What is, and the Differences Between IMEI, ESN, and MEID

IMEI (International Mobile Equipment Identity) is a 15- or 17-digit code (usually unique) given to every single mobile phone. The function of an IMEI is to identify the phone.

IMEI can usually be found printed inside the battery compartment of the phone. A phone is only given one IMEI number.

Beside using the codes to identify valid devices by a GSM network, it can also be used for stopping a stolen phone from accessing the network.


IMEI numbers connected to a GSM network are all stored in a database (Equipment Identity Register – EIR) containing all valid mobile phone equipment.

In most mobile communications devices, these hidden numbers will appear on the display if you enter *#06# (star-pound-zero-six-pound) on the dialpad.

When a phone is turned on, its IMEI number would be transmitted and verified by the network. When a phone is reported stolen or is blacklisted, its number is marked invalid.

First 8 digits of IMEI are Type Allocation Code (TAC) – it indicates the mobile phone brand and model. The first two digits are the Reporting Body Identifier, indicating the GSMA approvd gruop that allocated the TAC. The rest last 7 digits are defined by manufacturer (6 are its serial number and 1 is check digit).

Difference Between IMEI and ESN,
ESN, or electronic serial number, is also unique identifier for cellphones. This 32-digit number is linked to the user’s account and holds her or his information including network and account information.

ESN serves as both the SIM card and the IMEI number because it carries both the cell phone’s unique identifier as well as the network (user) information. And because of that, the carrier must be informed whenever the user wants to change phones – not as simple as switching out a SIM card.

There are two primary mobile service provider technologies we use today – Global System for Mobiles (GSM) and Code Division Multiple Access (CDMA). A mobile phone is manufactured to support either GSM or CDMA, but not both. A unique identification number was then assigned by phone manufacturers to each handset according to the technology it supports. ESN’s are currently mainly used with CDMA phones whereas IMEI numbers are used by GSM phones. However, ESNS are slowIy being phased out in favor of the MEID.

What is MEID?
MEID stands for Mobile Equipment Identifier, a longer identification number (14 digits long) that is more similar to IMEI number. This unique number is also used to identify your cell phone that utilizes the CDMA technology for wireless service.