Turn on / off 3G
1) Type on phone *#1546792*# (or run hidden program in \Windows\AdminSettings.exe)
2) You should see "Admin Settings" window with options:
- Version
- Preconfiguration (to enter this menu type *#81230*#. Here you can change language and network operator specific settings)
- Network & Call Settings
- Internal
3) Chose Network & Call Settings > Network Mode
4) Selecting GSM - turn off 3G
5) Selecting Auto - turn on 3G