The read command returns the currently selected Universal Integrated Circuit Card (UICC) slot.
%CSUS: <slot>
The read command parameter and its defined values are the following:
The following command example reads the slot when virtual iUICC is selected:
AT%CSUS?
%CSUS: 2
OK
The following command example reads the slot when physical UICC slot 1 is selected:
AT%CSUS?
%CSUS: 0
OK