For debugging, to check the initial connection as below. Note the BC660K-GL is the successor and is designed to be backwards compatible to this BC66.
at+qcgdefcont=”IP”,”<APNstring>” //this only needs to be setup once. After setup, reboot.**see note below
at+cgdcont=1,”IP,”<APNstring>” //set the APN for data connection. **
at+cpsms=0;+cedrxs=0 //disable any power-saving modes for now
at+qband=3,5,8,28 //for Aus NB-IoT set B5, B8, B28
[2020-01-31_11:30:20:406]ati;+cimi;+cereg=2;+qsclk=1;+cscon=1 //initiation for debugging,
[2020-01-31_11:30:20:424]Quectel_Ltd
[2020-01-31_11:30:20:424]Quectel_BC66
[2020-01-31_11:30:20:424]Revision: BC66NBR01A10
[2020-01-31_11:30:20:424]505026930000000 //IMSI
[2020-01-31_11:30:20:484]
[2020-01-31_11:30:20:484]OK
[2020-01-31_11:30:20:531]
[2020-01-31_11:30:20:531]+IP: 100.67.247.88 //attach success
[2020-01-31_11:30:36:509]at+cesq
[2020-01-31_11:30:36:523]+CESQ: 25,6,255,255,12,43
[2020-01-31_11:30:36:523]OK
[2020-01-31_11:31:01:659]at+cereg? //check registration state
[2020-01-31_11:31:01:676]+CEREG: 2,1,”33C7″,”01433171″,9 // all good
[2020-01-31_11:31:01:676]OK
[2020-01-31_11:31:21:856]
[2020-01-31_11:31:21:856]+CSCON: 0 // this URC shows the state of the radio TX. 0=off 1=on
[2020-01-31_11:31:27:328]at+qping=1,”8.8.8.8″,10 //check connectivity – ping to Google DNS
[2020-01-31_11:31:27:350]OK
[2020-01-31_11:31:29:514]
[2020-01-31_11:31:29:514]+CSCON: 1 //radio TX has turned on
[2020-01-31_11:31:29:808]
[2020-01-31_11:31:29:808]+QPING: 0,”8.8.8.8″,32,2440,48
[2020-01-31_11:31:33:559]
[2020-01-31_11:31:33:559]+QPING: 0,”8.8.8.8″,32,2740,48
[2020-01-31_11:31:36:736]
[2020-01-31_11:31:36:736]+QPING: 0,”8.8.8.8″,32,2170,48
[2020-01-31_11:31:39:890]
[2020-01-31_11:31:39:890]+QPING: 0,”8.8.8.8″,32,2140,48
[2020-01-31_11:31:39:903]
[2020-01-31_11:31:39:903]+QPING: 0,4,4,0,2140,2740,2372 //ping success
[2020-01-31_11:32:12:657]
[2020-01-31_11:32:12:657]+CSCON: 0 //radio TX turned off
[2020-01-31_11:34:46:754]
[2020-01-31_11:34:46:754]+CEREG: 2,”33C7″,”01433171″,9
[2020-01-31_11:34:47:080]
[2020-01-31_11:34:47:080]+CEREG: 1,”33C7″,”01433171″,9
[2020-01-31_11:34:49:198]
[2020-01-31_11:34:49:198]+CSCON: 1
[2020-01-31_11:35:43:304]
[2020-01-31_11:35:43:304]+CSCON: 0
** Setting the APN: After any change in APN, reboot to make this setting active. After successful attach, this APN shall be persistent, stored in flash for next power-on. Note that for BC660K-GL, the network may send an APN to use. In this case you may see the APN read is different from what was manually set.