When is EC25-V up, ready to be used?

IoT Modules LTE Standard Module
1

Which AT-cmd to use, to DEFINITELY determine that the EC25-V is fully up, after a power cycle of the modem ?
I found out, that modem is not ready for use, when ttyUSBx shows up (openwrt host) .

2

Hi @speibl
You can use AT+CPIN? Command to check whether the SIM card is correctly identified, AT+QENG=“SERVINGCELL” command to check whether the network was successfully registered.