众所周知，所有的手机都是通过输入“*#06#”来查询IMEI号.

有关IMEI/IMEISV,从网上查了些资料,其中比较权威的是GSM Assocication的文档, 里面详细介绍了整个IMEI的情况.

http://imeidb.gsm.org/imei/DG06.pdf,    “IMEIAllocation and Approval Guidelines”

IMEI(International Mobile Equipment Identity)国际移动设备标识码

The International Mobile Equipment Identify number (IMEI) uniquely identifies an individual mobile station. The IMEI is unique to every ME and thereby provides a means for controlling access to GSM networks based on ME types or individual units.

 The “IMEI”consists of a number of fields total 15 digits, all digits have the range of 0 to 9 coded as binary coded decimal. Values outside this range are not permitted.

Some of the fields in the IMEI are under the control of the “Reporting Body”. The remainder is under the control of the Type allocation holder.

The IMEI format valid from 01/01/03 is as shown below:

 

TAC:

The TAC identifies the type allocation code, formerly known as the type Approval code,for the type of the ME. It consists of two parts, the first part (NN) defines the reporting body allocating the TAC and the second part (XXXXYY) defines the ME type.

These 6 digits together with the reporting body 2 digit identifier uniquely identify each ME type.

Serial Number:

The serial number (SNR) is used to uniquely identify each individual ME of a particular ME type. The number range is allocated by the reporting body but assigned to individual mobile station by the manufacturer.

Check Digit:

The check digit shall be calculated according to Luhn formula, the check digit is a function of all other digits in the IMEI. The purpose of the check digit is to help guard against the possibility of incorrect entries to CEIR and EIR equipment.

IMEI Software Version Numbers (SVN)

The networkcan also request the IMEISV from Phase 2(or later) ME, the IMEISV shall containthe first 14 digits of the IMEI plus software version number (SVN).

The SVN shall be incremented when the ME software is modified. Allocation of the 2 digits SVN may be controlled by the reporting body, SVN of “99” is reserved for future use.

Here is the example for SVN using by MS manufacturer.

SVN	S/W version Comments
00	The initial version
01	The trial version
02	the official version
03	Maintenance version

The SVN is a separate field from the IMEI, although it is associated with IMEI, and when the network requests the IMEI from the MS, the SVN (if present) is also sent towards the network. It comprises 2 decimal digits.

It’s very important for network operator using, in the case of any S/W upgrade in the future after the device commercialized, the operator can use IMEISV on the core network side to trace how many devices was updated.

In LTE network,it is sent by the device in the 'Security Mode Complete’ signaling message during the procedures of attaching to the network.