To the naked eye, there isn’t much difference between consumer and IoT/M2M SIMs. The SIM in your mobile phone looks pretty much like the SIM in an IoT device, but there are critical differences. Your phone SIM is a commercial UICC plug-in, while an IoT device that is enabled to remotely manage subscriptions and has space for a removeable SIM is using an eUICC plug-in SIM. So, while they may look the same, the capabilities of eUICC SIMs are revolutionary for the IoT market- and the most secure eUICC formfactor on the IoT market today is the embedded SIM.
Let’s look at the different layers of an eUICC SIM and how those layers need to match in order for the SIM to work.
How are the layers linked together?
The hardware Operating System (OS) and electrical profile work like a minicomputer, with the different layers needing to be compatible for the SIM to function correctly. Not just any OS with work with any hardware, though, and it’s the hardware and OS compatability that decides if a SIM can support eUICC functionality.