Will AT&T unlocked iPhone work on Verizon or any carrier?

Discussion in 'iPhone' started by bobright, Sep 20, 2012.

  1. macrumors 601

    Joined:
    Jun 29, 2010
    #1
    An AT&T rep said the pone wouldn't work on Verizon is this true (some bull about them using a different sim)? Is this just them blowing steam up my ass so as to not go to them?

    I mean I thought unlocked meant it can be used with any service. I sold the phone on eBay and am just curious don't want angry buyers saying they can't use the phone with certain carriers.
     
  2. macrumors member

    Joined:
    Apr 3, 2010
    #2
    My understanding is the 3G CDMA theoretically could work, but that Verizon won't activate it since it's not a phone intended for their network.

    Others can correct me if I'm wrong though.
     
  3. Moderator

    Nermal

    Staff Member

    Joined:
    Dec 7, 2002
    Location:
    Whakatane, New Zealand
    #3
    Correct. Verizon maintains a "whilelist" of phones that can be connected and this list only includes devices sold by Verizon.
     
  4. macrumors 6502a

    Joined:
    Aug 13, 2007
    Location:
    Yorba Linda, CA
    #4
    No, Unlocked AT&T phone will only work on TMobile or possibly other local carriers that use gsm. They will not work with verizon or sprint.
     
  5. macrumors Nehalem

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #5
    It can be unlocked and used with any GSM carrier.
    Big difference. Verizon and Sprint are CDMA and they wont allow any other carriers iphone on their network.
    Hope the buyer is more educated than you on the topic.
     
  6. thread starter macrumors 601

    Joined:
    Jun 29, 2010
    #6
    LOL ok makes some sense I am sure they will be good.

    I take it most people buying unlocked will be using them on the cheaper priced services such as cricket and use edge data etc ?
     
  7. macrumors Nehalem

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #7
    Correct.
    Either Tmobile or other prepaid gsm carriers or to also be able to use them internationally with any gsm sim.
    Cricket is CDMA btw so it will never work on that carrier either.
     
  8. macrumors 65816

    Joined:
    Jan 29, 2008
    Location:
    Chicago
    #8
    I don't think Cricket is GSM either, I believe they have their own version of the iPhone as well (as does Virgin Mobile). I think Simple Mobile, Straight Talk, and T-Mobile are the main alternatives. There may be some regional carriers too.

    The advantage is that you pay less monthly, but the disadvantage is you typically lose visual voicemail, MMS (I think), and maybe limited to 2g (EDGE) data unless you are using a MVNO that rents from AT&T.

    The best way to use Virgin Mobile or Cricket or another iPhone carrier that's prepaid is to just buy the iPhone through them.
     
  9. thread starter macrumors 601

    Joined:
    Jun 29, 2010
    #9
    ok got a question though, what if the phone was purchased "unlocked" at the full price Apple sells them 7-800 or whatever the ridiculous price is, and it wasn't later unlocked via itunes like mine was. would the phone purchased that way work with CDMA or GSM? or would they have to be on GSM as well?

    If they are completely different I might need to re-list my auction and state this as the phone really isn't fully unlocked then, or so it seems that way after hearing this.
     
  10. macrumors 6502

    Joined:
    Mar 16, 2012
    Location:
    Melbourne Australia
    #10
    /facepalm :eek:
     
  11. stevedusa, Sep 20, 2012
    Last edited: Sep 20, 2012

    macrumors regular

    Joined:
    Jun 12, 2012
    #11
    Many of you are still in the woods about this whole unlock thing.

    The lock we are talking about here is called a "subsidy lock". As we all know it's a method of keeping that phone to only operate with the carrier's network.

    There are two network modes being used in the States. One is GSM, which consists of AT&T and T-Mobile. The other is CDMA, which consists of Verizon and Sprint.

    The difference here is that how the phones operate and behave on each network.

    A GSM phone identifies the subscriber (YOU) via the little chip called a SIM (Subscriber Identification Module). While the CDMA device uses a BURNT-IN, READ-ONLY ESN (Electronic Serial Number) to identify both the device AND the subscriber.

    In certain parts of the world certain CDMA carriers DOES use removable subscriber ID modules, but they are not called SIM, instead they are called R-UIM (Removable User Identification Module). It behaves just like a SIM card on GSM phone but THEY ARE NOT INTERCHANGEABLE. i.e. you can't use a SIM card on a CDMA phone and vice versa.

