink1 is required on Telemetry port 2, and Mavlink2 on Telemetry 1

Did you find a work around for this?