Phone switches to 1X signal when i make phone calls. Why doesn't it stay in 4G LTE like it is before i make the call?

[Kurto-san]

I just noticed that my Xperia switches to 1x mode when I make phone calls.  It is 4G LTE before the call, as soon as I hit send to make the call it goes to 1X.  It sounds like crap also.  Anyone have any ideas why it would be doing this?  I have reset it and that didn't help (holding down the power and volume down button until it resets).

[dilbertaz · Accepted solution]

Phone calls on Verizon use the 1xRTT network unless your phone supports VoLTE and is set for Advanced Calling.

[elliew]

4G LTE is your data network (4G vs 3G)

[shaggyguy]

The phone supports volte which is required to use the Internet and make calls at the same time. Unfortunately verizon has not updated this phone to be able to do that.