WiFi calling on non-T-mobile phone

    I like T-mobile. Especially because it allows me to bring my own phone to the party. Just plug your own SIM and it works. However, it appears that the very useful WiFi calling app (the app that allows people to call your own number when you are connected to a WiFi network) cannot be just installed. It can only come with an approved phone bought from T-mobile.


    Anyone knows how to resolve this? I really like this application, especially in the ares where T-mobile network is not available (or too expensive, like overseas). But T-mobile doesn't really sell all possible phones.

      All replies

      • e2k

        Re: WiFi calling on non-T-mobile phone

        The short answer to this question is that with a non-T-Mobile phone, you're on your own.


        It is possible (in some cases) to get wifi calling on a non-T-Mobile phone, but your phone must be using a T-Mobile based ROM (firmware). For example, I have an unlocked/rooted Samsung Galaxy S3 model SGH-I747 (sold by AT&T). After conducting extensive research, I found that I was able to install a modified T-Mobile stock ROM on my phone (a stock ROM is the software package that is distributed by the carrier). Since it is based on a T-Mobile stock ROM, it has the T-Mobile proprietary software that allows me to make calls via wifi.


        When I activated my T-Mobile account, the Representative at the T-Mobile store warned me that she could not guarantee that I would get the full functionality on a non-T-Mobile phone, and specifically said that wifi calling would not work (although I knew otherwise). In other words, she did her job correctly by setting the expectations from the onset.


        Depending on type of phone you have, wifi calling may be possible. However, you need to be prepared to do some hacking/tinkering with your phone, which could potentially render it useless if not done correctly. I would not recommend doing this unless you are a power user, and are comfortable with computers, smartphones, rooting, and flashing ROMs.


        What kind of phone do you have?

          • I have XPERIA Z3 Compact. One of the few usable non-giant phones on the market.

            So are you saying that WiFi calling requires some heavy proprietary SW to run? Sad. It is a very good feature, just as is the bring your own phone.

              • smplyunprdctble

                Re: WiFi calling on non-T-mobile phone

                It doesn't require heavy proprietary software.

                But it requires proprietary software.


                There's OS hooks that T-Mobile built into their devices that are required in order to get WiFi Calling to work.  Without these OS hooks (which aren't in non-T-Mobile built ROMs), WiFi Calling will not work.  There's no way around it.


                That said, WiFI Calling is supposed to be built into Android Lollipop in the spring for the Nexus 6.  That means the code should be available to be built into other devices.  Whether or not it happens is yet to be seen.

              • Hi e2k,


                I too have an att I-747 and am now Tmobile.


                I was wondering which ROM you decided on?  I've been looking at some of the TMobile ROMs that I could find, but not sure which one to pick.  Since you found a ROM that worked, I'd like to know which one it was.



                  • e2k

                    Re: WiFi calling on non-T-mobile phone

                    db2015 wrote:


                    I was wondering which ROM you decided on?


                    Hi db2015,


                    The ROM I chose to install is S3Rx 3.0 TouchWiz 4.3 NC2 (4-5-14) Full AROMA. It is a rooted stock ROM. Before installing, your phone should be rooted (or at least have TWRP or CWM installed so you can flash the ROM) & have the latest bootloader and modem installed for the I747 (not the T999).


                    Once installed, the ROM worked like a charm. There are a lot of options in terms of how to customize the ROM (you'll have several screens of options to go through just before the ROM is installed), but don't let that intimidate you. You can always change the customizations later, as it might take some experimenting to determine which options you prefer.


                    Good luck!

                  • Hey e2k.  Can you get me a link for that stock rom?  Everytime I try to flash a tmobile rom onto my i747 it fails a check?

                      • e2k

                        Re: WiFi calling on non-T-mobile phone

                        armedburrito wrote:


                        Hey e2k.  Can you get me a link for that stock rom?  Everytime I try to flash a tmobile rom onto my i747 it fails a check?




                        It works fine for me, but use at your own risk.

                          • Thanks so much man.  This is my first smart phone, and I did my first root yesterday.  This guide got me onto wifi calling, with my I747.  Unfortunately, the phone pad doesn't seem to work right, so I can't change the band I'm on using the USSD codes, but when I don't have data, I generally default onto CDMA only anyways.


