Read command

The read command reads current network registration status.

Response syntax:

+CEREG: <n>,<stat>[,[<tac>],[<ci>],[<AcT>][,<cause_type>],[<reject_cause>][,[<Active-Time>],[<Periodic-TAU>]]]]

The read command parameters and their defined values are the following:

<n>
0 – Disable unsolicited result codes
1 – Enable unsolicited result codes +CEREG:<stat>
2 – Enable unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>]
3 – Enable unsolicited result codes +CEREG:<stat>[,<tac>,<ci>,<AcT>[,<cause_type>,<reject_cause>]]
4 – Enable unsolicited result codes +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>][,,[,[<Active-Time>],[<Periodic-TAU>]]]]
5 – Enable 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
<tac>
String in hexadecimal format. 2-byte Tracking Area Code (TAC).
<ci>
String in hexadecimal format. 4-byte E-UTRAN cell ID.
<AcT>
7 – E-UTRAN
9 – E-UTRAN NB-S1
<cause_type>
0 – <reject_cause> contains an EPS Mobility Management (EMM) cause value. See 3GPP TS 24.301 Annex A.
<reject_cause>
EMM cause value. See 3GPP TS 24.301 Annex A
<Active-Time>
String. 1 byte in 8-bit format.

Indicates the Active Time value (T3324) allocated to the device in E-UTRAN. For the coding and value range, see the GPRS Timer 2 IE in 3GPP TS 24.008 Table 10.5.163/3GPP TS 24.008.

<Periodic-TAU>
String. 1 byte in 8-bit format.
Indicates the extended periodic Tracking Area Update (TAU) value (T3412) allocated to the device in E-UTRAN. For the coding and value range, see the GPRS Timer 3 IE in 3GPP TS 24.008 Table 10.5.163a/3GPP TS 24.008.

The following command example reads the current registration status:

AT+CEREG?
+CEREG: 2,1,"002F","0012BEEF",7
OK