SIST ETS 300 508 E3:2003

SIST ETS 300 508 E3:2003 is the Slovenian adoption of ETS 300 508 Edition 3 from SIST/ETSI. It specifies the purpose, composition and operational use of the International Mobile station Equipment Identity (IMEI) in the GSM Phase 2 digital cellular telecommunications system. The standard is aimed at mobile station manufacturers and GSM network operators that need to identify equipment, control access, and support stolen-equipment blocking and traceability.

What does SIST ETS 300 508 E3:2003 specify?

SIST ETS 300 508 E3:2003 specifies how the IMEI is used to identify mobile station equipment in GSM and how networks can act on that identity. It covers the IMEI itself, the Equipment Identity Register (EIR) lists, the handling of emergency calls, and the separate MS Software Version Number (SVN).

The document is organized into a short introduction and seven main clauses:

• general principles
• composition of the IMEI
• use of the equipment identity register
• procedure
• use of IMEI in case of emergency calls
• MS Software Version Number (SVN)

Annex A is normative and covers IMEI check digit computation.

What are the key requirements of SIST ETS 300 508 E3:2003?

Identity, uniqueness and tamper resistance

Clause 0.3 and Clause 2 state that each individual mobile station equipment shall have a unique IMEI, and the manufacturer shall implement it unconditionally. Clause 2 also says the IMEI shall not be changed after final production and shall resist tampering by physical, electrical or software means. In practice, manufacturers need a secure identity assignment process and records that let them trace each produced unit.

What the IMEI is for

Clause 2 explains that the IMEI complements the IMSI, which is tied to subscriber use and charging, by identifying the equipment itself. This matters because a network may need to recognize a specific device even when different subscribers use it. The standard says this helps control stolen equipment and equipment that should no longer be allowed for technical reasons.

IMEI composition and check digit

Clause 3 says the IMEI is 14 digits plus a check digit, and that the check digit helps detect manual entry errors. The check digit is defined by the Luhn formula and is not applied to the SVN. For readers, this means the identity has a built-in error check for administrative use, such as customer-care handling of reported stolen devices.

Equipment Identity Register lists

Clause 4 defines three operator-controlled lists in the EIR: white, grey and black. The white list contains permitted equipment identities, the black list contains barred equipment identities, and the grey list is for equipment that is tracked but not barred unless other conditions apply. In practice, the operator decides how strictly to use these lists.

Network checks and actions

Clause 5 says the IMEI check shall be possible at any access attempt, except IMSI detach, and during an established call when a dedicated radio resource is available, according to the PLMN security policy. If the EIR returns “black-listed” or “unknown” equipment, the network shall terminate the attempt or call and indicate “illegal ME” to the user. The same clause treats these cases as authentication failure, which blocks call establishment and location updating, while still allowing emergency calls.

Emergency calls and SVN

Clause 6 allows the network to request the equipment identity after an emergency call has been set up when the IMSI is not sent first. Clause 7 adds a separate 2-digit SVN to identify software versions of a type-approved mobile. The SVN is associated with the IMEI and is sent with it if present; the white list uses the IMEI, while the black and grey lists may also use the SVN.

Annex A check digit method

Annex A defines the IMEISV structure as TAC, FAC, SNR and SVN, then explains how to compute the IMEI check digit from the first 14 digits only. For practical use, this annex gives the exact method needed to verify or generate the check digit in administrative systems.

What terms does SIST ETS 300 508 E3:2003 define?

• International Mobile station Equipment Identity (IMEI) - a unique number allocated to each individual mobile station equipment in GSM.
• International Mobile Subscriber Identity (IMSI) - the subscriber identity used to operate an MS and to support subscriber-related network use.
• Equipment Identity Register (EIR) - the network register that uses white, grey and black lists to control equipment access.
• Software Version Number (SVN) - a separate 2-digit field that identifies software versions of a given type approved mobile.
• International Mobile station Equipment Identity and Software Version Number (IMEISV) - the 16-digit identity made up of TAC, FAC, SNR and SVN.
• Type Approval Code (TAC) - the 6-digit part of the IMEISV that identifies the approved type.

Who uses SIST ETS 300 508 E3:2003?

SIST ETS 300 508 E3:2003 is used by mobile station manufacturers, GSM network operators and administrations that manage equipment identity policies. Manufacturers use it to assign and protect unique IMEIs and keep production records. Network operators use it to check devices against EIR lists, trace equipment, and decide whether to allow, track or bar access.

What changed in SIST ETS 300 508 E3:2003 from the previous edition?

The foreword states that this ETS corresponds to GSM technical specification GSM 02.16 version 4.5.0.

Which standards are used with SIST ETS 300 508 E3:2003?

• GSM 01.04 (ETR 100) - provides definitions, abbreviations and acronyms used elsewhere in the specification.
• GSM 02.17 (ETS 300 509) - gives the functional characteristics of Subscriber identity modules and is used for the IMSI context.
• GSM 03.03 (ETS 300 523) - defines numbering, addressing and identification, including the detailed IMEI structure.
• ISO/IEC 7812 (1989) - provides the numbering system and registration procedure used for the Luhn check digit method.

What does the SIST ETS 300 508 E3:2003 document contain?

The document contains a short foreword, an introduction, the main clauses on IMEI purpose, composition, EIR use, procedures, emergency calls and SVN, and a normative Annex A. Annex A gives the IMEI check digit computation, including the representation of the IMEISV, the step-by-step Luhn calculation, and a worked example. The main text explains how the IMEI supports device-level control in GSM and how operators can use it in network access decisions.