AT&T blocking unlocked phones?


Last Updated: 2012-01-17 04:56:47
  1. MrHoon

    MrHoon New Member

    I have a galaxy s2 white unlocked and recently I have been getting alot of problems with it

    Everything works fine except the data portion. I looked all around the internet only to see that there are very very few people with the same problem as I

    I got it fixed at one point where out of 10 tech support guys only 1 guy knew what I was talking about and spent nearly 20 minutes trying to help me and it did! Until today the internet stopped working once again

    I called up their tech service and eventually found another guy. he spent 20 minutes trying to help me and even told me "Last week I had another guy who had the same problem and same phone as you and I fixed it for him"

    But today he said it just didn't work. He told me that I might be one of those unlucky few OR that it might be a problem with my sim card.

    My sim card is the really old sim card from the Iphone 3G phones (The blue one with the corny blue flame with 3G written inside). Im hoping this is the source of my problem, but it doesn't make sense.

    Just hours ago 3G and HSPA+ was running totally fine even with the old ass sim card. Im hoping changing my sim card will fix this whole debacle but something tells me it won't...

    Can you guys help a man out? I can't even return my phone anymore since so much time passed by and it would be a total bummer if my phone is now a paperweight.

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  2. colnago

    colnago Well-Known Member

    FWIW, I have read multiple posts on various forums, stating that "getting a new SIM card helped resolve my connectivity issues", for both AT&T and T-Mobile, for various phones.
  3. Medeksza

    Medeksza Member

  4. colnago

    colnago Well-Known Member

    What APN settings are you using? I have had no problems, for the past year or so, with my T-Mobile branded Motorola Defy on AT&T's 3G network. One thing you may have to do is create a new APN entry, and name it something other than the default, and use the new APN, vs. what is created by the SIM card (e.g. att, or Ma Bell, etc.). I only have:

    APN: wap.cingular
    MMSC: http://mmsc.cingular.com
    MMS proxy: wireless.cingular.com
    MMS port: 80
    MCC: 310
    MNC: 410

    ...everything else is either blank, or set to default.
  5. Medeksza

    Medeksza Member

    My APN settings were as follows:
    I tried your settings and it worked just the same as my previous settings, meaning the 3G connection would last from about 1 to 15 minutes, and then drop, display the "refreshing sim data" error, reconnect, and repeat. My data plan is called Media Net Unlimited or "GPRS WAP UNLTD DOM - MN21" on my bill. Also MMS messages don't work at all.

    When I put the sim card in my old Nokia N79 phone, everything works, data works and stays connected, and MMS messages work fine too.
  6. chicknlil

    chicknlil Well-Known Member

    My bet is that the media Net Unlimited is the root of your problems. That's not the same as a smartphone plan. I'd imagine if you got the proper plan, your issues would go away.

    As for the OP, I'd imagine a new SIM would solve that issue.
  7. colnago

    colnago Well-Known Member

    Did you try with the Proxy server info as (blank), and the APN type as (default)? I have the same data plan, and with those settings (again, literaly only the APN name and MMS settings are the settings with values) and I am not having your problem.

    Again, this is with a full feature Android phone, from a different carrier. Try changing the connection name from "Media Net" to "Att Test".
  8. colnago

    colnago Well-Known Member


    I have full internet access via the same Media Net plan, including VoIP/video calls, using both Android and non-carrier branded Nokia "smart phones".
  9. Medeksza

    Medeksza Member

    I figured out a work around for my issues. If I force the phone to use a 2G EDGE connection instead of 3G H+ it maintains a reliable (albeit slower) data connection. If its set to 3G or set to automatically decide which network mode to use then I get the frequent random disconnects. I'm still wondering whether this is a provider/plan issue or a hardware issue though.
  10. Screech

    Screech Well-Known Member Contributor

    I agree with colnago. I too have MediaNet unlimited on my phone with no issues. Prior to the SGS2 I had a Sony Ericsson Aino (unbranded non-smart phone from Sony store) and both work fine once I manually entered my APN settings.
  11. rui-no-onna

    rui-no-onna Well-Known Member

    For what it's worth, I have no such issues with an unlocked Samsung Nexus S i9020a bought from ebay when I temporarily used it with my brother's iPhone 3GS SIM card with the requisite 3G data plan.
  12. Baldilocks

    Baldilocks Well-Known Member

    My unbranded Galaxy S II works just fine on the $10 Unlimited MediaNet plan. My H+ speeds average right around 4-5Mbps and I stay connected without fail.
  13. KaBiela

    KaBiela New Member

    OP, I was doing a Google Search and found this post-- as I have the exact same problem. I have a unbranded unlocked Galaxy S II i9100 and using an old AT&T "3G with Fire logo" SIM card.

    My phone keeps switching from H+ to 3G (you can see the icon on the top tray) and the connection is very unreliable, dropping connection and reconnecting every few seconds. It's fine for small email downloads, but anything sustained, it won't do as the connection is dropped... Quite frustrating...

    The SIM card is from like 2007 so it's old; maybe it's a card thing, as others have noted... SMS, MMS, Phone all work fine. It's just the data (3G/HSPA+)...
  14. colnago

    colnago Well-Known Member

    HSPA to HSPA+ switching is normal, especially in a marginal signal area, where signal strength is below -91dBm. If the switching is happening in a stable area, where signal I'd consistently between -55dBm to -65dBm, then I'd be concerned about the phone, then the SIM.

    In my experience w/Samsung, the signal levels are typically 8-10dBm worse than other phones I have...could mean the difference between a stable connection or not.
  15. nb_mitch

    nb_mitch Well-Known Member

    Get a new SIM card, I got one last month when I broke my lost/Dell Streak, just walked into a store and asked, checked my info and gave me a new SIM so I could use my old Blackberry until I got a replacement.

    And it was FREE, not much from At&t comes for free ;)
  16. the co0kie

    the co0kie Well-Known Member

    Get a new sim card, 3g similar cards have problems in new phones and they might have to activate hspa+ for your account, they usually have to do it
  17. Therethennow

    Therethennow Member

    The Galaxy SII is a 4G phone, right? (I should totally know this already.)

    You can't use the old, 3G or earlier AT&T SIM cards in a 4G AT&T phone. You'll have problems with your data, because it runs exclusively on the new 4G network. Your calling will still work, since the network falls back to the older technology to handle calls.
    If your 4G phone came with a new 4G SIM card, make sure you don't misplace it, because AT&T will probably tell you that you need to use the new card to fix the data issue. I'm genuinely surprised more people haven't called in to AT&T about this yet. (Can you guess what my day job is, lol?)
  18. Baldilocks

    Baldilocks Well-Known Member

    Wrong.

    It will work just fine with any AT&T SIM card. The Galaxy S II is an HSPA+ phone. While considered 4G by AT&T, it's not the same thing as 4G LTE.

    You do not need a '4G' SIM card to use the high speed network with the GS II.

    The reason no one has called in to AT&T about it yet, is because there is no reason to.

    Again, the information you have supplied is false.
  19. nonie

    nonie Active Member

    Att told me the 3g sim,will not work in the 4g phone.

    Wish it did, I'd buy it.
  20. colnago

    colnago Well-Known Member

    Again it depends on which "4G" they are referring...HSPA+, or LTE.
  21. Baldilocks

    Baldilocks Well-Known Member

    Exactly. You don't need a '4G' SIM card to use an HSPA+ phone.

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