What does eSIM mean?

eSIM has been one of the key topics within the mobile communications industry but it is only now that we are seeing eSIM enabled phones becoming more easily available. If you are someone who recently bought a new iPhone or Google Pixel, you may already have used the eSIM technology.

eSIM stands for ’embedded’ SIM and as the name suggests it is a SIM card that is embedded in a mobile device. The mobile device can be any device that can be connected to a mobile network. Examples include smartphones, smartwatches etc.

Now, before we dive into the details of the embedded SIM, let’s first try to understand what a SIM is. It may seem like an obvious one for many, but it is important to clarify that first.

What is a SIM?

A SIM or SIM card stands for Subscriber Identity Module and is a small card with an integrated circuit which can be inserted into a mobile phone to connect a phone user to the mobile network. Essentially, it is a circuit board that has all the information from a particular mobile operator programmed into it. It can also store other user-specific details like the contact list, etc. When you insert a SIM card into a mobile phone, it identifies the mobile phone to the mobile operator and is recognised by its Integrated Circuit Card Identifier (ICC-ID). Every SIM also has an IMSI number (International Mobile Subscriber Identity) which is a unique number assigned to each SIM.

The mobile phones nowadays have different requirements when it comes to the size of the SIM that can fit into the phone. As a result, SIMs nowadays come in various sizes such as standard SIM, micro SIM and nano-SIM in order to accommodate all mobile phones. There is also a new terminology ‘Triple SIM’ which means all of these three sizes of the SIM on one card so that they can fit into any phone.

Why do we need an eSIM?

With eSIM, mobile device manufacturers are able to build or embed a circuit-board directly inside the mobile device which customers can then configure based on their needs. eSIM technology gives more control to the customers by allowing them to be able to programme the embedded SIM in order to register with any mobile operator of their choice.

eSIM is an evolution of the existing SIM and there are clear benefits that make it worthwhile. There may also be some limitations, for example, if your eSIM enabled phone stops working, you can’t just pull the SIM out and insert into any other phone straightaway. There are two key players for eSIM; the first one, of course, the device manufacturers but then we also have the mobile operators who need to build capabilities in their systems to generate a QR code for customers so they can register on their mobile networks. As a result, when the overall technology matures, we may see devices with eSIM being the only option (no physical SIM) and the operators may be able to deliver eSIMs remotely and mostly online without having to give a physical eSIM pack with a QR code. At the moment, the process is not there yet and still evolving.

eSIM makes it easier for customers to switch from one mobile operator to another. Also, if a customer wants two lines, one as their primary line and other as a backup, they can keep both profiles on the phone and switch as and when needed. Many new smartphones are using eSIM technology to provide an ‘additional’ SIM so basically they have a slot for a regular physical SIM and one built-in eSIM option so you can have two SIMs in one phone essentially making your phone a dual SIM phone.

Another benefit you may hear about is that having an eSIM in a device saves space for the device manufacturer which they can use for adding other features to the device. That benefit may only apply to those devices that are using eSIM as a replacement for the physical SIM. It may not be so relevant in cases where manufacturers are using eSIM as an additional SIM together with a physical SIM.

The benefits of eSIM technology go beyond mobile phones as it can help all mobile-connected devices including wearables e.g. smartwatches. If as a device manufacturer, you don’t need a separate slot for a SIM card, you are in a better position to build the device in a smarter way. If you have ever used a smartwatch with a physical SIM before, then you can imagine how much smarter the watch would be if it was using an eSIM instead. It is important to note that the specification for eSIM has been done by GSMA (GSM Association). You can read more about eSIM on their website.

How does an eSIM work?

If you are looking for an eSIM today, in the UK at least, you receive an ‘eSIM pack’ from your mobile operator. The eSIM pack has a QR code on it which is like a barcode. When you start the setup process, it allows you to scan the QR code which then creates an eSIM profile on your phone for the number and operator who issued you the code. You are able to use your QR code more than once in case you need it for any reason e.g. if you accidentally delete the profile.

There may be a limit on the number of times you can do that though. However, you can only use one QR code on one mobile phone. When you use your code on one phone, it gets locked to that phone. If you then decide to change your phone, you will need to request a new eSIM pack which will give you a new QR code. You then need to swap your mobile number to the new phone also. It may seem like a bit of a hassle but it is important for security reasons to avoid any potential misuse.

In order to set things up, you will need to go into your mobile phone settings menu to start the setup process. The settings are different for Android and iPhone, and some Android phones may have slight variations also. But generally, as a guide, you should be looking for that part in the Settings menu where they ask you for the mobile network or operator information.

Once you are all set up, you can use your eSIM just like a normal SIM. You can store multiple profiles on your phone for different operators and you can switch as needed. However, you can only use one at a time.

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