mine works the same, although I'm on 3G only. I thought maybe using 4G/LTE might be different.

 

You can only do that on the Maxx when you're on 4g. You can't use data and voice simultaneously while on 3g, unlike your Thunderbolt.

 

VERY FEW phones will do SVDO (simultaneous voice and data) on 3G...there may not be ANY new phones that do.

Best check into it before you jump too fast.

 

I believe the Rezound does SVDO.

What everyone has said so far is completely correct. Remember all of those commercials about the iPhone only being able to do simultaneous voice and data over 3G on AT&T and not on Verizon? That's because until the Thunderbolt, no CDMA device supported it. And even with the Thunderbolt, it unofficially supports it. You won't see that used as a selling point on any device because it's not a completely mature, ready for prime time technology. So far, HTC is the only company incorporating it on Verizon.

You can do simultaneous voice and data on any LTE phone as long as you have a LTE signal, but the Thunderbolt and Rezound are the only devices on Verizon that allow it on 3G as well.