Turn Voice & Data On / Off - HD Voice - Microsoft Lumia 735
HD Voice isn't recommended if you use a 1X/3G Network Extender or a TTY/TDD device.
HD Voice on the smartphone must be turned on if you use a 4G Network Extender.
If located in Alaska, it's not recommended to turn off HD Voice for troubleshooting purposes as it causes the device to roam off the Verizon Wireless network.
HD Voice calling requires both parties to be in Verizon 4G LTE coverage, have HD voice capable devices and be provisioned for HD Voice to do simultaneous voice and data.
For more info on signal strength and coverage view this video.
HD Voice is included in existing voice plans and minutes are billed as regular voice calls.
Ensure HD Voice is activated.
From the Start screen, swipe left to display the apps list.
Alternatively, tap All apps (located in the lower-right, may require scrolling).
Tap Settings .
Tap Advanced Calling.
Tap Activate Advanced Calling switch to turn on or off . Once service is upgraded to HD Voice, it is turned on by default.