What is an IMEI number?
The International Mobile Equipment Identity (IMEI) is an unique number to identify 3GPP and iDEN mobile phones and also some satellite phones. The number can be found most of the time inside the battery compartment of mobile phones. It can also be shown on most of the phones on the display by entering the following code:
*#06#. Trough the IMEI number, a GSM network can identify valid devices. When a phone gets stolen, through this number, the device can be locked out from accessing the network by the provider. The locking out therfore makes the stolen phone usless for that specific GSM network. Sometimes it is also possible to lock out the phone on other networks as well. The IMEI is only identifying the device but not the subscriber.