# The raw data as you might read it fro the file
$raw = '2010/02/03 10:52:03.123456'; print length $raw;;
26

## First unpack in your main loop
$level1hex = unpack 'H*', $raw; print $level1hex;;
323031302f30322f30332031303a35323a30332e313233343536

## Now re-unpack it two different ways in you print_trailer() sub
$level2text = unpack 'A*', $level1hex; print $level2text;;
323031302f30322f30332031303a35323a30332e313233343536

$level2hex = unpack 'H*', $level1hex; print $level2hex;;
33323330333133303266333033323266333033333230333133303361333533323361333033333265333133323333333433353336

##</code><code>##

my @trlname = (
        "Record Type", "Date",    "Record Size",     "Number Record",
        "Application", "Version", "Data Rec. Type",  "Extra",
        "newLine"
);
my @trlsize = (6, 28, 8, 14, 32, 10, 6, 32, 2);

##</code><code>##

my @fields = unpack 'A6 A28 A8 A14 A32 A10 A6 A32 A2', $data;

print $trlname[ $_ ], ' : ', $fileds[ $_ ] for 0 .. $#fields;

##</code><code>##

sub print_trailer {
        my $data = shift;
        my @fields = unpack 'A6 A28 A8 A14 A32 A10 A6 A32 A2', $data;
        
        print $trlname[ $_ ], ' : ', $fields[ $_ ] for 0 .. $#fields;
}

...
        while (read (DATA, $data, DATALEN) != 0) {

                if ($data =~ /^T/) {
                        print_trailer($data) if ($raw);
                } else {
                        display_data($hex);
                }
        }