at the linux console....
db selintra-work setprop global EXTLEN 3
Now issue a commit from the server-manager.
Make sure that you have no 4-digit extensions already defined when you issue this command. Otherwise, you will end up with 4-digit extensions which you can neither access nor delete.
To set 4 digit...
db selintra-work setprop global EXTLEN 4
Now issue a commit from the server-manager.
Kind Regards
S