Transferring an old iPhone after I upgrade?

Question

I'm about to upgrade from the iPhone 3G to the iPhone 4, and I'm not sure what will happen to my old device once my phone number is transferred.

Specifically, I want to give the old device to my girlfriend, who is on a AT&T non-smartphone. What will I have to do to move her to the iPhone 3G? Will she need to sign up for an iPhone specific data plan if I put the sim card in there? WIll it work like any old phone if I just put the simcard in there?

In short, I'm not sure what will happen, and what I need to do.

Answer 1

I just did this myself - I upgraded to an iPhone 4 and gave my sister my iPhone 3G. I put her AT&T SIM inside and she was instantly able to send & receive calls and texts. Since she doesn't want to pay for data (yet), she used the new iOS 4 network setting to turn off cellular data. I have heard that AT&T scans their network and automatically adds data plans to 'smartphones', but so far this hasn't been the case.

If she does want to use data, have her call up AT&T and let them know about the phone switch on the plan and they can sign her up for the iPhone data plan - it's $15/month for 200MB and $25/month for 2GB. You may be able to do this yourself online - I haven't tried - but contacting AT&T is quick and relatively painless and is guaranteed to work.

One other thing - if her SIM is ancient (pre-3G), then you may need to get a new one that supports 3G from an AT&T retailer or call AT&T and they can ship you a new one. They may charge a nominal fee (~$10) for this service.