Guide to Blacklisted Cellphones

Guide to Blacklisted Cellphones

11 Jul 2016

New cellphones can be expensive. Especially if you are looking for something top of the range. This is particularly true if you want to get yourself an unlocked cellphone, that is not tied to a specific service provider. For this reason, buying a used cellphone can lead to significant cost saving.

But there is a potential risk in buying a used phone. It could be blacklisted. If you are unlucky enough to buy a blacklisted cellphone it will be useless. You also run the risk of having problems with the police, who may well be looking for a stolen phone.

What are the chances of a second hand cellphone being blacklisted? Let’s look at some statistics. In 2013, over 3.2 million cellphones were reported stolen in the U.S.A. This is twice the number that were stolen in 2012. This means that many of the used cellphones that are on sale online, on auction sites and similar marketplaces, could well be stolen.

If you buy one, there is a clear risk that it could be blacklisted, meaning you have wasted your cash on a useless phone. If you are convinced that you want to buy a used cellphone, you need to understand what blacklisting is, and how to make sure you buy a cellphone safely.

The International Mobile Equipment Identifier (IMEI)

All cellphones, as well as tablet devices that can use a SIM card, have a unique identifying code. This code is called the International Mobile Equipment Identifier (IMEI). In many countries around the world, cellphone operators allow owners to report a device as being either lost or stolen, which will result in its unique IMEI being blacklisted.

The IMEI is used to identify the device on the network, and the service provider can then block services to this specific device. This is known as IMEI blacklisting. When this happens, it is possible that the device identifier will be shared with other service providers. This means that even if the device is swapped to a different cell network, it will be identified and blocked. This shared device checking database will effectively make the blacklisted phone useless.

In 1982, Groupe Speciale Mobile (GSM) defined the original international standard for digital cellular telephony. As of the end of 2015, the number of global GSM connections exceeded 10 billion. This is more than the entire world population.

This huge volume of active GSM connections requires close and careful control. Cellphone communications can be abused by criminal or terrorist organizations. Therefore, a unified database of EMEI codes was developed, named the GSMA central IMEI Database. This empowers cellphone operators to centrally store and manage information on blacklisted devices, at an international level.

IMEI Network Broadcasts

Each time a cellphone owner tries to make a call, the SIM card is used to identify the caller on the operator’s network. As long as the caller has credit, and their account is active, they will be allowed to make the call. However, before the SIM card check takes place, the cellphone or tablet will broadcast its IMEI to the cellphone operator. If your phone has been blacklisted due to being reported as lost or stolen, or if it is locked to a different network carrier, the outgoing call will be blocked.

Other cellular network protocols also use a similar security device to the IMEI. Code Division Multiple Access (CDMA) enabled devices use an Electronic Serial number (ESN). The ESN can be used in the same way as EMEI to blacklist CDMA devices.

The IMEI of a device also helps the cellphone carrier to identify the type of device being used. If you connect to a network using an iPhone, the provider will know. If you then switch your SIM card in to a Google Android device, or a BlackBerry, the carrier will know the next time the device connects to the network. IMEI is used for this function, it has nothing to do with the owner’s profile, or the SIM card.

What Happens when a Phone is Blacklisted?

Every time you switch on a cellphone whilst it has a SIM card installed, and then attempt to make a call, the IMEI is checked. This is done automatically as part of the initial handshaking between the cellphone and the network. Devices on the IMEI blacklist will be blocked from the network.

The CTIA manages the cellphone blacklist in the U.S.A. Most large telecoms companies use this blacklist, including AT&T, Cellcom, Nex-Tech Wireless, Sprint, T-Mobile USA, and Verizon Wireless. These companies also link back to the original GSM IMEI database.

In the U.K. things work a little different. Each time a cellphone has a SIM card inserted and is powered up, the IMEI is checked against the Central Equipment Identity Register (CEIR). This is a unified EMEI database. If your cellphone has an IMEI that is blacklisted on the CEIR/IMEI database, then the service provider will either deny your device a signal entirely, or not allow the device to make a connection to the network. In this situation, the cellphone is as good as junk, it cannot be connected to any cell network.

Why Are So Many Blacklisted Phones for Sale?

As we have seen so far, cellphone operators have taken significant steps towards making the theft of cellphones a potentially worthless endeavour. If a cellphone is stolen, and then blacklisted, it becomes useless. However, there is a way around this problem. The stolen phone can be sent overseas, for use on a cellphone network that does not share IMEI data with the network it was originally registered too, and was subsequently blacklisted on.

