You can select which network modes (3G and/or GSM) your mobile phone can use. Your choice depends on the data speed you can achieve.
Tap the Menu key.
Scroll to Tools and tap the Navigation key.
Scroll to Settings and tap the Navigation key.
Scroll to Phone and tap the Navigation key.
Scroll to Network and tap the Navigation key.
Scroll to Network mode and tap the Navigation key.
Highlight Dual mode, UMTS or GSM and tap the Navigation key.
3G enables you to achieve higher data speeds than GSM. If you select Dual mode, your mobile phone automatically switches between the two network modes provided that you're within range of a 3G network. If you select UMTS, your mobile phone can only connect to 3G networks. If you select GSM, you can't achieve high data speeds.
