ITU-T Recommendations

The purpose of Recommendation ITU-T E.212 is to define a unique international identification plan for public fixed and mobile networks providing users with access to public telecommunication services. The E.212 identification plan was originally developed for the use in public land mobile networks (PLMN). The plan is hierarchical and identifies geographic areas, networks and subscriptions. The main body of this Recommendation describes the pure identification plan. Guidance on how to use this resource is described in the annexes. The international mobile subscription identities (IMSIs) are independent from the national numbering plans. In general, this Recommendation uses the term subscription because an IMSI identifies subscriptions for access to public telecommunication services.