Hello guys, I’m working with the BG95-M3 module and I’m having trouble connecting to LTE with a specific SIM card.
My initial configuration sequence is:
AT+QCFG=“nwscanmode”,3,1 // Configures the module for LTE-M (eMTC) only.
AT+QCFG=“iotopmode”,0,1 // Configures the module to operate in LTE-M mode.
AT+CGDCONT=1,“IP”,“APN” // Sets the PDP context with the correct APN.
AT+QICSGP=1,1,“APN”,“apn”,“apn”,1 // Configures the profile for the APN
After this setup, I wait for the module to register with the network using:
AT+CEREG?
But the response is always:
+CEREG: 0,2
Based on ChatGPT’s suggestion, I used additional commands to diagnose the issue:
- Check the network and band details:
AT+QNWINFO
2.Result:*
+QNWINFO: “eMTC”,“72406”,“LTE BAND 3”,1700
- Inspect the serving cell:
AT+QENG=“servingcell”
4.Result:*
+QENG: “servingcell”,“LIMSRV”,“eMTC”,“FDD”,724,06,2985D16,346,1700,3,5,5,C7DF,-82,-11,-58,23,39
- Check neighboring cells:
AT+QENG=“neighbourcell”
6.Result:*
+QENG: “neighbourcell intra”,“eMTC”,1700,346,-12,-82,-56,0,39,7,14,6,58
Results and Observations:
- The
AT+QNWINFOcommand confirms that the module is attempting to connect to the LTE-M network on LTE BAND 3, associated with the operator code72406. - The
AT+QENG="servingcell"result indicates that the module is in LIMSRV (Limited Service) state. While it successfully attaches to the cell (MCC/MNC: 724/06, EARFCN: 1700), registration is incomplete. The observed signal parameters are:- RSRP (Signal Strength): -82 dBm (Good)
- RSRQ (Signal Quality): -11 dB (Fair)
- SINR (Signal-to-Noise Ratio): -58 dB (Poor)
Analysis:
The LIMSRV state suggests that the module has partial access to the network but cannot complete registration. This may be caused by network restrictions, incorrect configurations, or environmental interference (as indicated by the poor SINR values).
Additional Note:
The AT+CPIN? command was tested and returns READY, confirming that the SIM card is properly recognized by the module.
