If you cannot obtain service
•If you cannot obtain network service the reception strength may be too weak. Move to a higher elevation, a window or an open space and make sure that there is nothing obstructing the antenna.
•Once you have switched on your phone do not cover the internal antenna area above the finger Stop with your hand.
Roaming 
If you are out of range of your “Home” Network Operator, especially when abroad, another network operator may be selected automatically, subject to signal strength and roaming agreements between network operators.
16GB