Comprehensive technical knowledge base covering 12 GSMA eSIM specifications. 84+ articles on Remote SIM Provisioning — SGP.02, SGP.22, SGP.32, SGP.41, SGP.29, SGP.23, SGP.25, SGP.26 and more.
Imagine… you wake up in the morning. What do you do? You stretch, check your phone, see what’s on your schedule, and get ready for the day. IoT devices have a morning routine too: except theirs happens every time they power on, and it all takes place in milliseconds!
When an IoT device boots up (or wakes from a deep battery-saving sleep), here’s what happens:
The eSIM chip’s tiny operating system boots up. The main manager (ISD-R) wakes up and takes charge.
The manager checks: “What profiles do I have? Which ones are enabled? Which are disabled?”
The device selects the chip’s manager by its ID number (AID) : like calling a specific person in a busy office.
The translator (IPA) wakes up too. If it lives inside the chip (IPAe), it starts running there. If it lives in the device (IPAd), it boots separately.
The translator reads the chip’s contact list (eIM Configuration Data): “Who are my trusted remote managers?”
If there’s an enabled profile, the modem tries to connect to the network. Can it reach the internet? Great! If not… time for the parachute.
The eSIM chip has a tiny filing cabinet of important files:
| File | What’s Inside |
|---|---|
| EF.DIR | Directory of all apps on the chip |
| EF.ICCID | The chip’s serial number |
| EF.EID | The chip’s unique 32-digit ID |
| EF.EIMCFG | Contact list of trusted managers ✨ new for IoT! |
| EF.NOTIF | Pending report cards waiting to be delivered ✨ new for IoT! |
| EF.SMDP | Address of the default profile factory |
| EF.SMDS | Address of the message board server |
During boot, the chip also checks: “Do I have a Fallback Profile?” If no normal profile works, the chip can automatically switch to this emergency backup profile. It’s like checking your parachute before you jump: you hope you never need it, but you’re glad it’s there!
The fallback profile is usually a basic one from the device manufacturer: just enough connectivity to call for help, not for normal operations.
Once connected, the device sends a DeviceInfo card to the control centre:
The control centre uses this card to decide how to talk to this specific device. A tiny sensor gets gentle, lightweight messages: a powerful gateway gets richer commands.
The eSIM chip’s unique ID (EID) is 32 digits long: that’s enough numbers to give a unique ID to every single grain of sand on Earth… many times over!