SIM card – Wikipedia

Integrated circuit card for a fluid device
“ Micro-SIM ” redirects here. For the ship’s company, see MicroSim Corporation A distinctive SIM batting order ( mini-SIM with micro-SIM cutout ) TracFone Wireless SIM card has no distinctive carrier markings and is only marked as a “SIM card” A SIM card ( wide phase Subscriber Identity Module or Subscriber Identification Module ) is an integrated circuit ( IC ) intended to securely store the international fluid subscriber identity ( IMSI ) number and its refer key, which are used to identify and authenticate subscribers on mobile telephone devices ( such as mobile phones and computers ). technically the actual physical card is known as a universal incorporate circuit batting order ( UICC ) ; this smart card is normally made of PVC with embed contacts and semiconductors, with the SIM as its primary part. In drill the term “ SIM wag ” refers to the entire whole and not simply the IC.

A SIM contains a unique serial number ( ICCID ), external fluid subscriber identity ( IMSI ) number, security authentication and ciphering data, temp data related to the local anesthetic network, a list of the services the drug user has access to, and two passwords : a personal designation total ( PIN ) for ordinary use, and a personal unblock key ( PUK ) for PIN unlocking. In Europe, the serial SIM number ( SSN ) is besides sometimes accompanied by an external article phone number ( IAN ) or a european article issue ( EAN ) required when registering on-line for the subscription of a prepay menu. It is besides possible to store contact data on many SIM cards. SIMs are constantly used on GSM phones ; for CDMA phones, they are needed entirely for LTE -capable handsets. SIM cards can besides be used in satellite phones, smart watches, computers, or cameras. [ 1 ] The first gear SIM cards were the size of credit and bank cards ; sizes were reduced several times over the years, normally keeping electric contacts the same, so that a larger tease could be cut down to a smaller size. SIMs are movable between different mobile devices by removing the card itself. eSIM is replacing physical SIM cards in some domains, including cellular telephone. eSIM uses a software-based SIM embedded into an unremovable eUICC .

history and procurement [edit ]

The SIM tease is a type of smart menu, [ 1 ] the footing for which is the silicon integrated circuit ( IC ) chip. [ 2 ] The theme of incorporating a silicon IC nick onto a plastic card originates from the belated 1960s. [ 2 ] Smart cards have since used MOS integrated circuit chips, along with MOS memory technologies such as brassy memory and EEPROM ( electrically effaceable programmable read-only memory ). [ 3 ] The SIM was initially specified by the european Telecommunications Standards Institute in the specification with the count TS 11.11. This specification describes the physical and logical behavior of the SIM. With the development of UMTS, the stipulation knead was partially transferred to 3GPP. 3GPP is immediately responsible for the farther development of applications like SIM ( TS 51.011 [ 4 ] ) and USIM ( TS 31.102 [ 5 ] ) and ETSI for the further development of the physical card UICC. The beginning SIM tease was developed in 1991 by Munich smart-card godhead Giesecke & Devrient, who sold the first 300 SIM cards to the Finnish wireless network operator Radiolinja. [ 6 ] [ 7 ] today, SIM cards are omnipresent, allowing over 7 billion devices to connect to cellular networks around the earth. According to the International Card Manufacturers Association ( ICMA ), there were 5.4 billion SIM cards manufactured globally in 2016 creating over $ 6.5 billion in tax income for traditional SIM poster vendors. [ 8 ] The heighten of cellular IoT and 5G networks is predicted to drive the growth of the addressable market for SIM card manufacturers to over 20 billion cellular devices by 2020. [ 9 ] The presentation of embedded-SIM ( eSIM ) and distant SIM provision ( RSP ) from the GSMA [ 10 ] may disrupt the traditional SIM card ecosystem with the entrance of newly players specializing in “ digital ” SIM circuit board provision and other value-added services for mobile net operators. [ 3 ]

purpose [edit ]

