# !perl      DebugBCD.pl
open (inFILE, "<C:/Dev/Perl_Dev/ItemExp/TESTFILE.DAT") || 
                    die "Cannot open file\n";

# The first 6 bytes of my test file contain the 12 digit UPC Barcode 123456789910

binmode (inFILE);
seek (inFILE,0,0);
read (inFILE,$inBuf,6);
print "Len=".length($inBuf)."  Raw Data = $inBuf \n";  # This prints the graphics 

$Test = DecodeBCD($inBuf);
print $Test;                    # This prints   48 48 52 48 I expected 1 2 3 4

close inFile;

sub DecodeBCD {
   my ($i,@lo,@hi,$Byte,$Bits,@pairs);
   my $Hi,$Low;
   my $LoMask = 15;
   my $HiMask = 240;
   my $Zone = 0x30;
   for ($i = 0; $i < 2; $i++) 
   {
      $Byte = substr($_[0],$i,1);
      $lo[$i] = ($Byte & $LoMask) | $Zone;        # These OR statements seem to
      $hi[$i] = (($Byte & $HiMask) >> 4) | $Zone; # result in JUST the $Zone piece,
      $pairs[$i] = join("",$lo[$i],$hi[$i]);      # Implying that the & result is Zero.
      print "\nLo $i=".$lo[$i]."    Hi $i=".$hi[$i]."     $pairs[$i]\n";
   }  
   print "(@pairs)\n";
   chomp ($Dummy = <STDIN>);
   join('',@pairs);
}