As root, I ran this command
devc-ser8250 -b 1200 -u 3 port 1E0 &
and QNX 6.x mounted 2 serial ports in /dev: ser3 and ser4. Why did I get two?
Secondly, when I connect my line monitor to the uart starting at 1E0 I can only talk to it by writing to ser4, not ser3 as I would expect.
Thirdly, is there a command to display the settings for a port?