Forum Discussion

mausmang's avatar
mausmang
Newbie Caller
9 years ago

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.

  • Hey there!  Just checking, you are a current T-Mobile customer and having problem with your service using an unlocked Moto G7?  Have you checked your APN settings to make sure everything is set up properly?  (This may be located under Settings>Network & Internet>Mobile Network>Advanced>Access Point Names)

    You should have an APN that is labeled as T-Mobile (or T-Mobile US LTE or something similar).  If you don't, you'll want to add it- select the big plus sign (or if you don't see one, tap the 3 dots in the upper right hand corner and select "Add New".  Input the following:

    • APN: fast.t-mobile.com
    • Proxy: Not set
    • Port: Not set
    • Username: Not set
    • Password: Not set
    • Server: Not set
    • MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
    • MMS proxy: Not set
    • MMS port: 80
    • MCC: 310
    • MNC: 260
    • Authentication type: Not set
    • APN type: default,supl,hipri,fota,mms
    • APN protocol: IPv6
    • APN roaming protocol: IPv4
    • APN enable/disable: Enabled
    • MVNO type: None
    • MVNO value: Not set
  • mausmang's avatar
    mausmang
    Newbie Caller

    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.

  • tmo_chris's avatar
    tmo_chris
    Spectrum Specialist

    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's avatar
    mausmang
    Newbie Caller

    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's avatar
    tmo_chris
    Spectrum Specialist

    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.

  • stevetjr's avatar
    stevetjr
    Connection Cadet

    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's avatar
    mausmang
    Newbie Caller

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

    5045I

    GSM 850/900/1800/1900

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

    VoLTE B12

  • stevetjr's avatar
    stevetjr
    Connection Cadet

    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;

    Supported T-Mobile networks