MEID

A mobile equipment identifier (MEID) is a globally unique number identifying a physical piece of CDMA2000 mobile station equipment. The number format is defined by the 3GPP2 report S.R0048 but in practical terms, it can be seen as an IMEI but with hexadecimal digits.

An MEID is 56 bits long (14 hex digits). It consists of three fields, including an 8-bit regional code (RR), a 24-bit manufacturer code, and a 24-bit manufacturer-assigned serial number. The check digit (CD) is not considered part of the MEID.

The MEID was created to replace ESNs, whose virgin form was exhausted in November 2008. As of TIA/EIA/IS-41 Revision D and TIA/EIA/IS-2000 Rev C, the ESN is still a required field in many messages—for compatibility, devices with an MEID can use a pseudo-ESN (pESN), which is a manufacturer code of 0x80 (formerly reserved) followed by the least significant 24 bits of the SHA-1 hash of the MEID.

The separation between international mobile equipment identifiers (IMEIs) used by GSM/UMTS and MEIDs is based on the number ranges. There are two administrators: the global decimal administrator (GDA) for IMEIs and the global hexadecimal administrator (GHA).

As of August 2006, the TIA acts as the GHA to assign MEID code prefixes (0xA0 and up), and the GSM Association acts as the global decimal administrator. http://www.babt.com/gsm-imei-number-allocation.asp

The TIA also allocates IMEI codes, specifically destined for dual-technology phones, out of the RR=99 range. Other administrators working under GSMA may also allocate any IMEI for use in dual-technology phones. Every IMEI can also be used as an MEID in CDMA2000 devices (as well as in single-mode devices designed with GSM or other 3GPP protocols) but MEID codes may also contain hexadecimal digits and this class of MEID codes cannot be used as an IMEI.

There are two standard formats for MEIDs, and both can include an optional check-digit. This is defined by 3GPP2 standard X.S0008.

The hexadecimal form is specified to be 14 digits grouped together and applies whether all digits are in the decimal range or whether some are in the range 'A'-'F'. In the first case, all digits are in the range '0'-'9', the check-digit is calculated using the normal base 10 Luhn algorithm, but if at least one digit is in the range 'A'-'F' this check digit algorithm uses base 16 arithmetic. The check-digit is never transmitted or stored. It is intended to detect most (but not all) input errors, it is not intended to be a checksum or CRC to detect transmission errors. Consequently, it may be printed on phones or their packaging in case of manual entry of an MEID (e.g. because there is no bar code or the bar code is unreadable).

...
Wikipedia