$re = '/^((\(\+{0,2}[0-9]{1,2}\)|\+{0,2}[0-9]{0,2})?([0-9 ]+)?)$/m';
$str = '508 736 756
505050505
+48 505 505 505
(+48) 505 505 505
++48 505 505 505
(++48) 505 505 505
(23)692 36 99
23 692 36 99
() 692 36 99
(2) 692 36 99
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php