my %hex = map { $_ => 1 } qw( AB CD B1 );

my @records = (
   pack("A2Ca7",  "RT", 7, "testing"),
   pack("A2CH16", "CD", 8, "01020304FFDDEC19"),
);

foreach my $record (@records) {
   my ($kw, $rdata) = unpack("A2C/a", $record);

   $rdata = uc(unpack('H*', $rdata))
      if $hex{$kw};

   print "$kw $rdata\n";
}