SIM card, account question

Discussion in 'iPhone' started by michaelsaxon, May 4, 2009.

  1. michaelsaxon macrumors 6502

    Nov 15, 2006
    I currently have an iPhone 3G and my wife has a 1G iPhone.

    AT&T just suspended my account for the period of time that I'll be in Afghanistan and switched us from a family plan to a single plan for my wife.

    I'd like to give my wife my iPhone 3G and then sell her iPhone 1G. Is it as easy as taking her SIM card out of her phone and putting it in my 3G or will that not work? AT&T lady said so, but she seemed unsure.

  2. StoneGaijin macrumors regular

    Feb 11, 2008
    Minneapolis, MN
    I believe yes, you can do it without issue. I'm not positive however,
  3. courtney.bella macrumors member


    Mar 23, 2009
    I think you'll need a new SIM, because you'll need a 3G SIM for her, since her original iPhone is not 3G.
  4. goosnarrggh macrumors 68000

    May 16, 2006
    OP: Check your original iPhone's SIM card. Does it have a 3G fireball logo? If so, then it will work perfectly fine in the iPhone 3G. IIRC at least some, if not all, original iPhones came with 3G-capable SIM cards.
  5. michaelsaxon thread starter macrumors 6502

    Nov 15, 2006
    Strangely, my wife's SIM card worked great in my 3G. I placed my SIM card in her 1G, however, and iTunes forced the activation screen. I'm not sure why.
  6. dave006 Contributor


    Jul 3, 2008
    Just West of East
    There is not a difference in the SIM, almost any SIM within the last 36 months will work just fine. There is not a special iPhone SIM or a special 3G SIM. :)

    The original iPhone pairs with the SIM during the iTunes activation. That's why her SIM works just fine in your iPhone 3G but your SIM does not work in the original iPhone without completing the iTunes activation to pair the iPhone with the SIM.

  7. angemon89 macrumors 68000


    Feb 5, 2008
    The place where Apple designs stuff
    Will AT&T find out and start charging her more since she's only paying $20 for data?
  8. michaelsaxon thread starter macrumors 6502

    Nov 15, 2006
    I already switched her plan with AT&T angemon89.

    Thanks for the explanation Dave!
  9. goosnarrggh macrumors 68000

    May 16, 2006
    To be clear, the 3G standard did specify some additional modules to be included on what is commonly referred to as a "3G SIM card", which were not present in previous generations of GSM SIM cards. As such, previous generations of SIM cards would NOT connect to 3G networks. "3G SIM cards" are generally backwards compatible, and provide full functionality with, 2G phones and 2G networks.

    (Historical note: in the 2G GSM specification, the concept of the physical card and the GSM SIM application running on it were inexorably bound together. In 3G networks, the card itself, technically called a UICC, Universal Integrated Circuit Card, may run several different application modules, including a SIM module to provide access to 2G networks, and a USIM module to provide access to UTMS networks. In theory, a "3G SIM card" could also contain a CSIM module to provide connectivity to traditional CDMA networks as well, but most exclusive GSM and UTMS providers wouldn't bother including such modules on their cards, and most phones capable of connecting to traditional CDMA networks either don't have any hardware present to accept external subscriber identity modules, or else they've been locked down by their carriers to ignore any external modules even if you inserted them.)

    That being said, after AT&T started rolling out "3G SIM cards", they stopped issuing the older 2G SIM cards, so any relatively recent card issued by AT&T is likely a UICC containing both a GSM SIM module for 2G connectivity and a UTMS USIM module for 3G connectivity.

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