What is ESN and why care if it is 'clean'?

If you are learning about the mobile phone market, especially used mobile phones, you will hear a lot about ESN and people always insist on whether a phone is "clean" or not. . So what exactly does ESN stand for and say whether the phone is 'clean' or not?

What is ESN?

Start with the basics and then move on to how you can use that knowledge to protect yourself, as a consumer, like. ESN stands for Electronic Serial Number (electronic serial number) and is the unique identifier for all FCC mobile devices in the early 1980s. Electronic serial numbers are attached to devices. CDMA (CDMA only refers to the type of radio in a mobile device - such as a Sprint device with a CDMA device). Later, the electronic serial number system was modified to MEID (to explain a narrow group of ESNs available), and still used for CDMA devices. Another number to note is the IMEI number (the Interational Mobile Station Equipment Identity), which is the same number as ESN for GSM-based phones (eg ATT & T ).

Although ESN, MEID and IMEI are separate identifiers, ESN has been widely used as a way to capture all serial numbers (in any format possible) for the phone to be addressed. updated. Thus, you will see that ATT's iPhone usually refers to the ESN number, although it is actually IMEI, not ESN. In fact, people often do not distinguish between these two numbers unless we specifically mention a specific identification number.

Why is ESN important?

Now, let's find out why ESN is important to you as a consumer. Mobile phones are valuable and suppliers will benefit from it (meaning the actual price of the iPhone you just bought is not really $ 99, the provider is subsidizing a lot of electricity. Your phone through the extended contract you just signed). They use ESN as a tool to track phones and, when necessary, can prevent the phone from joining the network.

There are two main reasons why ESN is blacklisted: The phone is reported stolen or the phone is connected to an unpaid account for the mobile service provider.

The first case is actually quite rare, many US-based mobile carriers have not actively used ESN this way for a long time. In fact, AT&T just started to record and put the stolen phone IMEI number in blacklist since November 2012, after pressure from government agencies. The second case, without payment of services or not performed under contracts, is much more common. Most of the phones you see with a "bad ESN", ie blacklisted, are because the previous owner of the phone has not yet paid the bill.

So how can you use this information to protect yourself? You can refuse to buy a phone with no 'clean' ESN. When it comes to eBay listings, it's hard to completely protect yourself when you're giving things to sellers. First, you should try to buy from sellers on eBay who want to sell a lot of products but don't want complex profit constraints, or headaches with customer service. Contact them and request the ESN of the phone, so you can test yourself before you buy. If they refuse, choose another seller. It is not wise to pay a few hundred dollars for a phone without knowing whether you can activate it with your service provider.

When buying a direct phone, one of the easiest ways to avoid having a headache is to appoint a phone seller to a mobile service store that you plan to use. In some cases, this is the only way to check ESN correctly. For example, Sprint no longer checks ESN over the phone.

In the store, you can hand the phone to the agent and ask them to check if the phone can be used on their network. Offer to meet with the seller at the store so you can activate your phone right away, which is a great way to avoid fraud. Sellers will not want to see you at the store, if they have a 'blacklisted' phone.

Ways to test ESN yourself

What if there is no nearby store that you can visit? In this case, you will need to test the ESN yourself. Over 99.99% of phone numbers, ESN (or equivalent numbers) are in batteries, on stickers. Open the case, remove the battery and look at the number on it. On non-removable devices like the iPhone, you can find identification numbers in the system menu.

Once you have this number, you can learn information in one of two ways. You can call the support line of the specific service provider you want to use. This is the best way to get accurate information. This will take longer than the online testing method described below, but it allows you to directly confirm that the phone will work on the network you want to use. It is important that you specifically call someone. For example, suppose you have a Sprint branded phone that you want to use on Ting, a Sprint retailer. Call Ting, not Sprint. If the phone has been activated previously as a Ting phone, Sprint will permanently ban the phone and will report that it has a bad ESN, and Ting will happily activate it once. half. The same thing happens for most other major suppliers and their agents. The main service providers will often list the phones that have been used with their agents, but agents do not have any problems with them.

If you don't want to / can't call service providers, there are quite a number of websites that test ESN online . These sites will provide you with information about whether an ESN is 'clean' or not. Although there are no problems using the ESN check online, it must be emphasized that the only truly reliable method is to call the service provider directly.

For online testing, some of the more popular or trusted websites are Swappa.com (a phone buying company / gadget, you can see their tool in the screenshot above. ) and CheckESNFree.com . As a general rule, the more online ESN test information is, the better. In the screenshot above, we get valid ESN test information, service providers and even model numbers. For old or unavailable phones, you will get a simple style response like " This is a valid ESN" (This is a valid ESN), but there is no other specific information.

Armed with knowledge of what ESN is and how to use ESN to confirm the status of your phone, you will be able to protect yourself from scammers and getting stuck with a phone that is listed. black book. Good luck!

See more:

1. Check the quality of old phones before buying with TestM application
2. Things to note before buying an old Samsung phone
3. Instructions for checking the origin of Android and iOS phones