I have had an iPhone ever since the 1st gen was released. I never had problems using data while talking on my iPhone until around the time iOS5 came out. Now I rarely can send MMS pics while talking but I can receive them. If I hang up, I can send them just fine. This goes for other iphone users I know on the AT&T network. and most apps that require internet just spin until i hang up the phone. Is this a known issue?