XL RTK & RX pin options

Hi Drotek Team,

one more question. I’ve searched through the forum and found some relevant topics, but still could not form a complete understanding (probably because in these topics there were links to some schematics that do not work anymore).

An XL RTK module features Telemetry and Rover ports.

  1. TX of both is the same, it is connected to the TX of UART1 on M8P chip.
  2. It is defined by the switch if the Tel RX or the Rov RX is connected to the RX of UART1 on M8P chip.

What I lack to understand is how the use of BOTH (in case of separate Autopilot and RTCM corrections receiver devices) is possible?
With the M8N based version we used the only connector for autopilot and it was connected to UART1 of M8N. The same would make sense with M8P.
The RTCM corrections should as well arrive to the UART1 of u-blox.

So what are physically these 2 separate information channels into u-blox (if I get it right that they are separate)? Could you share some schematics that would explain the situation?

Best Regards,


Please use only the rover connector if your RCTM corrections arrive from your autopilot.
The telemetry port on RTK XL is necessary when you want the standalone mode with a telemetry radio kit between the rover and base modules.

Hi Jerome,

thanks for the fast answer. Just a minor summary from my side to make completely sure I understand,

the setup using the “telemetry” port looks like the following:

  • “Rover” port is connected to the autopilot that can or can not do RTCM corrections.
  • “Telemetry” port is connected to the radiolink (if any) to the base receiver “on the ground”.
  • The switch allows us to hard way (between the flights) switch our overall setup between 2 modes:
  • “talk to autopilot and do the standalone GPS, or even RTK, if autopilot can provide RTCM”
  • “do not talk to autopilot, just compute and spit out (to everything that is connected to tx pin, e.g. to autopilot) GPS in the preconfigured mode using the RTCM corrections from the radio channel”

Is that correct?

Actually, there are 2 different modes:

  1. Drone mode: you connect the autopilot to the rover connector of the rover GPS.
    you connect the base GPS to your laptop with QGC and USB cable.
    Then, you use your telemetry radio between laptop and autopilot to send RTCM corrections.

  2. Standalone mode: you connect your telemetry radio to telem connector on base/rover GPS. The base sends RCTM corrections to the rover via this communication way.

I hope it’s more clear.

OK, thanks Jerome.

Best Regards,