Serial ports Pixracer

I have pixracer with GPS to GPS port, telemetry to telemetry1, OSD to telemetry2 and I want to connect second GPS. At is the second GPS port on SERIAL4_ What is the label of this hardware connector?
Thank you

It should be the FrSky port labeled on the board.

I’ve tried to connect a second GPS to the Serial 4 / FrSky port but even though the serial mapper says the port is configurable, I cannot connect the GPS unit successfully. I can connect the GPS to serial 1-3 (TELEM1, TELEM2, and GPS labeled ports on the board).

Have you successfully connected a GPS to FrSky on Serial 4?

I think the Pixracer FrSky port has an internal inverter, unlike the other serial ports.