Module connection setup

This section is intended to provide you a quick guide on how to setup the connection of your R4/R5 modules  using AT commands so that you can easily test the service. For a complete documentation, refer to document  SARA-R4 / SARA-R5 Internet applications development guide

Network setting verification

The  following  example  reports  the  AT  commands  necessary  to  reach  the  activation  of a PDP context at first then a data socket by starting from the power-up of the module and the control of the pre-existing settings.

Network registration check

LTE radio access technology

Verify that the module is registered on the LTE network

+COPS: 0,0,"Your MNO",7


+CGDCONT: 1,"IP","MNO_APN_url","",0,0,0,2,0,0,0,0,0,0,0

where is the IP Address assigned to your device by the MNO. For a complete list of the parameters you are invited to look at the AT Command manual

GPRS/eGPRS radio access technology

Verify that the module is registered on the 2G network

Profile activation

SARA-R5 modules

+UUPSDA: 0,""

SARA-R4 modules

After these sequence  you are ready to use the CellLocate service issuing the AT+ULOC command to get the location, as described in the getting started guide.

Check radio signal

It might be also useful to check the radio signal with


The module response is in the format 

+CSQ: <signal_power>,<qual>

+CSQ: 24,5

The response provides the RSSI (Received Signal Strength Indication) and the quality indicator (represented by RSRQ). The value mapping for both parameters is provided in the two tables below

DNS verification

The CellLocate  client in the cellular module needs to resolve the url endpoint provided in the UGSRV command regardless if you are using the Device to Service endpoints (, ) or the Service to Service mode with your application server endpoint

In the case you are not able to get a position from CellLocate service, you might verify if you are getting the DNS IP address from the service provider. For this purpose you can use the following command to verify the PDP context providing in input the ID of the connection (1 in the following example)


+CGCONTRDP: 1,5,"TSIOT","","","",""

The reply (+CGCONTRDP) provides back the following relevant information:

If you do not get back this information , it means that the connection is not properly established and it's not possible to use CellLocate service. If you are getting back the only the device IP address but not the DNS IPs, it means that the network operator is not providing you such information. In this case:

You can set any public DNS IP, just choosing your preferred ones.

To verify if  DNS IPs are properly set you can use the following AT commands:



+UUPING: 1,32,"","",114,85

+UUPING: 2,32,"","",114,77

+UUPING: 3,32,"","",114,77

+UUPING: 4,32,"","",114,74

The response uses the following format

+UUPING: <retry_num>,<p_size>,<remote_hostname>,<remote_ip>,<ttl>,<rtt>

Note:  for security reason the u-blox CellLocate service endpoints (, not reply to ping command.








Private APN and Firewall

In case that all your devices are using a private APN and a there is a firewall to restrict the connections, be aware that:

SARA-R5 connection troubleshooting guide

This section explains how to identify and solve some typical issues related to network connection.

First module connection

When the module connects to the network for the first time (or after a refurbish procedure), it can take several minutes to connect (between 5-10 minutes) depending upon the signals and quality of the network in that area. This is due to the fact that the module comes with a pre-set MNO profile value, either global or Europe. Hence, the module starts scanning for all the band masks that fall under the global/Europe MNO.

To speed up the connection, it is recommended to set the profile to the MNO of the region the module is being used in:


To further speed up the connection, it is recommended to provide the specific band mask using

AT+UBANDMASK = <RAT>, <bitmask1>[,<bitmask2>]

A reboot shall be applied (AT+CFUN=16) to apply the above changes.

After the connection is established, the network settings are saved in the module for the successive connections.


It is the range of radio frequencies supported in the area the module is being used in. A band mask can be obtained by searching for the bands used by the network operators in a given area. If the device is already connected to the network, you can use this command to see the used bands


Before querying the bands, you  need to set the module using the command below:


Subsequent connections

After the first connection, the subsequent connections take considerably less time, usually seconds, to connect to the network. The time is reduced because the module first looks to the saved settings from the previous connection and use those first to try to connect to the network.

Behavior after firmware update

During the firmware update, the module loses the saved settings from the previous connection. Thus, after every firmware update, the module will take longer time to connect to the network like it took for the first connection establishment.

To speed up the connection, it is recommended to note down the UBAND mask and MNO before the next firmware update and configure the module accordingly before trying for a fresh connection after the firmware update.

Poor connectivity condition

If the SARA-R5 module frequently loose the network connection, start with the basic debugging steps given as following:


 For power saving, 0 means the mode is disabled and 1 refers to mode enabled.

If after basic debugging, SARA-R5 module continues to lose network connection frequently, this may be be caused by a poor network connectivity area or weak signal strength.  You can verify it by using the 


Move the device to a good network visible area. Being placed in poor network connectivity area, the module takes longer time to connect to the network and may often lose network connection based on signal quality.

Roaming behavior

When the SARA-R5 module is in roaming mode, the module can take longer than usual to connect to the network. As best practice:


Reboot the SARA-R5 module to make the setting effective and for quicker successive connection using this command:


Firmware update of SARA-R5 on XPLR-IOT-1 Kit

SARA-R5 on XPLR-IOT-1 kit uses two UARTs to carry out its tasks. When the module on the kit is subjected to firmware update, one of the two UARTs is disabled. To bring it back to work, connect the device to m-center and use the following AT command:


NOTE: For further connectivity details of SARA R5 with XPLR-IOT-1 kit, refer to section 5.3 of XPLR-IOT-1 kit user guide.