Subscriber Identity Module
Jul 28, 2010 at 12:08 am in GSM by LT contributor
A subscriber identity module (SIM) on a removable SIM card securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony devices (such as mobile phones and computers). The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device.
-Wikipedia
The Subscriber Identity Module (SIM) is a small smart card which contains both programming and information. The SIM card provides the actual identity for the subscriber. During initial registration all the relevant subscriber data are inserted into the SIM card and the activity is known as personalization.
A mobile phone cannot make or receive any calls except emergency calls without a SIM. Each SIM card is registered in a particular GSM network(HPLMN), and can be recognized by another network only if the HPLMN have agreement between themselves to support the subscriber, i.e., the subscriber has roaming facility.
A SIM comprises a micro-controller it has 5Kb of ROM and 2kb of EPROM and it is divided into different distinct zones:
| The manufacturer zone: | The chip is programmed with the manufacturer identity and the component number of the chip. |
| The secret zone: | This zone contains data that cant be read or over-written. This data control the access to the functions activating the card, the sender key, the key proving service, and the code carrying key. |
| Status zone: | Stores the keys needed to access the protected data. |
| Confidential zone: | This zone holds the permanent protected data which is only accessible via the sender key or the code carrying key ( authentication and ciphering algorithms.) |
| The transaction zone : | After personalization of the card, this area stores subscriber data that can be accessed with or without a key (PIN), according to the conditions written in the manufacturer’s zone. |
| The open zone: | This zone contains the non-confidential data that can be freely read. |
One of the advantages of the GSM architecture is that the SIM may be moved from one Mobile Station to another. This makes upgrades very simple for the GSM telephone user.
Data stored in SIM Card.
- Universal subscriber identity module
- International mobile subscriber identity (IMSI)
- Security Authentication
- ciphering information
- Temporary information related to the local network
- list of the services
- Passwords (PIN & PUK).
- Integrated circuit card identifier (ICC-ID)
- Issuer identification number (IIN)
- Individual account identification
- Check digit
- Location area identity
- SMS messages and contacts
Standard Size of SIM Card:
- 85.60 mm Ă— 53.98 mm x 0.76 mm
- 25 mm x 15 mm x 0.76 mm
- 15 mm Ă— 12 mm x 0.76 mm
Operating Voltage:
- 5 Volt
- 3 Volt
- 1.8 Volt
Please tell something about sim memory organization
around 120KB and more……