[superlawyer15]

So ..before the launch there was a lot of debate as to what the removal of DTM means
I'm sad to confirm that it results in the inability to talk and surf on LTE

The phone reverts to hspa+/3g once you are in a phone call

While this is by no means a deal breaker
I just wanted to let the rest if you know

[Laura Knotek]

That's an AT&T issue. AFAIK, all of their LTE devices do that.

[Citizen X]

The phone reverts to hspa+/3g once you are in a phone call

Just like my Lumia 900. Are you aware of any phone on At&T that doesn't do this?

[Laura Knotek]

Just like my Lumia 900. Are you aware of any phone on At&T that doesn't do this?

I don't know of any. The iPhone on AT&T does that too.

[crav4speed]

All LTE phones do this. LTE is for data only until VoLTE is implemented. When a phone call or a text comes in or goes out, it uses the 3G network.

[superlawyer15]

On Verizon I could talk on the phone and surf on lte

Its not a volte issue
You don't need the voice call routed on lte to use data on lte

[crav4speed]

On Verizon I could talk on the phone and surf on lte

Its not a volte issue
You don't need the voice call routed on lte to use data on lte

VoLTE has not been implemented on any network in the USA. On Verizon phones, calls and text are routed through their CDMA network and since you can't talk and use data simultaneously on CDMA, Verizon phones route the call through CDMA and keep the LTE radio active for data use, hence the reason for a sim card on Verizon phones. GSM phones work differently in that the radio disables LTE and routes voice and data through 3G. 3G allows for simultaneous voice and data so it's not an issue with GSM phones.

Edit: Sorry... Verizon does have VoLTE but I'm not sure if any devices actually support it yet.