The phone is powered on, its ID is read by the equipment operator. If you lose your phone or have it stolen, there still remains a chance to recover – but only if you know IMEI of your phone.
To find the serial number of the phone in several ways. The easiest: just type the command "*#06#" (without the quotation marks), the serial number of your phone immediately appear on the screen.
The serial number on the phone. To see it, turn off your phone, remove the cover and remove the battery. The IMEI written on the body under the battery beside the barcode.
The identification number is printed on the box of the phone, often it helps to know IMEI of a lost phone. While with the phone, nothing happened, the owner is not usually interested in its serial number. It's wrong if you don't keep the box from your phone, be sure to write down the IMEI in a notebook, computer file or store it in any other safe place.
If your phone is stolen, contact the police a statement. Insist that law enforcement authorities asked the mobile operator to search for your phone. Contact the cellular company itself, asking you to track IMEI stolen phone should not be – most likely you will say no.
Sometimes buying a phone is done with hands, no papers. Not to buy a stolen phone, check his ID number on databases of stolen phones. To find such a base just type in the search string "stolen phone database", you will get many relevant links. In case of theft of your phone don't forget to add an identification number to these databases.
Identification number are not only phones but also USB modems. If you for some reason wish to maintain your anonymity and change in modem SIM card, it almost gives nothing, as the IMEI of the modem remains the same and always will be easy to find.