Cellphone theft is a major international criminal trade. A completely controlled black market that sees locally stolen phones, shipped to countries with less stringent IMEI blacklisting processes. Additionally, some devices can be modified, with the IMEI being changed. This process is illegal in many countries, for obvious reasons.

The situation is further complicated, due to the fact that IMEI blacklist databases are often incomplete, or out of date. In many cases, submitting an IMEI is a voluntary process instigated by the device owner. Quite often, simply moving a stolen handset to a different country, sees it working again on a new network.

Cellphone theft also has other risks. Although there is value in the physical phone, there could potentially be even more value in examining its usage history. Some 77% of smartphone owners use their device to handle online banking and other financial transactions. However, only around 25% of these smartphone owners actually have any form of security application installed on their device. This means that a thief can potentially pull critical personal data from a stolen phone, and use it for fraudulent activities.

Unlocking versus Unblocking

Unlocking a cellphone, is entirely different to unblocking a cellphone. When a device is unlocked, it is simply open to being moved to a different service provider’s networks. There is nothing illegal in doing this. On the other hand, unblocking a cellphone is the process of changing the IMEI to get around IMEI blacklisting. This is an illegal activity, only phone manufacturers are allowed to change the IMEI. Getting caught doing this, could lead to a prison term.

Verify the Seller Before Buying

Around 74% of all used cellphones are purchased online. Mostly from auction or classifieds sites. If you are committed to buying a used phone from one of these types of marketplaces, there are a few steps you should take to safeguard yourself.

Possibly the best way to avoid buying a blacklisted cellphone online, is to use reputable marketplaces that offer some form of consumer protection. Both eBay and Amazon allow buyers to leave reviews of individual sellers. Make sure the seller of the phone you are interested in, has positive reviews.

Other online sites such as Glyde and Swappa offer further ways that consumers are protected. For example, Swappa offers an escrow feature, where the buyers funds are held by the site, until they have checked the phone over, and confirmed it is OK. If there is a problem, the escrow funds are returned to the buyer.

When making a payment for a used cellphone, using a credit card or PayPal will also add a further layer of protection, as a chargeback can be actioned if the phone turns out to be blacklisted.

For Apple devices, making sure that a smartphone has not been blacklisted is a little simpler. Apple enables owners to use Apple iCloud to check the Activation Lock Status of a device online. Once you have the IMEI from the seller, just use it to check whether the device is currently locked. Locked devices are unusable until the correct Apple ID and password has been used.

Buying a used smartphone or tablet online always comes with a risk, so you need to go in to the transaction with your eyes open, and take measures to ensure you do not purchase a blacklisted device.

Check the IMEI

The International Mobile Station Equipment Identity or IMEI for a device can be checked online using a number of different websites, completely free. The largest of these sites are:

For Canada this site can be used:
For the U.S.A use sites offered by, T-Mobile, Ringplus, and Ting.
The Australian Mobile Telecommunications Association Website also enables IMEI checking: or
There are a number of third party sites that enable IMEI checking such as:

So it is possible to perform a basic check of an IMEI before you make a purchase. As long as the seller gives you the correct IMEI. The service provider or cellular network provider will also be able to check the blacklist status of a device. There are plenty of IMEI checking sites around, Google can provide a good list. For a little more comprehensive check, there is a paid service named Checkmend. However, there is a downside of using this service to check an IMEI. If the device you check is indeed blacklisted, you may be contacted by the police, who use the data provided by Checkmind to track down stolen phones.

What to Do If You Phone Is Not Blacklisted

If you have managed to successfully purchase a used smartphone or tablet, that has not been blacklisted, you are going to need to ensure that it will work on your chosen cell network. This is pretty simple to do. Just visit

This is a website that maintains the largest database of cellphones and service providers in the world. It can help to remote unlock a very wide range of devices, very easily using remote unlocking. In most cases, this only takes a few minutes. guarantees to be the lowest cost service of its kind. The company backs up this guarantee by offering to match any price found for performing a remote unlock for a specific device.

Buying a used smartphone or tablet can be a great way to procure a device that would be out of your price range new. But as we have seen, there are some risks that need to be negated, in order to safely buy the phone of your choice. This article has given good advice on how to avoid these risks and make a safe purchase.

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