AT&T iPhone 6s with Verizon or T-Mobile service

Discussion in 'iPhone Tips, Help and Troubleshooting' started by nadia p., Feb 12, 2016.

  1. nadia p. macrumors newbie

    Mar 18, 2013
    I own an unlocked iPhone 6s I purchased from AT&T that has been unlocked by AT&T. I've been looking at switching carriers to either Verizon or T-Mobile which seem to offer better calling packages.

    Verizon has confirmed that the iPhone 6s's IMEI number works on their network. What I don't know is how well this works and wondered if anyone had any feedback if they've done this before. I would prefer not to have to sign-up and then find out it works but not very well.

    T-Mobile from what I understand should work and they are offering a very good calling plan, at least for me, since I call Canada and México frequently. I don't know how well this works either since I believe AT&T's iPhone 6s does not have T-Mobiles extended frequency/network as if the phone was purchased from Apple or T-Mobile directly.

    If anyone can help offer any suggestions, advise or their own experiences I'd be grateful. I really don't want to have to keep paying for "start-up" fees to be able to test and see which carrier works best with this phone. The data usage and speeds are not that much of an interest to me, I currently use less than 200mb per month now.
  2. jpiszcz macrumors 6502

    Mar 28, 2010
    I did the same thing with my unlocked iPhone 6S Plus:

    1. T-Mobile charged $15 for the SIM in the store and ~$72 for the first month (6GB Plan) = $87/total
    2. Verizon charged ~$97 or so for the 3GB plan for the first month. (there was a $20 actiivation fee) so it would of been $77/month in theory.
    3. ATT 3GB plan is $65/mo with employer discount.

    VERIZON Experience using an unlocked iPhone 6S Plus (in Northern VA)
    1. I noticed the LTE signal is nowhere near that of AT&T.
    2. With AT&T typically you will have 3-5 bars everywhere you go (on LTE) (-82 to -102)
    3. With Verizon, I found myself typically having 1-2 bars, sometimes 3, if I drove near a tower (within 100ft) I would get 4 bars.
    4. If you use Verizon on LTE and you are on a call using VoLTE calling and you lose LTE signal and go down to 3g, it will drop because there is no handoff from LTE to 3G.

    T-Mobile Experience using an unlocked iPhone 6S Plus (in Northern VA)
    1. I could not hear party when I called (I tried to call out 2-3 times, nothing)- called again later 8-10+ minutes later and it worked, but this is not acceptable to me, not being able to make a phone call with 5 bars or -82dbm.
    2. Robot voice/slow motion (experienced this once or twice)
    3. Delayed text messages (some text messages - I did not receive until > 24 hours later)
    4. FaceTime over cellular was not working correctly (other users reported this too) and they opened a case and said they would call me back in three days, 1-2 weeks later, I did not hear anything from them and the problem was not fixed. Basically FaceTime over cellular is unusable on iPhone and it is something I use regularly.
    5. Visual voicemail stopped working (someone called and left a message earlier in the day) and on my iPhone is showed a red circle with no number in it. I rebooted the phone/etc, same issue. Visual voice mail was not available, it kept dialing to the voicemail telephone number to get the message that way.

    After all of this, I was done. If folks can live with these issues or do not experience them, nice! The speed with T-Mobile was #1 bar-none, but basic functionality (and coverage for some in rural areas) is lacking.



    Here are some statistics in Northern Virginia for LTE only, speeds are in Mbps

    - ATT: Fairly reliable but does occasionally drop calls when driving and sometimes when stationary, extremely slow performance in Northern VA during peak hours.
    - T-Mobile: Voice quality not as good as Verizon, great speed/performance, coverage an issue if not in a populated area.
    - Verizon: Best voice quality, best network but throughout and network is horrible in buildings.

    T-Mobile Download and Upload Average over 58 speedtests:

    $ cat t | awk '{total += $6/1000; count++} END { print total/count }'
    $ cat t | awk '{total += $8/1000; count++} END { print total/count }'

    Verizon Download and Upload Average over 25 speedtests:

    $ cat v | awk '{total += $6/1000; count++} END { print total/count }'
    $ cat v | awk '{total += $8/1000; count++} END { print total/count }'

    AT&T Download and Upload Average over 36 speedtests:

    $ cat a | awk '{total += $6/1000; count++} END { print total/count }'
    $ cat a | awk '{total += $8/1000; count++} END { print total/count }'

    ++EDIT: calculations were /1000, forgot to update the text here
    --- Post Merged, Feb 12, 2016 ---
    I am highly interested to hear any other people who have an unlocked AT&T iPhone 6S/6S PLus and your experiences on other carriers (particularly Verizon, see this):
    --- Post Merged, Feb 12, 2016 ---

    Also why are you looking at switching carriers? What issues do you have with AT&T?
  3. nadia p. thread starter macrumors newbie

    Mar 18, 2013
    Thank you so much for you comments jpiszcz, I really appreciate it.

    I find many people tell me it works but as you've mentioned how well and how reliable is it is what counts. As there seems to be several models of iPhone 6s it would be interesting to learn which models people have to help put things into perspective.

