Elite From Hong Kong, joined Jun 2006, 2760 posts, RR: 10 Posted (3 months 2 weeks 4 days 2 hours ago) and read 525 times:
Hi all,
Just got an unlocked iPhone 5 in Hong Kong and am trying to use it in the US with AT&T - this is allowed, but AT&T mysteriously can't get it to work on their systems. I'm not ready to just throw out my brand new iPhone, so I was wondering if this was an AT&T problem and what other carrier would work.
rutankrd From United Kingdom, joined Sep 2003, 1998 posts, RR: 5 Reply 1, posted (3 months 2 weeks 4 days 2 hours ago) and read 503 times:
Yes its an ATT problem "closed door"- Your Hong Kong Sim if set up for international roaming should work on the ATT network at International Rates, however the ATT pre-pay cards ONLY work for calls and not for DATA on 3G and give up on LTE what with the differing bands and support around the world.
Catch 22
You could try T-Mobile US pre-payment Sim that might work but will limit you to GPRS 2.5G speeds for DATA as they use a unique and unsupported 3G frequency.
Forget Verizon and Sprint - they don't allow activation of the built-in CDMA radios on none supplied phones period and again your LTE radio frequencies might not be compatible in any case.
The US mobile industry works very hard to make international roaming as difficult as possible.
You may have to search for a third party SIM solution, with caveat rates tend to be higher for DATA and texting from an iPhone may not work
Elite From Hong Kong, joined Jun 2006, 2760 posts, RR: 10 Reply 2, posted (3 months 2 weeks 4 days 2 hours ago) and read 494 times:
Quoting rutankrd (Reply 1): You could try T-Mobile US pre-payment Sim that might work but will limit you to GPRS 2.5G speeds for DATA as they use a unique and unsupported 3G frequency.
I'm a technological idiot - does this mean if I get a plan (they have a decent plan, $50 for unlimited) the sim card might not also work?
StarAC17 From Canada, joined Aug 2003, 3225 posts, RR: 9 Reply 3, posted (3 months 2 weeks 4 days 1 hour ago) and read 479 times:
Quoting Elite (Reply 2): I'm a technological idiot - does this mean if I get a plan (they have a decent plan, $50 for unlimited) the sim card might not also work?
It should work for calls and texts without an issue.
What it means is that your Data speeds will be a lot slower and run at 2G speeds and not the faster 3G or 4G LTE speeds because your Iphone can't find the frequency that US providers use.
The Iphone 5 should get 3G basically everywhere but you won't get LTE in the US.
Quoting Elite (Reply 2): I'm a technological idiot - does this mean if I get a plan (they have a decent plan, $50 for unlimited) the sim card might not also work?
It should but there is no guarantee.
The only good thing is if you get a plan and it doesn't work out you can cancel it after a month or two as you won't be locked into a contract because you are providing the phone.
StarAC17 From Canada, joined Aug 2003, 3225 posts, RR: 9 Reply 5, posted (3 months 2 weeks 4 days ago) and read 454 times:
Quoting Elite (Reply 4): I'd be fine with just 3G, but right now with my AT&T sim I'm not even picking up 2G. No data whatsoever.
I would talk to AT&T about this and possibly make a trip to the Genius Bar as you should have an EDGE connection at least if it works as a phone. Try turning the LTE off and see if that makes a difference because it may be looking for an LTE signal it can't find and won't find 3G at all.
This link gives some Info about using an unlocked Iphone 5 in the US.
ABQ747 From United States of America, joined Dec 2006, 833 posts, RR: 1 Reply 6, posted (3 months 2 weeks 3 days 7 hours ago) and read 396 times:
Quoting rutankrd (Reply 1): You could try T-Mobile US pre-payment Sim that might work but will limit you to GPRS 2.5G speeds for DATA as they use a unique and unsupported 3G frequency.
That used to be the case, but T-Mobile has been refarming their spectrum to the more common 1900 MHz frequency.
Here's a map of the cities where T-Mobile has 3G coverage for the iPhone: http://www.airportal.de
The reason New Mexico is so windy is because Texas sucks and Arizona blows.
willzzz88 From United States of America, joined May 2011, 95 posts, RR: 0 Reply 7, posted (3 months 2 weeks 3 days 4 hours ago) and read 371 times:
The reason this does not work is because you need to change the APN (technical profile for data routing on the phone) to AT&T's because you have an unlocked iPhone and its not on a automatic configuration for some reason (some SIM's do it automatically). You can either change the APN or completely restore the phone to factory configuration using iTunes which will do the same thing.
