Electronic Serial Numbers (ESN) and MEID

ESN Migration to MEIDs

Definition: An electronic serial number (ESN) is the unique identification number embedded or inscribed on the microchip in a wireless phone by the manufacturer. Each time a call is placed, the ESN is automatically transmitted to the base station so the wireless carrier's mobile switching office can check the call's validity. The ESN cannot easily be altered in the field. The ESN differs from the mobile identification number (MIN), which is the wireless carrier's identifier for a phone in the network. MINs and ESNs can be electronically checked to help prevent fraud.

How is TIA involved? TIA, which took over the ESN function from the Federal Communications Commission's (FCC) Wireless Telecommunications Bureau in September 1997, manages and coordinates manufacturer codes for subscriber equipment in the cellular service, personal communications services and other wireless services that conform to the cellular radiotelecommunications intersystem operations family of standards, TIA/EIA-41; advanced mobile phone service (AMPS), TIA/EIA-553 and subsequent revisions; narrowband analog mobile phone service (NAMPS), TIA/EIA-691 and subsequent revisions; code division multiple access (CDMA), TIA/EIA-95, TIA/EIA/IS-2000 and subsequent revisions; and time division multiple access (TDMA), TIA/EIA-136 and subsequent revisions.

Contact: John Derr of TIA at +1.703.907.7791 or email jderr@tiaonline.org.

The Codes

Application/Modification Forms

Mobile Equipment IDentifiers (MEID)

Definition: A Mobile Equipment IDentifier (MEID) is a globally unique number for a physical piece of mobile station equipment. Equipment identifiers are 'burned' into a device, and should be resistant to modification. An ESN type can be distinguished as a pseudo ESN (pESN) based on the first 8 bits ("manufacturer" code) as derived from the MEID using the SHA-1 algorithm to reduce a 56-bit MEID to a 24-bit ESN. The pESN codes are not unique, but will not match any UIMID or true ESN (tESN) because they have a unique manufacturer code of 0x80 (decimal 128). The ESN will migrate to the MEID with assignments anticipated to begin in the 2004 to 2005 timeframe.

How is TIA involved? TIA, which already acts as the ESN Administrator, will act as the Global Hexadecimal Administrator (GHA) to assign MEID code prefixes. TIA will also coordinate with the International Mobile Equipment Identifier (IMEI) Global Decimal Administrator (GDA), the GSM Association, to administer codes for multi mode equipment. Support in standards is rapidly being developed. The TIA Committee TR-45 ESN/UIM/MEID Ad Hoc, in cooperation with 3GPP2, is actively working with industry to assist a smooth transition from ESN to MEID. The following library of MEID documents is intended to assist the understanding and migration from the finite ESN numbering resource to MEID:

Click here for more information.

Information on UIM (User Identity Module) and E-UIM (Expanded User Identity Module) used in R-UIM (Removable User Identity Module) Cards

The UIM_ID is a 32-bit identification number for the Removable User Identity Module card (R-UIM). Each UIM_ID is meant to be unique, i.e., different from any other assigned UIM_ID and Electronic Serial Number (ESN). The UIM_ID shares the same numbering space with the ESN. It is anticipated that the 32-bit numbering space for both the UIM_ID and the ESN will be exhausted completely in the near future.

An Expanded R-UIM identifier (E-UIM_ID) solution is needed to address issues associated with the impending exhaustion of the existing 32-bit UIM_ID/ESN numbering space. The purpose of introducing a new identifier is to define a larger numbering space.

A Word About Fraud

Source: FCC

Cellular fraud is defined as the unauthorized use, tampering, or manipulation of a cellular phone or service. Cellular industry estimates indicate that carriers lose more than $150 million per year to cellular fraud, with the principal cause being subscription fraud. Subscriber fraud occurs when a subscriber signs up for service with fraudulently obtained customer information or false identification.

In the past, cloning of cellular phones was a major concern. A cloned cellular telephone is one that has been reprogrammed to transmit the electronic serial number (ESN) and telephone number (MIN) belonging to another (legitimate) cellular telephone. Unscrupulous persons obtain valid ESN/MIN combinations by illegally monitoring the transmissions from the cellular telephones of legitimate subscribers. Each cellular telephone is supposed to have a unique factory-set ESN. After cloning, however, because both cellular telephones then have the same ESN/MIN combination, cellular systems cannot distinguish the cloned cellular telephone from the legitimate one.

In an Order, the commission adopted a rule (22.919) requiring that all cellular telephones for which type acceptance is sought after January 1, 1995, must be designed such that the factory-set ESN can not be reprogrammed. At the same time, the commission stated that it considers any knowing use of cellular telephone with an altered ESN to be a violation of the Communications Act (Section 301) and alteration of the ESN in a cellular telephone to be assisting in such violation. The Wireless Telephone Protection Act (Public Law 105-172) was signed into law on April 24, 1998, expanding the prior law to criminalize the use, possession, manufacture or sale of cloning hardware or software.

The cellular equipment manufacturing industry has deployed authentication systems that have proven to be a very effective countermeasure to cloning. Authentication supplements the use of the ESN and MIN with a changing encrypted code that can not be obtained by off-the-air monitoring.

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