IMEI is a unique identifier assigned to the radio module installed in mobile devices such as phones, tablets, and smartwatches. It is often mistakenly considered the identifier of the phone itself, but in reality, it only applies to the radio equipment. If a phone supports two SIM cards, it will have two IMEI numbers since each SIM card operates through a separate radio module. IMEI is assigned to devices operating in GSM, WCDMA, and IDEN networks, including 2G, 3G, 4G, and LTE.
Purpose and Origin of IMEI
With the emergence of mobile phones, the need arose to identify the device using the network. A SIM card could not solve this issue because it is removable. Law enforcement and security agencies required a method to track a device regardless of SIM card changes. To address this, IMEI was introduced as a way to uniquely identify a device connected to a mobile network.
If a phone supports dual SIM functionality, it contains two radio modules. Since IMEI identifies the radio module, a phone with two SIM slots will have two IMEI numbers—IMEI1 and IMEI2.
Why Mobile Operators Supported the Introduction of IMEI
Mobile operators supported the implementation of IMEI both due to government regulations and for their own interests. In case of illegal activities, they can demonstrate cooperation with authorities. Additionally, if a phone is stolen, the owner can request its blocking via IMEI. However, not all operators worldwide exchange IMEI data, so a phone blocked in one country may still work in another. In some cases, a legitimate owner can unlock the device by proving legal ownership, though this service is often paid (for example, in the U.S., the fee starts at $10).
IMEI Structure and Registration Codes
IMEI contains information about the registering organization, the device model, and the serial number of the radio module. Let’s analyze the IMEI 869493026608130:
- 86 – The code of the organization that registered the device in the database (in this case, TAF, China).
- 949302 – The device model code assigned by the manufacturer. For example, this code may correspond to a Huawei phone.
- 660813 – The serial number of the radio module, not the phone itself.
- 0 – The check digit, calculated using the Luhn algorithm to verify IMEI validity.
The first two digits of the IMEI do not indicate the country of manufacture, as many believe, but rather the organization responsible for registering the device. Here are some of them:
| Code | Organization | Country |
|---|---|---|
| 00 | Test IMEI | Various countries |
| 01 | PTCRB | USA |
| 35 | Comreg | Ireland |
| 44 | BABT | United Kingdom |
| 49 | BZT/BAPT | Germany |
| 86 | TAF | China |
| 91 | MSAI | India |
IMEI Verification and Its Importance
The serial number in IMEI refers to the radio module rather than the phone itself. Each phone also has a separate serial number assigned by the manufacturer. IMEI can be checked using online services such as IMEI.info to determine if a device is blacklisted due to theft or fraud. Additionally, IMEI can be used to identify the phone model, manufacturer, and technical specifications.
Understanding IMEI helps users protect their devices, verify authenticity, and identify potential restrictions before purchasing second-hand phones.
