Why? Well I'm an expert in comms protocols, I implemented serial protocols in embedded systems for many years. That's why someone has asked me to implement a difficult legacy protocol, and it cannot be done using ordinary serial port drivers because of the Sync Trauma requirements.
It would be very straightforward if I could access the UART registers directly, indeed I have done this on a micro controller with an 8250 like UART. But ideally I want to do this directly with a PC serial port, but I'm no expert on windows

Now googling a bit I soon found both InpOut32 and WinIo. Everydody says these will allow direct port access, but I can't make either work. All I get is 0xFF from the serial I/O space, can't even use the scratchpad register (base + 7).
Again, googling around, I see a lot of people with the same problem. And everybody says it 'should' work, but nobody seems to have concrete success stories.
I note also that while many people are using these drivers, the primary use is for paralell port access.
So, I'm wondering, is it really possible to access the serial port with these devices?
Does anybody have concrete success?
(Note, I am talking about real serial ports, i.e. COM1 with base address given as 0x3f8 in device manager, and I have tried with the port activated and non activated, and the port does work. )