#we are packing nibbles (4 bits) at a time
# H is big-endian order
# h is little-endian order (swaps adjacent nibbles)

my $raw = pack 'H*', '8447000c0000110a0350';

#decode back to input string...
print unpack ('H*', $raw), "\n"; # prints: 8447000c0000110a0350
print unpack ('h*', $raw), "\n"; # prints: 487400c0000011a03005

#need to set binmode when writing raw binary data...
open (BIN, '>', 'test.bin') || die "can't open test.bin";
binmode(BIN);
print BIN $raw;
close BIN;

##</code><code>##

# v1 is a little-endian 16 bit (short) so needs 2 bytes
# if substr didn't limit to 2 bytes substr($raw,1) works also
# unpack will use first 2 bytes.
my ($len) = unpack 'v1',substr($raw,1,2);#substr deals in bytes not nibbles.
print $len,"\n";                          #prints 71
print unpack ('v', substr($raw,1)),"\n";  #prints 71
print unpack ('x v', $raw ),"\n";         #prints 71

##</code><code>##

record:
   unsigned char  record_type   8 bits
   unsigned short length        16 bits little endian
   ... some data type and description of these sections...