1. Signal strength will be indicated in the Notifications bar. When you are within range of a cellular tower the indicator will show more bars. If you are not in range of a cellular tower you will have fewer bars/less signal strength.
   
2. If 3G is available, the 3G symbol will appear next to the signal strength indicator in the Notifications bar.
   
3. Enabling Airplane Mode disables all network connections. When it is turned on, the Airplane icon will be displayed in the Notifications bar.