Thi really didn't make sense to me because I assumed data and voice were independent but.... Just upgraded from original iPhone to 3G and I have noticed some selective (location specific) call quality issues which only show up when 3G is turned on. Turning 3G off immediately fixes the problems. For example, I had a terrible phone reception at a hotel but the day before I had great reception on my old phone. Just for kicks, I turned 3G off and immediately, the phone reception improved. Today, same exact issue at my office different city entirely). Anyone else encountering this? Any fixes (other than turning off 3G)?