    I had some suspicions that Verizon may not function as well on AT&T's model of iPhone 6s yet I thought T-Mobile might have a greater potential for success being that they too are GSM based vs. CDMA based like Verizon.
  4. C DM macrumors Sandy Bridge

    Oct 17, 2011
    For iPhone 6s (and 6s Plus), T-Mobile, Verizon, and Sprint use the same models (just AT&T has a slightly different one as far an additional LTE band 30 that it supports):
  5. jpiszcz macrumors 6502

    Mar 28, 2010
    Found the link:

    See the underlined part below.

    For operational and marketing reasons, there will be four models: A1633[/A1634], A1687[/A1688], A1690[/1], and A1699[/1700].

    All models are mobile phones with multimedia functions (music, application support, and video), Cellular GSM/GPRS/EGPRS/CDMA2000 1x Advanced/EVDO Rev.A /WCDMA/HSPA+/DC-HSDPA/HSUPA, LTE FDD/TDD & Carrier Aggregation / TD-SCDMA, VoLTE radio, IEEE 802.11a/b/g/n/ac radio 2x2 MIMO, Bluetooth radio and NFC. The rechargeable battery is not user accessible.

    All models have identical PCB layout, design and functionality except A1634 has Tx and Rx filter for Band 30.

    Model A1633[/A1634] was set as the primary model for testing.
  6. nadia p. thread starter macrumors newbie

    Mar 18, 2013
    Great feedback! I have a better understanding of the hardware specs per model number now. Mine is model A1633.

    Is there a way to find out which LTE Band the phone is connected to? I looked under Settings... but wasn't able to find anywhere this is shown. This seems very useful to know to when comparing speedtests and/or voice quality.
  7. jpiszcz macrumors 6502

    Mar 28, 2010
  8. nadia p. thread starter macrumors newbie

    Mar 18, 2013
    Hi jpiszcz, I think you're on to something. I'll see if Verizon and/or T-Mobile will allow me to insert one of their SIM cards into my iPhone 6s to see which LTE bands they use. If they do or I end up purchasing service I'll report back my findings.
  9. nadia p. thread starter macrumors newbie

    Mar 18, 2013
    hi! I wanted to let you know I signed up for Verizon's service on a trial period today. Using *3001#12345#* I've checked the LTE bands I've been able to access. So far with only a few hours use I've accessed Freq Band Indicator 4 and 13.

    The "bars" or signal strength at the retail store was of course 5 and home they are 2. So far the call quality has been exceptionally clear, very good customer service, I've not yet attempted to download anything to see which band, data size and time it takes to download. I need to come up with a few testcases that I can try to measure when connected to various LTE bands.

    Let me know what else anyone would like me to test, I'll try my best.
  10. nadia p. thread starter macrumors newbie

    Mar 18, 2013
    I have discovered one important fact which has been confirmed by both Apple and Verizon.

    If you have an unlocked AT&T iPhone 6s (A1633) and you activate Verizon as the carrier there is a iOS 9.2.1 software limitation specific to Verizon's Visual Voicemail only which will only allow this feature to work when Cellular Data is enabled regardless if Wi-Fi is enabled or not.

    If Cellular Data is disabled you will see the following message displayed in the Phone app's Voicemail feature.

    Visual Voicemail is currently unavailable.
    Call Voicemail

    When this happens two things occur, first you won't receive any updated notifications in the Phone app's Voicemail feature of new voice messages left for you to retrieve. Second you'll have to enable Cellular Data to download new messages to your phone, this can not be done over Wi-Fi with this particular model due to this software limitation You may still call Voicemail to check and monitor your messages.

    While Cellular Data is disabled the only way to receive visual notification under the Phone app's Voicemail feature is to disable Verizon's Visual Voicemail using Verizon's app itself or on-line through Verizon's web site.
  11. jpiszcz macrumors 6502

    Mar 28, 2010
    > The "bars" or signal strength at the retail store was of course 5 and home they are 2

    What is the actual number at the top left (signal strength/dbm) when it is 2?
  12. Kinkade macrumors member

    Jun 19, 2007
    I have been thinking about taking my unlocked 6s to either T-Mobile or Verizon. I get very poor indoor signal in the LA/OC area of California.

    I tried both a Verizon sim and a T-mobile sim and found that both had better connection and speeds, but Verizon was the best indoors.

    For a while AT&T was getting better. A year ago I was able to stop using my microcell because their coverage indoors had become so much better.

    But it seems like whatever improvements they made disappeared. In the last few months I have had to turn LTE off and use 4G indoors, but even that is often crap.

    The reason I haven't switched is that I am grandfathers into an unlimited plan and average 6GB a month, sometimes going over 10, and I have a very decent employee discount on my plan. The competitors rates simply don't compare.
  13. rigormortis macrumors 68000


    Jun 11, 2009

    I've tried doing field test mode, just to see what LTE channel my iPhone is using at any given time, and a lot of them are blank. i just don't get it. is there a program besides field test mode that will tell you if your iPhone is on channel 12?
  14. jpiszcz macrumors 6502

    Mar 28, 2010
    Turn off wifi then turn on airplane mode and turn airplane mode off when in the screen the band should update

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