Hi. Sorry for making so many new threads on these forums but I'm getting nervous as I'm approaching my Verizon Wireless contract end. Finally! Anyway, because the iPhone 3G is sold in India through Vodafone and Airtel, is it possible to put one of those SIM cards into the At&t iPhone i get and make it work without unlocking? I figured that maybe all iPhones are programmed to work with all the SIM cards that Apple has released the iPhone with (At&t, 02, etc.). So, will my At&t iPhone work with a Vodafone/At&t SIM or are U.S. iPhones only allowed to work on At&t networks? Thanks a lot in advance. And if you have any suggestions for this thread of mine, feel free to help.
https://forums.macrumors.com/threads/593831/:)
Out of the box, an iPhone originally sold through Apple or AT&T in the USA will
only work with an AT&T SIM card issued in the USA. If you wanted to make it work with a SIM card issued from any other network or from any other country, you'd have to unlock it.
There is currently no network-authorized or manufacturer-authorized service for providing SIM unlocks for iPhones sold in the USA.
However, some unauthorized hacks do exist. While there is no unauthorized method yet which would unlock it purely in software, there do exist some adapter cards which are inserted in the SIM slot along with your off-network SIM card which fool the iPhone into thinking it's using an AT&T card. These cards don't modify any of the iPhone's internal hardware or software so they oughtn't damage your iPhone; however, if you use them you should avoid using updated iPhone firmware from Apple until the 3rd party manufacturer says it's ok, because there is no guarantee that the adapters will work with every version of iPhone software.
