$re = '/^(?:(?:\(?(?:00|\+)([1-4]\d\d|[1-9]\d?)\)?)?[\-\.\ \\\\\/]?)?((?:\(?\d{1,}\)?[\-\.\ \\\\\/]?){0,})(?:[\-\.\ \\\\\/]?(?:#|ext\.?|extension|x)[\-\.\ \\\\\/]?(\d+))?$/im';
$str = '(+351) 282 43 50 50
90191919908
555-8909
001 6867684
001 6867684x1
1 (234) 567-8901
1-234-567-8901 x1234
1-234-567-8901 ext1234
1-234 567.89/01 ext.1234
1(234)5678901x1234
(123)8575973
(0055)(123)8575973';
preg_match_all($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