Subscriber identity module
The SIM ( subscriber identity module from the English for " subscriber identity module ") is a smart card that is inserted into a mobile phone and used to identify the user in the network. With her make mobile operator subscribers mobile phone connections and data connections.
The SIM is a small processor and memory ( usually in the ID-000 format, which is broken out of an ID -1 format card). PIN for it can be protected from unauthorized use. With the help of SIM Mobile is the equipment (ie, usually the mobile phone ) mapped to a network and authenticates. For these purposes on the SIM IMSI stored, which is transmitted unencrypted in web search and booking into a radio network and a listening in on mobile phone calls and narrowing down the location of the mobile phone within a radio cell allowed ( IMSI catcher ). Others on the SIM number stored sequences and algorithms are used for encryption of voice and signaling data ( Ciphering ). The SIM is also used to store temporary, network-related data as well as preferred and restricted networks. In addition, may be integrated a telephone and notebook memory for Short Message Service messages ( SMS) and the memory of the last called phone numbers. SIM and mobile equipment form the Mobile Station together in GSM.
In Germany 2012, there were approximately 115 million SIM cards in circulation.
- 3.1 Mini - SIM (UICC )
- 3.2 Micro- SIM (Mini - UICC)
- 3.3 Nano - SIM
- 3.4 Combined SIM
Technology
The SIM card is often ( 85.6 mm × 54 mm) delivered in large ID -1 format. The smaller the ID-000 part (25 mm × 15 mm) can be broken out. Due to the increasingly smaller mobile devices is a small ID-000 format has been introduced in the course of time for the D-network devices. Meanwhile, there are a variety of devices, instead using the more smaller micro-SIM. The Apple iPhone 5 even the smallest format, the nano - SIM is installed.
A so-called SIM Toolkit makes it possible to deposit small programs on a SIM card, such as information services, with which you can let yourself find the latest information about politics, sports, weather, etc.. The mobile operators O ₂, E-Plus, T -Mobile and Vodafone use the to offer their home zone service. Using the SIM Toolkit is displayed there, whether the phone is in the " home zone ". Functions such as charging or queries the credit balance (if prepaid " prepaid " cards ) are possible. The advantage of applications on the SIM card is that they can be used regardless of the device used ( thus no apparent change in the cell phone functionality to be changed ).
Several manufacturers are currently working on the development of a SIM card that has more space, similar to the known memory cards such as SD cards. This memory, so far up to 64 GB, can then free other documents to be used for eg MP3 audio or.
As SIM Access Profile refers to a technique by which the SIM data of a Bluetooth-equipped mobile device to read from a device permanently installed eg in the car and this itself establishes the radio link. This allows the data transfer improved by the permanently installed outdoor antenna and reduce the power consumption of the mobile phone.
In dual- SIM mobile phones or with the help of dual SIM adapters two or more SIM cards can be accommodated in a single device that are active then either simultaneously (concurrently ) or alternatively ( alternately ).
Contacts
There are eight contact surfaces on a SIM card. Different cards vary in the number and distribution, however, are specified only these eight contacts with the following assignment:
On Vcc and GND of the SIM card is supplied with the operating voltage. There are SIM cards with an operating voltage of 1.8 volts, 3 volts and the older generation of cards and 5 volts. This voltage is printed normally on the SIM card. If a SIM card with a "wrong" voltage used in a mobile phone, it can lead to error messages, crashes, or unusually fast battery discharge.
If a SIM card is not responding to requests of the mobile device, it can be restarted using the reset contact. CLK on the clock of the mobile terminal for synchronizing the taking place over the I / O- contact data transfer is transmitted.
The programming voltage Vpp is only optional in the preparation is required to initialize or clear the internal software of the card. The normal read and write operations to the user area of a SIM card (eg in the context of the use in a mobile device ) do not require this voltage.
The two additional contact pins are reserved for still rare eight-pin SIM cards as they are to be used in future mobile devices - currently there are several competing designs for which these contacts are to be used, inter alia, have SIM cards with very high storage in the call, which could be coupled by means of a variant of the USB protocol. Other ideas involve special encryption functions or Near Field Communication (NFC ). Current European mobile phones use but still only six-pin SIM card.
