The maximum length of the ICCID is 19 characters. It starts with the IIN (Issuer Identifier Number), maximum 7 digits, composed of:
the Major Industry Identifier (MII); "89" is assigned for telecomunication purposes;
the country code (variable, 1 to 3 digits, according to E.164);
an issuer identifier number (variable, but fixed number of digits whithin a country or world zone where appropriate);
The individual account identification number (I# + A#) is variable but with a fixed number of digits for each particular issuer identifier number.
The last digit is the parity check digit computed according to the Luhn formula (see ISO/IEC 7812-1, Annex B).
When the MNO (Mobile Network Operator) orders a number of UICCs to a Smart Card Manufacturer, it provides the first IMSI and the number of cards required. Alternatively, the MNO can provide an input file with the required personalization data (PIN1, PUK1, PIN2, PUK2, ADM1, ADM2...) for each IMSI.
The MNO will receive back the smart cards, each one with the ICCID stored in the EF-ICCID file and also engraved or printed on the UICC body. The MNO will securely receive a response file providing for each IMSI, the ICCID, the secret key and the associated personalization data.
The ICCID is not stored in the HLR/HSS. The secret key is stored in the AuC.
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)
The Check Digit complements the 14 digits of the IMEI. It 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 TS 23.003, annex B.