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This is one of the most commonly asked questions by anyone in the market for a used cell phone or tablet. Simply put, a device with a bad ESN is one which has been blacklisted or blocked by its carrier.

There are numerous reasons why a device might have a bad ESN, here are the most common:

  • Reported lost or stolen
  • Attached to an active account
  • Device has an outstanding balance
  • Account with carrier has an outstanding balance

That was a straightforward answer to the question. To better understand, lets go more in-depth and explain what an ESN is.

 

What is an ESN?

 
An ESN is an Electronic Serial Number. Every device has a unique serial number and this is what the wireless carriers use to connect a phone to an account. ESN can also be refereed to as “MEID” or “IMEI”. These are all the same thing, they are just used by a different networks which use different naming convention.

In the United States there are 2 major networks being used, GSM and CDMA.

CDMA networks use an ESN or an MEID and GSM networks use an IMEI as device identifiers.

Below is a list of the biggest carriers in the United States and there corresponding network.

All four carriers

 

CDMA Networks

  • Verizon Wireless
  • Sprint

GSM Networks

  • AT&T
  • T-Mobile

 

Now that we are better informed, lets go through the process of checking if a device has a bad ESN.

 

Ways to check your ESN

 
The most reliable way to check if a device has a bad ESN is to call the carrier. The only problem is that carriers are not very forward when giving out personal device information. You may have to call them a few times, before you can get the carrier to run a check on said device.

No worries, we have other tools at our disposal. There are numerous websites we can use to run a check online. Here are a few:

Verizon Wireless 

https://www.verizonwireless.com/bring-your-own-device/

Sprint

https://swappa.com/esn

T-Mobile

https://www.t-mobile.com/verifyIMEI.aspx

AT&T

http://www.checkesnfree.com – Run a Blacklist check

“CheckESNfree” is one of the most reliable websites when it comes to free ESN status checks. The ESN of all major carriers can be conveniently checked from their website. This is why we at swopsmart use checkESNfree.com as our main source when reviewing device’s ESN.

Now that we know what a bad ESN is and the ways we can check a devices ESN status, we can make sure we protect ourselves from scammers and/or getting stuck with a device that has a bad ESN.