Two or three days ago my iPhone 5 began displaying a new icon at the top to the right of the AT&T and signal bar. It looks like an old style telephone handset with an arrow pointing to the right. I've never seen this display previously. I'm guessing it might be a missed call indicator of some kind, but it doesn't go away after looking at the recents. Anyone know what it really is? This is my 5th iPhone and I've never seen this icon.