Section: 6.2.1 Composition of IMEI
Content: The International Mobile station Equipment Identity (IMEI) is composed as shown in figure 10. Figure 10: Structure of IMEI The IMEI is composed of the following elements (each element shall consist of decimal digits only): - Type Allocation Code (TAC). Its length is 8 digits; - Serial Number (SNR) is an individual serial number uniquely identifying each equipment within the TAC. Its length is 6 digits; - Check Digit (CD) / Spare Digit (SD): If this is the Check Digit see paragraph below; if this digit is Spare Digit it shall be set to zero, when transmitted by the MS. The IMEI (14 digits) is complemented by a Check Digit (CD). The Check Digit is not part of the digits transmitted when the IMEI is checked, as described below. The Check Digit is intended to avoid manual transmission errors, e.g. when customers register stolen MEs at the operator's customer care desk. The Check Digit is defined according to the Luhn formula, as defined in annex B. NOTE: The Check Digit is not applied to the Software Version Number. The security requirements of the IMEI are defined in 3GPP TS 22.016[ International Mobile station Equipment Identities (IMEI) ]  [32].