So I'm trying to detect through Visual Basic 6.0 when a voltage change occurs on one of the pins of the serial/parallel port. The whole thing is pretty simple; no data transfer/handshaking/etc ...

When released in 1991, Visual Basic (VB) was similar to Microsoft's QuickBASIC. Because of its graphical interface, VB became very popular, and after migrating to Visual Studio .NET in 1999, VB 6. ...