Чтение и запись в COM порт

   
        Procedure SetComPort(comPort : string); stdcall; external 'comReadSend.dll';
        Function   COMOpen : boolean; stdcall; External 'comReadSend.dll';
        function    COMClose : boolean; stdcall; External 'comReadSend.dll';
        Procedure InicializeCOMPort(var hwnd : THandle); stdcall; External 'comReadSend.dll';
        procedure DestroyCOMport; stdcall;  External 'comReadSend.dll';
        function    GetOpened : boolean; stdcall; External 'comReadSend.dll';
        function    WriteComStr( str : string) : integer; stdcall; External 'comReadSend.dll';
        function    DSRState : boolean; stdcall; External 'comReadSend.dll';
        Function   RLSDState : boolean; stdcall; External 'comReadSend.dll';

unit Unit1;
 
interface
 
uses
...
 
const
 
  READ_COM_STR = WM_USER+4242;
type
  TForm1 = class(TForm)
...
    procedure readMessages(var msg : TMessage); message READ_COM_STR;
 
  private
    { Private declarations }
 
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
 
...
 
function OemToAnsiStr(const OemStr: string): string;
begin
  SetLength(Result, Length(OemStr));
  if Length(Result) > 0 then
    OemToCharBuff(PAnsiChar(OemStr), PwideChar(Result), Length(Result));
end;
 
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  InicializeCOMPort;
  SetHandle(handle);
  COMOpen;
 
  MyHread := TMyHread.Create(false);
  MyHread.running := true;
  MyHread.Priority := tpTimeCritical;
  MyHread.FreeOnTerminate := true;
end;
 
 
procedure TForm1.readMessages(var msg: TMessage);
begin
  Memo1.Lines.Add(PChar(msg.LParam));
end;
 
 
procedure TForm1.BitBtn1Click(Sender: TObject);
begin
   WriteComStr('BLA BLA BLA');
end;

procedure TBCommPort.BComPortRxChar(Sender: TObject; Count: Integer);
var
  s : string;
begin
  BComPort.ReadStr(s, count);
  s := OemToAnsiStr(s);
  SendMessage(Handle, READ_COM_STR, 0, DWORD(PChar(s)));
end;