Turn Voice & Data On / Off - HD Voice - LG Lancet™
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 area, 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.