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Using ActiveXperts Serial Port Component with Delphi

ActiveXperts Serial Port Component is a software development kit (SDK) that enables the user to communicate to a device over a serial interface.

Such a device can be: a weight indicator, a modem, a scanner, or any other device that is equiped with a serial port. It can even be another PC, connected via a NULL modem cable.

ActiveXperts Serial Port Component features the following:

Direct COM port support (like 'COM1')
TAPI (Windows Telephony Device) support (like 'Standard 56000 bps Modem');
Support for RS-232/RS422/RS485, up to 256 simultaneous ports;
Support for all types of Hayes compatible modems;
Support for serial cable as well as USB cable or Bluetooth connections;
Support for Virtual COM ports (i.e. COM ports redirected through the network);
Hardware flow control (RTS/CTS, DTR/DSR) and software flowcontrol (XON/XOFF) support;
Configurable baudrate/parity/stopbits, full buffered data transfer, text/binary data transfer.

Step 1: Download and install the ActiveXperts Serial Port Component

Download the ActiveXperts Serial Port Component from the ActiveXperts Download Site and start the installation. The installation guides you through the installation process.

Step 2: Create a new Delphi Project

Launch Delphi from the Start menu. Choose 'New' from the 'File' menu and select your preferred kind of application, for instance: 'VCL Forms Application - Delphi for Win32'. A new Form is displayed in the workspace.

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Step 3: Refer to the ActiveXperts Serial Port Component Library and create the objects

Now that a new project has been created, you must add a reference to Serial Port Component in the project to be able to use the ActiveXperts Serial Port Component object. To do so, choose 'Import Component...' from the 'Component' menu. The Import Components' dialog appears. Select 'Import a Type Library':

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In the 'Registered Type Libraries' page, select 'Serial Port Component 2.2 Type Library' and click 'Next':

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In the 'Components' page, leave all fields default and click 'Next':

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In the 'Install' page, select 'Create Unit' and click 'Next':

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The interface code is generated now and is shown in the AXSERIAL_TLB tab of the project.

Step 4: Declare and create the object

From the Project Manager, open Unit1.bas and add the AXSERIAL_TLB to the 'Uses' statement to refer to the ActiveXperts Serial Port Component library:

(Click on the picture to enlarge)

In the 'private' or 'public' section, declare the following objects:

   objComport    : IComPort

You can now create the objects, for instance in the 'FormCreate' function:

   objComPort     := TComPort.Create(Form1).DefaultInterface;

Step 5: Send an AT command to a connected Hayes compatible modem

You can now send and/or receive data to and/or from a serial port.

The following code shows how to query a modem:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, AxSerial_TLB, ShellAPI, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    comboDevice: TComboBox;
    comboSpeed: TComboBox;
    Label3: TLabel;
    comboFormat: TComboBox;
    Label4: TLabel;
    comboHwFlow: TComboBox;
    Label5: TLabel;
    comboSwFlow: TComboBox;
    buttonOpen: TButton;
    buttonClose: TButton;
    GroupBox2: TGroupBox;
    Label6: TLabel;
    Label7: TLabel;
    editData: TEdit;
    checkDTR: TCheckBox;
    checkRTS: TCheckBox;
    buttonSubmit: TButton;
    Label8: TLabel;
    Label9: TLabel;
    GroupBox3: TGroupBox;
    editReceived: TMemo;
    Label10: TLabel;
    GroupBox4: TGroupBox;
    checkCTS: TCheckBox;
    checkDSR: TCheckBox;
    checkDCD: TCheckBox;
    checkRI: TCheckBox;
    GroupBox5: TGroupBox;
    Label11: TLabel;
    Label12: TLabel;
    Label13: TLabel;
    editResult: TEdit;
    editLogfile: TEdit;
    Button2: TButton;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure buttonOpenClick(Sender: TObject);
    procedure buttonCloseClick(Sender: TObject);
    procedure buttonSubmitClick(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure checkDTRClick(Sender: TObject);
    procedure checkRTSClick(Sender: TObject);

  private
    objComport  : IComport;

    procedure EnableControls ();

    function GetResult () : Integer;
    function GetTempDirectory () : String;

  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var numDevices : Integer;
var i          : Integer;
begin
  objComport := CoComport.Create ();

  comboDevice.Items.Add( 'COM1' );
  comboDevice.Items.Add( 'COM2' );
  comboDevice.Items.Add( 'COM3' );
  comboDevice.Items.Add( 'COM4' );

  numDevices := objComport. GetDeviceCount ();

  for i := 0 to numDevices do begin
    comboDevice.Items.Add( objComport.GetDevice( i ));
  end;

  comboDevice.ItemIndex := 0;

  comboSpeed.Items.Add('Default');
  comboSpeed.Items.Add('110');
  comboSpeed.Items.Add('300');
  comboSpeed.Items.Add('600');
  comboSpeed.Items.Add('1200');
  comboSpeed.Items.Add('2400');
  comboSpeed.Items.Add('4800');
  comboSpeed.Items.Add('9600');
  comboSpeed.Items.Add('14400');
  comboSpeed.Items.Add('19200');
  comboSpeed.Items.Add('28800');
  comboSpeed.Items.Add('33600');
  comboSpeed.Items.Add('38400');
  comboSpeed.Items.Add('56000');
  comboSpeed.Items.Add('57600');
  comboSpeed.Items.Add('115200');
  comboSpeed.Items.Add('128000');

