Issue #2026269 by Spleshka: Fixed Different default values for filter_allowed_protocols() variable.

CHANGELOG.txt

@@ -1,6 +1,8 @@
 
 Drupal 7.23, xxxx-xx-xx (development version)
 -----------------------
+- Fixed inconsistent support for the 'tel' protocol in Drupal's URL filtering
+  functions.
 - Performance improvement: Allowed all hooks to be included in the
   module_implements() cache, even those that are only invoked on HTTP POST
   requests.

modules/filter/filter.module

@@ -1461,7 +1461,7 @@ function _filter_url($text, $filter) {
   // we cannot cleanly differ between protocols here without hard-coding MAILTO,
   // so '//' is optional for all protocols.
   // @see filter_xss_bad_protocol()
-  $protocols = variable_get('filter_allowed_protocols', array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal', 'rtsp'));
+  $protocols = variable_get('filter_allowed_protocols', array('ftp', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'rtsp', 'sftp', 'ssh', 'tel', 'telnet', 'webcal'));
   $protocols = implode(':(?://)?|', $protocols) . ':(?://)?';
 
   // Prepare domain name pattern.