reading a signal from the paralell port 
Author Message
 reading a signal from the paralell port

Can anyone help me for reading or detecting a signal on the LPT1
i want to connect a swith on the parallel port and i want to detect with vb
if the swith is open or closed.

Vanhooren Franky

Sat, 30 Nov 2002 03:00:00 GMT  
 reading a signal from the paralell port

Depending on what OS and version of VB you are using...

You can download VBASM.ZIP (VB/16, Windows 3.1 or Windows 95/98), or
WIN95IO.ZIP (VB/32, Windows 95) from

Then, use the vbOut routine.  For example,

  vbOut &H378, MyData%

The complementary function is vbInp, to read I/O.

Similar functions are included in Stamina from MicroDexterity; again,
suitable for Windows 95, only.

I have an ActiveX OCX (look for IOOCX.OCX) on my homepage that you can
download that has some extra features that may be of interest.

If you need to do this under Windows NT, you can use a kernel-mode driver,
such as TINYPORT (go to to download this shareware
driver).  Also, there are two commercial add-ons that provide I/O under both
Windows 95 and Windows NT.  You can get information (and order these at a
discount) from my homepage.  Just click on the VBxpert button and look at
DriverX OCX from Tetradyne or WinRT OCX from Blue Water Systems.  These
commercial products also allow read/write access to RAM, and support
hardware interrupts.  There is a similar object, called WinDriver from
KRFTech ( that I am now starting to evaluate.
I have a link to it on my homepage, too.  This is quite a powerful toolset.

You can get detailed information on these things from the book, Parallel
Port Complete, by Jan Axelson.  Check this out on my homepage.  Just click
on the Books link.

Richard Grier (Microsoft Visual Basic MVP)
Hard & Software
12962 West Louisiana Avenue
Lakewood, CO  80228
303-986-2179 (voice)
303-986-3143 (fax)
Author of Visual Basic Programmer's Guide to Serial Communications, 2nd
Edition ISBN 1-890422-25-8 (355 pages).
For information look on my homepage at
Use the Books link to order.  For faster service contact the publisher at

Fri, 06 Dec 2002 03:00:00 GMT  
 [ 2 post ] 

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