What you need to know about them

Most of us don’t pay attention to details like IMEI and IMSI numbers. When we have to, we don’t know what it is or even how to find them. Do we need to know them or how they differ even from each other? These are important questions regarding your privacy and security. We will answer them before it is too late for you to understand.

Many of us have heard of the IMEI number because it is very useful for find lost smartphones. But what about IMSI numbers and what is their role.

Let’s find out.

1. What is the IMEI number

IMEI stands for International Mobile Equipment Identity. Each mobile phone (and new mobile access point dongles) is assigned a unique IMEI number, which is printed on the inside, usually behind the battery. They are made up of 15 digits. Phone manufacturers assign unique IMEI numbers to each phone, and these numbers remain unchanged for the rest of their lives. So even if you are traveling to other countries, telecommunications operators can identify the country of origin of the sale and registration of the phone.

The GSM (Global System for Mobile) Association uses IMEI numbers to store them in a global mobile database which is also central for all network operators, phone manufacturers and other qualified parts of the industry. During the regular course, the number is useful to identify elements such as your subscription usage (voice calls, Internet) and also to determine if there are problems with the quality of the services. The IMEI number is as important as the serial number of other products. IMEI numbers are therefore used to identify the authenticity of a telephone with registration via a SIM card. This means that a false or incorrect IMEI number could prevent telephony services. In addition, the IMEI numbers only prove the authenticity of the phone and do not establish any direct relationship with the buyer. For example, you may have bought a new phone to give to your parents or spouse. Although you can be the buyer (technically), the end user of the phone will be different. A bit unrelated, I know, but I just wanted to be clear.

Telecommunications companies often use exceptional circumstances such as detecting locked or invalid phones on the network used for suspicious activity. In the case of CDMA phones, manufacturers use a different terminology called Mobile Equipment Identifier (MEID) or Electronic Serial Number (ESN).

READ:   What happens when you block a sender in Outlook: GT explains

The IMEI number is the first thing a customer service manager from a telecom operator asks if your phone is lost or stolen.

2. What is the IMSI number

IMSI stands for International Mobile Subscriber Identity. The telecommunications company assigns a unique number to the SIM card it issues to its subscribers. IMSI numbers are 15 digits long (but not always) and can be used to find the subscriber’s country and mobile network, among other details related to the SIM card. It is linked to the SIM card rather than to the phone itself.

It should be noted that to protect the privacy of the subscriber, telecommunications operators instead use another number called TMSI (Temporary Mobile Subscriber Identity) while providing services to the owner of the SIM card. The telecommunications company uses the TMSI to communicate with its subscriber. They are also shorter and much easier to transmit.

3. How to find the IMEI and IMSI numbers

If your phone comes with a removable battery unit, you can find the IMEI number printed on the bottom of the battery. You can also find it printed on the original box, but you threw it away a long time ago, right? Alternatively, you can dial the code * # 06 # in your phone numbering application to reveal a pop-up window with your IMEI number. It usually has 15 digits and is programmed into the phone.

Have you noticed two IMEI numbers in the screenshot above? This is because I use a dual SIM phone, and each must be registered with the operator. Usually, only the last digits are different in such cases. It helps the carrier to identify and track these phones with IMSI numbers.

Several smartphones have started to display the IMEI number in the About section under Settings. Check if your phone also displays the IMEI number.

As an end user, you do not need the IMSI number attached to the SIM card. Some mobile manufacturers list the IMSI number in the settings under the About or About phone section, but this is rare.

Note: Some apps also claim to help find it, but we don’t recommend them. It is not worth it and chances are that the information will be used to track the user in question. If you need to, call your telecom operator.

4. When to use IMEI and IMSI numbers

Since IMEI numbers are unique and cannot be changed easily, they are very useful for tracking and recovering lost or stolen phones. It is used to identify the mobile because all IMEI numbers are stored in a global register called Equipment Identification Register (EIR). Your telecommunications provider has the power to blacklist or block the phone. When a phone is blacklisted on all networks, no SIM card will ever work on it. This means that the phone is practically useless. I think Wi-Fi should still work.

READ:   Everyone can now access their Instagram DMs on the web

Hackers use alternative tools to make a quick profit by changing the IMEI number. This is called unlocking, which is a criminal Offence in many countries. These hackers use tools to assign a new IMEI number (also known as identity theft) to the phone so that it can be unlocked and used again with another SIM card. You may face legal consequences of the spoofing of the IMEI mobile number if it is caught in its use for harmful activities.

However, when you transfer your SIM card from one phone to another, the IMSI number is transported to the new phone with the SIM card. The IMEI number stays with the phone because it is linked to the phone. Telecom operators use the IMSI number to identify the customer and all the services for which they have registered. This includes your calling, messaging, Internet and other business services.

5. Security concerns

It is important to protect your IMEI and IMSI from prying eyes of harmful applications and trackers. Hackers can use the IMEI number to track and locate your movements. Heck, they can even spoof them to use financial apps after stealing your data.

On a related note, if you come across a phone without an IMEI number, it is an invalid or counterfeit phone. You shouldn’t buy this no matter what the attractive price is. How do you know that your IMEI number is valid? Well, you can match the one shown in the software interface with the one printed on the back and the packaging box. Another way to check it is to use the LUHN formula.

Likewise, IMSI numbers can be used by hackers to track users, intercept calls, messages, and hijack mobile data. The IMSI number is linked to the SIM card and is used directly to provide relevant services to the subscriber. Hackers can create a spoofed access point to catch data associated with the IMSI number before relaying it to the nearest cell tower and vice versa. Many Hollywood movies show this call tracking trick and everything. However, the actual use of such a technique is an extremely complicated process. Not impossible however.

READ:   Top 4 power strips with USB-C power supply for fast charging

Since the IMSI number is linked to the SIM card and used when communicating with cell phone towers, it can also be used to track user movements. In this case, the location of the cell towers is used to triangulate your position.

That said, IMEI and IMSI can be extracted by mobile applications to create a personally identifiable profile based on your usage pattern. For example, depending on your browsing activities, several companies may show you specifically targeted advertisements. And you may be wondering how this company knew you wanted to buy a new jacket? Well, it could be any application that you have blindly allowed to access all the information on your phone. Why else do you think your phone is spying on you? Well, this is how you get “personalized targeted advertising” from personally identifiable profiles.

Find the identity of your phone

The IMEI is linked to the phone and is used to identify the phone. IMSI is linked to the SIM card and is used to identify the subscriber and the services assigned to him. IMSI moves from phone to phone with the SIM card, but IMEI stays with the handset. As an end user, you will find IMEI useful for blocking lost or stolen phones.

This is the essential. It is a good idea to store your IMEI number in a safe place so that when the time comes, you can quote it. If the IMEI number is visible in the About Settings section, just take a screenshot and save the image to the cloud.


Lost your smartphone and don’t know its IMEI number? Do not worry. Click the link below to find out how you can still find the IMEI number.

Last updated on April 10, 2020


Leave a Reply