Unlocked phones


    I am having some issues with unlocked phones.


    I have several of devices and none of the work properly on T-Mobile.   When I call support they basically blow me off because I am not using a T-Mobile branded handset.   They also assume that when you say "unlocked" phone that you have taken another carriers phone and had it SIM unlocked and are taking the phone from another carrier to T-Mobile.


    What support also does not seem to get is that there is a wide variety of factory unlocked phones that are designed for the North American GSM frequencies and some of these phones actually have features such as Band 12, VOLTE and WiFi calling.


    2 phones I am having trouble with specifically are the BLU R1 HD and the Alcatel Pixi4 (5).


    The BLU does not support Band 12/Volte.   The Alcatel does support Band 12.Volte.


    The Alcatel seems to work fine when it is on a 4G LTE single and the VOLTE indicator is lit.


    When these phones are showing that they are on a 4G signal, when you call the phone,the phone sometimes will not ring.   This is not consistent.  About half the time the phone will ring, but the other half the time the phone does nothing and the call rolls to voicemail.


    When the phone is called you can watch the signal icon change from 4G to 3G and the phone MIGHT begin to ring.   Sometimes the 4G indicator fails to change at all.   I have this issue at home, in the car and at work.   I do not think this is a signal quality issue.


    Both phones have no problem making outbound calls.


    I setup a new line of service on a new SIM and I have the same issue with the new number/account.  I also borrowed a T-Mobile SIM from a buddy, and it had the same issue.


    I went to ATT and setup a new prepaid account with them and these phones work perfectly. I would move my business to ATT but their data speeds are far too slow.


    What can be done to rectify this issue?   I think there is a problem with the 4G/3G handoff in my area, but I can't get T-Mobile to take this issue seriously.

      All replies

      • stevetjr

        Re: Unlocked phones

        Well from Alcatel's website the Pixi4 (5) doesn't actually support any of T-Mobile's LTE frequencies; (2, 4, & 12)


        GSM quadband 850/900/1800/1900. UMTS 850/900/1900/2100. HSPA+ (42M bit/s DL. 11Mbit/s UL) LTE B1/3/7/8/20/28A


        Also it doesn't support T-Mobile's primary HSPDA+ network which runs on the 1700/2100 Band 4.  Also T-Mobile really doesn't have a 3G network per se.  Their HSPDA+42 network (4G non LTE) is just backward compatible to HSPDA+21, HSPDA+ or HSPDA (3G) but is all the same network and radios on the tower.


        Here is a list of the T-Mobile frequencies used;


        T-Mobile network bands & technologies

          • mausmang

            Re: Unlocked phones

            You are looking at the specs for the global model.   I don't have that.



            GSM 850/900/1800/1900

            3G: B2/4/5; LTE: B2/4/5/7/12/17

            VoLTE B12

              • stevetjr

                Re: Unlocked phones

                Ok, even with those specs it doesn't support T-Mobile's HSPDA+ primary

                frequency (3G, 4G non LTE) which is Band 4 1700/2100 so if it drops off LTE

                it will drop all the way to 2G. If it can't maintain or complete a VoLTE

                call T-Mobile branded devices will roll back to 4G non LTE, maybe because

                it can't go find anything there it gets hung??

                  • mausmang

                    Re: Unlocked phones

                    Okay I was under the understating that G3 B4 is 1700/2100.


                    So then why does the BLU R1 HD have the same fault?


                    TechnologyGSM / HSPA / LTE
                    2G bandsGSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2
                    3G bandsHSDPA 850 / 1700(AWS) / 1900 / 2100
                    4G bandsLTE band 2(1900), 4(1700/2100), 7(2600), 17(700)
                      • tmo_chris

                        Re: Unlocked phones

                        Hey mausmang


                        I wanted to check and see if it was possible for you to try your SIM card in your buddies phone that let you barrow his SIM card. If his is a T-Mobile branded phone and the issue persists with your SIM in his phone, we can safely say that the issue with the network rather than the phone. If the issue is with the network, our tech support team can open an engineering ticket for you to have this looked at.

                          • mausmang

                            Re: Unlocked phones

                            Been there done that.  Ticket 13895274 was opened on Oct 28.  They don't take problems with unlocked phones seriously.  I can tell you that I just picked up a LeEco S3 and it works flawlessly.   Also I can report that all of the phones that are problematic have Mediatek chips.   Phones with Qualcomm chips have no problems.

                              • tmo_chris

                                Re: Unlocked phones

                                So with non-T-Mobile phones is is hard to say if they are going to work properly with all aspects of our network as they were not designed with the purpose of being used on our network. We ask that you test the sim in a known working T-Mobile phone so that we can see if the network is at fault as there are to many variables with non-T-Mobile phones.

                                  • mausmang

                                    Re: Unlocked phones

                                    Yes I have done this.  My SIM works fine in a T-Mobile branded phone.   But you know as well as I, that this SIM should work in ANY unlocked GSM phone provided that it supports US/T-Mobile frequencies.   Obviously this is not the case.   Doesn't matter now anyway....I have switched to another carrier and now all is well.