Electronic Serial Number (ESN) is a unique string of numbers assigned to a specific manufacturer, stored in a microchip in cordless phones. This number is automatically sent to the base station each time a connection is made. Thanks to this, the mobile operator is able to check the validity of each connection. This code can be used for time tracking and registration. It is extremely helpful in preventing fraud.
Where can I find ESN?
There are 3 serval ways to verify Electronic Serial Number, find them all:
- Below the battery
When you remove the battery from most devices, you will find a sticker or label with ESN.
- On the original packaging
On the original packaging, there should be a sticker with numbers and barcodes, Electronic Serial Number should also be there.
- Use the handset
For some devices, you can find the ESN number directly on the handset. This process depends on the manufacturer and model of the device. In most cases, it is located in the Settings > About phone and Status.
How looks ESN construction?
32-bit ESN has 8 bits which is a manufacturer code, 18 bits is a unique Serial Number, and then 6 bits for all future applications.