To use AT&T HD Voice, both caller and receiver need an AT&T HD Voice-capable phone and must be located in an AT&T HD Voice coverage area.
- To turn AT&T HD Voice on, swipe down from the notification bar, then tap the Settings icon.
- From the CONNECTIONS tab, scroll down and tap More networks.
- Tap Mobile networks
- Tap Mobile data.
- Tap the Enhanced LTE Services checkbox.
- To turn AT&T HD Voice off, go to Settings > CONNECTIONS > More networks > Mobile networks > Mobile data > then tap the Enhanced LTE Services checkbox.
Note: Turning AT&T HD Voice off will also disable AT&T Video Call and Advanced Messaging. Learn more about AT&T HD Voice.