SARA-R42 - Application note
UBX-20050829 - R02
Network registration
Page 22 of 58
C1-Public
Command
Response
Description
AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","","0.
0.0.0 0.0.0.0.0.0.0.0.0.0.0
.0.0.0.0.0",0,0,0,2,0,0,0,0
,0,0
OK
Read IP type and APN for EPS attach bearer.
AT+CGDCONT=1,"IPV4V6","cust
om_APN"
OK
Set APN name ("custom_APN" for example) and the
PDP type ("IPV4V6" for example) for EPS attach
bearer.
AT+CFUN=1
OK
+CEREG: 1,"0001","01a2d001"
,7
+CGEV: ME PDN ACT 1
Turn on the modem radio.
URCs indicate the registration status change.
Table 9: Change of PDN settings example
7.2.3
Attach types
All profiles use Combined Attach (CS & PS); if successful, both data and SMS services are allowed. If
LTE attach is successful for EPS only services, still SMS can be supported (the so called “SMS only”
case). If LTE attach is not successful for SMS, the module can try registration on a different RAT (e.g.
2G RAT).
The
+USVCDOMAIN
AT command can be used to change how the module attaches to the network if
the factory-programmed attach type is not accepted by the network.
7.2.3.1
NB-IoT networks: ePCO handling
On NB-IoT, where CP CIoT EPS optimizations are mandatorily active, the 3GPP standard prescribes
that the extended Protocol Configuration Options (ePCO) container is used in Network Access
Stratum (NAS) messaging when attaching to an LTE network. Some NB-IoT mobile operators do not
support ePCO container; therefore, if ePCO is used in the attach for such a network, this will result in
lack of DNS capabilities, e.g. for NB-IoT networks that are known to not support ePCO or when
+CGCONTRDP
AT command does not return any DNS in NBIoT, it is recommended to use
+UCFGCIOT
AT
command to disable the ePCO feature and fallback to PCO negotiation, as shown in
Command
Response
Description
AT+COPS?
+COPS: 0,0,"NB-IoT Network"
,8
OK
Module registered on NB-IoT network.
AT+CGDCONT?
+CGDCONT: 1,"IP","default",
"192.168.20.2",0,0,0
OK
The module activated the EPS bearer with a valid IP
address.
AT+CGCONTRDP
+CGCONTRDP: 1,5,"default","
192.168.20.2","192.168.20.1
",""
OK
DNS references not available in the
+CGCONTRDP
AT
command.
AT+UCFGCIOT=3,0
OK
Disable the ePCO feature through the
+UCFGCIOT
AT
command.
AT+CFUN=15
OK
Reboot the module to apply the configuration.
AT+COPS?
+COPS: 0,0,"NB-IoT Network"
,8
OK
Module registered on NB-IoT network.
AT+CGDCONT?
+CGDCONT: 1,"IP","default",
"192.168.20.2",0,0,0
OK
The module activated the EPS bearer with a valid IP
address.
AT+CGCONTRDP
+CGCONTRDP: 1,5,"default","
192.168.20.2","192.168.20.1
","185.215.195.114"
OK
DNS references now available in the
+CGCONTRDP
AT
command.
Table 10: ePCO feature disabling