SIM chip structure and packaging 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 operational electric potential 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 corroborate 5 V, 3 V and 1.8 V. [ 3 ]
4 by 4 millimetres ( 0.16 in × 0.16 in ) silicon chip in a SIM poster which has been peeled assailable. Note the thinly gold bond wires, and the regular, orthogonal digital memory areas. Modern SIM cards allow applications to load 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 3GPP in TS 11.14. ( There is an identical ETSI specification with different numbering. ) ETSI and 3GPP maintain the SIM specifications. The main specifications are : ETSI TS 102 223 ( the toolkit for chic cards ), ETSI TS 102 241 ( API ), ETSI TS 102 588 ( application invocation ), and ETSI TS 131 111 ( toolkit for more SIM-likes ). SIM toolkit applications were initially written in native code using proprietorship APIs. To provide interoperability of the applications, ETSI chose Java Card. [ 11 ] A multi-company collaboration called GlobalPlatform defines some extensions on the cards, with extra APIs and features like more cryptanalytic security and RFID contactless use added. [ 12 ]

Data [edit ]

SIM cards store network-specific data used to authenticate and identify subscribers on the network. The most crucial of these are the ICCID, IMSI, authentication key ( Ki ), local area identity ( LAI ) and operator-specific emergency count. The SIM besides stores other carrier-specific data such as the SMSC ( Short Message service center ) count, service provider name ( SPN ), service dialling numbers ( SDN ), advice-of-charge parameters and value-added overhaul ( VAS ) applications. ( Refer to GSM 11.11. [ 13 ] ) SIM cards can come in versatile data capacities, from 8 KB to at least 256 KB. [ 7 ] All can store a maximal of 250 contacts on the SIM, but while the 32 KB has room for 33 mobile network codes ( MNCs ) or network identifiers, the 64 KB interpretation has room for 80 MNCs. [ 14 ] This is used by net operators to store data on favored networks, by and large used when the SIM is not in its home network but is roaming. The network operator that issued the SIM card can use this to have a earphone connect to a choose network that is more economic for the supplier rather of having to pay the network operator that the phone discovered first. This does not mean that a telephone containing this SIM card can connect to a maximum of only 33 or 80 networks, rather it means that the SIM tease issuer can specify only up to that number of prefer networks. If a SIM is outside these prefer networks, it uses the first or best available net. [ 9 ]

ICCID [edit ]

Each SIM is internationally identified by its incorporate circuit card identifier ( ICCID ). ICCID is the identifier of the actual SIM calling card itself : i.e. an identifier for the SIM chip. Nowadays ICCID numbers are besides used to identify eSIM profiles, and not entirely physical SIM cards. ICCIDs are stored in the SIM cards and are besides engraved or printed on the SIM poster body during a process called personalisation. The ICCID is defined by the ITU-T recommendation E.118 as the primary account number. [ 15 ] Its layout is based on ISO/IEC 7812. According to E.118, the total can be up to 19 digits long, including a one discipline finger calculated using the Luhn algorithm. however, the GSM Phase 1 [ 16 ] defined the ICCID distance as an opaque data field, 10 octets ( 20 digits ) in length, whose structure is specific to a mobile net hustler. The number is composed of the following subparts : Issuer identification number (IIN) Maximum of seven digits :

  • Major industry identifier (MII), 2 fixed digits, 89 for telecommunication purposes.
  • Country code, 2 or 3 digits, as defined by ITU-T recommendation E.164.
    • NANP countries, apart from Canada, use 01, i.e. prepending a zero to their common calling code +1
    • Canada uses 302
    • Russia uses 701, i.e. appending 01 to its calling code +7
    • Kazakhstan uses 997, even though it shares the calling code +7 with Russia
  • Issuer identifier, 1–4 digits.
    • Often identical to the mobile network code (MNC).[17]

Individual account identification

  • Individual account identification number. Its length is variable, but every number under one IIN has the same length.
    • Often identical to the mobile subscription identification number (MSIN).[2]

Check digit

  • Single digit calculated from the other digits using the Luhn algorithm.

