When you decide to venture into the world of IoT, many decisions need to be made. This can range from what platforms you use to host your data, do you build a brand new unit or use an existing one and how you plan to connect your devices to the Internet.

In this post, we look at an aspect of the last one, namely, should you consider using a standard SIM slot or venture down the path of an eSIM. For a great explanation of what an eSIM is, click here. We examine six things you need to know, three on the “pro” side and three on the “con” side. 

Finally, we decided to add in “Scott’s take” for each one, where Novotech’s VP of Engineering, Scott Deyoe, adds in a comment on each point.

Advantages of eSIMs you should know:

Smaller footprint

If you are adding connectivity to something the size of an automobile, you may not care as much about the advantage of a smaller footprint (space is taken up) on your system board. However, since many IoT devices are small, even worn on the wrist, any extra space savings is much appreciated. Simply, the size taken up by any physical SIM card is multiple times bigger than what is needed for an eSIM solution.

Scott’s take -– While size may not be an issue for an automobile, harsh environmental conditions are an excellent application for eSIMs as their temperature range typically exceeds that of a plastic moulded SIM.

No mechanical failure of the socket

More and more, IoT devices are being used in vital applications. This includes things like water treatment systems, traffic control applications and monitoring of critical energy facilities. 

For these applications, failure can lead to significant issues, both financial and safety-related. Engineers designing these solutions must do what they can to remove any possible failure points.

As there is no actual physical socket, an eSIM solution's reliability level is generally much higher than on a traditional SIM-based design.

Scott’s take: Like the first issue, removing the mechanical socket associated with a traditional SIM also eliminates the requirement for ESD protection for a SIM socket.

Easier / simpler design

While many like to add fancy features into devices that may not need it, engineers of critical systems know that the simpler, the better. Simple designs mean that there are fewer ways for failure and, as a bonus, are generally lower cost to design, build and maintain.

Scott’s take -– Combining the improved environmental performance by eliminating the mechanical socket and extra circuitry required for ESD protection results in the most robust design possible.

Improved ESD protection

By removing the need to insert a physical device into the SIM slot, there is a reduction in [SD] the potential for ESD (electrostatic discharge). This is ideal for protecting the components on the board, especially in a critical application.

Scott’s take –[SD]  Reducing ESD exposure is always a plus as the symptoms of ESD can be sporadic.

Disadvantages of eSIM that you may want to consider:

May be more difficult to switch than you would think it should be

In theory, this point should be on the positive side, and it may very well be as the technology develops. When you do not have to physically swap out one SIM card for another to change providers, the switch should be effortless, especially for hard to reach devices in the field. However, according to many customers, this has not always been the case. Many have complained that the swaps have not gone as smoothly as desired. This is something to keep in mind, especially related to the second point.

Scott’s take: Typically, the SIM profile changing is managed by a third party clearing house with the credential profile required to change carriers.

Not all carriers support all features.

Related to the previous point, not all carriers support all of the features of eSIMs at this time. This means that if you wish to switch cellular providers during your deployment, you may find you have fewer options to do so. This would limit your choices, which can hurt both from a coverage standpoint and from the ability to get competitive pricing in some cases.

Scott’s take -– As mentioned previously, the carriers decide whether to participate in the eSIM exchange process. While almost all carriers have eSIM available today, not all support changing the carrier.

No ESD protection 

As we spoke of earlier, many IoT deployments involve very sensitive deployment, such as monitoring critical infrastructure. One of the ways that these devices are protected is against Electrostatic discharge to prevent damaging vital components. 

Traditional SIM card based deployments offer a higher level of protection than eSIMs, which may be a drawback for some.