Talk:SIM card

Merger proposal
There is a separate article for micro-SIM that replicates some of the text and images from this main article. Is there any opposition to merging these two articles? --Rubena (talk) 00:31, 28 March 2010 (UTC)


 * I agree that they should be merged. So far as I can see the only thing that separates a "micro-SIM" from a "SIM" is the physical size. (After the articles are merged, I might be sufficiently motivated to add appropriate references to ISO/IEC 7810 for the sizes.) Mitch Ames (talk) 01:36, 28 March 2010 (UTC)


 * It turns out that the table of sizes is a template, included in both articles, so I've added the 7810 sizes. If SIM and micro-SIM are merged, the template should probably be deleted and its contents moved into the merged article. Mitch Ames (talk) 03:09, 28 March 2010 (UTC)


 * Disagree The differences between the 3FF (micro-SIM) and the previous SIM, the Mini-SIM, are much more than just making the physically card smaller. I could do that with a pair scissors. One of the main additions is the ability to authenticate the cellular towers that it's connecting to where as previously only the tower authenticated the SIM card; (ex: unregistered Femtocells like magicJack's, cell network spoofing attacks, or GSM SIM card unlocking) beyond that, there are many other underlying changes to the chip, which should go into its article. I expect the mico-SIM article to have a strong up-tick as the iPad is released in the coming weeks and people coming to wikipedia for info are interested mainly in what the micro-SIM is and why it's different from the SIM currently in their cell phone and therefore deserves its own article. Justin Ormont (talk) 04:58, 28 March 2010 (UTC)


 * If the articles are kept separate I suggest that the Other SIM sizes section be deleted from micro-SIM, because it is not relevant if all micro-SIMs are the same size (15x12mm). Mitch Ames (talk) 09:05, 28 March 2010 (UTC)


 * I support the merge proposition... Justin, i'm sorry but a 3ff card is exactly the same as most uSim cards. in the only source used to justify the differences, all so-called "new features" described are on the UICC, i.e. the smartcard circuitry which equips uSim, as you can see in  or ... And i think GSMA is a reliable source in the SIM card domain, isn't it ?
 * 3FF card size is defined in ETSI 102 221, available at no cost online on http://etsi.org/ and, as you can see, UICC is not limited to 3ff card. Zeugma fr (talk) 16:28, 7 April 2010 (UTC)
 * Thanks for the ETSI 102 221 reference. I've updated SIM Card sizes to include it. Mitch Ames (talk) 01:55, 8 April 2010 (UTC)
 * One more point : Micro-SIM real name is 'Mini-UICC'... —Preceding unsigned comment added by Zeugma fr (talk • contribs) 16:45, 7 April 2010 (UTC)
 * Good point. I'm thinking about updating SIM Card sizes with the names from ETSI TS 102 221 (ID-1 UICC, Plug-in UICC, Mini-UICC) but that should really be done at the same time that all references in the articles (including the title) are updated/merged. Mitch Ames (talk) 02:01, 8 April 2010 (UTC)


 * Should the UICC article be merged with SIM/Micro-SIM as well? Mitch Ames (talk) 02:01, 8 April 2010 (UTC)
 * I don't know for sure, even if i work in the smartcard/telecom domain (i've been working for Ingenico, Gemalto, now working for Xiring). The naming subject is a mess, even inside well-known industry actors. The general convention is that the general subject you're working on helps you to pinpoint what you're talking about.
 * For example, the acronym SIM originally describe the circuitry used for subscriber authentication, and does not necessary need to be a smartcard. UICC is more precise, it contains CC, which tells that it is a circuitry on something removable.
 * Usage have made the terms recovering multiple subjects, for example, SIM can now be replaced by SIM-circuitry, SIM-Card format, SIM-application toolkit (API), ...
 * the good practice, when writing specifications or norms, is to describe precisely what you are talking about, for example "UICC module on ID-000 card, with UMTS masks". But this is not correct for general public or common acceptance.
 * If i was responsible for a reorganization, i would do this :
 * SIM would describe the original SIM card, format ID-1 and ID-000, limited to GSM/GPRS, and would point to a uSIM_(telephony) article for UMTS/CDMA/3G matters
 * UICC should be a link inside the uSIM article,
 * UICC should still be a separated article, as the UICC circuitry can be found in different forms (usb key, micro sd card... see http://www.gemalto.com/uicc_role/form_factors.html).
 * Mini-UICC or Micro-SIM would be a paragraph inside the uSIM article.
 * I just saw that the disambiguation page uSIM is correct...
 * This is just my NSH opinion.... Zeugma fr (talk) 13:38, 8 April 2010 (UTC)

Suggestions to "Usage in Mobile Phone Standards" section
In this section, I noticed the second sentence reads, "The equivalent of a SIM in UMTS is called the Universal Integrated Circuit Card (UICC), which runs a USIM application, while the Removable User Identity Module (R-UIM) is more popular in CDMA-based devices e.g. CDMA2000."

HOWEVER, that is not entirely true if you compare that with the UICC entry at that says, "In a GSM network, the UICC contains a SIM application and in a UMTS network it is the USIM  application."

Therefore to reads like the UICC is the physical card itself while the application is what identifies the card as SIM or USIM.

Maybe that sort of distinction/clarification should be made somewhere?

Theharlans (talk) 15:18, 22 June 2010 (UTC)Thanks, Jim.