    Don't get confused with having a SIM card inside a CDMA devices that supports LTE. Keep in mind that LTE is a GSM extension. In order to have your device operate on a LTE network, you HAVE to use the SIM card. For CDMA/LTE hybrid device the sole and only purpose of that SIM card is to operate on LTE network. While the voice and legacy data (EvDO/1xRTT) still relies on CDMA.

    Here's the tricky part. To lower the cost and minimize the amount of model variants of the iPhone 5. Apple decided to cramp BOTH operation modes into the phone, and only kept the LTE radio different due to carrier differences.

    In the States, CDMA devices uses the ESN method for the carrier to identify them on the network. There no such a thing as a subsidy lock on a CDMA device as the identification module is permanently fixed inside the phone. Unlike GSM counterpart phones all you have to do is take the SIM card with you. With CDMA devices you can't, at least in the States.

    The reason being it's a pure business decision. Carriers, especially CDMA carriers simply don't want devices that were not designed for their network to operate on their network. Thus the ESN whitelist exist. Technically just like GSM devices, CDMA devices don't discriminate where and whom it works on, unless the carrier tells it so.

    When people stated that it's unlocked, that means the phone has no subsidy lock on GSM part. CDMA is a different story all together.
     
  12. macrumors 6502

    fibrizo

    Joined:
    Jan 23, 2009
    #12
    I understand what you are trying to get across to people, but you're wrong also. Sprint CDMA phones have a MSL code, or "Master Subsidy Lock". You need this code to enter new MINs, MDNs, and PRLs etc. With this, it is possible to take a Sprint phone, like I did with nexus S 4G, and use it CDMA only on Page Plus (Verizon MVNO). That said, you are right in saying no you can only use Verizon iPhones on Verizon's network. An unlocked iPhone will only work on GSM networks.
     
  13. macrumors regular

    Joined:
    Jun 12, 2012
    #13
    Ah the MSL... thanks for reminding me on that one. It's been a while since I left Sprint and I remember trying to get CS to give me the MSL so I can edit the cycle rate to make the phone ring earlier lol.

    But yeah it is a way to reprogram the ID of the device. However ESN still remain untouched even if you have the MSL, I believe.
     
  14. macrumors Nehalem

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #14
    No, they're both the same thing and work the same.
    Either purchased factory unlocked or officially unlocked by the carrier(at&t).
    It can ONLY work on GSM networks.
     
  15. thread starter macrumors 601

    Joined:
    Jun 29, 2010
    #15
    I guess rest assured for me then, here's the deal.

    In no way am I trying to be dishonest or anything but my iPhone was sold earlier and paid for on ebay a few hours ago. Now when I listed it, you know how you search for the pre-filled item descriptions when listing? I listed it as "Factory Unlocked" because I had just unlocked it and that's all that came up. The other descriptions which didn't mention being unlocked all had info about the phone being tied to AT&T.

    Sooo fast forward to now if you say having it unlocked by AT&T is the same as being purchased unlocked from Apple I should be alright then? I was about to notify them just now that it will only work on a GSM carrier and if they want a full refund I'll issue it...but if all unlocked iPhones be it from the factory are this way I'm thinking there's no need for that. I just might do it anyway hopefully this makes sense.
     
  16. thread starter macrumors 601

    Joined:
    Jun 29, 2010
    #16
    So as a follow up refunded the guy and am relisting my phone can ya give me some tips on listing, Juiced

    Should I put it was unlocked by ATT and can only be used GSM carriers??

    I dont want to screw anything up this time
     
  17. macrumors Nehalem

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #17
    Yes.
    You can put it as carrier unlocked that can be used with any gsm carrier.
    That should be clear enough. You'll sell it quick.
     
  18. thread starter macrumors 601

    Joined:
    Jun 29, 2010
    #18
    I was hoping you'd respond to me soon as I wanted to list my phone before the night falls, I did just that. I wanted to be fully upfront though so I just put it was unlocked by AT&T and can be used with any gsm carrier.

    Thanks so much man it's really appreciated.
     
  19. macrumors regular

    Joined:
    Jun 18, 2010
    Location:
    Wichita, KS
    #19
  20. macrumors Nehalem

    Applejuiced

    Joined:
    Apr 16, 2008
    Location:
    At the iPhone hacks section.
    #20
    Nice, good luck bro.
    Hope you find a buyer for it fast.
     

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