I use the DR2 Global outside USA, in Europe and have some problem concerned with the USSD commands.
there are some important codes such as : #100* to check balance, #135* to buy some extra megabytes and #115* to take some extra talking time in credit.
When I enter a code the USSD code is running infinitely.
Do you have a same problem?
There is no problem with the signal strength and network coverage, but the signal indicator is always at one point.