Telecommunications systems
US6453167B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1999 |
| Grant date | Sep 17, 2002 |
| Priority date | — |
| Expiry date | Dec 7, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W4/14
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
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 (22), to which data can be addressed over the air. Some of the locations (22) 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 (24) can be read over the air only when the subscriber enters a personal identification number. Locking control files (27, 28) are used to control read/write access to the locations (22, 24) respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.