, evildictait​or wrote

Hang on; since serial ports are handled by the Microsoft class driver, rather than by individual device drivers, are you sure you can't just ask for permission to talk to the class driver and open it as a character device for in/out access?

Not that I can tell.  Now, I am not an expert on the subject by any means, but I have given it the ol' college try and searched extensively with no luck.  Particularly, the following MSDN article suggests that serial drivers are not supported:  http://msdn.microsoft.com/en-us/library/windows/apps/hh464945.aspx.