The full form of SIM is the Subscriber Identity Module. As the name suggests, a SIM card’s primary function is to connect the user with the network and give them a unique identity with a phone number. Thus, the SIM card is an access card to the network you want to connect with. In essence, it acts as credentials that let you log in to the mobile network. But what other functions does a SIM card have, besides data and calls?
The major services provided by a SIM card are to enable a user to make and receive calls, send and receive SMS, and have access to the data. But these are not the only things a SIM card can do—there are several other things a SIM card can perform. Some perks are important and can only be performed by a SIM card. Other functions of a SIM card, though functional, are not as relevant nowadays. Let’s get into it.
Basic functions of a SIM card
Once again, the main function of a SIM card is to authenticate the subscriber, grant them access to the cellular network and bill them correctly. With that in mind, it’s essential to note that no other component of your phone or tablet can do this. That’s why, in this case, the SIM card becomes irreplaceable. Although you can use a smartphone without a SIM card, you cannot use cellular network services this way. To clarify, you will be unable to call, text, or utilize mobile data that can be used over a cellular network without a SIM card.
SIM card functions that aren’t cellular data and calls
There are many functions of a SIM card, both for the user and the operator. A SIM card is a pivotal component for the network operator, as it helps them run their mobile network business. But a smartphone user can call, text, and access data without it, only using a Wi-Fi connection. We provided more SIM card functions except for calls and data below:
1. A SIM card is useful to network operators
It provides them with some operator-centric services such as call completion and automatic handset configuration, which helps reduce the cost of billing for their customers. Consequently, it aids them in increasing their Average Revenue Per User (ARPU).
2. Mobile network operators can communicate with it
Not only communicate, but also remotely manage a SIM card using Over-the-Air (OTA) technology. For example, the carrier can easily update a SIM card with new services and applications without asking the user to upgrade his handset or visit the local store. You can often find those updates within the SIM toolkit.
3. SIM acts as a storage medium
SIM cards can keep a few hundred phone contacts, some SMS data, and information related to different networks on roaming. A SIM card’s storage (ranging from 32 KB to 256 KB only) is now dwarfed by the huge internal memory of modern smartphones. Hence, its use is now limited and considered unreliable.
4. It authenticates users
The SIM card also holds an authentication key. Only when this key matches the copy of the key stored on your mobile network’s database are the subscribers granted access to the network. Your network needs to authenticate your account, and your SIM card has all the information related to this. One such piece of information is the ICCID (Integrated Circuit Card Identifier), unique to every SIM—physical or virtual.
5. SIM cards represent a shield against misuse
We explained all about these measures when we answered how secure a SIM card truly is. Besides PIN (Personal Identification Number), it is, by proxy (through your phone number) pivotal for two-factor authentication measures lots of software and websites employ nowadays.
The SIM card has limited functionality apart from calling and data access, but it is, nonetheless, crucial. Accessing a cellular network without one is almost impossible. The SIM card will likely remain required in the future, as long as cellular networks exist. Its shape, size, and form may change, but it probably won’t disappear entirely.