First of all thank you for your useful answer.
I dont use IESM card with Ethernet port on the modem. It is FXT009.
I have found a problemmatic modem which can not detect SIM card eventhough it is plugged. AT+WSWH will return +WSWH: 0 (open). I read the documantation and it says that AT+WSWH shows SIM holder status. So can we say SIM holder can not detect SIM card? Or can it still be because of sliding switch?
i looked at SIM card holder pins and see that Xtend modem has extra pins for sliding switch. That means embedded module checks both SIM holder detection pin and sliding switch pin. Do you mean disabling SIM sliding switch detection by saying “disable SIMDETECT feature by at+wfm”? However, there is no SIMDETECT option in the documantation for at+wfm command.
This problem appairs often and gives me headache. I want to find the certain reason.
Do you know a way to disable sliding switch detection? i want to see if sliding switch causes the problem or not.