Verizon decided to send me a Network Extender (free) because of phone calls. They claim the bars on the phone has to do with Data, which I have 4G LTE and 3-5 bars. Now, the Verizon rep said phone calls and 4G have nothing to do with each other? I thought that is how VoLTE is working? Now totally confused. If I have great 4G LTE and have AC on, why am I needing the Network extender? confusing
She is mostly right. The network extender is used for phone calls (using CDMA) and, if you are close enough, it can also be used to carry 3G data. When you have a connection to the extender, you should see a small flashing house icon above the signal bars (and, when you make or receive calls, you will hear a weird tone when the call is engaged.) However, with my extender at home (I have two, actually - a newer 3G model at home at an older 1xRTT model at my summer house, but this is talking about the 3G one), when I am at the edge of the range I will occasionally see that I have a weak 3G or LTE signal with the tower that's closest to my house.
VoLTE will only work when you are connected to a Verizon tower carrying LTE data. Otherwise, the phone falls back to normal Verizon CDMA calls. Verizon does not yet have LTE extenders, though (unless I missed something...)
If you go to settings / More... / Mobile networks / Network type and strength it will show the actual signal rather than using the unreliable bars in the status bar. Right now I am seeing just 1x at -88 dBm from my extender (which is a pretty good signal), but occasionally I will see an LTE signal at something like -128 dBm (which is pretty weak for LTE.) And this is true even though I am connected to my home WiFi - it still shows LTE signal strength, even though the phone is using WiFi to carry data.
So, again, if you have a weak LTE signal, the Turbo will fall back to CDMA for phone calls, as there is likely not enough bandwidth in the LTE data connection, and that's probably why Verizon sent you an extender. (You're lucky - I had to pay for mine, though I did buy both of mine when they were on a rare sale.)