There is no difference at all.

EVDO (Evolution Data Optimized) is a 3G (3rd generation) technology. It allows the user to access high speed internet over his mobile device on a CDMA network.

Hope this helps.

3G is Radio technologies for Wireless mobile networks. Its an evolution above GSM technology which is widly used all round the world. In short We can Say that 3G is combination of various Mobile technologies like GSM and CDMA. The main advantages are 1. Convergence of GSM and CDMA as a single entity 2. Better Bandwidth and Security Aspects.

Yes it is a 3G smartphone.

There is a small chance you have no enabled 3G. To do this follow these steps. Go to Settings > General > Network and Enable 3G should be set to on. Also your area may not have 3G capabilities. In this case there is no 3G signal for 3G to work. To check 3G coverage contact your provider. Also if your iPhone is a 1st Generation and not the iPhone 3G you do not have 3G capabilities.

3g