SIM stands for Subscriber Identity Module or Subscriber Identification Module. It is known as an integrated circuit (IC) and it’s meant to store the international mobile subscriber identity (IMSI) number and its related key. This data is used to identify and authenticate subscribers on cellular devices. In other words, without this information, you cannot make calls or send text messages.
Did you know there’s more than one type of SIM?
When most of us think of SIM, we picture the physical card. This is known as a universal integrated circuit card (UICC). The other SIM types are fundamentally the same in that they carry an identity to present to the network. Each will then decide what network(s) you have access to. One major difference with a physical SIM card is that it can be taken out of one cellular device and moved into another. If you need to switch carriers or phones, this makes it easy.
Eventually, manufacturing companies started embedding SIM cards into the motherboard on devices. This became known as the eSIM and can be a bit smaller than a physical SIM. You’ll generally see these in smartwatches. Since these cannot be moved from one device to another, they are electronically programmable.
eSIM technology actually makes switching carriers even easier – at least in some ways. Instead of waiting for a new SIM card to ship or going out to pick one up, you can make the switch right on your phone with information provided from your carrier. If your phone has an eSIM inside there will be settings that allow you to configure it. You’ll be able to switch between lines and carriers, and manage your accounts. There are also phones with dual eSIM technology. In this case, you can support multiple accounts on one device.
So, if a SIM card is a UICC, then an eSIM is an EUICC (Embedded Universal Integrated Circuit Card). An iSIM or Integrated SIM, also known as the Integrated Universal Integrated Circuit Card (iUICC), takes up the least amount of space as it’s the smallest of the technologies. It is capable of everything that the eSIM is capable of.
As you know, a physical SIM card requires a dedicated slot on a cellular device, while an eSIM requires a dedicated chip soldered to the device’s circuit board. In comparison, an iSIM is embedded within a Tamper-resistant element (TRE) on the device’s system-on-a-chip (SoC). It eliminates the need to depend on discrete SIM hardware and can be activated wirelessly using an industry-wide secure protocol.
In an article released earlier this year, Qualcomm highlighted the main benefits that iSIM technology offers for smartphones, laptops, smartwatches, and other IoT devices and gadgets:
- Simplifies and enhances device design and performance by releasing space previously occupied within a device
- Consolidates the SIM functionality into the device’s main chipset alongside other critical capabilities such as GPU, CPU, and modem
- Enables remote SIM provisioning by the operator leveraging the existing eSIM infrastructure
- Opens mobile service connection capabilities to a host of devices that previously could not have SIM capabilities built-in
Are companies rushing to adopt eSIM or iSIM technology?
eSIM has actually been around since 2016, but hasn’t been used much outside of IoT and wearable devices. iSIM can lead to some vertically integrated solutions because you’re no longer having to source parts separately. Ideally, both would make everybody’s lives easier, but companies have to upgrade their processes for the sake of customers. Currently, there isn’t really a good process for building a device with an eSIM and then personalizing it with the carriers that you want. Once an eSIM carrier profile has been installed on an eUICC, it operates the same as a physical SIM, complete with a unique ICCID and network authentication key generated by the carrier. For example, if you get an eSIM from T-Mobile, it’s only going to access T-Mobile. It’s not the type you can just move to a different carrier.
While carriers are finally starting to adopt eSIM, it’s still a slow process and they haven’t really done the same for iSIM yet. For iSIM to catch on, the module manufacturers have to provide good backends for people to be able to then personalize the connectivity. So, with regards to the process, there has to be some kind of functionality for the control of that iSIM to be given over to the solution providers so that they can decide on things like the network provider identity.
The use of iSIM in different forms of smart devices will allow various service providers and industries to harness a large number of data points that can then be harnessed to not only optimize physical assets like devices but also operations and services. Vodafone and Qualcomm showcased a proof of concept working with an iSIM (see earlier article) and demonstrated how an iSIM could be a valuable commodity in upcoming smartphones. For now though, companies like Apple are sticking to the eSIM technology with devices like their iPhone 14.
So what does all this mean to me?
As the cellular industry and the technology involved progresses, it’s likely we’ll be seeing more eSIM and iSIM integration. With the high bandwidth and low latency benefits brought by 5G, it seems more companies are going to adopt the technology. Perhaps in an effort to keep the overall size of devices down, increase security for users, or to create more universally accessible devices. Whatever the case may be, the important thing to note is that eSIM and iSIM are really no different than the traditional SIM “card.” You may not be able to touch either of them, but because of their application, the possibilities for the future are greater.