                            I might change to one of the other OS options to use USSD codes, but for now, I'm better off than I was before.

                              • e2k

                                Re: WiFi calling on non-T-mobile phone

                                I once played with my network settings, and I stopped getting LTE. I had to re-flash the stock firmware (AT&T stock, not the modified TMO stock that I gave the link for) with odin in order to make LTE work again (a master reset did not work).


                                So you might try re-flashing the stock i747 ROM with odin (you will lose root), then rooting again. After a successful root, you can re-flash S3Rx. There's certainly no guarantee it will work, but I'd say it's worth a try.


                                Also, did change your APN settings to those of T-Mobile?


                                armedburrito wrote:


                                Unfortunately, the phone pad doesn't seem to work right, so I can't change the band I'm on using the USSD codes, but when I don't have data, I generally default onto CDMA only anyways.


                                I'm not sure how your phone would go into CDMA mode, since the i747 doesn't receive CDMA. Do you mean WCDMA?


                                LTE (4G)

                                band 4 / 1700 MHz   AWS (Americas)

                                band 17 / 700 MHz   Lower 700 (USA (AT&T))


                                WCDMA (3G / 4G)

                                band 1 (I) / 2100 MHz   IMT (Europe, Asia, Africa, Oceania, Brazil, India, Israel)

                                band 2 (II) / 1900 MHz   PCS (Americas)

                                band 5 (V) / 850 MHz   Cellular (Americas, Oceania, Brazil, Israel)


                                GSM (2G)

                                850 MHz / band 5   Cellular (Americas, Oceania, Brazil, Israel)

                                900 MHz / band 8   (Europe, Asia, Africa)

                                1800 MHz / band 3   DCS (Europe, Asia, Africa)

                                1900 MHz / band 2   PCS (Americas)

                        • tmo_phillip

                          Re: WiFi calling on non-T-mobile phone

                          Discussion successfully moved from Magenta Lounge to Non T-Mobile

                          • I'm in a similar boat as ilya. I've been with T-Mobile for over 10 years. When it came time to upgrade my phone, I wanted to stay with a Windows Phone because it would be easy to sync over all my info. However, I didn't want to pay $600 for the HTC and I wanted something better than the Lumia 635 or whatever. I asked around and Googled, but there didn't seem to be any mid-range Windows Phone in the foreseeable future. I was getting ready to jump ship even though I didn't really want to. Then I found out that I could get an unlocked Lumia 1020 from the Microsoft Store that was right in my price range. Success! I've had the phone for a couple of days now and I love it. Now I find out that I can't get Wi-Fi Calling on this device?


                            Seems like I should've jumped ship after all. I can't seem to win staying loyal to T-Mo.

                              • smplyunprdctble

                                Re: WiFi calling on non-T-mobile phone

                                No offense, but why it it T-Mobile's fault that a T-Mobile specific feature isn't available on a non-T-Mobile phone?


                                That's like complaining to Dell that their software won't work on an Asus.

                                  • Wasn't this whole TMO advertisement that the users can bring their own phones to TMO network? It seems that I don't have to get my phone from TMO only. I can just buy a phone, put a TMO SIM into it and it works. They forgot to tell one fine print.

                                    Besides, this isn't T-mobile's phone only feature. It is just an application that can be downloaded. If they really wanted it they could verify that the phone has T-mobile SIM before working. It seems a bit of an oversight or just laziness.

                                    We shall see. Rumors are that this feature will be built into Android 5.

                                      • tidbits

                                        Re: WiFi calling on non-T-mobile phone

                                        Unrealistic expectations is what I see.  It's more than a simple "download"  There's security hooks in conjunction with the HAL, and RIL.  Would you be happy let's say because they just plopped WiFi calling and then your personal information was leaked from your own home because of some simple exploit?


                                        Now with the Android 5.0 it allows payloads to be downloaded provided the manufacturer allows this to happen.  For example my Moto X(2014) does not allow this even if it has 5.0. Custom roms for 5.0 don't allow this either(CM12 for example).  So it still comes down to the manufacturer for their unlocked devices.

