Why is the TELEM2 port different?

Hi there,
I wanted to connect an esp32 to the pixhawk4 via Mavlink. Everthing works on the TELEM2 port, I can request and read data streams etc. but with the other TELEMx it’s not working.
I only receive the heartbeat. I tested it on three different pixhawks.

The baud rate is the same on both devices and the protocol is set to mavlink1. I also changed the baud rate to slower speeds but even then, only TELEM2 works. Different pins on the ESP32 side were tester as well without success.
I have run out of ideas now…

(I noticed the voltage on pin TELEM2 (tx) is not constant when I measure with my voltage meter, while on all other TELEM ports it is constant)

Can someone help me please? I would be very happy

Please copy the SR1_* parameters to SR2_* parameters.

problem solved:

  • the TLEM1 port obeys the SR1_* stream rates
  • the TLEM2 port obeys the SR2_* stream rates

Hi @amilcarlucas,
thanks for your help, I now get telemetry data on the other ports as well! But I still don’t understand it. Why does the pixhawk not obeys my requested stream rates, only the ones in the parameters? Something wrong with my request? Do I have to change the request code somehow depending on the telemx port?


I think that is not implemented. What is implemented is per message interval requests

And that one is much better and fine granular than SR*_ parameters and MAV_REQUEST_DATA_STREAM

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