This is bread and butter stuff for Perl and there are many better ways to achieve what you are after. Some are likely to be outside your current comfort zone so sift through the following and see what you like the look of:

use warnings;
use strict;

while (<DATA>) {
    chomp;
    my @numbers = unpack ("(a2)*", $_);

    print "unpacked: @numbers, ";

    @numbers = /(..)/g;
    print "matched: @numbers, ";

    @numbers = ();
    push @numbers, substr $_, 0, 2, '' while length $_;
    print "substr'd: @numbers\n";
}

__DATA__
0912203749
0725284648
0608294149
0622424347
1219303436
1729313449
1015162331
[download]

Prints:

unpacked: 09 12 20 37 49, matched: 09 12 20 37 49, substr'd: 09 12 20 
+37 49
unpacked: 07 25 28 46 48, matched: 07 25 28 46 48, substr'd: 07 25 28 
+46 48
unpacked: 06 08 29 41 49, matched: 06 08 29 41 49, substr'd: 06 08 29 
+41 49
unpacked: 06 22 42 43 47, matched: 06 22 42 43 47, substr'd: 06 22 42 
+43 47
unpacked: 12 19 30 34 36, matched: 12 19 30 34 36, substr'd: 12 19 30 
+34 36
unpacked: 17 29 31 34 49, matched: 17 29 31 34 49, substr'd: 17 29 31 
+34 49
unpacked: 10 15 16 23 31, matched: 10 15 16 23 31, substr'd: 10 15 16 
+23 31
[download]