                                        • smplyunprdctble

                                          Re: WiFi calling on non-T-mobile phone

                                          Yes, but the advertisement does say some features may not be available.  Otherwise people would be making the same complaint because they have an iPhone 4 (or another iDevice that hasn't got WiFi Calling built in).  Or even *gasp* Blackberry!


                                          T-Mobile developed the WiFi Calling software.  It requires proprietary hooks to be compiled into the OS.  T-Mobile has shared the code with the OS developers to have it built in by default.  It's up to the OS creators (and subsequently the manufacturers) to build anything into their OS.


                                          Your comment about Android 5 -- Yes, Google has committed to publishing WiFi Calling in Lollipop sometime in "early 2015."  That doesn't mean a Samsung Galaxy S5 on AT&T that gets Lollipop will have WiFi Calling enabled in the OS because Samsung / AT&T may decide to disable that portion of the OS because it doesn't apply to AT&T.  That's not T-Mobile's fault if it's disabled, is it?  (The disabling of WiFi on AT&T devices is purely hypothetical, nobody knows how it's really going to shake down when WiFi Calling gets pushed into the Android OS.  But, features of an OS have historically been known to be disabled based on manufacturer / carrier.)

                                      • stevetjr

                                        Re: WiFi calling on non-T-mobile phone

                                        evie5 wrote:



                                        Seems like I should've jumped ship after all. I can't seem to win staying loyal to T-Mo.

                                        Jump where??  Only one other carrier Sprint (and only very recently) even has Wi-Fi calling and Sprint restricts it to domestic only where as T-Mobile doesn't care where in the world you are and doesn't charge you to use it to/from a US number, I use it internationally all the time. The Red and Blue have said they plan to do it down the road but don't seem to be in a big hurry even though T-Mobile made the technology open source years ago so anyone could use it.


                                        This isn't something T-Mobile does to "keep it to themselves", it has to be embedded into the OS for security reasons because it has to have access to the SIM card so it can be on the "carrier network" and "apps" cannot access the SIM card.  Microsoft, Android and until recently Apple could have put this in all US carrier versions but opted not to with Apple only recently baking it into the OS and Google apparently doing the same for Lollipop. Now in the case of Apple you won't see the choice unless you have the carrier specific (T-Mobile) update and I suspect that is because ATT & Verizon didn't want their customers to even see the option (even grayed out) because it is a service they don't offer so Apple probably obliged and hid the option unless you get the specific T-Mobile carrier update.

                                      • kevinmcmurtrie

                                        Re: WiFi calling on non-T-mobile phone

                                        I just upgraded a Moto X Pure to Marshmallow.  There's VoLTE but no WiFi calling.


                                        Rumor is that Cyanogenmod 13 (CM13) contains its own WiFi calling.  I have an unused OPPO Find 7 that will be perfect for experimentation once a build becomes available.  OPPO fully supports rooting so the phone is quite resistant to becoming bricked.


                                        Stock Android has too much Google shovelware and not enough customization so I'm looking forward to CM13 on my main phone once it's stable.

                                        • lucunlocked

                                          Re: WiFi calling on non-T-mobile phone

                                          I have a non-T-Mobile, unlocked Samsung Galaxy S7 edge SM-G935U.  I can tell you VoLTE and Wi-Fi calling work right out of the box.  There is no firmware, no stock roms, no apps, nor anything to install.  Just pop in a T-Mobile SIM and VoLTE and Wi-Fi calling are good to go.  

                                          • stevetjr

                                            Re: WiFi calling on non-T-mobile phone

                                            georgenj327 there is no official way that would be supported by TMO or Samsung.   You could look on XDA developers and see if someone has successfully ported a TMO load to the Verizon Note 3 but that would at your own risk loading and or bricking the phone.  Even if there were a version it would probably require keeping the Verizon radio software as that was still when the radios especially the Sprint and Verizon phones were different than the AT&T and TMO phones due to CDMA which were specific to Sprint/VZW.


                                            The other drawback to a device that old is it doesn't support any of TMO's low band (band 12 or 71) which vastly improves coverage both indoors and out nor the new AWS 3 band 66.

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