[Bossman]

As Snaimon posted above, The first callback is UM. As long as you have the UM sim in that phone, the first call back is always going to be from UM. When you hear the first callback(UM has called the number you were trying to reach, your 909#), you answer, you will hear it ring, then hangup (no charges yet). The next callback will be from CBW (they have called your number), you will hear it ring, once they answer, charges start with CBW.

If you make the mistake if calling your destination# first, you will receive a callback from UM only, when you answer you will hear your destination# ring, once they answer your charges with UM will start. plus the .25 euro connection charge.

Wow! testing it from here (USA) will cost you a lot since incoming calls are not free here. I used mine extensively on a recent cruise, and CBW+UM worked flawlessly!