My iPhone indicated that I did not have a SIM card. I turned the phone on and off, toggled the airplane mode on and off, made sure I had the most recent software update on the phone, none of which worked. I then restored the iPhone and at the end of the restoration process have the message in the iTunes window of my iMac (which I had the iPhone plugged into for the restoration): "There is no SIM card installed in the iPhone you are attempting to activate"