With the GSM Phase 1 stipulation using 10 octets into which ICCID is stored as pack BCD, the data field has room for 20 digits with hexadecimal finger “ F ” being used as filler when necessity. In commit, this means that on GSM SIM cards there are 20-digit ( 19+1 ) and 19-digit ( 18+1 ) ICCIDs in use, depending upon the issuer. however, a single issuer constantly uses the same size for its ICCIDs. To confuse matters more, SIM factories seem to have varying ways of delivering electronic copies of SIM personalization datasets. Some datasets are without the ICCID checksum digit, others are with the digit. As required by E.118, the ITU-T updates a tilt of all current internationally assign IIN codes in its Operational Bulletins which are published doubly a month ( the last as of January 2019 was No. 1163 from 1 January 2019 ). [ 18 ] ITU-T besides publishes complete lists : as of January 2019, the list issued on 1 December 2018 was current, having all issuer identifier numbers before 1 December 2018. [ 19 ]
SIM cards are identified on their individual operator networks by a unique international mobile subscriber identity ( IMSI ). Mobile network operators connect mobile earphone calls and convey with their grocery store SIM cards using their IMSIs. The format is :

  • The first three digits represent the mobile country code (MCC).
  • The next two or three digits represent the mobile network code (MNC). Three-digit MNC codes are allowed by E.212 but are mainly used in the United States and Canada. One MCC can have both 2 digit and 3 digit MNCs, an example is 350 007.
  • The next digits represent the mobile subscriber identification number (MSIN). Normally there are 10 digits, but can be fewer in the case of a 3-digit MNC or if national regulations indicate that the total length of the IMSI should be less than 15 digits.
  • Digits are different from country to country.

Authentication keystone ( Ki ) [edit ]

The Ki is a 128-bit value used in authenticating the SIMs on a GSM mobile network ( for USIM network, the Ki is still needed but other parameters are besides needed ). Each SIM holds a unique Ki assigned to it by the operator during the personalisation action. The Ki is besides stored in a database ( term authentication center or AuC ) on the carrier ‘s net. The SIM batting order is designed to prevent person from getting the Ki by using the smart-card interface. rather, the SIM card provides a function, Run GSM Algorithm, that the call uses to pass data to the SIM card to be signed with the Ki. This, by plan, makes using the SIM poster mandatary unless the Ki can be extracted from the SIM card, or the carrier is bequeath to reveal the Ki. In practice, the GSM cryptanalytic algorithm for computing a signed response ( SRES_1/SRES_2 : see steps 3 and 4, below ) from the Ki has certain vulnerabilities [ 14 ] that can allow the origin of the Ki from a SIM circuit board and the make of a duplicate SIM card. authentication process :

  1. When the mobile equipment starts up, it obtains the international mobile subscriber identity (IMSI) from the SIM card, and passes this to the mobile operator, requesting access and authentication. The mobile equipment may have to pass a PIN to the SIM card before the SIM card reveals this information.
  2. The operator network searches its database for the incoming IMSI and its associated Ki.
  3. The operator network then generates a random number (RAND, which is a nonce) and signs it with the Ki associated with the IMSI (and stored on the SIM card), computing another number, that is split into the Signed Response 1 (SRES_1, 32 bits) and the encryption key Kc (64 bits).
  4. The operator network then sends the RAND to the mobile equipment, which passes it to the SIM card. The SIM card signs it with its Ki, producing Signed Response 2 (SRES_2) and Kc, which it gives to the mobile equipment. The mobile equipment passes SRES_2 on to the operator network.
  5. The operator network then compares its computed SRES_1 with the computed SRES_2 that the mobile equipment returned. If the two numbers match, the SIM is authenticated and the mobile equipment is granted access to the operator’s network. Kc is used to encrypt all further communications between the mobile equipment and the operator.

Location area identity [edit ]

The SIM stores network state information, which is received from the placement area identity ( LAI ). operator networks are divided into placement areas, each having a alone LAI act. When the device changes locations, it stores the new LAI to the SIM and sends it rear to the operator network with its new location. If the device is exponent cycled, it takes data off the SIM, and searches for the anterior LAI .
Most SIM cards store a act of SMS messages and phone book contacts. It stores the contacts in simple “ mention and number ” pairs. Entries that contain multiple earphone numbers and extra call numbers are normally not stored on the SIM tease. When a drug user tries to copy such entries to a SIM, the handset ‘s software breaks them into multiple entries, discarding information that is not a telephone number. The total of contacts and messages stored depends on the SIM ; early models stored american samoa few as five messages and 20 contacts, while modern SIM cards can normally store over 250 contacts. [ 20 ]

