Patterns
You can define a pattern to control edition of any attribute.
By default no patterns are defined. You can create one by adding a property in attributes map and a message in the custom lang file by setting the pattern_item message.
For example to add a pattern on phone item:
Edit or create
/etc/service-desk/config.local.inc.php:
$attributes_map['phone']['pattern'] = "\+33 [0-9] [0-9]{2} [0-9]{2} [0-9]{2} [0-9]{2}";
Edit or create
/etc/service-desk/fr.inc.php:
$messages['pattern_phone'] = "+33 1 23 45 67 89";