Apple iPhone OS 3.1 - Manual (Page 57)

Set iPhone to add the correct prefix when dialing from another country: In Settings,
tap Phone, then turn International Assist on. This lets you make calls to your home
country using the numbers in your contacts and favorites, without having to add a
prefix or your country code. International Assist works for U.S. telephone numbers only.
When you make a call using International Assist, “International Assist” appears on the
iPhone screen, alternating with the “calling ...” message, until your call is connected.
Note: International Assist is not available in all areas.
Set the carrier to use: In Settings, tap Carrier, then select the carrier you prefer. This
option is available only when you’re traveling outside your carrier’s network. You can
make calls only on carriers that have roaming agreements with your iPhone service
provider. For more information, see “Carrier” on page 141.
Important: Voice and data roaming charges may apply. To avoid data roaming charges,
turn Data Roaming off.
Turn Data Roaming on or off: In Settings, choose General > Network and turn Data
Roaming on or off. Data Roaming is turned off by default.
Turning Data Roaming off helps to avoid data roaming charges when traveling outside
your carrier’s network by disabling data transmission over the cellular network. You
can still access the Internet if you have a Wi-Fi connection. If Wi-Fi network access isn’t
available, however, you cannot:
Send or receive email •
Browse the Internet •
Sync your contacts, calendars, or bookmarks with MobileMe or Exchange •
Stream YouTube videos •
Get stock quotes •
Get map locations •
Get weather reports •
Purchase music or applications •
Other third-party applications that use data roaming may also be disabled.
If Data Roaming is turned off, you can still make and receive phone calls, and send and
receive text messages. Voice roaming charges may apply. Visual voicemail is delivered
if there’s no charge; if your carrier charges for delivery of visual voicemail when
roaming, turning Data Roaming off prevents the delivery of visual voicemail.
To enable email, web browsing, and other data services, turn Data Roaming on.
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