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    ESN (Electronic Serial Number)

    An Electronic Serial Number is a code created to identify mobile devices.

    An ESN is 32 bits long, and the distribution of information in those bits has changed as the standard has evolved.

    The first 8 bits originally represented the manufacturer code, leaving 24 bits for the manufacturer to assign codes to mobile devices. This system allowed for up to 256 manufacturers and up to 16,777,215 unique codes for each manufacturer’s mobile devices.

    To allow for more manufacturers, the manufacturer code was extended to 14 bits, leaving 18 bits for the individual mobile device codes. With this system, the manufacturer could only assign up to 262,144 codes.

    Electronic Serial Numbers are most commonly represented using either 11-digit decimal numbers or 8-digit hexadecimal numbers, an example of which is shown below:

    esn ESN (Electronic Serial Number)

    Background and Regulation of Electronic Serial Numbers

    The ESN was created by the United States Federal Communications Commission in the early 1980s, and originally used for the very first analog mobile phone technology, the AMPS.

    Administration was afterward taken over by the Telecommunications Industry Association in 1997, and the TIA still manages and coordinates ESN distribution.

    Applications of the ESN System
    • The ESN is particularly useful for identifying stolen cellular phones even if the SIM card is changed.

    • An ESN can also be used to prove that a certain mobile device was used to make or receive a call.

    • Other key uses include manufacturer tracking for inventory and warranty claims.

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    1. Edwin

      26 March, 2012 at 12:47 am

      About your missing daughter,Iam a construction worker,I travel all over.If you like,send me a face pic and I will keep an eye out.1 In a million shot but hey thats worth somthing.

    2. Cathy

      12 October, 2011 at 1:47 am

      If I am selling a used phone on ebay and the buyer asks if my esn is clean how do I know and should I give the number to them or is it a scam

    3. Shianne

      24 September, 2011 at 8:18 pm

      So if you are looking at a used phone from ebay and it says bad ESN is the phone basicly junk? Or can you make it so it good again or what?

    4. arun tayal

      10 September, 2011 at 8:50 am

      plz del no to esn no software

    5. Lee

      10 June, 2011 at 2:25 am

      I take it this phone in question has 3/4G support? even though its not activated it will still try to create a connection to the 3/4G network. with this in mind, i would think the MAC address on the phone is logged by the phone company when it trys to connect to the cell network. This MAC addy is unique and maybe the cell company has a db with each phones MAC address in relation to ESN or even the user/owner of the phone.

    6. Chris C.

      31 May, 2011 at 4:35 pm

      It is possible. In most cases for a phone company to do this they must have a court order to break customer confidentiality.  If there is an open investigation on the matter the police or investigating agency would have the proper means to obtain such information.  They more than likely have already tried this procedure in the first stages of the investigation.  I hope she is found safe.

      • MIke

        4 June, 2011 at 3:20 pm

        Thanks Chris for the information, I actually just called the cell company and had my name put on the account as the ESN number was clean. I’m gonna call and advise them I lost the phone and didn’t have it activated before I lost it. Hope it works. Otherwise we will have to go back to the police. We actually had given them the information when she first went missing, seems a little discouraging that they didn’t know this would work…they said if the phone wasn’t activated we were lost.

        • MIke

          4 June, 2011 at 3:38 pm

          Called the cell company today and they stated that they could not locate the phone with the ESN number…guess we have to go back to just looking for her.

          Seem like a great idea at the time.

    7. MIke

      27 May, 2011 at 7:29 am


      I’m getting conflicting information from cell phone providers…I have a daughter who is missing, she is an adult though, she was given a cell phone that had previously been activated but the person changed his phone and used the number on a new phone.  We are hoping to find her using this unactivated phone…can the company ping the phone if we know the ESN number? Realize the phone would have to be powered up….she uses it as an mp3 player from time to time and if it was on can they locate it with this ESN number? Or are we out of luck? No GSP with this model HTC Touch



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