R – Best VM for Delphi development with parallel port

Yes, you can send and receive at the same time.

Try this page for using VB http://www.aaroncake.net/electronics/vblpt.htm

And a good page on parallel ports http://www.lvr.com/parport.htm

This site is a good source for programming the parallel port.

The basic idea is that you need a DLL, add-on or library that allows you to access the I/O Ports of the PC. For Windows XP on up you need a specific driver that will allow you do this as the OS doesn't offer access out of the box.

The Parallel port will generally reside at one of three address 278,378, 3BC. This port. have the bytes you are reading or writing.

The (base)+1 port allows access to the status bytes. IE. 279,379, 3BD

The (base)+2 port allows access to the control bytes. IE. 27A,37A,3BE

The parallel port documentation will tell not only how to implement the common modes (like bi-directional) but how to control the port at the byte level to implement your own custom.

Back in the day there was only the standard mode available. You pump out your bytes at the (base) port. Some application, like mine, manipulated individual bits of that ports as form of cheap Digital I/O Controller. We did use the status and control bytes as additional inputs and outputs. There were commands you can send to the Parallel Port chip configure the modes precisely.

Today there are are hundreds of sites with example of using the Parallel Port to solve all kinds of problems. I would be surprised that one of doesn't have something you can use for you specific application.

Again the book I recommend starting with is Parallel Port complete. It tells just about everything you need to start with. If your application is too esoteric for that book it will give a springboard from which you can find the exact setup you need.