Integrated SIM (iSIM) FAQ — Altair & G+D

iSIM allows IoT device vendors to offer smaller, more power-efficient devices to meet massive consumer and industrial demand.

NB-IoT and CAT-M. 2G is also available in specific modules.

G+D’s SIM software runs on an isolated hardware secure element integrated inside the Altair chip, adhering to G+D’s strict security assessment standards.

Yes, Multi IMSI applications are supported.

The integrated SIM is approved by multiple global Tier-1 MNOs and MVNOs, including AT&T and LGU+. Additional Tier-1 operator onboarding is in progress.

Yes. The activation process is identical to that of traditional SIM cards.

Not currently. The integrated SIM is compliant with ETSI/3GPP, so only remote file administration is supported — for example, changing profile content. In future phases, it may evolve to comply with upcoming GSMA standards.

Yes. Beyond the iSIM cost advantage itself, device makers benefit from a reduced BOM, smaller form factor, no SIM tray requirement, and lower handling and processing costs compared to discrete SIM cards.

All resources are statically assigned to iSIM and securely assessed to be protected from change.

No. All resources are statically assigned to the iSIM and protected from change.

The integrated SIM works in any cellular device. For IoT, the ALT1250 modem supports R14 LTE CAT-M/NB-IoT and 2G networks; the ALT1255 modem supports R14 NB-IoT with 2G fallback.

It is compliant with ETSI/3GPP. In future phases, it may evolve to comply with upcoming GSMA standards.

The integrated SIM is commercially deployed globally. In-country personalization is supported — for example in India — and Altair and G+D can guide customers through the process.

The current integrated SIM, based on the ALT1250 modem, targets LTE CAT-M/NB-IoT devices. The same integrated SIM architecture will carry forward into the next-generation chip with 5G NR capabilities.

Yes. A specific data set is pre-generated, bundled with the secure operating system, and provisioned during the manufacturing process.

The iSIM-enabled part numbers are ALT1250ST, ALT1250SB, and ALT1255SB.

Yes. OTA services including remote file management are supported.

The ALT1250 and ALT1255 modems are qualified for industrial grade and are currently used in automotive after-market applications. AEC-Q qualification is not planned at this time.