IMEI and ESN: Everything You Need To Know

February 26, 2019

There are two major mobile service provider technologies used across the globe: the Global Systems for Mobiles (GSM), and the Code Division Multiple Access (CDMA). Every mobile phone is made to support either GSM or CDMA, but no gadget can support both regardless of how advanced its technology is.
Manufacturers assign a unique number to every phone they produce depending on the technology it supports. Those that support CDMA use an identification number known as Electronic Serial Number (ESN), while those that GSM ones use International Mobile Equipment Identification (IMEI).


The difference between ESN and IMEI

The main difference between IMEI and ESN is that the former is associated with a specific mobile gadget and doesn’t in any way identify a subscriber or individual. Instead, GSM uses a SIM-card (Subscriber Identity Module Card to store information about the customer. Whenever a client wants to switch phones on this network, all he needs to do is insert his sim card in the new device, and he will start making calls immediately.

On the other hand, the latter doesn’t use a SIM card to store customer information. Instead, the CDMA network uses ESN to identify both the device and the customer. For this reason, when a client changes his phone or activates a new service, he must the provider will first have to associate him with the account before he can make any calls.


Why is ESN important?

ESN is a unique electronic serial number that is used for device identification by the manufacturer. This number is essential in the sense that it can be used to block your phone when it is stolen. Yes, all you need to do is report the number to your provider, and it will be blocked without delay.
At times, this number is also used to track spare parts for your device when a need arises.


Is IMEI as important?

Yes. In case you lose your phone, your provider can block the phone. You will then be issued with another SIM card, which you can insert in a new device and start making calls. Nonetheless, you must ensure that you back up your data so that you can recover it in such an eventuality.


Locating IMEI and ESN

A primary similarity between ESN and IMEI is that they can be located, using different methods.
ESN is typically printed on the phone’s battery, or on the box in which your phone was packed. Nonetheless, in case you don’t find it in these two places, you can easily find it by going to settings> about phone > ESN. Since it can be difficult to memorize this number, safely record it somewhere for future reference.

Locating IMEI is also simple and straightforward. Some manufacturers will engrave this number on the SIM tray, but if you don’t find it there, simply dial *#06#, and your gadget will display the number. Just like the ESN number, don’t forget to record it safely. Its relevance is undisputable.


Why you should keep your IMEI a secret

Some people believe that since manufacturers scribble IMEI numbers on boxes, they are not numbers that should be treated as top-guarded secrets. This is wrong. Once your IMEI gets into the wrong hands, it can be used for malicious activities. Smart hackers might clone your device and enjoy free services at your expense. Worse still, there are those that will use it to access your sensitive information and online banking details, and use them to satisfy their mischief. Therefore, when ditching your phone box, ensure you get rid of the sticker bearing your IMEI number or simply shred or burn the box.


What to do if your iPhone has a blacklisted IMEI or bad ESN.

You have bought a good iPhone 6 or iPhone 7, but upon checking its status online or contacting the carrier, you notice that it has a bad ESN, or its IMEI is blocked.

You start thinking that your money has gone down the drain. But look – there are lots of things you can do and get value for your money. They include;

  • If you bought the phone in its current state, ask the seller for a refund or replacement
  • Request the carrier to clean the ESN or IMEI.However, note that not all carriers will grant this request.
  • Use the phone as a gaming console
  • Swap the logic board. Remember, an iPhone blocked in the USA will work in another country if you change the chips. Nonetheless, this might as well damage your device.
  • Unlock the device and sell it to foreigners at a discount. They will buy it since they might be able to use it in their countries.
  • Sell the gadget online
  • Rip the phone apart and sell it as spare parts!


Finally, the importance of ESN and IMEI numbers cannot be stressed enough. Therefore, make sure you copy them on another phone or record them in a notebook. Regardless of the method you choose, make sure you keep either of these numbers a secret!

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