I tried to search but I'm new to Sprint and just got the epic 4g coming from N1 and AT&T. Had a question regarding the 3g icon. Most of time instead of seeing the up and down arrows under the 3g icon, I see a "D" and if I have 4g on I see the 4g logo with the letters "zzz"..what is the "D" and if this means it is idle 3g how can I stop this? Does this mean that my gmail etc does not sync unless I use an application that needs to use data? Thanks!