for iOS 5.1 software

Reset your usage statistics Go to Settings > General > Usage > Cellular Usage, then tap Reset Statistics
to clear the data and cumulative time statistics.
Show battery percentage Go to Settings > General > Usage and turn on Battery Percentage.
Siri
Enable Siri: Go to Settings > General > Siri.
For information about using Siri and changing Siri settings, see “Setting options for Siri” on
page 42.
Network
Use Network settings to congure a VPN (virtual private network) connection, access Wi-Fi
settings, or turn cellular data roaming on or o.
When an app needs to use the Internet, iPhone does the following, in order, until connected:
Connects over the most recently used available Wi-Fi network  .
Shows a list of Wi-Fi networks in range, and connects using the one you choose. Â
Connects over the cellular data network, if available. Â
If iPhone is connected to the Internet via the cellular data network, the , , , or icon appears
in the status bar.
The 4G and 3G GSM cellular networks support simultaneous voice and data communications.
For all other cellular connections, you can’t use Internet services while you’re talking on the
phone unless iPhone also has a Wi-Fi connection to the Internet. Depending on your network
connection, you may not be able to receive calls while iPhone transfers data over the cellular
network—when downloading a webpage, for example.
GSM networks: On an EDGE or GPRS connection, incoming calls may go directly to voicemail
during data transfers. For incoming calls that you answer, data transfers are paused.
CDMA: On EV-DO connections, data transfers are paused when you answer incoming calls.
On 1xRTT connections, incoming calls may go directly to voicemail during data transfers. For
incoming calls that you answer, data transfers are paused.
Data transfer resumes when you end the call.
Turn Cellular Data on or o: Go to Settings > General > Network, then turn Cellular Data on
or o.
If Cellular Data is turned o, all data services will use only Wi-Fi—including email, web browsing,
push notications, and other services. If Cellular Data is turned on, carrier charges may apply. For
example, certain features and services such as Siri and Messages transfer data, and your use of
these features and services could impact charges to your data plan.
163
Chapter 32 Settings