Understanding ICCID Numbers for IoT Connectivity (2023)

In the realm of telecommunications, particularly in the context of IoT connectivity, the ICCID (Integrated Circuit Card Identification) number plays a pivotal role as a unique identifier for circuit cards, such as SIM cards. In this comprehensive guide, we delve into the intricacies of ICCID numbers, exploring their structure, significance, and practical applications.

What is an ICCID Number?

The ICCID serves as a distinct marker for SIM cards, aiding devices in identifying themselves when connecting to networks. It is crucial in the retrieval and updating of information on SIMs over the air, making it an indispensable element in the IoT landscape.

The Structure of an ICCID Number

Understanding the structure of an ICCID is essential for grasping its composition. The International Telecommunication Union (ITU) provides a breakdown, exemplified by an Onomondo SIM ICCID: 89 + 45 + 73 + 0000271204 + 3. Each segment, from MII (Major Industry Identifier) to the checksum, contributes to the unique identification of the SIM.

Major Industry Identifier (MII) and Country Code (CC)

The initial digits, 89, signify the MII, indicating the telecommunication purpose of the circuit card. The subsequent digits represent the Country Code (CC), such as 45 for Denmark, reflecting the geographical origin of the card.

Issuer Identifier Number (IIN) and Individual Account Identification Number (IAIN)

The ICCID includes an Issuer Identifier Number (IIN), exemplified by Onomondo's operator code 73. The Individual Account Identification Number (IAIN) sets apart individual IoT SIM cards globally, facilitating remote activation and identification.


Validating the integrity of the ICCID, the checksum is derived using the Luhn algorithm, ensuring accurate transmission of the identifier.

How to Find a SIM’s ICCID Number

Locating the ICCID is vital for managing SIM cards efficiently. While it is usually printed on the card, remote operation necessitates alternative methods, such as AT commands.

Via AT Commands

Although ICCID retrieval through AT commands varies among manufacturers, specific examples include:

  • U-blox: AT+CCID
  • Nordic Semiconductor: AT%XICCID
  • Telit: AT#CCID
  • Quectel: AT+QCCID
  • Cinterion: AT+CCID

Via Onomondo Platform and API

On the Onomondo platform, the ICCID is accessible in the SIM information panel. Utilizing the Onomondo API provides a streamlined approach to obtaining ICCIDs connected to your account.

ICCID, IMSI, and IMEI: Deciphering the Differences

To avoid confusion, distinguishing between ICCID, IMSI (International Mobile Subscriber Identity), and IMEI (International Mobile Equipment Identity) is crucial.

  • ICCID: SIM card identifier
  • IMSI: Identifies SIM card users
  • IMEI: Device identifier

For IoT, ICCID proves more static and reliable for SIM identification.


Mastering the nuances of ICCID numbers is imperative for effective IoT connectivity management. Whether through AT commands or platform-based solutions like Onomondo, understanding ICCIDs empowers users to navigate the intricacies of SIM card identification with precision. For further insights into IoT connectivity testing, explore our guide on . Elevate your IoT experience with comprehensive knowledge of ICCID numbers and their practical applications.

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