For best results enter one or two keywords related to what you are looking for
This setting is between your phone and the network.
To change the setting dial the following code as though you were making a phone call.
**61*+447953222222*11*XX# where XX is the number of seconds before the call is sent to voicemail. This can be any number from 5 to 30 in increments of 5. i.e. 5, 10, 15, 20, 25 or 30.
For example, to increase the time to 30 seconds before the call is sent to voicemail you would enter:
**61*+447953222222*11*30#