what is the difference between CDMA and GMA networks?
CDMA stands for Code Division Multiple Access
GSM stands for Global System for Mobile communication
You typically find CDMA networks located in the U.S. although I believe that Russia uses it some also. GSM is found in more locations and is typically more travel/global friendly. A few carriers in the U.S. use GSM technology, most notably AT&T and T-Mobile.
It use to be that you could tell the difference between devices due to the fact that GSM uses a SIM card and CDMA does not, however, with the birth of LTE CDMA devices now use a SIM card as well. Although it is for different reasons, typically related to the LTE network.
Here is a great article that goes through the differences and comparisons for both network types. http://www.pcmag.com/article2/0,2817,2407896,00.asp
