AT
OK
AT+CGDCONT=1,IP,"CMNET",010.000.000.172
OK
AT+CGDCONT?
+CGDCONT: 1,"IP","CMNET","10.0.0.172",0,0
OK
AT+CGQREQ=1,2
OK
AT+CGATT=1
OK
AT+CGATT?
+CGATT: 1
OK
AT+CGATT=?
+CGATT: (0,1)
OK
AT+CGACT=1,1 (此处有几次是AT+CGACT=1,1 返回OK。但依然在CONNECT后...NO CARRIER)
ERROR
AT+CGACT=?
+CGACT: (0,1)