$data[1] = "\xA3";  
  $data[2] = "\x05";
  $data[3] = "\x00";
  $data[4] = "\x00";
  $data[5] = "\x00";
  $data[6] = "\x00";
  $data[7] = "\x00";


  $data[0] = normalChecksum8(@data);

####################################################################
sub normalChecksum8
{
my $a;
my $b;

foreach (@_) 
{ $a += pack("C",$_); }

  $b = $a / 256;

  $b = $a / 256;
  $a = ($a - 256 * $b) + $b;
  $b = $a / 256;

  return pack("C", (($a-256*$b)+$b));
}