iotgsmat-commandtelecommunicationnb-iot

SIM7020E responds on AT+COPS=? with ERROR


HW: SIM7020E NB-IoT HAT (from waveshare) + RPI3B + NB-IOT SIM from Vodafone CZ.

I am trying connect to NB-IOT network without success (automatic, manual), AT+COPS command show behavior that I don't understood.

AT
OK

ATI
SIM7020E R1752

AT+CGMI
SIMCOM_Ltd

AT+CGMM
SIM7020E

AT+GMM
SIM7020E

AT+CCID
898823900000********

AT+CPIN?
+CPIN: READY    

AT+CFUN?
+CFUN: 1

AT+COPS?
+COPS: 0

Response isn't constant, most common value are listed.

AT+CSQ          
+CSQ: 15,0      
+CSQ: 14,6
+CSQ: 15,0
+CSQ: 14,7
+CSQ: 15,7
+CSQ: 16,0

AT+CMEE=2

Until this moment everything seems OK. This command in most case end with ERROR +-99% , other time return network list. I don't understood why AT+COPS=? return ERROR.

AT+COPS=?
+CME ERROR: operation not allowed

AT+COPS=?
+COPS: (1,"23003","23003","23003",9),(1,"23001","23001","23001",9),,(0-4),(0-2)

When I try manually connected to existing, non existing network (AT+COPS=1,2,"23003" AT+COPS=1,2,"23001" AT+COPS=1,2,"23099") with inserted Vodafone SIM card it will stop responding to any command until power cycle.

When I try commands without inserted SIM card (AT+COPS=? AT+COPS=1,2,"23003" AT+COPS=1,2,"23001" AT+COPS=1,2,"23099") it will respond CME ERROR: SIM failure or CME ERROR: SIM not inserted.


Solution

  • After problems with SIM7020E NB-IoT HAT, I tried using BC66-TE-B-KIT (devkit with BC66 chip) with same result. After while I found that I don't have configured Default PSD Connection Settings.

    Required Default PSD Connection Settings on BC66:

    AT+QCGDEFCONT="IP","nb.m2mc"
    

    Required Default PSD Connection Settings on SIM7020x:

    AT*MCGDEFCONT="IP","nb.m2mc"
    

    After setting PSD connection to NB-IOT network start working.