BenQ Z2 - Manual (Page 126)

110 Menus
For detailed information on how to properly configure GPRS
and CSD settings, contact your network operator.
3. Press (Save) to save the settings.
4. Scroll to the server that you would like to use and press the
Joystick button (OK) to confirm your choice.
Clear Cache
Clears webpage content that the browser temporarily stores in
memory.
NAP Settings
Used to configure GPRS or CSD settings according to the network type
used by the phone.
Service Number
Displays the service number that the network operator has stored on
the SIM card.
Requires the support of the network operator.
SIM ToolKit Menu
This SIM Tool Kit (STK, for short) Menu is only available if provided by
your network operator. For details, contact your network operator.
Requires the support of the network operator.