Help Me Understand Wifi-Calling Limitations per Carrier

[ThermoDust]

I recently switched to T-Mobile from AT&T. iPhone = No problem turning on Wifi Calling. Microsoft 640 Wifi calling not an option to even enable. How is it that Wifi-Calling is baked into Windows 10 Mobile but it doesn't work unless you have a carrier branded phone? Or is it that the Apple phone stack is more advanced?

 

[libra89]

I think it might be something about carrier permissions. For some reason, it doesn't work with Windows Phone, but the Nexus 6p, 5x, and the iPhone have some kind of auto permission/toggle that allows it.

 

[jpharwood]

The AT&T and T-Mobile versions each have slightly different ROM. The T-Mobile ROM has an additional LTE band as well as having wifi calling enabled. There is a thread on the 640 forum with directions on how to install the T-Mobile ROM on your phone. I think it was titled "de-branding...". Good luck, having wifi calling is a big plus

 

[ma678]

I recently switched to T-Mobile from AT&T. iPhone = No problem turning on Wifi Calling. Microsoft 640 Wifi calling not an option to even enable. How is it that Wifi-Calling is baked into Windows 10 Mobile but it doesn't work unless you have a carrier branded phone? Or is it that the Apple phone stack is more advanced?

Op, you will have to debrand your At&t lumia 640, flash T-Mobile ROM, change product code to T-Mobile's, and update nvi to get wifi calling on your 640.

 

[ThermoDust]

I think most misunderstood my post. I know I can change my phone over by applying the t-mobile rom. My comment was on the fact that it is harder than it should be in comparison to an iPhone for example. With the iPhone all I had to do was get AT&T to unlock my phone and then when I switched to t-mobile I just turned on a toggle, bam wifi-calling worked.

With Windows 10 Mobile, all be it an AT&T "version", you cannot do something as simple as that.

The one thing I am wondering is can the Lumia unlocked(carrier neutral) 950 or 650 work on Wifi-Calling on any or all of the carriers?

 

[Bob Hanson]

@ThermoDust: Blame AT&T. Their ROM disables t-mobile features.

 

[libra89]

I think most misunderstood my post. I know I can change my phone over by applying the t-mobile rom. My comment was on the fact that it is harder than it should be in comparison to an iPhone for example. With the iPhone all I had to do was get AT&T to unlock my phone and then when I switched to t-mobile I just turned on a toggle, bam wifi-calling worked.

With Windows 10 Mobile, all be it an AT&T "version", you cannot do something as simple as that.

The one thing I am wondering is can the Lumia unlocked(carrier neutral) 950 or 650 work on Wifi-Calling on any or all of the carriers?

There will be the toggle, but it most likely wouldn't work because the carrier has to approve it or something along those lines.