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.
The device can enter Power Saving Mode (PSM) state in LTE idle mode when the <Active-Time> parameter has a valid value where at least one of bits 6–8 is set to 0. The length of PSM sleep is the value that remains from the value configured for periodic TAU after active time has elapsed, which is T3324 subtracted from T3412.
<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.
A deactivated value where bits 6–8 are set to 1 after a successful LTE Attach or TAU means that the network configures the periodic TAU or PSM cycle length using a non-extended format with General Packet Radio Services (GPRS) timer instead of GPRS timer 3. The configured value of T3412 can be read with the %XMONITOR command. The response includes the value in a format selected by the network.

The following command example reads the current registration status:

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