AT+NBAND=20 //Set APN for PDP context, (“”) from operator
AT+CGDCONT=1,”IP”,”u.iot.mt.gr.hu” //Enable network registration, connection & PSM URCs
AT+CEREG=2
AT+CSCON=1
AT+NPSMR=1
Manual operator selection:
1. Turn on the modem:
AT+CFUN=1 // set MCC MNC values, ex: 123456 pre MCC=123 MNC=56
2. Log in ( 30 seconds ):
AT+COPS=1,2,”21630″
3. Registration:
/ wait 30 sec for NW registration of URC 1=home alebo 5=roaming /
+CEREG:1,xxxx,yyyyy,z
+CEREG:5,xxxx,yyyyy,z
Send/Receive UDP data:
1. create an UDP socket
AT+NSOCR= DGRAM,17,16666,1
0
2. send UDP message
AT+NSOST=0,83.58.228.64,16666,12,48656C6C6F20576F726C6421
0,12
+NSONMI:0,12
3. received UDP message
AT+NSORF=0,12
0,83.58.228.64,16666,12,48656C6C6F20576F726C6421,0
4. close socket
AT+NSOCL=0
https://www.soselectronic.com/articles/quectel/have-you-tried-nb-iot-2178