GSM codes for various network services
The following codes are the standard GSM codes for various network services. Most Nokia phones have easier ways to activate them through the menus. Check the guides for your model.
Call Diverting
All
To Activate: * * 21 * NUMBER # [SEND]
To Cancel: # # 21 # [SEND]
To Check: * # 21 # [SEND]
No Answer
To Activate: * [...]