  comboSpeed.ItemIndex := 0;

  comboFormat.Items.Add('Default');
  comboFormat.Items.Add('n,8,1');
  comboFormat.Items.Add('e,7,1');

  comboFormat.ItemIndex := 0;

  comboSwFlow.Items.Add('Default');
  comboSwFlow.Items.Add('Enabled');
  comboSwFlow.Items.Add('Disbaled');

  comboSwFlow.ItemIndex := 0;

  comboHwFlow.Items.Add('Default');
  comboHwFlow.Items.Add('Enabled');
  comboHwFlow.Items.Add('Disbaled');

  comboHwFlow.ItemIndex := 0;

  EnableControls ();

  GetTempDirectory ();
end;

{////////////////////////////////////////////////////////////////////////////////}

function TForm1.GetTempDirectory: string;
var Buffer: array[0..MAX_PATH] of Char;
begin
  GetTempPath(SizeOf(Buffer) - 1, Buffer);
  editLogfile.Text := StrPas(Buffer) + 'Pop3Log.txt';
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.EnableControls ();
var bEnabled  : Boolean;
begin
  if objComport.IsOpened = -1 then bEnabled := true else bEnabled := false;

  buttonOpen.Enabled := Not bEnabled;
  buttonClose.Enabled := bEnabled;
  buttonSubmit.Enabled := bEnabled;
  editData.Enabled := bEnabled;
  checkDTR.Enabled := bEnabled;
  checkRTS.Enabled := bEnabled;
  editReceived.Enabled := bEnabled;
end;
{////////////////////////////////////////////////////////////////////////////////}

function TForm1.GetResult : Integer;
begin
  Result := objComport.LastError;
   editResult.Text     := 'ERROR ' + IntToStr ( Result ) +  ' : ' + objComport.GetErrorDescription( Result );
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.buttonOpenClick(Sender: TObject);
begin

  objComport.Device     := comboDevice.Text;

  if ( comboSpeed.Text <> 'Default' ) then begin
    objComport.BaudRate   := StrToInt ( comboSpeed.Text );
  end;

  if comboFormat.ItemIndex = 1 then begin
    objComport.StopBits := objComport.asSTOPBITS_1;
    objComport.Parity   := objComport.asPARITY_NONE;
    objComport.DataBits := objComport.asDATABITS_8;
  end;

  if comboFormat.ItemIndex = 2 then begin
    objComport.StopBits := objComport.asSTOPBITS_1;
    objComport.Parity   := objComport.asPARITY_EVEN;
    objComport.DataBits := objComport.asDATABITS_7;
  end;

  objComport.HardwareFlowControl := comboHwFlow.ItemIndex;
  objComport.SoftwareFlowControl := comboSwFlow.ItemIndex;

  objComport.ComTimeout := 100;

  objComport.LogFile := editLogfile.Text;
  
  objComport.Open ();

  if GetResult () = 0 then begin
    EnableControls ();
  end;
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.buttonCloseClick(Sender: TObject);
begin
  objComport.Close ();

  if GetResult () = 0 then begin
    EnableControls ();
  end;
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.buttonSubmitClick(Sender: TObject);
begin
  objComport.WriteString( editData.Text );
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.Timer1Timer(Sender: TObject);
var Buffer :  WideString;
begin
    if ( objComport.IsOpened = -1 ) then begin

      if ( objComport.QueryCTS () = -1 ) Then
        checkCTS.Checked := true
      else
        checkCTS.Checked := false;

      if ( objComport.QueryDSR () = -1 ) Then
        checkDSR.Checked := true
      else
        checkDSR.Checked := false;

      if ( objComport.QueryDCD () = -1 ) Then
        checkDCD.Checked := true
      else
        checkDCD.Checked := false;

      if ( objComport.QueryRI () = -1 ) Then
        checkRI.Checked := true
      else
        checkRI.Checked := false;

      Buffer := objComport.ReadString ();

      if Length ( Buffer ) > 0 then begin
        editReceived.Lines.Add(Buffer);
      end;
    end;
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.Button2Click(Sender: TObject);
var LogFile : PAnsiChar;
begin
  LogFile := StrNew(PChar(editLogFile.Text));

  ShellExecute ( 0, 'open' , LogFile, '', '', SW_SHOW )
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.checkDTRClick(Sender: TObject);
begin
  if objComport.IsOpened = -1 then begin

    if checkDTR.Checked = true then
      objComport.RaiseDTR( 1 )
    else
      objComport.RaiseDTR( 0 );
    GetResult ();
  end;
end;

{////////////////////////////////////////////////////////////////////////////////}

procedure TForm1.checkRTSClick(Sender: TObject);
begin
  if objComport.IsOpened = -1 then begin

    if checkRTS.Checked = true then
      objComport.RaiseRTS( 1 )
    else
      objComport.RaiseRTS( 0 );
    GetResult ();
  end;
end;

{////////////////////////////////////////////////////////////////////////////////}

end.

There are many working samples included with the product. You can also find them on the ActiveXperts FTP site: ftp.activexperts-lab.com/samples/serial-port-component.