Hi @qojote
Sorry for the delayed answer. I could reproduce the behaviour.
Actually when you set RTS active low, then the output on Ixora is high, since there is a Inverter integrated in the RS-232 Line Driver which is on the board.
Regarding your issue, you are right, the RTS is high only after setting up the IoCtl and some time after the transmission has finished, which is not what you want.
It seems this is a bug, as reported here. The solution seems to be use the mainline kernel driver, where you can use the RTS_Pin being any gpio. You need to check if this fits your requirements, since changing a GPIO through the driver (software) will take more time the hardware. In this case, the recommendation will be to add a inverter on your carrier board.
Best regards,
Jaski