Telecommunications System

Abstract

Abstract of the Disclosure

In a telecommunications system such as a global mobile telephone network in which each subscriber unit includes a Subscriber Identity Module (SIM card), each SIM card has fixed memory locations, to which data can be addressed over the air. Some of the locations can not be overwritten from the subscriber unit but can be accessed therefrom on the entry of short simple codes, each associated with one of the locations. Further fixed memory locations can be read over the air only when the subscriber enters a personal identification number. Locking control files are used to control read/write access to the locations respectively.

Description

Detailed Description of the InventionCross Reference to Related Applications[0001] This application claims priority under 35 USC Section 120 and is a continuation of U.S. Application No. 09 / 455,628, filed Dec. 7, 1999, now U.S. Patent No. 6,453,167, which is a continuation of U.S. Application Ser. No. 08 / 557,147, filed Apr. 19, 1996, now U.S. Pat. No. 6,011,976, which is a national application of prior International Application No. PCT / GB94 / 01295, filed June 15, 1994. U.S. Application Nos. 09 / 455,628 and 08 / 557,147 are incorporated herein by reference.Background of Invention[0002] This invention relates to a telecommunications system. In particular, but not exclusively, it relates to a mobile communications system such as a cellular mobile radio or telephone system.[0003] A recent innovation in such systems has been the introduction of Subscriber Identity Modules (SIM cards). These are integrated circuit cards which can be releasably inserted into a mobile telephone and which cont...

AI Technical Summary

Benefits of technology

[0007] Thus, for example, a set of telephone numbers, each with an identifying alphanumeric tag, can be transmitted to the SIM card, allowing users easy access to commonly used services such as hotels, car hire or airline reservations. This feature is known as a Value Added Service Directory.

[0008] A message may be retrievable by the subscriber on the entry of simple, short codes into the subscriber unit, each memory location corresponding to a particular code. A message may include a telephone number and, once stored, may be able to be overwritten over the air. Preferably, the or each host station is operable to transmit a request for information stored in a subscriber unit. The information may be included in a message and it may also include information which is stored in a secure memory location, accessible only when the subscriber enters a personal identification number (PIN number). The information may include credit deta

Problems solved by technology

However, if a message is received which would overfill

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