Originally Posted by southwestcomm
What is RUIM? You can use the SIM provided by Sprint or use a pre-paid SIM from a carrier in the country you are traveling in. There isn't NAM programming.
A RUIM is basically a GSM sim card but for CDMA phones, if I recall correctly a RUIM card can work on a GSM phone but a GSM card can not work on a RUIM phone.. So it might be possible to use the RUIM card on the sprint phone outside the USA as long as its acting as basically a GSM card.. But you would only need or use a RUIM in a few countries that have CDMA networks.
But dont quote me on that.. My guess is the RUIM card in theory should work but like I said will only connect to GSM networks.
On a side note we usually call a RUIM card a CSIM (CDMA sim), we have somewhat of a movement to make US CDMA carriers allow for this so you could basically do what GSM users do with sim cards. With Verizon opening the phones up this might happen in the future.