TELECOMMUNICATIONS SYSTEM

摘要

User data for a telecommunications system (5) is stored at addresses (60a, 60b), etc. in registers (6a, 6b). Each address is accessible for purposes of call-routing, billing etc. by two different user identities; a subscriber identity (IMSI) and a directory number (MSISDN), used respectively by the telecommunications system (5) itself and by users of the system. To allow flexibility of allocation of the user identity types, a translation register (9) is provided which converts MSISDN directory numbers to IMSI subscriber identities, thereby requiring each address (60a, 60b, etc.) in the registers (6a, 6b) to be accessible only by the subscriber identity. This allows a directory number (MSISDN) to be reallocated from one subscriber identity to any other, whether having an address in the same register (6a) or another (6b). This in turn allows subscriber identities (IMSIs) to be permanently allocated to equipment, but transferable between users, increasing flexibility of the system whilst reducing the potential for fraud by "cloning" (unauthorised reprogramming of equipment to duplicate a subscriber identity).