By the way, you could speed up your processing of that data enormously by skipping the split multiple maps over hex and chr et al. by using:

$s = '48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21';;
$s =~ tr[ ][]d; 
print pack 'H*', $s;;
Hello, world!
[download]