AT^SCKS sometimes returns inaccurate results

Taken from Cinterion's wiki.

Under rare circumstances and depending on the SIM card, it is possible AT^SCKS on MC75i responds <SimStatus>=0 although a SIM is inserted. This does not happen if a SIM PIN is enabled.

Suggested workarounds:
-If polling is used, AT^SIND="simstatus",2 will provide accurate results -If the customer's application expects URC notifications, either ^SSIM READY (enabled via AT^SSET=1) can be used, or +CIEV: simstatus,<indDescr> (enabled via AT^SIND="simstatus",1 and appropriate AT+CMER setting, i.e. <mode>=1..3). For details, please see AT Command Guide specification -The SIM PIN could be enabled -You could advise them to use AT+CPIN? instead.