以下主要介紹SIM(Subscriber Identity Module) card的邏輯接口，附兩篇有關SIM的介紹性文章：
The files are organised in a hierarchical structure and are of one of three types as defined below. These files may be either administrative or application specific. The operating system handles the access to the
data stored in different files
 |
| Logical Model of SIM |
Files are composed of a header, which is internally managed by the SIM, and optionally a body part.
The information of the header is related to the structure and attributes of the file and may be obtained by using the commands GET RESPONSE or STATUS. This information is fixed during the administrative phase.
The body part contains the data of the file.
File Identifiers
A file ID is used to address or identify each specific file. The file ID consists of two bytes and shall be coded in hexadecimal notation. They are specified in clause 10.
The first byte identifies the type of file, and for GSM is:
- '3F': Master File;
- '7F': Dedicated File;
- '2F': Elementary File under the Master File;
- '6F': Elementary File under a Dedicated File.
File IDs shall be subject to the following conditions:
- the file ID shall be assigned at the time of creation of the file concerned;
- no two files under the same parent shall have the same ID;
- a child and any parent, either immediate or remote in the hierarchy, e.g. grandparent, shall never have the same file ID.
In this way each file is uniquely identified.
Master File(MF)
The unique mandatory file containing access conditions and optionally DFs and/or EFs.
Dedicated Files(DF)
A Dedicated File (DF) is a functional grouping of files consisting of itself and all those files which contain this DF in their parental hierarchy (that is to say it consists of the DF and its complete "subtree").
A DF "consists" only of a header part.
- DFGSM which contains the application for both GSM and/or DCS1800;
- DFTELECOM which contains telecom service features.
Both files are immediate children of the Master File (MF) and may coexist on a multi-application card.
Elementary File(EF)
An Elementary File (EF) is composed of a header and a body part. The following three structures of an EF are used by GSM.
Transparent EF
An EF with a transparent structure consists of a sequence of bytes. When reading or updating, the sequence of bytes to be acted upon is referenced by a relative address (offset), which indicates the start position
(in bytes), and the number of bytes to be read or updated. The first byte of a transparent EF has the relative address '00 00'. The total data length of the body of the EF is indicated in the header of the EF.
Linear Fixed EF
An EF with linear fixed structure consists of a sequence of records all having the same (fixed) length. The first record is record number 1. The length of a record as well as this value multiplied by the number of
records are indicated in the header of the EF.
NOTE 1: It is not possible, at present, to have more than 255 records in a file of this type, and each record cannot be greater than 255 bytes.
NOTE 2: This structure was previously referred to as "formatted" in GSM.
Cyclic EF
Cyclic files are used for storing records in chronological order. When all records have been used for storage, then the next storage of data shall overwrite the oldest information.
An EF with a cyclic structure consists of a fixed number of records with the same (fixed) length. In this file structure there is a link between the last record (n) and the first record. When the record pointer is
set to the last record n, then the next record is record 1. Similarly, when the record pointer is set to record 1, then the previous record is record n. The last updated record containing the newest data is record number 1, and the oldest data is held in record
number n.
For update operations only PREVIOUS record shall be used. For reading operations, the methods of addressing are Next, Previous, Current and Record Number.
After selection of a cyclic file (for either operation), the record pointer shall address the record updated or increased last. If an action following selection of a record is aborted, then the record pointer shall
remain set at the record at which it was set prior to the action.
NOTE: It is not possible, at present, to have more than 255 records in a file of this type, and each record cannot be greater than 255 bytes.
Methods of selecting files
After the Answer To Reset (ATR), the Master File (MF) is implicitly selected and becomes the Current Directory. Each file may then be selected by using the SELECT function in accordance with the following rules.
Selecting a DF or the MF sets the Current Directory. After such a selection there is no current EF.
Selecting an EF sets the current EF and the Current Directory remains the DF or MF which is the parent of this EF. The current EF is always a child of the Current Directory.
Any application specific command shall only be operable if it is specific to the Current Directory.
