Samsung SGHT989 User Manual page 214

Network mode
You can configure your phone to either manually detect and use
either a 2G (GSM) or 3G (WCDMA) data network connection.
Press
Wireless and network
Mode.
Using the 4G Network
To confirm you are always using the fastest possible connection,
the phone has an automatic detection method where it finds both
the fastest and most stable connection/communication method.
This phone is capable of using either 4G/3G services for this
connection.
Note: WCDMA is only available on the 4G network.
Press
1.
Wireless and network
Mode.
Tap GSM/WCDMA (auto mode). A check mark displays next
2.
to this option to indicate that it is active. This is the default
mode for this phone.
209
and then tap (Settings)
Mobile networks Network
and then tap (Settings)
Mobile networks Network
Using the 2G (EDGE) Network
If you are not using applications that require the 3G network
speed (any application that accesses the network or uses a
browser), using the 2G network saves battery life.
Press
1.
Wireless and network
mode.
Tap GSM only. A check mark displays next to this option to
2.
indicate that it is active.
Note: Connecting to 2G networks slows the data transfer speed and time.
Using the 3G Network
If you are using applications that require the 3G network speed,
follow these instructions to connect to the 3G network.
Press
1.
Wireless and network
mode.
Tap WCDMA only. A check mark displays next to this option
2.
to indicate that it is active.
and then tap (Settings)
Mobile networks Network
and then tap (Settings)
Mobile networks Network