Formats [edit ]

SIM cards have been made smaller over the years ; functionality is mugwump of format. life-size SIM was followed by mini-SIM, micro-SIM, and nano-SIM. SIM cards are besides made to embed in devices .
From left, life-size SIM ( 1FF ), mini-SIM ( 2FF ), micro-SIM ( 3FF ), and nano-SIM ( 4FF )

SIM card formats and dimensions
SIM card format Introduced Standard reference Length Width Thickness
Full-size (1FF) 1991 ISO/IEC 7810:2003, ID-1 85.6 mm (3.37 in) 53.98 mm (2.125 in) 0.76 mm (0.030 in)
Mini-SIM (2FF) 1996 ISO/IEC 7810:2003, ID-000 25 mm (0.98 in) 15 mm (0.59 in) 0.76 mm (0.030 in)
Micro-SIM (3FF) 2003 ETSI TS 102 221 V9.0.0, Mini-UICC 15 mm (0.59 in) 12 mm (0.47 in) 0.76 mm (0.030 in)
Nano-SIM (4FF) early 2012 ETSI TS 102 221 V11.0.0 12.3 mm (0.48 in) 8.8 mm (0.35 in) 0.67 mm (0.026 in)
2016 ETSI TS 102.671 V9.0.0
JEDEC Design Guide 4.8, SON-8
GSMA SGP.22 V1.0
 —  —  —

All versions of the non-embedded SIM cards share the same ISO/IEC 7816 pin arrangement .

Full-size SIM [edit ]

The full-size SIM ( or 1FF, 1st form factor ) was the first base shape factor to appear. It was the size of a credit card ( 85.60 millimeter × 53.98 millimeter × 0.76 millimeter ). belated smaller SIMs are much supplied embedded in a life-size card from which they can be removed .
The memory chip from a micro-SIM tease without the fictile support plate, following to a US dime bag, which is approx. 18 millimeter in diameter x-ray double of a mini-SIM, showing the chip and connections The mini-SIM ( or 2FF ) card has the like contact arrangement as the life-size SIM card and is normally supplied within a life-size wag aircraft carrier, attached by a total of linking pieces. This arrangement ( defined in ISO/IEC 7810 as ID-1/000 ) lets such a card be used in a device that requires a life-size batting order – or in a device that requires a mini-SIM card, after breaking the connect pieces. As the life-size SIM is no longer used, some suppliers refer to the mini-SIM as a “ standard SIM ” or “ regular SIM ” .
The micro-SIM ( or 3FF ) card has the lapp thickness and contact arrangements, but abridge length and width as shown in the table above. [ 21 ] The micro-SIM was introduced by the european Telecommunications Standards Institute ( ETSI ) along with SCP, 3GPP ( UTRAN/GERAN ), 3GPP2 ( CDMA2000 ), ARIB, GSM Association ( GSMA SCaG and GSMNA ), GlobalPlatform, Liberty Alliance, and the Open Mobile Alliance ( OMA ) for the purpose of fitting into devices excessively small for a mini-SIM card. [ 17 ] [ 22 ]

The form gene was mentioned in the December 1998 3GPP SMG9 UMTS Working Party, which is the standards-setting body for GSM SIM cards, [ 20 ] and the shape agent was agreed upon in recently 2003. [ 23 ] The micro-SIM was designed for backward compatibility. The major issue for backward compatibility was the contact area of the chip. Retaining the same touch area makes the micro-SIM compatible with the anterior, larger SIM readers through the manipulation of formative cutout surrounds. The SIM was besides designed to run at the same speed ( 5 MHz ) as the prior version. The like size and positions of pins resulted in numerous “ How-to ” tutorials and YouTube videos with detail instructions how to cut a mini-SIM batting order to micro-SIM size. [ 24 ] The chair of EP SCP, Dr Klaus Vedder, said [ 23 ]

ETSI has responded to a market need from ETSI customers, but additionally there is a strong desire not to invalidate, overnight, the existing interface, nor reduce the performance of the cards .

