What is a Phone ESN, and how do I check if it is Clean?

ESN stands for Electronic Serial Number and was initiated by the FCC in the early 1980s as a unique identification number for all mobile devices. On a CDMA network such as Sprint or Verizon, an ESN is a serial number connected to any handset. A CDMA ESN is a unique identifier that allows the handset to be authenticated and wired to the cell tower instead of using a SIM card as GSM networks do. The carrier will typically blacklist the ESN linked to that phone if a phone is stolen, claimed as an insurance loss, or used unlawfully. A blacklisted ESN makes it difficult for a phone to connect to the network that has provided it.

Why does the ESN matter to you, the consumer?

Cellphones are valuable, and providers have a vested interest in them (after all, the actual price of the iPhone you just picked up is not $99. Through the extended deal you just signed, the provider is massively subsidizing the cost of your phone). They use ESNs as a method for monitoring phones and blocking phones from their network when appropriate. There are two key reasons that an ESN will be blacklisted: the mobile has been declared stolen, or the phone with an outstanding balance is connected to a cellular carrier account.

How to check if it is clean ESN

If a system has a clean ESN, it means that it is 100 percent ready for its intended carrier to enable. It must not have unpaid fees due or any balance relating to it on the carrier agreement and must NOT be registered as missing or stolen. People would assume the computer to have a poor ESN in any of these situations.

To check if an AT&T iPhone has a clean ESN, follow the steps:

  1. On AT&T’s website, go to the AT&T System Unlock Page.
  2. Click on “Unlock a device.”
  3. When asked if you are an AT&T wireless client, press ‘No’.
  4. Specify the IMEI
  5. Prove that you are not a robot, and press “Yes” to inquire about legal matters.
  6. Your ESN is free to go if the next page confirms the computer is eligible for activation! If not, the device is still AT&T supported.

To check if a Verizon iPhone has a clean ESN then follow the steps:

  1. Go to the Verizon Check IMEI link on the Verizon website.
  2. Type in your IMEI number where “Device ID” is defined.
  3. Wait for the next site to load – it will inform you whether your computer is compatible.

To check if a Sprint iPhone has a clean ESN then follow the steps:

  1. Go to the list of Ting BYOD on Ting’s website (this is more accurate than the Sprint website)
  2. Enter your IMEI number, where it says “Enter your IMEI number for phones.”
  3. Wait for the next page to launch. If your computer is compliant, it will inform you.

Note: Ting is a telecommunications carrier that operates on the Sprint network. The explanation of why checking the IMEI on their website is better is that Sprint does not provide its own IMEI online checking service.

To check if a T-Mobile iPhone has a clean ESN then follow the steps:

  1. Go to the T-Mobile Check IMEI page on the T-Mobile website.
  2. Input your IMEI number into “IMEI Status Check” where it says
  3. Wait for the next page to launch. If your computer is compliant, it will inform you.

The best resource to use for testing your IMEI number is Swappa.com if your computer is not used on any of these carriers. For the four main pages, people should not recommend using Swappa because it often gives the wrong ESN status. However, Swappa is the best choice for any carrier that does not have a tool to search the carrier’s ESN directly.

What makes an iPhone have a bad ESN?

For different causes, an iPhone may have a compromised ESN:

  • The original user could not pay off the iPhone.
  • Some person’s account is already operating on the iPhone.
  • The iPhone was reported missing or stolen.

You need to contact the carrier back and let them know you find the phone if you misplaced your mobile and reported it as lost to your carrier for insurance reasons but later found the phone again. Otherwise, there will still be a bad ESN on the computer (because it is even recorded as lost) and any person will not enable it. For either of the three factors mentioned earlier, any device with a bad ESN would cause the iPhone to be unable to trigger on the carrier account of another client.

How can you use this information to protect yourself?

Without a clean ESN, you can refuse to purchase a phone. It’s impossible to fully defend yourself when it comes to eBay listings when you are at the mercy of the seller in many ways. Next, you can try to buy from eBay vendors who specialize in handing over phones, and they are the most likely to manage the ESN and are invested in not having to cope with the issues of refunds and headaches of customer service. Call them and ask for ESN phones so that you can review them before making your bid on your own. Shop somewhere if they refuse; it is unfair to ask you to bid several hundred dollars for a phone without knowing if your carrier will even enable it.