in reply to Re^2: Accessing Serial port on windows and Linux
in thread Accessing Serial port on windows and Linux
By using ioctl, at least on Linux. The various serial port modules take care of that when you use them. I think Windows has something similar, RTFM. In the worst case, you get the OS defaults for the port.
Note that /dev/S01 is usually not your first serial port. That would be named /dev/ttyS0, and the second one /dev/ttyS1. USB converters usually appear as /dev/ttyUSB0, /dev/ttyUSB1, and so on. (/dev/S01 seems to be a typo or a system-specific device.)
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)