If your carrier supports VoLTE
On your iPhone, go to Settings > Cellular > Cellular Data Options. If your carrier supports Voice over LTE (VoLTE), you'll see these options:
- Off: Turns off LTE
- Voice & Data: Allows voice calls and cellular-data use over LTE
- Data Only: Allows cellular-data use, but not voice calls over LTE
If calls drop frequently or call quality is poor when using VoLTE, try turning off VoLTE. To turn off VoLTE, select the option for Data Only. If calls improve with VoLTE turned off, get help from your carrier.
If your carrier doesn't support VoLTE
If your carrier doesn't support VoLTE and is a GSM carrier, you'll see one of these options:
- LTE or 4G: Allows cellular-data use over the LTE or 4G network when available.
- 3G: Allows cellular-data use over the 3G network when available.
- 2G: Allows cellular-data use over the 2G network when available.
Depending on the wireless carrier, 4G can indicate either a UMTS or LTE connection. If your carrier doesn't support VoLTE and is a CDMA carrier, you'll only see an option to Enable LTE. This allows cellular-data use over the LTE network when available.
Learn more about cellular data networks.