No, but I found the reason of the problem: The USB-to-Serial adapter cable I mentionned has different voltage levels for the logical 0s and 1s so it was not compatible with original COM ports.
...

Thanks for your suggestions, jephthah!

I used the Windows HyperTerminal program to test both COM ports. The protocol I am using is really simple, I write the string "mem" to the port and receive...

Sorry, but this link isn't very useful. There are no C code examples either, only VB.NET and C#.NET.

Hi there,

recently I wrote a small C program utilising the Windows API to communicate with a device over the serial port (COM1, a real serial port of my PC).

This worked fine, but I am aware...