I'm using in my work GSM Module Linq L651. While working, I ran into a problem: the module registers on the network for a very long time. For one minute it found some network, and then it registers on the network for 5 minutes. There is AT commands example to connect to my server.
+CPIN:READY
OK
//1 minutes left
AT+CSQ
+CSQ: 19,99
OK
AT+CFUN=1,1
OK
//5 minutes left
AT+COPS?
+COPS: 0,2,"25002", 0
AT+CGATT=1
+CGATT:1
OK
AT+CGACT=0,1
OK
AT+CGDCONT=1,"IP","internet"
OK
AT+CIPMUX=0
OK
AT+CSTT="internet","gdata","gdata"
OK
+CIICR
+CSCON: 1
+CSCON: 0
COMMAND NO RESPONSE!
AT+CGACT=1,1
OK
AT+CIPSTART="TCP","XX.XX.XXX.XX",60001
OK
+CSCON: 1
+CSCON: 0
+CSCON: 1
CONNECT OK
I tryed to set some connect modes like AT+COPS=0 automatic mode.
I use a laboratory power supply for supply, also i have bypass capacitors in supply chain too. So, it is not may be a supply problems.
I also tried different firmware versions. But I didn't get a good result.
What am I doing wrong? A similar module (Quectel BC92) on a similar board works fast.
I wrote to module manufacturer. He answer that i should set network priority before registration:
For GSM Priority:
AT+CFUN=0 //set sim minimal functionality
AT+CFGDUALMODE=1,0 ////dual mode single standby+close fastwitch
AT+CFGRATPRIO=2 //GSM priority
AT+CFUN=1 //set sim ful functionality
For NB Priority：
AT+CFUN=0
AT+CFGRATPRIO=4
AT+CFGDUALMODE=1,1
AT+CFUN=1
For NB Only：
AT+CFUN=0
AT+CFGRATPRIO=4
AT+CFGDUALMODE=0
AT+CFUN=1
Then need set mode use command AT+CFGDFTPDN=<mode> save settings and reeboot module. After that it connect to operator wery fast