function TRS232.ReadString(var aResStr: string; aCount: word ): boolean;
var
  nRead: dword;
  Buffer: string;
  Actual, Before: TDateTime;
  TimeOutMin, TimeOutSec, lCount: word;
begin
  Result := false;
  if not Connected then
    if not Connect then
      raise Exception.CreateHelp('RS232.ReadString:' +
      ' Connect not possible !', 101);
  aResStr := '';
  TimeOutMin:=TimeOut div 60;
  TimeOutSec:=TimeOut mod 60;
  if (not Connected) or (aCount <= 0) then
    EXIT;
  nRead := 0; lCount := 0;
  Before := Time;
  while lCount < ACOUNT do
  begin
    Application.ProcessMessages;
    SetLength(Buffer,1);
    if ReadFile( FComPortHandle, PChar(Buffer)^, 1, nRead, nil) then
    begin
      if nRead > 0 then
      begin
        aResStr := aResStr + Buffer;
        inc(lCount);
      end;
      Actual := Time;
      if Actual-Before>EncodeTime(0, TimeOutMin, TimeOutSec, 0) then
        raise Exception.CreateHelp('RS232.ReadString: TimeOut !', 103);
    end
    else
    begin
      raise Exception.CreateHelp('RS232.ReadString: Read not possible !', 104);
    end;
  end;
  Result:=true;
end;