I tried to test the different COM Interfaces using managed code.
I used API functions to list the available Interfaces and get COM1, COM2 and COM3.
I guess, UARTA is COM1 and so on.
I see signals coming from UARTA_Tx and UARTB_Tx, but UARTC_Tx alias COM3 doesn’t work.
I also checked the registry and found out, that the pin numbers were listed correct.
It isn’t neccessary to configure the GPIO Pins to function as UART signals for UARTA or UARTB, so I guess it is also not neccessary for COM3, but maybe this is wrong.
With best regards