This Technical Specification defines: i) an identification plan for mobile subscribers in the GSM system; ii) principles of assigning telephone and ISDN numbers to mobile stations in the country of registration of the mobile station; iii) principles of assigning mobile station roaming numbers to visiting mobile stations; iv) an identification plan for location areas and base stations in the GSM system; v) an identification plan for MSCs and location registers in the GSM system; vi) principles of assigning international mobile equipment identities; vii) principles of assigning zones for regional subscription.