See subject. I can't seem to find a clear answer on this. I don't care if it's 1G Internet during a call, I just don't want to miss emails and iMessages like what has been happening on the 4S.
You will not get any data unless your connected to wifi while on a call. Only thing that will come in is text messages. All other data is put "on hold" till the call is ended.
You will not get data over 3G/EVDO while on a call, only over wifi. It's a limitation of the Qualcomm chip.