View cellular network signal, turn international roaming or your mobile data connection on or off.
CHECK NETWORK CONNECTION AND STRENGTH:
1. ACCESS CELLULAR DATA: Swipe down from the Notification bar, then select the  Settings icon.
Note: Mobile data is on by default. Turning off the mobile data will not allow any data to be transferred over the wireless network. Wi-Fi access, voice function, and standard text messaging are still allowed. You can also turn data on/off using your myAT&T account. Learn more about disabling or activating AT&T Mobile Share member’s data usage by device.
2. Select Network & Internet, then select Mobile network.
3. TURN ON/OFF INTERNATIONAL DATA & MOBILE DATA: Select the desired switch to enable or disable the desired service.