Accepting Data from Telephone Central via MSComm

Hi all,
I'm trying to write a program to accept data from Telephon Central via MSComm, to Insert these data to a database.

before write a procedure to insert the data to the database, I want to write the data to a text file just for try.

unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, OleCtrls, MSCommLib_TLB;
type
  TForm1 = class(TForm)
    MSComm1: TMSComm;
    Edit1: TEdit;
    Memo1: TMemo;
    procedure FormShow(Sender: TObject);
    procedure MSComm1Comm(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
        MyFile: TextFile;
        Line: String[80];
  end;

var
  Form1: TForm1;

implementation
{$R *.dfm}

procedure TForm1.FormShow(Sender:TObject);
begin
  Line:= '';

  AssignFile(MyFile, 'c:\TryMSComm2.txt');
  Append(MyFile);

  Form1.MSComm1.PortOpen:= True;
end;

procedure TForm1.MSComm1Comm(Sender: TObject);
var InputData: String;
begin
  InputData:= Form1.MSComm1.Input;

  if((InputData = #19)or(InputData = #17)or(InputData = #13))then
    // Do Nothing
  else if(InputData = #10)then
    begin
      Writeln(MyFile, Line);
      Line:= '';
    end
  else
    Line:= Line + InputData;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  CloseFile(MyFile);

  Form1.MSComm1.PortOpen:= False;
end;

end.

and use a value 1 as an InputLen of MSComm property to accept only one char.

Each line of data contain 80 character.

This code is working succesfully, but when I frequently open the text file while the program is running to see what happend I see that at each write to the text file It write 124 character
mean one line and a half and when "just" close the program the remaining half line is writen.

I changed the Input buffer size more than one but the problem still exist.

Can any one help me how to solve this problem.

Thanks,
Khalid.