I have a 4S, unlocked. My friend is lending me a simcard for a France with voice and data on it, and I'm just wondering if my U.S. bought phone will be compatible with their 3G bands. Thanks.
It should work, there is no difference between the iPhones sold in Europe and those sold in the US. SO as long as your phone is actually unlocked there should be no problem.
"AT&T projects their 3G network on 1900mhz (and recently started projecting on 850mhz as well). T-Mobile projects their 3G network on 1700mhz (and we believe owns 2100 but isnt using it yet, see 3G Revelation post for more details on that). Most European phone companies (where most unlocked phones are made for) use 900mhz or 2100mhz to project their 3G networks."
"AT&T projects their 3G network on 1900mhz (and recently started projecting on 850mhz as well). T-Mobile projects their 3G network on 1700mhz (and we believe owns 2100 but isnt using it yet, see 3G Revelation post for more details on that). Most European phone companies (where most unlocked phones are made for) use 900mhz or 2100mhz to project their 3G networks."
T-Mobile USA uses the 1700mhz band for 3G which isn't supported by the iPhone, but the 900mhz and 2100mhz bands used in Europe are supported by the iPhone. So it will work