September 10, 2021

How to Select a SIM for Long-lasting and Trouble-free IoT Applications

Historically, the development of cellular IoT applications has been based on the reuse of technologies for person-to-person communication. Modules were basically rebuilt mobile phones with some sensors attached, while networks were based on the available 2G technology. However, as things have developed and as IoT applications have grown and become critical for companies and even society, the development has changed. Now, modules are designed, and operators are using specific business models and rolling out network technologies exclusively for IoT. This makes perfect sense since the requirements are different from handsets and the scale is now huge. 

When selecting a SIM card, many application developers are not making educated choices. Most SIMs that are used in IoT applications are still following specifications developed for use in handsets. In handsets, the environment is well known, and it is relatively easy to exchange a worn-out SIM.  This is far from the case for an IoT application. The Premium Industrial SIM – created specifically for IoT, has been developed with features that make it suitable for most IoT use cases.  

Let’s see what some of those features are:  

Environmental conditions

Commercial-grade SIM cards are designed for use in cell phones, with the specifications designed for normal weather conditions, to last for a few years and to do that in an environment that is relatively well protected from dust, humidity, and vibrations.  

The Premium Industrial  SIM can withstand tougher environmental conditions. Temperature, vibrations, shock, salt, and corrosion are just some examples of environmental effects where the tolerance is higher.  


How about longevity? This brings up the question of write and erase cycles, and the memory of the SIM card.  The memory can only guarantee a specific number of write and erase cycles. This  is a crucial factor when talking about devices  that are meant to last for many years, that change location (cells  and/or towers)  and sometimes  networks  (like a tracking service, etc.) It also matters if a device  needs to re-authenticate to  the  network regularly, or if  recurring  power-cycling of the device occurs. The Premium Industrial SIM is optimized to ensure longevity, with significantly more write and erase cycles compared to standard SIMs. 

Form Factor

The choice of form factor is often overlooked when designing the device. Obviously, there are size issues that stipulate how small the SIM needs to be, but there are some other things to consider.  

The most common form factors are the different plug-ins – 2FF, 3FF or 4FF, aka mini, micro, nano – which you likely know from your cell phone. Often these come in 3-in-1 versions that solve some logistical challenges regarding stocking up with multiple form factors. However, before using the multi form factors in a large-scale deployment, you should be aware that the cutting in the SIM cards for the multiple versions also reduces the durability of the SIM card. And there are differences in thickness for the 4FF, which complicates things further. To get the maximum endurance from a plug-in SIM, single form factor SIMs are recommended. 

The most durable form factor for IoT is embedded, also known as MFF2. These SIMs are not cards, i.e., they have no plastic holder but are instead a chip that you solder directly to your circuits. This removes the risk of the contacts being worn out or that the SIM is stolen. However, it is also more complex to embed the chip and makes it impossible to change SIM without changing the circuit board.  

Commercial lock-in effects

For long-lasting IoT applications, one of the biggest challenges is the long-term lock-in effect to the Connectivity Service Provider (CSP). This is especially true for embedded SIMs, but many applications are rarely touched and changing SIMs can be a very expensive project. To create an IoT application where the CSP may need to be replaced during the devices’ lifetime, GSMA has developed a standard called Remote SIM Provisioning or eSIM, where the data on the SIM can be exchanged securely over the air. When the device is to be long-lasting, it is recommended to have a SIM that fulfils this standard and where the CSP will allow such a change. 

What about Tele2 IoT?

We have re-developed our Premium Industrial SIM product that addresses these challenges and ensures a long-lasting IoT solution. This SIM fulfils the standards for environmental conditions and has special functionality to ensure a very high amount of write and erase cycles. As this SIM is built to last, we will also pre-package it with functionality for changing operators, as an insurance and more.

There is a lot to think about when choosing the ideal IoT solution.  Choosing the right  SIM is a big part of these choices, and we are here to help you. With Tele2 IoT’s Premium Industrial SIM, you will be sure that you have the endurance that you need from this critical component, as well as the ability to change operators, in case it would be necessary sometime in the future. 

Stay tuned for more news about our Premium Industrial SIM offering – or you can reach out for further discussions.  

Marcus Gidén
Commercial Product Manager
Tele2 IoT

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