GSM CODES FOR VARIOUS NETWORK SERVICES

The following codes have been a prevalent GSM codes for various network services. Most Nokia phones have easier ways to spin upon them by a menus. Check a guides for your model.
Call Diverting
All
To Activate: * * twenty-one * NUMBER # [SEND]
To Cancel: # # twenty-one # [SEND]
To Check: * # twenty-one # [SEND]
No Answer
To [...]