#!/usr/bin/perl -w
use strict;
use constant DLE=>0x10;
my $dle = sprintf ("%02X", DLE);
my $msg = pack ("CCCCC", 0x31, 0x32, 0x10, 0x10, 0x33);
# match $dle's expanded, replacement is not expanded ?
$msg =~ s/\x{$dle}\x{$dle}/\x{$dle}/g;
printf ("%02x " x length($msg) . "\n", unpack ("C*", $msg));