$re = '/((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}(?!([^<]*>)|(((?!<a).)*<\/a>))/';
$str = '<div id="departments">
<ul>
<li>Department 1 - 8141113900</li>
<li>Department 2 - pavan 8141119300</li>
<li>Department 3 - (555) 123-6789</li>
</ul>
</div>
<input type=\'text\' value=\'(555) 123-6789\' />
(555) 123-6789 <a href=\'\'>(555) 123-6789</a><a href=\'(555) 123-6789\'>(555) 123-6789</a>
<li>Department 1 -<b> (555) 123-1234</b></li>
<li>Department 2 - (555) 123-4321</li>
<li>Department 3 - (555) 123-6789</li>';
preg_match_all($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