With the following code (1) you can change how long your mobile phone rings (5, 10, 15, 20, 25 or 30 seconds). The default ring time is 30 seconds.
(*)*61*+32495075000(*)*[how many seconds]#
(1) The usage of this code is only an option in Belgium and on foreign networks supporting these codes. Depending on your phone you may need to use one or two * at the start of the code and before the number of seconds you're going to set.