IoT SIM cards comprise multiple data including the IMSI or International Mobile Subscriber Identity which works as a unique identifier for mobile subscribers. It is comprised of three distinct digit parts: Mobile Country Code (MCC) shows the primary operating country of the subscriber and is represented by 2-3 digits. Mobile Network Code (MNC) denotes Mobile Network Operator to which the subscriber is affiliated and includes 1-3 digits. Mobile Subscription Identification Number is a unique part of each IMSI for every subscriber that consists of 1-9 digits.
After the IoT device is powered on or connects to a cellular network, it sends a registration request to the network. The request includes the IMSI among other information. The cellular network uses IMSI to authenticate the IoT device ensuring the device is authorized to connect to the network. As soon as the authentication is successful, the cellular network assigns an IP (Internet Protocol) address to the IoT device and establishes a connection. This allows the device to communicate with other devices or services over the internet. The IMSI is also used to track the usage of IoT devices within the network. It helps the mobile network operator monitor data usage, apply appropriate billing, and manage network resources efficiently.
A multi-IMSI refers to a SIM card that contains multiple IMSIs. This enables the SIM card to dynamically select the appropriate IMSI to use in different countries. When a SIM card moves across different countries, it automatically identifies and chooses the best IMSI for that particular location. This ensures optimal connectivity and service quality for IoT devices on the network. By having multiple IMSIs, it becomes possible to optimize data costs and coverage based on the specific country being accessed.
The IMSI and ICCID are two separate identifiers within the SIM profile, often leading to confusion. However, they have distinct roles and differ from each other. While the ICCID is a 19 or 20-digit number located on the back of the SIM card, serving to identify the SIM itself, the IMSI identifies the subscriber. When several IoT devices are connected to the same service, they may share one single IMSI. Conversely, each SIM will have a unique ICCID assigned to it.
