function ASCIIStrToHexStr(Str: string): string;
var
  I: Integer;
  S: string;
  Value: Integer;
begin
  if Length(Str) < 2 then
  begin
    Result := '';
    Exit;
  end;

  S := '';
  for I := 1 to (Length(Str) div 2) do
  begin
    Value := SToI(Str[I * 2 - 1]) * 16 + SToI(Str[I * 2]);
    S := S + chr(Value);
  end;

  Result := S;
end;