Snyder General Serial Number Nomenclature

The decimal format of pseudo ESNs will therefore begin with 128. For the decimal format the first three digits are the decimal representation of the first eight bits (between 00 and 255 inclusive) and the next eight digits are derived from the remaining 24 bits and will be between 000007215 inclusive. Pseudo-ESNs are not guaranteed to be unique (the MEID is the unique identifier if the phone has a pseudo-ESN).ĮSNs are often represented as either 11-digit decimal numbers or 8-digit hexadecimal numbers. The remaining 24 bits are the least significant bits of the SHA-1 hash of a mobile equipment identifier (MEID). Manufacturer code 0x80 is reserved from assignment and is used instead as an eight-bit prefix for pseudo-ESNs (pESN). 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.

The first eight bits of the ESN were originally the manufacturer code, leaving 24 bits for the manufacturer to assign up to 16,777,215 codes to mobiles. 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. The administrative role was taken over by the Telecommunications Industry Association in 1997 and is still maintained by them. Federal Communications Commission (FCC) to uniquely identify mobile devices, from the days of AMPS in the United States starting in the early 1980s. Electronic serial numbers ( ESNs) were created by the U.S.

Snyder General Serial Number Nomenclature