SIM Application toolkit commands

Aleksander Morgado aleksandermj at
Wed May 3 13:24:13 UTC 2023

> > Does ModemManager support SIM application tool kit with proactive SIM
> > commands? My assumption is most of these SIM application tool kit
> > commands should be handled by the modem but I'm unclear what is the
> > role of host CPU / ModemManager in these commands? For example, many
> > SIMs support multi-IMSI i.e. depending on the location, a particular
> > IMSI is used for network connection. When a SIM changes its IMSI, the
> > SIM application tool kit applet sends a REFRESH proactive command to
> > the host device (or modem). This instructs the device to re-read the
> > data on the SIM, including the new IMSI.
> Currently, ModemManager does not support any SIM application tool kit
> commands. SIM toolkit apps displaying emergency numbers etc. are
> currently not possible with ModemManager.
> >
> > So how shall ModemManager know that IMSI has been changed and what it
> > is supposed to do? What is the role of ModemManager in handling these
> > commands?
> If the modem emits an AT URC / QMI / MBIM Indication, ModemManager
> might be able to handle it, but I'm not sure.

This is right. As we don't support generic SIM STK operations in MM.
We currently only support the multi-IMSI scenario on QMI modems when
they send an explicit notification about the change (e.g. UIM Refresh
indication, see 5c0db3743209b78d8c7b7558e337e6df25951bae).

I actually need to investigate the IMSI switch procedure while in
MBIM, it's in my TODO list for the next weeks. I assume that maybe
using the STK service we could be notified of the same.


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