Hi Asic1984,
If you use NT technology (Win2000, XP) the frendly instructions
inport and outport
dont work anymore (like in win98 for example).
(to see haw they previously work under win98, and a discusion abaut SPP, EPP protocols modes plz see post )
In NT you must use a kernel driver to comunicate with HW.
Those drivers must be first instaled on your PC .
Then you can use Win API functions to comunicate with kernel driver from C++
In C# you cannot call directly any "unmanaged" API functions!!
Therefore in C# you must use PlatformInvoke to "manage" them!
This is not a trivial task!
Also note that Paralel port is a "legacy" device (read: no future).
Therefore is highly recomended to use other bus (USB for instance).
Also some controls pins are inverted in SPP mode , and some hand-shake pins are active low in EPP mode, that's why you observed some "inverted levels" at conector (this is normal). For protocol details see Paralel Port standard.