eUICC: Your Guide to Connected IoT Deployments

What is an eUICC SIM card?

Quick eUICC definition: 

eUICC (Embedded Universal Integrated Circuit Card) is a functional concept for remotely managing SIM profiles, bringing benefits to both IoT devices and your entire deployment. At its very core, eUICC is a software component running on a specific type of SIM hardware that allows you to store multiple operator profiles and switch between them remotely.

Main benefits of eUICC SIMs


You only need one SKU to manage global deployments


Ability to change operators throughout the lifecycle of your device


Protect against changes in roaming regulations

Future proofing

Access to both existing and future Tele2 IoT eUICC-based services

Let’s break it down some more: since the start of cellular IoT, when it was still referred to as M2M, IoT devices relying on cellular networks for connectivity have used traditional “UICC” SIM Cards (Universal Integrated Circuit Card). UICC SIMs are “static”, meaning that after manufacturing there is no way to replace the operator on the SIM. In the recent years however, technology advances have brought us the next generation of SIM Cards, namely the eUICC SIM (Embedded Universal Integrated Circuit Card).

With eUICC, it’s no longer ‘put the SIM card in the device, and what it is at deployment is what you get for the rest of the device’s lifetime’ – eUICC SIMs take things up a few notches: you can download profiles, change operator, or even have multiple operators on the same SIM, something that isn’t possible with traditional UICC SIMs. The capabilities of eUICC SIMs are revolutionary for the IoT market – and the most secure eUICC formfactor on the IoT market today is the embedded SIM.

A single SIM for multiple global deployments

Previously, when deploying IoT with traditional UICC SIMs, you needed to understand where your devices would end up in the world so you could install SIM cards with the carrier profile needed to operate in those regions. This could cause complications in your supply chain because managing different SIM with different operators would add significant complexity to your manufacturing and logistic process. With eUICC, once your devices are out in the field, remote provisioning allows you to set them up with the carrier profiles best suited to serve your connectivity needs. So, instead of having multiple different SIM cards in the same device in order to, for example, facilitate optimal roaming in different markets, eUICC means you need just one SIM that enables you to activate the optimal profile for the country you’re in even after deployment.

Additional profiles can be downloaded and managed remotely throughout the device’s life cycle and you can change your operator or service provider without having to physically change out your SIM cards, something that can be both costly and logistically challenging, particularly for enterprises who have large-scale, global IoT deployments, as well as those who have deployed hard-to-reach devices. Additionally, eUICC SIMs are available in all standard form factors, meaning that switching to eUICC-enabled SIM cards is possible without the need to completely change your device.

The difference between eSIM and eUICC

To put it in the simplest of terms, an eSIM is a single virtual SIM card that takes advantage of eUICC’s capabilities.  

While eUICC and eSIM share common goals, their specific functions, features, and applications in IoT differ. eSIM is a virtual SIM card embedded in devices, while eUICC is the technology that enables eSIM’s remote management capabilities. In other words, eUICC is the foundation that makes eSIM technology possible. Additionally, eUICC is designed to store multiple SIM profiles, allowing for seamless switching between different MNOs, whereas eSIM is a single virtual SIM card that takes advantage of eUICC’s capabilities.

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The layers of an eUICC SIM – how are they linked together?

If we look at the different layers of an eUICC SIM, we need to understand how those layers need to match in order for the SIM to work. The hardware Operating System (OS) and electrical profile work like a minicomputer, with the different layers needing to be compatible for the SIM to function correctly. Not just any OS with work with any hardware, though, and it’s the hardware and OS compatability that decides if a SIM can support eUICC functionality.

eUICC functionality allows the SIM to remotely download, switch, and enable a different profile. This means there is no need to physically change the SIM – you can switch between different profiles in the same MNO, or from one MNO profile to a different MNO profile.

The Tele2 (MNO) profile and eUICC profile are personalizations of the SIM. They contain network keys and subscription identifiers (IMSI, ICCID, authentications keys.) The Tele2 profile can either be personalized when the SIM is produced in the factory, or it can be downloaded later through SM-DP (Data Preparation)/SM-SR (Secure Routing).

