sub xlat {
  my ($octets) = @_ ;
  return pack('B*', unpack('b*', $octets)) ;
} ;

##</code><code>##

my $test = "\xC5\x11\x01\x80\x5A" ;

print showbits($test), "\n" ;
print showbits(xlat($test)), "\n" ;
print showbits(xlat(xlat($test))), "\n" ;

sub showbits {
  my ($octets) = @_ ;
  my $s = unpack('B*', $octets) ;
  $s =~ s/([01]{8})(?=[01])/$1:/g ;
  return $s ;
} ;