Ok I sent my iPhone 5 off to Apple because the calls continuously would fail on it. I received a new phone & guess what.....this phone is doing it too. I am in a full signal area when this happens. I have a 16 gb white AT&t iPhone. With the first phone I replaced the SIM card, restored & backed up, restored & set up as new, turned the cellular connection off & back on. None of this made a bit of difference, so Apple told me to send it in & sent me a replacement. I am getting a bit irritated! I mean this is a phone & should work as one. Who cares what else it can do if it can't even hold onto a call in a full reception area! Any suggestions would be greatly appreciated. The odds of me getting a second phone with the same problem seem odd to me unless this is a big issue with the iPhone.