Basically you need to establish a Wi-Fi connection and go here: http://www.unlockit.co.nz/mobilesettings/
Select the US AT&T HSPA+ profile (you must have a 4G data plan to do this on your account) and install the APN profile. Your data should now work.
I do this for a new APN whenever a new SIM is inserted in a different market/country to get data. Yes Apple does make this difficult because they removed the end-user menu option.
Wow, thank you SO MUCH for your help - this is the method that worked.
Out of curiosity, what is the complete restore? Sounds like a good back up plan if somehow this gets screwed up as I go back and forth from Asia to the US.
Again, thank you everyone for helping out - I was terrified my iPhone 5 would just be a useless brick.
StarAC17 From Canada, joined Aug 2003, 3225 posts, RR: 9 Reply 9, posted (3 months 2 weeks 2 days 5 hours ago) and read 312 times:
Quoting Elite (Reply 8): Out of curiosity, what is the complete restore? Sounds like a good back up plan if somehow this gets screwed up as I go back and forth from Asia to the US.
A complete restore will restore the Iphone to the state it would be had it just out of the box. If the phone ever gives trouble this may have to be done. Be warned this deletes all your contacts, songs, videos, memo's from the phone etc. and if you have an updated version of iOS (there has been updates since the Iphone 5 came out).
I don't know if the APN settings are as easily accessed on an Iphone 5 as on an android (calling Klaus ) but on my Galaxy S3 you can erase them all and if you restart the phone the sim-card that is inserted should load them instantly.
Klaus From Germany, joined Jul 2001, 20857 posts, RR: 55 Reply 10, posted (3 months 2 weeks 1 day 19 hours ago) and read 294 times:
Quoting StarAC17 (Reply 9): A complete restore will restore the Iphone to the state it would be had it just out of the box. If the phone ever gives trouble this may have to be done. Be warned this deletes all your contacts, songs, videos, memo's from the phone etc. and if you have an updated version of iOS (there has been updates since the Iphone 5 came out).
There are separate buttons in iTunes.
Restore iPhone... restores the last downloaded iOS version that's already saved on disk or – after asking for permission – it looks for any available updates.
Before performing the restore, it will ask if it is to make a last backup of the device, which is generally recommended.
You can also simply reset the device by itself with Settings > General > Reset. It will effectively perform a factory reset. The newer encrypted devices will discard their encryption keys and so wipe their data immediately, older unencrypted devices (iPhone original, 3G; iPod Touch original, 2nd gen.) will take a while to actually overwrite their entire storage space.
This is also what you should do when using mail-in or bring-in replacement service (after making a last backup, of course!).
When you've got your replacement device, simply do this in iTunes:
Restore Backup... offers a selection of the available backups to restore from. Choose the one you want to use (usually the latest one) and wait for completion. The device should be restored exactly to the state of that backup (Note: Passwords are only stored in the backups in iTunes if you let iTunes encrypt its backups! Otherwise you'll have to re-enter your passwords again after restoring, such as WiFi or mail passwords.).
So you can choose what to do, exactly.
SIM changes should actually not require a restore, though. That would be pointless and unnecessary as far as I'm aware.
Quoting StarAC17 (Reply 9): I don't know if the APN settings are as easily accessed on an Iphone 5 as on an android (calling Klaus   but on my Galaxy S3 you can erase them all and if you restart the phone the sim-card that is inserted should load them instantly.
Normally iTunes or the device itself will automatically look up the correct settings when you insert the respective SIM, by looking up the respective carrier settings in Apple's online settings database (you may need a WiFi connection if you're doing that on the device itself instead of via iTunes).
If automatic configuration should not work for the SIM you're trying to use, this page should be helpful: http://support.apple.com/kb/HT2283?
Apple has related help pages there for all kinds of topics – don't hesitate to use the search feature at the top!
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From Hong Kong, joined Jun 2006, 2760 posts, 
From United Kingdom, joined Sep 2003, 1998 posts, 
From Canada, joined Aug 2003, 3225 posts, 
From United States of America, joined Dec 2006, 833 posts, 
) but on my Galaxy S3 you can erase them all and if you restart the phone the sim-card that is inserted should load them instantly.
From Germany, joined Jul 2001, 20857 posts, 
but on my Galaxy S3 you can erase them all and if you restart the phone the sim-card that is inserted should load them instantly.
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