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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.

References[edit]

External links[edit]


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

Republica

Republica
Mon, 11 Apr 2016 14:17:45 -0700

KATHMANDU, April 12: In a bid to meet national and consumer security requirements, make bogus handsets inoperable, enable tracking of mobile handsets, and control flourishing grey market of mobile phones, the government is making mobile phone ...

Fortune

Fortune
Fri, 04 Mar 2016 11:02:36 -0800

Filling out the form is simple and straightforward. You'll need to select the retailer where you purchased the smartphone and provide details specific to your device such as its electronic serial number. Additionally, Samsung requires a copy of your ...

Chicago Tribune

Chicago Tribune
Wed, 17 Feb 2016 07:44:09 -0800

The retailer would have to record the mobile equipment identifier, the international mobile station equipment identity or electronic serial number of the device. All information would then have to be turned over to the Gary Police Department by noon ...

Computerworld

Computerworld
Thu, 07 Jan 2016 06:10:57 -0800

During a short business trip to New York City this week, it dawned on me that I've often gotten practical security lessons in New York taxicabs. In the late 1990s, I frequently went to New York for consulting engagements. I generally took one of the ...

The Chicago Cusader

The Chicago Cusader
Thu, 03 Mar 2016 11:43:15 -0800

Used cellphone buyers would be required to take a picture of the device and record its mobile equipment identifier, international mobile station equipment identity or electronic serial number. The information would then have to be forwarded to the Gary ...

KGO-TV

KGO-TV
Tue, 23 Feb 2016 19:25:01 -0800

"The manager ran the information on the phone, the electronic serial number," explained Edwards. Edwards paid the seller $580 cash in the store, AT&T turned on service and Edwards used the phone for two months until it was blacklisted. Edwards says ...

The Globe and Mail

The Globe and Mail
Mon, 21 Mar 2016 19:37:30 -0700

Among them are the International Mobile Subscriber Number (IMSI) and the Electronic Serial Number (ESM). In 1996, a German company called Rohde & Schwarz starting selling something it called an IMSI catcher, to track those unique phone IDs. There are ...

Tom's Guide

Tom's Guide
Wed, 14 Oct 2015 09:30:00 -0700

Older phones without SIM cards have a similar number, called an electronic serial number (ESN) or mobile equipment identifier (MEID), baked into the device itself. Law enforcement officers obtain IMSI numbers of phones belonging to persons of interest ...
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