Can I throw a PAYG sim into an old iPhone?

April 28, 2010 7:14 AM

I'm on T-Mobile Pay As You Go but am thinking of buying a friend's old iPhone that he is selling very cheap. Can I unlock the phone and just throw my SIM card in? I currently have a Motorola L7 which I'm not too crazy about and although I understand the iPhone wouldn't have internet, I thought it might be a nice upgrade in terms of camera, having iPhone apps, etc. Will this work?
posted by gfrobe to Technology (11 answers total)

Your friend should be able to unlock the phone (I'm assuming you are in the UK) through their carrier, if it isn't unlocked already. That's different if you are talking about a US purchased iPhone, which will need a software unlock.

Once unlocked, you can just try it and see how well it works. Pop the SIM and put yours in and see what happens. You won't get 3G/EDGE internet if you don't have a data plan already, but otherwise it should work as a phone and get internet through wireless connections.

I use a PAYG SIM from O2 with a unlimited data bolt-on and it works fine. So, worse case, you can move your number to O2 and use their network – although I'm fairly sure all UK based PAYG plans would/could work (or at least those who also sell the iPhone themselves).
posted by qwip at 7:44 AM on April 28, 2010

Oh, and I'm assuming we're talking about an iPhone 3G or 3GS. Have no idea if the first generation iPhone would have any issues.
posted by qwip at 7:45 AM on April 28, 2010

Response by poster: "I'm assuming you are in the UK"

Sorry, my profile needed an update. I'm in the US so guess I would need software to unlock it. I'll google search that.
posted by gfrobe at 7:52 AM on April 28, 2010

T-Mobile and AT&T are both GSM carriers, although their 3G frequencies are different. In theory, you could put your T-Mobile SIM card in your iPhone and it would function, but you wouldn't be able to use their 3G network, which would mean internet access would be slower (2G speeds), and call quality may or may not be affected (not sure).

As you noted, you would have to unlock your iPhone first, which would void the warranty and potentially brick it if not done properly.

A few links I found about the process:

Will a T-Mobile SIM card work in my iPhone? (iPhone FAQ)
Youtube video of a T-Mobile-ized iPhone
Macworld article on unlocking your iPhone and swapping SIMs

From that last link:

One Macworld editor tried this approach — minus the faux-activation step — on his iPhone and was able to insert a T-Mobile SIM card from a co-worker and get the iPhone up and running on the T-Mobile network, as if it were her phone.

I don't know if the fact that it's a prepaid SIM changes anything, but I'd imagine not, as long as it's paid up.

Please take the above with a grain of salt though. I have never tried this, and am not a cell phone expert.
posted by Vorteks at 7:53 AM on April 28, 2010

Regarding my comments about 3G/2G speeds above, I should add that I am assuming that the iPhone's radio wasn't built to handle both frequencies, but it's possible that it was. I haven't looked up the specifications.
posted by Vorteks at 8:00 AM on April 28, 2010

I unlocked an old "2G" iPhone for my wife that works fine on T-Mobile. It was only ever Edge anyway, so you don't lose anything speed wise since AT&T and T-Mobile use the same frequencies there.

It was a minor pain to unlock since I had no idea what I was doing and no clue what firmware it was on, if at all possible it'd be good for your friend to unlock it while it's still on AT&T since then you'll at least have a valid SIM while you're trying to unlock it. Once it's unlocked you should just be able to swap in your PAYG SIM and be good to go.
posted by togdon at 8:06 AM on April 28, 2010

I don't know anyone who has bricked their phone from unlocking, though I suppose it's a possibility in the same sense dying when being given anaesthesia for an operation is a possibility. Chances are you'll be able to unlock the phone just fine. There are plenty of resources online explaining how to do so.

The only issues with jailbreaking and unlocking are that the process is tedious, and you can't update to the latest firmware updates till you find out the hackers have a jailbreak/unlock for them.
posted by chunking express at 8:17 AM on April 28, 2010

Regarding the Pay as you Go SIM: I did something similar with my nexus one, and just want to confirm what you said in the question, internet won't work with the pay as you go SIM due to a block on tmobile's side.
posted by garlic at 8:47 AM on April 28, 2010

Response by poster: It was a minor pain to unlock since I had no idea what I was doing and no clue what firmware it was on, if at all possible it'd be good for your friend to unlock it while it's still on AT&T since then you'll at least have a valid SIM while you're trying to unlock it. Once it's unlocked you should just be able to swap in your PAYG SIM and be good to go.

Thanks for the comments. Can anyone confirm whether or not I absolutely need the existing AT&T SIM in there to unlock the phone? Since my friend would be sending me the phone, it doesn't look like I'd have access to his AT&T SIM card. And he's not technical so I wouldn't want to ask him to do a complicated jailbreak process before sending it.
posted by gfrobe at 9:08 AM on April 28, 2010

You don't need an AT&T SIM. I've unlocked my old 2G iPhone for my wife with a Fido SIM. (It's locked to AT&T.)
posted by chunking express at 9:25 AM on April 28, 2010

I have a normal T-Mobile account and my jailbroken/unlocked iPhone 2G runs great on it. I personally did have the former owner's AT&T SIM in there when I unlocked it, but I don't know if it was necessary.
posted by exhilaration at 11:34 AM on April 28, 2010