I'm sorry because I still don't understand how this works. I have an AT+T Razor V3 with a SIM card. What do I need to do to make calls to the states from Japan? Do I rent a phone, buy a SIM card or ???? I'm arriving at Narita on Sept 30th and would like to take care of this at the airport. I've read all the posts and I still don't get it. Thanks!!