use Data::Dumper;
my $str = "\x0D\x0E\x0A\x0D\x0B\x0E\x0E\x0F";
my @bytes = unpack 'C8', $str;
print Dumper \@bytes;
# Now add up the byte-pairs
for (0..3) {
    $bytes[ $_ ] = $bytes[ $_*2 ] * 16 + $bytes[ $_*2 +1 ];
};
splice @bytes, 4; # we only need the first four entries
print Dumper \@bytes;

my $num = unpack 'N', pack 'C4', @bytes;
print sprintf "%08x (%i)", $num, $num;