The Operating System

In addition to matching with the hardware, the OS supports important features on the SIM. If there is a PIN active on the SIM, the PIN handling is in the OS, as are authentication, access, and management of files and data, along with loading and deleting applications. Encryption/decryption and tamper proof functions are also handled in the OS.

One eUICC profile, many MNO profiles

An eUICC SIM has one eUICC profile but can store multiple MNO profiles, although only one MNO profile will be enabled at a time. So, what are these profiles?

What about applets?

Profiles can also contain applets, which are small programs on the SIM dedicated to fulfilling a particular task. The task could be implementing the business logic to change a connectivity profile based on rules, such as when one network is not available and you want the next best available one. If the SIM has a local applet, this is stored in the Tele2/MNO profile. If it’s a global profile it will be in the eUICC profile. To provide interoperability applets are typically developed in JAVA. Today, Tele2 IoT has an applet that clears forbidden networks, and in 2024 local management and management of 5G stand-alone on eUICC will be launched.

Unique eUICC SIM identifiers

Every eUICC SIM has an EID (eUICC identifier) which is the administrational key in the hardware layer. If there is an MNO profile change the SIM will have a different ICCID and IMSI, but once the eUICC SIM is produced its EID is never changed.

The EID contains 32 digits compared to the ICCID’s 20. There is a shortened version of the EID printed on both the embedded and plug in eUICC chip. The EID is provisioned in the SM-SR, which is also responsible for managing the status of profiles on the eUICC.

Hardware & formfactors

When using a SIM that has eUICC capabilities it is important that the hardware is robust and long lasting. ETSI has a classification of the different environmental properties in which the SIM is graded.

On a SIM technical sheet, the environmental performance can be represented in a string, together with which version of ETSI specification was used. The string of letters can then be referred to in order to understand what the SIM can withstand.

For example, the environmental property temperature has the grades TS, TA, TB, and TC. The Premium industrial SIM is graded as TB in its ETSI, string while a commercial SIM is graded TS. The eUICC Premium Industrial SIM can be stored and operational in the temperature range of -40 °C to + 105 °C ,while the UICC commercial SIM can only be used in the temperature range of -25 °C to + 85 °C

As mentioned before there are two types of SIM cards: plug-in formfactors (2FF, 3FF, 4FF) that are removable, and embedded formfactors that are soldered into the device. The most popular embedded SIM on the IoT market is the MFF2 (M2M Form Factor).

As the abbreviation applies the MFF2 SIM is designed for M2M/IoT use cases and is delivered on what looks like an old film reel. It is one of the most secure chips due to being soldered into the device and the device can be designed in a way that makes it more robust in general. An embedded SIM is also a greener, more sustainable alternative to plug-in SIMs, with less plastic and metal per SIM.

The future of eUICC

With eSIM technology the connectivity service profile of the secure identity is separated from the physical chip it is stored on (GSMA M2M eUICC Architecture). As we all know, the physical chip comes in the following current form factors plugin (2FF-4FF) and embedded. When embedded was introduced it got the name eSIM. When the standard for a remotely provisioned Secure Identity was introduced it was also given the eSIM namewith the reasoning that in the future all remotely provisioned Secure Identities will be embedded. But as we are not at that point, this is causing a lot of wasted time spent on miscommunication.  

The fact that the function (that a profile can be remotely provisioned) and the formfactor (embedded) have the same name by GSMA makes it challenging for everyone launching the solution as it is quite complex to describe to customers.  

We at Tele2 IoT try to distinguish between this by using the following terminology: 

• A SIM is aUICC with a Tele2 subscription profile that cannot be changed over time. eUICCs and UICCs come in plug in and embedded form factors

• eUICC is a chip that can have one or many subscription identities (virtual profiles) downloaded and managed remotely

• Our eSIM is an eUICC with our subscription (profile) enabled on delivery, which can be changed, offering freedom and flexibility for our customers.

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