Originally Posted by Steve-hose
Ok so I am looking around in the Network settings and I see that you can select CDMA, Global, or GSM for the network, as well as select preferred carriers like T-Mobile, AT&T etc. I tried to hook up to GSM network but no dice. Do I need a USA sim card to be able to get on GSM signal if no Sprint is available? Is this possible in the USA? I read that this phone is "unlocked" so is it a matter of replacing the OEM sim card with one I purchase here? I assume the OEM sim card is for roaming overseas but it would be cool to have it switch to a GSM service in no Sprint areas in USA. I am a newb when it comes to sim cards so any help with this concept is appreciated.
This has nothing to do with the SIM card.
You can't use a GSM carrier while in the US with the 8830. The device doesn't support the wireless frequencies used by US GSM carriers. GSM on the 8830 will only work overseas.