Micro-SIM cards were introduced by versatile mobile service providers for the launch of the original iPad, and by and by for smartphones, from April 2010. The iPhone 4 was the first smartphone to use a micro-SIM calling card in June 2010, followed by many others .
The nano-SIM ( or 4FF ) batting order was introduced on 11 October 2012, when mobile service providers in respective countries started to supply it for phones that supported the format. The nano-SIM measures 12.3 mm × 8.8 millimeter × 0.67 millimeter ( 0.484 in × 0.346 in × 0.026 in ) and reduces the previous format to the contact area while maintaining the existing contact arrangements. A small rim of isolating substantial is left around the contact sphere to avoid abruptly circuits with the socket. The nano-SIM is 0.67 millimeter ( 0.026 in ) thickly, compared to the 0.76 millimeter ( 0.030 in ) of its predecessors. 4FF can be put into adapters for manipulation with devices designed for 2FF or 3FF SIMs, and is made dilutant for that purpose, [ 25 ] and telephone companies give due warning about this. [ 26 ] The iPhone 5, released in September 2012, was the first device to use a nano-SIM card, followed by other handsets .

security [edit ]

In July 2013, Karsten Nohl, a security research worker from SRLabs, described [ 27 ] [ 28 ] vulnerabilities in some SIM cards that supported DES, which, despite its historic period, is still used by some operators. [ 28 ] The attack could lead to the call being remotely cloned or let person steal payment credentials from the SIM. [ 28 ] Further details of the research were provided at BlackHat on 31 July 2013. [ 28 ] [ 29 ] In reply, the International Telecommunication Union said that the development was “ enormously significant ” and that it would be contacting its members. [ 30 ] In February 2015, it was reported by The Intercept that the NSA and GCHQ had stolen the encoding keys ( Ki ‘s ) used by Gemalto ( the manufacturer of 2 billion SIM cards annually ), enabling these intelligence agencies to monitor voice and data communications without the cognition or approval of cellular network providers or judicial oversight. [ 31 ] Having finished its investigation, Gemalto claimed that it has “ fair grounds ” to believe that the NSA and GCHQ carried out an operation to hack its network in 2010 and 2011, but says the count of possibly stolen keys would not have been massive. [ 32 ] In September 2019, Cathal Mc Daid, a security research worker from Adaptive Mobile Security, described [ 33 ] [ 34 ] how vulnerabilities in some SIM cards that contained the S @ T Browser library were being actively exploited. This vulnerability was named Simjacker. Attackers were using the vulnerability to track the localization of thousands of mobile call users in respective countries. [ 35 ] Further details of the research were provided at VirusBulletin on 3 October 2019. [ 36 ] [ 37 ]

Developments [edit ]

When GSM was already in use, the specifications were far developed and enhanced with functionality such as SMS and GPRS. These development steps are referred as releases by ETSI. Within these exploitation cycles, the SIM specification was enhanced as well : new voltage classes, formats and files were introduced .

USIM [edit ]

In GSM-only times, the SIM consisted of the hardware and the software. With the advent of UMTS, this appointment was split : the SIM was now an application and hence only software. The hardware separate was called UICC. This cleave was necessity because UMTS introduced a newfangled application, the cosmopolitan subscriber identity module ( USIM ). The USIM brought, among other things, security improvements like common authentication and longer encoding keys and an better savoir-faire book .

UICC [edit ]

“ SIM cards ” in develop countries today are normally UICCs containing at least a SIM application and a USIM application. This configuration is necessity because older GSM lone handsets are entirely compatible with the SIM application and some UMTS security enhancements rely on the USIM application .

early variants [edit ]

On cdmaOne networks, the equivalent of the SIM card is the R-UIM and the equivalent of the SIM application is the CSIM. A virtual SIM is a fluid phone number provided by a fluid net operator that does not require a SIM menu to connect earphone calls to a drug user ‘s mobile telephone .

