My 4S on 5.1.1 does this automatically. I don't think I've ever seen 3G but I've definitely seen o, E, and 4G. Ncsettings allows you to turn 3G/4G off and use Edge whenever you want. I use it when I have really awful 4G coverage. Although I haven't had anything less than 1 missing bar since moving to Houston. AT&T in Houston has an incredible network. Hope this helps clarify things a little bit more for you. If you're on an older firmware that doesn't have the built in 4G indicator, I believe cydia has something that corrects this. You do have a 4S correct? Cause anything lower than the 4S can't use the AT&T "4G" network.