Our device connects to a cell tower and then creates a socket to our gateway. I monitor +CEREG to see what it goes through to connect to a cell tower. Below is the meaning of the first two values. I'm mostly concerned with the second parameter.
+CEREG: <n>,<stat>[,[<tac>],[<ci>],[<AcT>][,<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]
<n>
0 – Unsubscribe unsolicited result codes
1 – Subscribe unsolicited result codes +CEREG:<stat>
2 – Subscribe unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>]
3 – Subscribe unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>[,<cause_type>,<reject_cause>]]
4 – Subscribe unsolicited result codes +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,,[,[<Active-Time>],[<Periodic-TAU>]]]]
5 – Subscribe unsolicited result codes +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,[<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]
<stat>
0 – Not registered. User Equipment (UE) is not currently searching for an operator to register to.
1 – Registered, home network
2 – Not registered, but UE is currently trying to attach or searching an operator to register to
3 – Registration denied
4 – Unknown (for example, out of Evolved Terrestrial Radio Access Network (E-UTRAN) coverage)
5 – Registered, roaming
90 – Not registered due to Universal Integrated Circuit Card (UICC) failure
Any idea why I would see the below +CEREG?
+CEREG: 0,4
+CEREG: 0,2
It may go on for a while with the above values until it connects with a +CEREG: 0,1.
Why would it return "2 – Not registered" or "4 – Unknown"?
