What is iSIM | How does it work, Pros Cons & differences

An iSIM, or Integrated SIM, is a technology that integrates cellular connectivity and SIM functionality directly into a System-on-Chip (SoC), removing the need for physical or separate electronic SIM cards (eSIMs). 

Integrated SIM (iSIM) works in the same way as Virtual SIM. However, the main difference is that iSIM integrates SIM functionality directly into a device's main processor (SoC), while eSIM uses a separate, reprogrammable chip within the device.

The core of the iSIM technology lies within a secure part of the SoC, meeting GSMA standards to ensure your identity is securely verified, and your connections are as reliable as they would be with any SIM card. This setup not only matches but in some ways, exceeds the capabilities of previous SIM technologies.

In this article, I'll cover how iSIM technology functions. iSIM components & its comparison with eSIM. Also its role in shaping the future of mobile phones and IoT devices.

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What is an Integrated SIM?

An iSIM merges the SIM's capabilities with a device's baseband chipset into one cohesive connectivity module. This approach, also known as the integrated Universal Integrated Circuit Card (iUICC), marks the newest evolution in SIM technology. It's particularly impactful for the Internet of Things (IoT) industry, offering a compact, secure, and versatile solution for connecting a wide array of devices seamlessly to cellular networks.

How does iSIM Work?

An iSIM, or Integrated SIM, works by incorporating SIM functionality directly into a device's System-on-Chip (SoC), a single chip that contains all the necessary electronic circuits and components for a device. This integration allows the iSIM to operate in a more secure and efficient environment compared to traditional or even embedded SIM cards (eSIMs).

When a device with an iSIM powers on, the iSIM uses its integrated circuit within the SoC to connect to a mobile network. It securely stores the user's subscription information and uses it to authenticate the device with the network provider, similar to how traditional SIMs work but without the need for a physical card.

iSIM works by allowing users to switch network providers or subscribe to new services digitally. This is done through secure downloads of subscription profiles directly from the service provider, eliminating the need for physical SIM card swaps or in-person visits to a service provider.

Components of iSIM

It's important to understand that unlike traditional SIM cards or even eSIMs, iSIMs don't have individual physical components. They are essentially a functional block built directly into the device's processor.

However, conceptually, an iSIM solution can be thought of as having three main parts:

Secure Enclave:

The Secure Enclave is a dedicated, highly secure area within the device's processor or chipset. It serves as the storage location for the subscriber's critical information, such as International Mobile Subscriber Identity (IMSI) (e.g., phone number) and security keys required for network authentication. This secure storage replaces the traditional removable SIM card, ensuring that sensitive data is tightly integrated into the device's hardware.

Subscription Manager:

The Subscription Manager is a software component responsible for managing the subscriber's profile and subscription information stored in the Secure Enclave. It handles tasks such as activating new subscriptions, updating existing ones, and enabling seamless switching between different carrier profiles. This component ensures that the subscriber's data is properly managed and maintained within the iSIM system.

Remote Provisioning:

Remote Provisioning is a key feature of iSIM technology that allows carriers to securely transfer and update the subscriber's information directly to the device over-the-air (OTA). This eliminates the need for physical SIM card swaps or manual interventions. The Remote Provisioning component facilitates the secure transfer of subscriber data from the carrier's network to the device's Secure Enclave, enabling remote activation, updates, and carrier switching without the need for physical interaction.

Advantages of iSIM:

iSIM technology offers several advantages in device design, particularly in terms of size, power efficiency & security over traditional SIM cards and even eSIMs:

• Smaller size: iSIMs are embedded directly into a device's chip, eliminating the need for a separate component. This is especially beneficial for smaller devices like wearables and Internet of Things (IoT) gadgets.
• Lower power consumption: Because they don't require additional hardware, iSIMs use significantly less power than eSIMs, which can extend battery life in resource-constrained devices.
• Enhanced security: iSIMs are built into a secure enclave within the device's main processor, offering greater protection against tampering and cyber threats.
• Simplified manufacturing: Integrating the SIM functionality directly into the chip eliminates the need for a separate SIM card slot, streamlining the manufacturing process for device makers.
• Increased flexibility: Like eSIMs, iSIMs allow users to switch between different mobile network operators remotely without needing a physical SIM card.

Physical SIM vs eSIM vs iSIM: What’s the difference

When it comes to SIM (Subscriber Identity Module) technologies, there are three main approaches: Physical SIM cards, eSIM (embedded SIM), and iSIM (integrated SIM). Let's break down the differences between these options:

Physical SIM Card: The SIM card has been the standard for many years. It's a removable smart card that stores your subscriber information, such as your phone number and authentication keys. This small card needs to be inserted into a dedicated slot or tray in your device to connect to your carrier's network. While physical SIM cards are widely used, they come with certain limitations.

eSIM & iSIM:

Both eSIM and iSIM are technologies that ditch the traditional physical SIM card, offering greater flexibility and design freedom for devices. However, they achieve this in slightly different ways:

eSIM (embedded SIM) replaces the physical SIM card with a tiny chip built into your device. This allows for sleeker designs, easy carrier switching via downloaded profiles, and enhanced security.

An iSIM (Integrated SIM) takes the concept of an eSIM a step further. It's not a separate chip but rather functionality built directly into the device's System-on-Chip (SoC). This eliminates the need for a separate eSIM chip, making it even smaller and more space-saving.

Pros and Cons from a User Perspective:

Physical SIMs:

• Pros: Widely used and universally compatible across global networks.
• Cons: Less convenient when switching carriers, as it requires physically swapping out the SIM card.

eSIMs:

• Pros: Allows for easier switching between carriers and can hold multiple profiles for travel or dual-line management.
• Cons: Not all carriers support eSIM technology, and device compatibility can be limited.

iSIMs:

• Pros: Offers the highest level of integration, freeing up space within the device for other components or slimmer designs. Enhanced security and the potential for broader IoT application.
• Cons: Currently, fewer devices and carriers support iSIM technology, though this is rapidly changing.

Is iSIM removable?

No, iSIM (integrated SIM) is not removable. Unlike traditional SIM cards or even eSIMs (embedded SIMs), iSIM functionality is integrated directly into the device's processor itself. There's no separate physical component to remove.

What is the use of iSIM?

At its core, iSIM technology allows devices to connect to cellular networks without the need for a physical SIM card or an eSIM soldered onto a printed circuit board.

• Wearables: Smartwatches, fitness trackers, and other wearables can benefit from the compact size and security of iSIMs for secure mobile connectivity.
• Internet of Things (IoT): A multitude of connected devices, from smart home appliances to industrial sensors, can leverage iSIMs for reliable and secure data transmission.
• Connected Cars: Secure and reliable communication is crucial for the future of connected vehicles. iSIMs can play a role in enabling advanced features like real-time traffic updates, remote diagnostics, and even autonomous driving.

What is the future of iSIM?

iSIM technology is still in its early stages, but it holds immense potential for the future of mobile connectivity. iSIM technology is expected to take off in a big way, with millions of devices using it by 2025. As iSIM technology matures and becomes more widely adopted, we can expect several advancements:

• Increased Adoption: More devices, beyond smartphones, will integrate iSIM technology.
• Enhanced Security Features: iSIM security protocols are likely to evolve further, offering even greater protection.
• Improved Standards: Standardization across manufacturers will ensure smooth functionality and wider carrier support.

What is iSIM in IAM?

It's important to clarify that iSIM can also refer to "Identity and Service Management" software suites used in enterprise environments. This type of iSIM is not related to mobile connectivity. It focuses on managing user access and permissions within an organization's IT systems