SIM FILE SYSTEM

The SIM maintains information in a series of “files” that are organized hierarchically, much like the operating system of a personal computer. These files may be for administrative purposes or be specific to the GSM user application. Data in these files are accessed through APDU commands sent to the operating system.
A file is composed of [...]

SIM COMMANDS

This transmission protocol uses Application Protocol Data Units (APDU), which can be either commands or responses. These are sent across the electrical interface between the SIM and the mobile equipment, or the SIM-ME interface for short.

CLA

INS

P1

P2

P3

Data

Command APDU format.

There are five fields in an APDU command. The class of instruction (CLA) is always A0 for [...]