Circuit
The I / O unit controls access to the SIM card. It is the interface of the CPU to the mobile device. The CPU is mainly used for memory management, although it can also run small programs. The memory consists of a ROM, a RAM and an EEPROM. ROM in the operating system of the card is stored. Also branding the mobile phone companies be stored there (eg start-up logo ). The RAM contains just used data, it is volatile. In the EEPROM user data is stored.
Life
SIM cards have a limited lifetime. With each of erase-write cycle of the non-volatile memory card (for example, at an authentication in the network), " aging " of the corresponding memory area. Originally guaranteed the manufacturer of the SIM chip 100,000 such cycles. In current chips, this value is 500000-1 million To make this process defuse protection mechanisms build the SIM producers in the operating system.
Regardless of some older SIM cards from current mobile phones are not recognized. One reason may be that the SIM card does not function with the voltage provided by the device. Another reason may be that the device requires a USIM card.
Formats
Since development of the UMTS standard by the European Telecommunications Standards Institute in the late 1990s, it is assumed that mobile devices be smaller in the future, or at least less space inside will have and therefore SIM cards with small size are required. Therefore, in addition to the UMTS -enabled smart card ( Universal Integrated Circuit Card, abbreviation UICC), a smaller version, the Mini - UICC considered.
The mini- UICC gained greater fame through the media-effective staging of the market entry of the Apple iPad as a micro-SIM card. Here is the introduction of a smaller SIM card nothing new: At the first change of the SIM card format, was as changed by SIM card card size to the mini - SIM cards in use today, there was like today instructions for building your own.
Mini - SIM (UICC )
The current customary mini- SIM card is 25 mm × 15 mm in size. The UICC is commonly as its predecessor called from the GSM networks as a SIM card.
Micro- SIM (Mini - UICC)
The micro-SIM, including third form factor card (abbr. 3FF ) is a smaller version of the mini - SIM card. In the micro-SIM, the outer lengths are only 15 mm × 12 mm. As regards the technical specifications of the circuit, there are no differences. With a special hole device can be made from a SIM or mini - SIM, a micro-SIM.
One of the first devices that used a micro-SIM card, the iPad was in 2010, followed by the Apple iPhone 4 But Nokia uses this type of card, so the Nokia N9 or the Nokia Lumia 800 also uses the Motorola Motorola Droid Razr on micro-SIM cards. Many other manufacturers have followed the trend and use their smart phones now micro-SIM cards.
Nano - SIM
The nano- SIM ( 4 FF ) "Fourth Form Factor" card is a smaller version of the Micro SIM. This is 12.3 mm × 8.8 mm × 0.67 mm again 40 % smaller than a micro-SIM and should thus saving valuable space in compact devices. Cards in the nano - SIM format provide the same functionality as larger cards. The standard also includes a mechanical backward compatibility, so a simplified distribution should be possible.
Apple and Nokia as first wanted to standardize on their version as each better. The ETSI decided in June 2012, finally, for the design proposal from Apple. This is compatible with those already in use micro-SIM cards. Currently this SIM version in iPhone 5, iPhone 5s, 5c iPhone, iPad mini, iPad Air, Nokia Lumia 1520 and the Motorola Moto X is used.
Combined SIM
Many vendors now provide so-called hybrid SIM cards that can be used for all sizes by "normal" breaks out big SIM card the small format Micro- SIM card from the.
Circumcision
Many Mini - and Micro- SIMs have eight contact surfaces, of which two contacts are only kept in reserve and are not connected. Therefore, it is possible to cut a standard SIM, not only to the mini-sized, but also on the size of a Micro-/Nano-SIM. The most common errors such manual blanks is that resulting chips establish a connection between two or more contacts, which the SIM when first using damaged or destroyed.
Country-specific
On 13 February 2009, the German Federal Council approved a Regulation of the Federal Ministry of Economics and Technology, according to the future emergency calls ( 110 and 112) can no longer be voted on without a SIM card. As more and more often groundless emergency calls from mobile phones without a map had been made, identifiable only through SIM card communication participants should now have this option.
Security
In July 2013 it was announced that supposedly several million SIM cards were not sure. Reason is an outdated encryption standard to allow attackers to hack sim cards from a distance, without noticing the cell phone owner. In Germany, the IT industry association Bitkom and the large German telecommunications provider Deutsche Telekom, Telefonica, E -Plus Group and Vodafone responded calmly.