Cellular IoT and eSIM fundamentals
Connect a fleet from the first prototype: identifiers, profiles, bearers and roaming logic in the order engineers meet them.
7 lessons
- Identity: four numbers and an eUICC ID
Subscription, card, device, number and chip: which identifier answers which question, and what a SIM swap actually changes.
- What is an eSIM? Profile and eUICC
An eSIM is a profile on an eUICC, not a chip. SGP.22 and SGP.32 decide who can change it; neither changes the IMSI, the number or market rules.
- What is multi-IMSI? Identities on one SIM
Multi-IMSI selects among several subscriber identities on one card. It changes the identity at the border, not the subscription or market rules.
- SGP.22 vs SGP.32: who activates
SGP.22 assumes a screen and a person. SGP.32 assumes a fleet and an eIM. The activation model decides which specification fits the device.
- Multi-IMSI vs eUICC: identity vs profile
Multi-IMSI changes the IMSI on one card. eUICC replaces the operator profile. The choice follows hardware life, movement and who manages the fleet.
- NB-IoT vs LTE-M vs Cat-1 bis vs Cat-4
The Cat number is not a rank. Payload, interval, mobility and destination bands decide the bearer. Compare the trade-offs before the module choice.
- Roaming: home routing vs local breakout
Two roaming architectures: send traffic home or exit near the device. What each changes in path, control, measurement and the rules that apply.
Terms you'll meet
Tools used
IoT & eSIM identifier toolkit
Decode and validate ICCID, IMSI, EID, IMEI and LPA activation codes in your browser. Nothing is uploaded.
Open the toolIoT battery-life estimator
Estimate battery life for LTE-M and NB-IoT devices from reporting interval, payload and power-saving settings.
Open the toolEARFCN & NR-ARFCN converter
Convert channel numbers to band and frequency and back, with NB-IoT and LTE-M bands marked.
Open the tool