Insert/Download eUICC profile within eSIM using "AT+CSIM=" command

Hi ! I’m new to eSIM and for a personal project, I want to reproduce the behaviour of sharing a mobile subscription between a smartphone and a smartwatch ( as Apple Watch and its paired Iphone do).

For that, I think i should insert or download the eUICC profile of my mobile subscription within the smartwatch I’m creating, but I don’t really find any relevant documentation on how to do that and even if is it possible…

Could someone explain me the high level of what should I investigate, starting from the fact that operators in Belgium allow to insert subscription of a user’s smartphone into its smartwatch.

I think that I should

  1. Download the profile and insert it by myself within the eSIM (with AT+CSIM command)
  2. use the AT+CSIM= command in order to update records/files of the eSIM and trigger a profile download with the network

Thanks in advance !!


So there are a couple of different ways to do this but the module OEM has essentially nothing to do with it.

  • End to end connection - Here the chip SIM will create an end to end secure connection with its own manufacturers backend server (so for instance Gemalto, Infineon, G&D, etc) where the carrier will have a profile loaded and waiting for it. This connection can be made over any bearer, be it cellular, WiFi, etc. It will then be loaded and operated with. In this instance the module is a pure bit pipe only seeing 1’s and 0’s with the application software having absolutely no control.
  • Local Provisioning Agent - Another way is for the host system to have a Local Provisioning Agent (LPA) - Rather than the SIM performing the connection the LPA would do this (over whatever bearer is available to them, I would expect this to be over WiFi on a handset. Once it has the profile information it would then load it onto the unit, on Qualcomm based units there are QMI API’s in place, if not then yes you would need to use the CSM/CRSM AT commands but what these consist of you would really need to talk to the SIM providers as they should have it figured out.

In the case of Sierra’s own Smart SIM we use the end to end method, its quite difficult in IoT because you have several separate entities trying to co ordinate whereas if you have a handset being bought by a single carrier and that same carrier buying the SIM cards it makes the coordination far simpler.



Oh yeah and the actuakl GSMA standard is SGP.22 and Infineon have an open source LPA here.



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Thank you a lot for your response !