<n>     Integer type   
      0    Disable network registration unsolicited result code   
      1    Enable network registration unsolicited result code: “+CEREG:<stat>”   
  2    Enable network registration and location information unsolicited result code:   
“+CEREG:<stat>[,[<tac>],[<ci>],[<AcT>]]”   
  3    Enable network registration, location information and EMM cause value information 
  unsolicited result code:   
“+CEREG:<stat>[,[<tac>],[<ci>],[<AcT>][,<cause_type>,<reject_cause>]]” 
  4    For  a  UE  that  requests PSM,  enable  network  registration and  location  information 
  unsolicited result code:   
“+CEREG:<stat>[,[<tac>],[<ci>],[<AcT>][,,[,[<Active-Time>],[<Periodic-TAU>]]]]”   
  5    For a UE that requests PSM, enable network registration, location information and 
  EMM cause value information unsolicited result code:   
+CEREG:<stat>[,[<lac>],[<ci>],[<AcT>],[<rac>][,[<cause_type>],[<reject_cause>][,[<A 
  c tive-Time>],[<Periodic-RAU>]]]] 
<stat>        Integer type, indicates the EPS registration status 
                    0      Not registered, MT is not currently searching an operator to register to 
1     Registered, home network 
                2     Not registered, but MT is currently trying to attach or searching an operator to register 
to 
                  3      Registration denied 
                    4      Unknown 
                    5      Registered, roaming 
                    6      Registered for “SMS only”, home network (applicable only when 
<Act> indicates NB-IoT) 
                    7      Registered for “SMS only”, roaming (applicable only when 
<Act> indicates NB-IoT   
                        8      Attached for emergency bearer services only 
                          9      Registered for “CSFB not preferred”, home network (not applicable) 
                        10      Registered for “CSFB not preferred”, roaming (not applicable) 
 
<tac>         String type; two bytes tracking area code in hexadecimal format (e.g. “00C3” equals 195 in 
  decimal) 
<ci>            String type; four bytes E-UTRAN cell ID in hexadecimal format