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Setting CEMODE of PLS8 with ModemManager | Telit Cinterion IoT Developer Community

January 12, 2024 - 6:23pm, 98 views

In regions (e.g. USA), where only LTE is available, i.e. 2G and 3G are shut down, it is required, to switch PLS8's CEMODE, i.e. the mode of operation of EPS to data centric.

As default after power-on and e.g. a change of the SIM, CEMODE=1 is set. That means (from the reference manual):

CS/PS mode 1 of operation. UE is voice centric and registers to CS and PS.

UE shall always try to ensure that voice service is possible. If it is unable to obtain voice service in the LTE network (e.g. CSFB and IMS voice are not supported or the configured preferences on how to handle voice services prevent usage of any available voice services), it shall disable the LTE capability.

Therefore PLS8 must be switched to data centric mode! As this cannot be done via AT+CEMODE command, there is a workaround by placing a file in the EFS storage of PLS8 with a command sequence:

AT^SBNW="efs","/nv/item_files/modem/mmode/tests_file",2
...

Is it possible, to do this somehow while ModemManager is used to control the network connection?

In the past, we did not use ModemManager but a self-written piece of code to check the CEMODE and occasionally transfer the file to EFS. But now we changed the system and have to use ModemManager/NetworkManager to do the network/modem management.

Did someone make patches to ModemManager plugin "Cinterion" in order to allow the command

mmcli -m 0 --3gpp-set-eps-ue-mode-operation=csps-2

?

Any help appreciated!

Regards

Wolfram