How do I know what kind of network the iphone is in?

For:

When the iphone has an icon at the top of the screen, it means that the phone is added to the Wi-Fi network and can use Wi-Fi for Internet access.

When the iphone has an icon at the top of the screen, it means the 3G network is currently in use.

When the iphone has an icon on the top of the screen, it means that the GPRS network is currently used, which is commonly known as the 2G network.

When there is an active network icon at the top of the iphone screen, it means that there is currently an application using the Internet feature.

When the iphone has an icon on the top of the screen, said that the current use of Edge network, is commonly known as 2.75G than GPRS a little faster.