Same pinout for XL RTK and Sirius RTK?


I’m just deciding on what to buy for an RTK setup. I have a question:

Why is the XL RTK connector B pinout different to the Sirius RTK connector A pinout? The RX/TX lines appear to be swapped…

I am trying to plan what I have to do to combine various components.

Many thanks for your help.

Both of them have the same connector because they have to be compatible with the Pixhawk 3.