Convert hex to ascii characters

You can trivially adapt the solution I presented here using the function base_convert_arbitrary.

Edit: I had not read carefully enough :) Base 16 to base 62 is still very doable, as above.

See it in action.

I think you're looking for this:

function hex2str($hex) {
    $str = '';
    for($i=0;$i<strlen($hex);$i+=2) $str .= chr(hexdec(substr($hex,$i,2)));
    return $str;
}

(From http://www.linux-support.com/cms/php-convert-hex-strings-to-ascii-strings/) (Works like this javascript tool: http://www.dolcevie.com/js/converter.html)

You mean want to convert a string of hex digits into actual hex values?

$hex_string = "A1B2C3D4F5"; // 10 chars/bytes
$packed_string = pack('H*', $hex_string); // 0xA1B2C3D4F5 // 5 chars/bytes.