Connection via LPT

Hi, anas.
You have no need of any Delphi components in order to work with LPT. For every LPT there are three IO addresses (Ports) which are: Data port, Status port and Control port. They are as follows:
 
for LPT1:
$378 - Data port (Read/Write)
$379 - Status port (Read)
$37a - Control port (Read/Write)

for LPT2:
$278 - Data port (Read/Write)
$279 - Status port (Read)
$27a - Control port (Read/Write)
.

If you are using Delphi1 or Delphi2 you should use code like this:

Port[xxx]:=SomeValue;   //  in order to write SomeValue to IO port #xxx
SomeVar:=Port[xxx];      //  in order to read IO port #xxx into SomeVar
.

If  you are using any 32 bit Delphi (Delphi 3 or Delphi 4) you should use this:

// to write SomeValue to IO port #xxx:
asm
  mov DX, xxx;
  mov AL, SomeVal;
  out DX, AL;
end;
.
// to read port #xxx into SomeVar:
asm
  mov DX, xxx;
  in AL, DX;
  mov SomeVar, AL;
end;
.
Where: xxx : IO port number
           SomeValue: Byte type value;
           SomeVar:     Any Integer type variable;

NOTES:
1.All this stuff will not work if your OS is WindowsNT, because it doesn't allow direct access to such resources as IO ports.
2.The meaning of every bit in Status and Control port is fully described in literature.  

Hi  Fatman

You have mentioned my problem in your NOTES   ( Yes I'm working with WINDOWS NT4)

I do work with DELPHI 3

there's a good component called tvichw32 probably here
also one called tserial i think that does nt lpt ports
http://sunsite.icm.edu.pl/delphi/
or
 www.torry.ru/

comes with good examples etc and is fine for nt
(it maybe shareware cant remember)
Regards Barry

Hi Anas nice to see you here, I'm interested in your quesion, so I'll check for notification.

Motaz A. Azim