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Topic: MKR 1400 modem screws while low signal condition (Read 436 times) previous topic - next topic


Dec 30, 2018, 03:12 pm Last Edit: Dec 30, 2018, 03:13 pm by elisedd

I have the problem that the GSM Modem (or more likely the SIM) stalls in some low signal condition (after multiple re- logins into the Network). In follow the AT+CPIN="1234"; command cause the modem to hang and all corresponding functions (like gsm.begin ) doesn't come back and live the MKR in a uncertain condition.

If this happens (unfortunately the behaviour is not safely reproducible) even a complete power down doesn't help. What helps is to remove the SIM, put it in a different mobile phone register with this phone to the Network, deregister and put the SIM back into the MKR.

After this procedure it works again for a couple of day's until the same problem occurs.

If the SIM or the modem is in this faulty stage I can reset the MKR or load an other sketch into it and interestingly the modem itself is responsive until the next AT+CPIN="1234" command is executed and I can send AT commands e.g. using the SerialGSMpassThrue Sketch. 

I already tried AT+CFUN16 to reset the SIM - unfortunately this doesn't have any success.

So I wonder what a normal mobile do to repair this condition. Does anyone here know a trick how to do a deep reset of the SIM card or how to bring the _complete_ System (SIM+Modem) into a factory condition?

AT&F or ATZ doesn't work here...

THX Ellis


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