Check out Richard Wolpert's description of what happens after a dropped call: "So you both call each other back at the same time and get each others voice mail. So you realize the other person is calling you back (you both realize this at the same time). So then you, and the other person, both decide to not dial again and wait for the other person to call you back."
He has a simple rule, available at his blog here:
- if you initiated the call and it drops you call the other person back.
- if you received the call and it drops you just wait for the call back.