What is the IMSI Number, and What is its Function?

We use SIM cards that connect our devices to the cellular network to enable connections. These SIM cards have a unique number that identifies users and operators. If your mobile device registers with the network, it will send you the code called IMSI.

The number contributes to managing the connectivity. Now, the question may arise in your mind: What is this number, and why do I need to know it?

In this article, I will go through the details of the IMSI number and try to answer all your queries.

What is the IMSI number?

IMSI refers to International Mobile Subscriber Identity, which is usually stored on SIM cards. It is a 15-digit unique code that is allotted to cellular network users.

The IMSI number can’t be changed, which is a preventive measure to avoid SIM swapping fraud. 

Components of IMSI

The IMSI number on the SIM card looks like a 15-digit number.

Three main components, MCC, MNC, and MSIN, combine to form an International Mobile Subscriber Identity number. These contribute to finding the subscriber. 

Mobile Country Code (MCC)

A mobile country code is a code that shows the subscriber’s home country identity. It may be the combination of two or three digits. It ensures that the global network can identify the subscriber without any restriction. 

Mobile network Code (MNC)

The mobile network code identifies the subscriber’s mobile network. The code may include two or three digits, which helps to differentiate your home network from the other carriers in the country. 

Mobile Subscriber Identification Number (MSIN)

Mobile Subscriber Identification Number MSIN is the code that identifies you as a subscriber in multiple networks. The code may contain 10 or more than 10 digits, which depends on the mobile country code and network code. 

How does IMSI analyse the network?

When your device connects with the supported network, a code is sent from your device to the network. Here, the IMSI analysis process is activated, which analyses your home network via code. It also confirms whether the network is allowed access or not. International Mobile Subscriber Identity confirms which network a mobile number belongs to. 

IMSI vs. ICCID vs. IMEI: Key Comparison!

IMSI, ICCID, and IMEI are important numbers. They help your phone work well and keep your information safe from unauthorized access. Here are the details of their specific function in communication. 

How to check the International Mobile Subscriber Identity number? 

There are multiple methods to check the IMSI. Some common methods you can use to check the International Mobile Subscriber identity include.

Check the Android Settings

• Open your Android device Settings.
• Now move to About Phone or About Device.
• Scroll down to find Status or SIM Status. 
• Here, in this section, you can see the IMSI number listed.

One thing to consider is that these steps are not similar in Android models. Therefore, you have to do it according to your device settings.

In iOS Devices

As iPhones have strict security and privacy policies, you cannot access the IMSI number directly from the iPhone. But there are some other methods you can use.

Use USSD Code

Dial *#06# in the dial bar of your device and press the enter button. If your device allows, the IMSI number will show on your screen. Sometimes, the devices show IMEI rather than IMSI due to security concerns. 

Use a SIM Card Reader

Using some specific tools, you can find the IMSI number. In this process, a SIM card reader is used to connect your SIM to the computer. Then, some specialised software is used to display this secret code. 

How does IMSI contribute to security protocols?

IMSI play a key role in the authentication of subscribers and their devices. When your device connects to the network, it sends the IMSI code to the carrier. The carrier checks if your account is valid. If it is, you can access the network services. 

This verification avoids SIM swapping and allows only authorised devices to access the network.

In SIM swapping, the hackers take over your mobile identity and access assets. SIM swap checks use an IMSI number and check the mobile network security. 

Conclusion

International mobile subscriber identity is the security code for the SIM card. It identifies the right subscriber of the cellular network. The code identifies the valid account users and confirms whether the network service is provisioning.

The main components of IMSI, including MNC, MCC, and MSIN, contribute to making the function possible. It ensures the device network security and avoids activities like SIM swapping. 

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