Send and Recieve by parallel port.

[smorteza]

Hi.
I need an example program to send and recieve data using parallel port.
Thanks.

 

[Griffyn]

Educated guess here.... Have you tried assigning a file variable to LPT1? I don't have a device to plug in to see if it responds with this method, but it's worth a try.

{$I+}
var
  lpt1 : file;
  s : String;
begin
  AssignFile(lpt1, 'LPT1');
  Reset(lpt1);
  { to write to the parallel port }
  s := 'this is going out';
  BlockWrite(lpt1, s, Length(s));
  { to read from the parallel port }
  try
    BlockRead(lpt1, s, 255);
  except
  end;
end.

To be honest, I'd be surprised if it worked. And you'd want to tailor it more to your needs. Have a read on the BlockRead and BlockWrite help topics in Delphi.

You may have more luck searching for something on Torry's.

 

[Spent]

Try using the component "TCom321"
I have used it some times and it works
You can set the speed,compressing etc.
Compatitable with telnet
I guaranty for it.

Spent
mail:teknet@mail.orbitel.bg

 

[rdale2]

Scroll down and look for "DLLs and Accessing Port Hardware..." on this page :

http://ourworld.compuserve.com/homepages/TK_Boyd/Tut.htm

http://ourworld.compuserve.com/homepages/TK_Boyd/Dt3k.htm

http://www.arunet.co.uk/tkboyd/ele1pp.htm

=^)

 

[mattlacey]

For anyone else who ends up searching here for how to send commands through a parallel connection, the following worked for me and is based on the post from Griffyn.

procedure TForm2.btnFeedLPT1Click(Sender: TObject);
var
   sl: TstringList;
 
begin
 
   sl := TstringList.Create;
 
   try
      sl.Add(#02 + 'F');
 
      sl.SaveToFile('LPT1');
   finally
      sl.Free;
   end;
end;

It just saves the command string to the port as if it was a file (like 'type'ing from DOS).

If anyone is interested I use this code for sending commands to thermal barcode printers. The minimal example above simply contains the command for the printer to 'feed'.