[Charlie Pelosi]

im using a 925 on tmobile and the wifi calling feature is very important to me.
I'd like to know if the 1520 on at& also has wifi calling. I'm thinking of switching.
Thanks!

[Big Papa Smurf]

As far as I know, wifi calling is for tmobile branded devices only.

[RumoredNow]

Big Papa Smurf nailed it. ONLY T-Mo branded phones get to run T-Mo WiFi calling App. Your phone won't even see the App in the Store.

[manicottiK]

im using a 925 on tmobile and the wifi calling feature is very important to me.
I'd like to know if the 1520 on at& also has wifi calling. I'm thinking of switching.
Thanks!

If you're thinking of switching networks from T-Mobile to AT&T, the importance of WiFi calling may diminish because AT&T currently has greater coverage (more area and more building-penetrating power) than T-Mobile. Over the coming year, the T-Mo macro network should improve in both of these areas as they deploy more of the 700 MHz spectrum that they bought from Verizon in early 2014. Likewise, AT&T and Verizon are both likely to deploy WiFi calling features in 2015 or 2016.

[Al4video]

None of this will matter unless you are on a branded device.

[RumoredNow]

None of this will matter unless you are on a branded device.

​...AND on the service it is branded to.

[Big Papa Smurf]

​...AND on the service it is branded to.

IE: A T-Mobile branded phone on T-Mobile service

[aximtreo]

Couldn't he use the 1520 on T-Mobile and maintain Wi Fi calling if the 1520 is unlocked?

[HoosierDaddy]

Couldn't he use the 1520 on T-Mobile and maintain Wi Fi calling if the 1520 is unlocked?

No, unlocking doesn't change that its not loaded with a T-Mobile ROM. T-Mobile Wi-Fi calling requires a special app. It won't be offered or installed on other phones. If T-Mobile offered a 1520 that was hardware identical, in theory you could load the T-Mobile ROM and be good to go but T-Mobile never sold any 1520s.

I don't know why the T-Mobile Wi-Fi calling app isn't offered for BYOD devices. I hope its because it couldn't possibly work without special firmware. If its because they just want to pressure you to buy phones from them, well that's very un-un-carrier like. So I'll believe its a firmware issue.

[manicottiK]

I don't know why the T-Mobile Wi-Fi calling app isn't offered for BYOD devices. I hope its because it couldn't possibly work without special firmware.

I believe (thus do not actually know) that the network protocol needed for "other network calling" isn't in Windows Phone 8.x.

Given that the iPhone 6 works with WiFi calling and that Verizon and AT&T have said that WiFi calling will eventually come to them, it would be interesting to know if an AT&T- or Verizon-branded iPhone 6 could use WiFi calling on T-Mo.

[HoosierDaddy]

Given that the iPhone 6 works with WiFi calling and that Verizon and AT&T have said that WiFi calling will eventually come to them, it would be interesting to know if an AT&T- or Verizon-branded iPhone 6 could use WiFi calling on T-Mo.

It couldn't if they require an app like T-Mobile does.

WiFi calling is basically just VOIP with the carrier being the VOIP provider. The apps have to talk to the VOIP servers of the carrier so there is virtually no way the Wi-Fi calling app for AT&T (for example) could work with the T-Mobile Wi-Fi calling VOIP servers. And we know T-Mobile won't install their app except on phones they sell.