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Electronic serial numbers (ESNs) were created by the U.S. Federal Communications Commission (FCC) to uniquely identify mobile devices, from the days of AMPS in the United States starting in the early 1980s. The administrative role was taken over by the Telecommunications Industry Association in 1997 and is still maintained by them. ESNs are currently mainly used with CDMA phones (and were previously used by AMPS and TDMA phones), compared to International Mobile Equipment Identity (IMEI) numbers used by all GSM phones.[1]

The first 8 bits of the ESN was originally the manufacturer code, leaving 24 bits for the manufacturer to assign up to 16,777,215 codes to mobiles. To allow more than 256 manufacturers to be identified the manufacturer code was extended to 14 bits, leaving 18 bits for the manufacturer to assign up to 262,144 codes. Manufacturer code 0x80 is reserved from assignment and is used instead as an 8-bit prefix for pseudo-ESNs (pESN). The remaining 24 bits are the least significant bits of the SHA-1 hash of a mobile equipment identifier (MEID). Pseudo-ESNs are not guaranteed to be unique (the MEID is the unique identifier if the phone has a pseudo-ESN).

ESNs are often represented as either 11-digit decimal numbers or 8 digit hexadecimal numbers. For the decimal format the first three digits are the decimal representation of the first 8 bits (between 000 and 255 inclusive) and the next 8 digits are derived from the remaining 24 bits and will be between 00000000 and 16777215 inclusive. The decimal format of pseudo ESNs will therefore begin with 128. The decimal format separately displays 8 bit manufacturer codes in the first 3 digits, but 14 bit codes are not displayed as separate digits. The hexadecimal format displays an ESN as 8 digits and also does not separately display 14 bit manufacturer codes which occupy 3.5 hexadecimal digits.

As ESNs have essentially run out, a new serial number format, MEID, was created by 3GPP2 and was first implemented by Verizon in 2006. MEIDs are 56 bits long, the same length as the IMEI and, in fact, MEID was created to be a superset of IMEI. The main difference between MEID and IMEI is that the MEID allows hexadecimal digits while IMEI allows only decimal digits – "IMEI shall consist of decimal digits (0 through 9) only".[2]

The last of the previously unused ESN codes were allocated in November 2008.[3] Applications for assignments were accepted until June 30, 2010 using reclaimed ESN codes, those previously assigned to AMPS or TDMA phones and therefore not present on CDMA2000 systems. Reclaimed codes have also been used for UIMID assignments. Codes are assigned according to industry guidelines.[4]

Although ESN assignments may still occur in the future based on applications received before June 30, 2010, there have not been any assignments made since December 31, 2010.


External links[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Electronic_serial_number — Please support Wikipedia.
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174 news items

BBC News

BBC News
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Wed, 17 Jun 2015 02:00:20 -0700

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London Loves Business

London Loves Business
Thu, 11 Jun 2015 03:43:01 -0700

They work by mimicking legitimate phone masts, connecting to all the mobiles in the vicinity, but they then pick up the international mobile subscriber number (IMSI) and electronic serial number (ESN), which can be used to give the precise location of ...


Sat, 06 Jun 2015 19:03:45 -0700

... an origination message (which are electronic signals of about ¼ second in length) which includes its MIN - mobile identification number - which is your mobile number along with the ESN - Electronic Serial Number, and the number that you have just ...


Thu, 02 Apr 2015 03:30:00 -0700

Once you receive your phone, check its electronic serial number (ESN), mobile equipment identifier (MEID) or international mobile equipment identity (IMEI) number to make sure the phone isn't locked. Find your phone's number in the settings menu or ...
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VeriTeQ's FDA cleared Q Inside Safety Technology™ acts as an electronic serial number in breast implants and other implantable and reusable medical devices to provide physicians and patients access to secure online databases to retrieve device ...

Riverfront Times (blog)

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Wed, 20 May 2015 06:11:19 -0700

When deployed, StingRay forces any cell phones in the area to send it a signal, the same way that a phone normally sends a signal to cell towers. Even if a cell phone is not in use, it still transmits its phone number and electronic serial number to ...
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Fri, 15 May 2015 06:00:34 -0700

Q Inside Safety Technology, which acts as an electronic serial number within implanted medical devices, is currently being used within EL's Motiva Implant Matrix® breast implants. Q Inside Safety Technology enables physicians and patients to access a ...

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