Embedded SIM ( eSIM ) [edit ]

Embedded SIM from M2M supplier Eseye with an arranger board for evaluation in a mini-SIM socket An implant SIM ( eSIM ) is a form of programmable SIM that is embedded immediately into a device. The open ride format provides the like electrical interface as the wax size, 2FF and 3FF SIM cards, but is soldered to a lap board as character of the manufacture summons. In M2M applications where there is no necessity [ 10 ] to change the SIM calling card, this avoids the prerequisite for a connection, improving dependability and security. An eSIM can be provisioned remotely ; end-users can add or remove operators without the necessitate to physically swap a SIM from the device. [ 38 ]

Integrated SIM ( iSIM ) [edit ]

An integrated SIM ( iSIM ) is a form of SIM immediately integrated into the model chip itself. As a consequence they are smaller, cheaper and more reliable than eSIMs, they can improve security and ease the logistics and production of minor devices i.e. for IoT applications. In 2021, the german Telekom introduced the nuSIM, an “ integrate SIM for IoT ”. [ 39 ] [ 40 ] [ 41 ]

custom in mobile phone standards [edit ]

SIM cards of diverse german mobile operators The use of SIM cards is mandate in GSM devices. The satellite telephone networks Iridium, Thuraya and Inmarsat ‘s BGAN besides use SIM cards. sometimes, these SIM cards work in regular GSM phones and besides allow GSM customers to roam in satellite networks by using their own SIM cards in a satellite earphone. Japan ‘s 2G PDC system ( which was shut down in 2012 ; SoftBank Mobile has already shut down PDC from 31 March 2010 ) besides specifies a SIM, but this has never been implemented commercially. The specification of the interface between the Mobile Equipment and the SIM is given in the RCR STD-27 annex 4. The Subscriber Identity Module Expert Group was a committee of specialists assembled by the european Telecommunications Standards Institute ( ETSI ) to draw up the specifications ( GSM 11.11 ) for interfacing between smart cards and mobile telephones. In 1994, the name SIMEG was changed to SMG9. Japan ‘s stream and next-generation cellular systems are based on W-CDMA ( UMTS ) and CDMA2000 and all use SIM cards. however, japanese CDMA2000-based phones are locked to the R-UIM they are associated with and thus, the cards are not interchangeable with other japanese CDMA2000 handsets ( though they may be inserted into GSM/WCDMA handsets for roaming purposes outside Japan ). CDMA -based devices in the first place did not use a removable circuit board, and the service for these phones is bound to a alone identifier contained in the handset itself. This is most prevailing in operators in the Americas. The first publication of the TIA-820 standard ( besides known as 3GPP2 C.S0023 ) in 2000 defined the Removable User Identity Module ( R-UIM ). Card-based CDMA devices are most prevailing in Asia. The equivalent of a SIM in UMTS is called the universal integrated circuit wag ( UICC ), which runs a USIM application. The UICC is still colloquially called a SIM card. [ 42 ]

SIM and carriers [edit ]