The following files may be selected from the last selected file:
- any file which is an immediate child of the Current Directory;
- any DF which is an immediate child of the parent of the current DF;
- the parent of the Current Directory;
- the current DF;
- the MF.
This means in particular that a DF shall be selected prior to the selection of any of its EFs. All selections are made using the file ID.
The following figure gives the logical structure for the GSM application. GSM defines only one level of DFs under the MF.
The following table gives the valid selections for GSM for the logical structure in figure 7. Reselection of the last selected file is also allowed but not shown.
Reservation of file IDs
In addition to the identifiers used for the files specified in this TS, the following file IDs are reserved for use by GSM.
Dedicated Files:
- administrative use:
'7F 4X';
- operational use:
'7F 10' (DFTELECOM), '7F 20' (DFGSM), '7F 21' (DFDCS1800), and '7F 2X', where X ranges from '2' to 'F'.
Elementary files:
- administrative use:
'6F XX' in the DFs '7F 4X';
'6F 1X' in the DFs '7F 10', '7F 20', '7F 21';
'2F 01', '2F EX' in the MF '3F 00';
- operational use:
'6F 2X', '6F 3X', '6F 4X' in '7F 10' and '7F 2X';
'2F 1X' in the MF '3F 00'.
In all the above X ranges, unless otherwise stated, from '0' to 'F'.
Content of Elementry Files
Elementry File Types
*
EF-ICCID : ICC Identification
*
EF-LP : Language Preference
*
EF-IMSI :
*
EF-KC : Ciphering Key kc
*
(O)EF-PMLNsel : MCC+MNC
*
EF-HPMLN : The time interval between two searches.
*
(O)EF-ACMmax : Accumulated Call Meter (max)
*
EF-SST: SIM Service Table
*
(O)EF-ACM : Accumulated Call Meter - total number of units for both the current call and the preceding calls
*
(O)EF-GID1 : Group Identifier Level 1 - identifiers for particular SIM-ME associations
*
(O)EF-GID2 : Group Identifier Level 2
*
(O)EF-SPN : Service Provider Name
*
(O)EF-PUCT : Price per Unit and Currency Table - The PUCT is Advice of Charge related information which may be used by the ME in conjunction with EFACM to compute the cost of calls in the currency chosen by the subscriber, as specified in TS GSM 02.24 [7].
This EF shall always be allocated if EFACM is allocated.
*
(O)EF-CBMI : Cell Broadcast Message Identifier Selection - Message format accepted by MS
*
EF-BCCH : Broadcast Control Channels
*
EF-ACC : Access Control Class - The access control class is a parameter to control the RACH utilisation.
*
EF-FPMLN : Forbidden PMLNs
*
EF-LOCI : Location Infomation - Temporary Mobile Subscriber Identity (TMSI)
- Location Area Information (LAI)
- TMSI TIME
- Location update status
*
EF-AD : Administrative Data - This EF contains information concerning the mode of operation according to the type of SIM, such as normal (to be used by PLMN subscribers for GSM operations), type approval (to allow specific use of the ME during type approval
procedures of e.g. the radio equipment), cell testing (to allow testing of a cell before commercial use of this cell), manufacturer specific (to allow the ME manufacturer to perform specific proprietary auto-test in its ME during e.g. maintenance phases).
*
EF-Phase : Phase Identification
*
(O)EF-ADN : Abbreviative Dialing Number
*
(O)EF-FDN : Fixed Dialing Number
*
(O)SF-SMS : Short Message
*
(O)EF-CCP : Capability Configuration Parameters - parameters of required network and bearer capabilities and ME configurations associated with a call established using an abbreviated dialling number, a fixed dialling number, MSISDN or a last number dialled.
*
(O)EF-MSISDN :
*
(O)EF-SMSP : SMS Parameters
*
(O)EF-SMSS : SMS Status - The provision of this EF is associated with EF-SMS.
*
(O)EF-LND : Last number dialled
*
(O)EF-EXT1 : Extension 1
*
(O)EF-EXT2 : Extension 2