Функция набора номера модемом

Code:

var

hCommFile : THandle;

procedure TForm1.Button1Click(Sender: TObject);

var

PhoneNumber : string;

CommPort : string;

NumberWritten : LongInt;

begin

PhoneNumber := 'ATDT 1-555-555-1212' + #13 + #10;

CommPort := 'COM2';

{Open the comm port}

hCommFile := CreateFile(PChar(CommPort),

GENERIC_WRITE,

0,

nil,

OPEN_EXISTING,

FILE_ATTRIBUTE_NORMAL,

0);

if hCommFile=INVALID_HANDLE_VALUE then

begin

ShowMessage('Unable to open '+ CommPort);

exit;

end;

NumberWritten:=0;

if WriteFile(hCommFile,

PChar(PhoneNumber)^,

Length(PhoneNumber),

NumberWritten,

nil) = false then

begin

    ShowMessage('Unable to write to ' + CommPort);

   end;

end;

procedure TForm1.Button2Click(Sender: TObject);

begin

{Close the port}

CloseHandle(hCommFile);

end;