The SIM calling card introduced a newfangled and significant clientele opportunity for MVNOs – mobile virtual network operators – who lease capacity from one of the network operators preferably than owning or operating a cellular telecommunication network and lone provide a SIM card to their customers. MVNOs first gear appeared in Denmark, Hong Kong, Finland and the UK. today they exist in over 50 countries, including most of Europe, the United States, Canada, Mexico, Australia and parts of Asia, and report for approximately 10 % of all mobile call subscribers around the world. [ citation needed ] On some networks, the mobile phone is locked to its aircraft carrier SIM card, meaning that the telephone only works with SIM cards from the specific carrier. This is more coarse in markets where fluid phones are heavily subsidised by the carriers, and the business model depends on the customer staying with the service provider for a minimum term ( typically 12, 18 or 24 months ). SIM cards that are issued by providers with an associated abridge are called SIM-only deals. common examples are the GSM networks in the United States, Canada, Australia, the UK and Poland. many businesses offer the ability to remove the SIM lock from a call, efficaciously making it possible to then use the call on any network by inserting a different SIM card. by and large, GSM and 3G mobile handsets can well be unbarred and used on any desirable network with any SIM tease. In countries where the phones are not subsidised, e.g., India, Israel and Belgium, all phones are unbarred. Where the phone is not locked to its SIM card, the users can easily switch networks by plainly replacing the SIM card of one network with that of another while using only one telephone. This is distinctive, for exemplar, among users who may want to optimise their carrier ‘s traffic by different tariffs to different friends on different networks, or when travelling internationally. In 2016, carriers started using the concept of automatic SIM reactivation [ 43 ] whereby they let users reuse expired SIM cards alternatively of purchasing new ones when they wish to re-subscribe to that operator. This is particularly useful in countries where postpaid calls dominate and where competition drives high churn rates, as users had to return to a aircraft carrier denounce to purchase a raw SIM each time they wanted to churn back to an operator .
normally sold as a product by fluid telecommunication companies, “ SIM-only ” refers to a type of legally binding narrow between a mobile network provider and a customer. The contract itself takes the class of a accredit agreement and is subject to a accredit check. Within a SIM-only narrow, the mobile network provider supplies their customer with just one part of hardware, a SIM card, which includes an agree sum of network use in exchange for a monthly payment. Network custom within a SIM-only contract can be measured in minutes, text, data or any combination of these. The duration of a SIM-only narrow varies depending on the cope selected by the customer, but in the UK they are available over 1, 3, 6, and 12-month periods. SIM-only contracts differ from mobile earphone contracts in that they do not include any hardware other than a SIM batting order. In terms of network custom, SIM-only is typically more cost-efficient than other contracts because the supplier does not charge more to offset the price of a mobile device over the contract period. The short shrink length is one of the cardinal features of SIM-only – made possible by the absence of a mobile device. SIM-only is increasing in popularity very cursorily. [ 44 ] In 2010 pay monthly based mobile call subscriptions grew from 41 per cent to 49 per cent of all UK mobile phone subscriptions. [ 45 ] According to german inquiry company GfK, 250,000 SIM-only mobile contracts were taken up in the UK during July 2012 alone, the highest figure since GfK began keeping records. Increasing smartphone penetration combined with fiscal concerns is leading customers to save money by moving onto a SIM-only when their initial contract term is over .

Multiple-SIM devices [edit ]

double SIM slots as shown on a chinese telephone double SIM devices have two SIM card slots for the consumption of two SIM cards, from one or multiple carriers. Multiple SIM devices are banal in developing markets such as in Africa, East Asia, South Asia and Southeast Asia, where variable star bill rates, network coverage and speed make it desirable for consumers to use multiple SIMs from competing networks. Dual-SIM phones are besides utilitarian to separate one ‘s personal telephone number from a business telephone issue, without having to carry multiple devices. Some democratic devices, such as the BlackBerry KeyOne, have dual-SIM variants ; however, dual-SIM devices were not park in the US or Europe ascribable to lack of demand. This has changed with mainline products from Apple and Google featuring either two SIM slots or a combination of a physical SIM slot and an eSIM .

Thin SIM [edit ]

A GPP-branded SIM interposer used to circumvent network restrictions on carrier-locked iPhones A thin SIM ( or overlay SIM or SIM overlay ) is a very thin device shaped like a SIM card, approximately 120 microns thick. It has contacts on its presence and back. It is used by sticking it on top of a regular SIM batting order. It provides its own functionality while passing through the functionality of the SIM card underneath. It can be used to bypass the mobile operating network and run custom applications, particularly on non-programmable cell phones. [ 46 ] Its acme surface is a connection that connects to the call in place of the normal SIM. Its bottom airfoil is a connection that connects to the SIM in identify of the phone. With electronics, it can modify signals in either direction, thus presenting a modified SIM to the telephone, and/or presenting a modified call to the SIM. It is a exchangeable concept to the Game Genie, which connects between a plot console and a game cartridge, creating a modify game. similar devices have besides been developed for iPhones to circumvent SIM calling card restrictions on carrier-locked models, therefore allowing otherwise SIM-locked iPhones to accept SIM cards other than the ones they were authorised to accept. [ 47 ] In 2014, Equitel, an MVNO operated by Kenya ‘s Equity Bank, announced its intention to begin issuing reduce SIMs to customers, raising security concerns by contest, peculiarly concerning the guard of mobile money accounts. however, after months of security testing and legal hearings before the nation ‘s Parliamentary Committee on Energy, Information and Communications, the Communications Authority of Kenya ( CAK ) gave the bank the park light to roll out its thin SIM cards. [ 48 ]

See besides [edit ]

References [edit ]

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