Design
There are three operating voltages for SIM cards: 5 V, 3 V and 1.8 V (ISO/IEC 7816-3 classes A, B and C, respectively). The operating voltage of the majority of SIM cards launched before 1998 was 5 V. SIM cards produced subsequently are compatible with 3 V and 5 V. Modern cards support 5 V, 3 V and 1.8 V.
The microcontrollers used for SIM cards come in different configurations. The typical ROM size is between 64 KB and 512 KB, typical RAM size is between 1 KB and 8 KB, and typical EEPROM size is between 16 KB and 512 KB. The ROM contains the operating system of the card and might contain applets where the EEPROM contains the so-called personalisation, which consists of security keys, phone book, SMS settings, etc., and operating system patches.
Modern SIM cards allow applications to be loaded when the SIM is in use by the subscriber. These applications communicate with the handset or a server using SIM application toolkit, which was initially specified by ETSI in TS 11.14. SIM toolkit applications were initially written in native code using proprietary APIs. In order to allow interoperability of the applications, Java Card was taken as the solution of choice by ETSI.
Read more about this topic: Subscriber Identity Module
Famous quotes containing the word design:
“What but design of darkness to appall?—
If design govern in a thing so small.”
—Robert Frost (1874–1963)
“Delay always breeds danger; and to protract a great design is often to ruin it.”
—Miguel De Cervantes (1547–1616)
“The reason American cars don’t sell anymore is that they have forgotten how to design the American Dream. What does it matter if you buy a car today or six months from now, because cars are not beautiful. That’s why the American auto industry is in trouble: no design, no desire.”
—Karl Lagerfeld (b. 1938)