Sim cutter
I removed
 * A device manufactured by NooSY Apple has now been released allowing the conversion of mini-SIM cards to micro-SIM cards via a mechanism not unlike that of a hole-puncher.

there's no way this belongs in the lead, which is intended to summarise the article and should only have key points. I question if this belongs at all. Perhaps brief mention of the existance of sim cutters but I don't see the need for any particular brand. Cutting a sim is hardly neuroscience and inventing one is hardly going to win you the nobel prize. I have my doubts most designs are even patentable. There are already lots of different variants and probably just going to be more as time grows on Nil Einne (talk) 08:22, 1 August 2010 (UTC)


 * ... and by far the cheapest design is a pair of scissors! 86.161.56.74 (talk) 15:07, 18 July 2011 (UTC)

IMSI vs. ICC-ID
Why is there a mobile station identification number inside the IMSI when there also is a individual account identification number inside the ICC-ID? Shouldn't one of them suffice? --Abdull (talk) 15:14, 5 January 2011 (UTC)


 * You may have multiple ICCIDs per single IMSI and this is potentially useful for IMSI reuse, when contact terminates (postpaid) or when "post grace" period ends (prepaid). Mobile operator may order new SIM card to be manufactured for the same IMSI with different ICCID, and keep KI, ADM1, SPC, PIN1, PUK1, PIN2 and PUK2 for both old and new SIM cards in its billing (most often old data are of historic interest only, because operator doesn't have physical access to the old SIM card anyway) --xrgtn (talk) 15:11, 26 April 2011 (UTC)

ICCID is not the same as IMSI
Reader beware!

24.87.67.125 (talk) 19:38, 6 January 2011 (UTC)

Possible errors in section: Authentication Key?
The current article states: "In practice, the GSM cryptographic algorithm for computing SRES_2 (see step 4, below) from the Ki has certain vulnerabilities[citation needed] that can allow the extraction of the Ki from a SIM card and the making of a duplicate SIM card."

My understanding is that the function used to derive SRES_2 from Ki is not specified in the GSM standard; rather, it is left to the operator to define this.

COMP128 is one implementation of the A3/A8 function that has been broken thereby allowing an attacker to derive Ki from a number of SRES_2 responses. IIRC, the implementation of COMP128 did appear in the GSM specs but as an example of a possible function for deriving Ki; It is not is mandated by GSM (which I see as implicit in the quoted text above.)

Should we clarify this? — Preceding unsigned comment added by 90.219.242.155 (talk) 23:06, 10 June 2011 (UTC)

Requested move

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the move request was: page moved. Vegaswikian (talk) 00:46, 3 January 2012 (UTC)

Subscriber Identity Module → Subscriber identity module – Correct capitalisation, per WP:TITLEFORMAT. The requested title already exists as a redirect, but I think the two should be swapped. Mitch Ames (talk) 07:33, 27 December 2011 (UTC)


 * Support, at least in the absence of any evidence that capitalisation is warranted. N oetica Tea? 22:02, 28 December 2011 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Removal of SIM adapters
Note: Care must be taken when removing a SIM adapter from a standard GSM SIM holder as it might bend or break SIM connector pins. I learnt it myself when I broke the pins. I found out on internet that this is a common mistake and many people have and are experiencing it. — Preceding unsigned comment added by 113.161.106.50 (talk) 03:00, 7 June 2012 (UTC)

Nano SIMs
Now that ETSI have announced the official Nano SIM standard, shouldn't there be some detailed mention of the upcoming Nano SIMs, apart from on the table? Khairul Islam 04:11, 6 July 2012 (UTC)

Sic transit gloria mundi
http://www.forbes.com/sites/parmyolson/2013/07/21/sim-cards-have-finally-been-hacked-and-the-flaw-could-affect-millions-of-phones/

Someone want to put a dollar figure on that? EllenCT (talk) 23:21, 25 July 2013 (UTC)

Incorrect citation and link
This article says, "As required by E.118, The ITU regularly publishes a list of all internationally assigned IIN codes in its Operational Bulletins. The most recent list, as of June 2012, is in Operational Bulletin No. 1005."

But OB 1005 does not in fact have a list of IINs. The current list is now in OB 1040 (pages 13--86) which was issued in 2013 November. It is updated frequently as issuers are added, deleted, et cetera.

http://www.itu.int/dms_pub/itu-t/opb/sp/T-SP-OB.1040-2013-OAS-PDF-E.pdf

--71.178.95.236 (talk) 02:39, 4 January 2014 (UTC)

Duo Sim card
I have no real technical knowledge of SIM cards, but recently received a "duo" sim card which was a "standard" SIM card with a micro SIM card emebedded in it. After a bit of head scratching looking at Wikipedia & Googling I discovered that you can renove the micro card, which is what I needed to do to fit it into my tablet. I feel that there should be a possibly brief mention of this in this article so that people don't search in vain.

Jrvzn (talk) 11:00, 22 August 2014 (UTC)

The company MicroSim
What happened to the company MicroSim that made PCB schematic capture and board generation, and circuit simulation simulation software? Thanks, Chris Arena Portsmouth, Rhode Island 68.9.188.136 (talk) 19:06, 25 September 2014 (UTC)

Which field corresponds to the 'user-known' number for the SIM?
Asking because I have a SIM sent to me by a UK phone provider that works for sending and receiving calls, but has a 'blank' phone number -- so my phone (Android) cannot tell me the number of my phone, and apps (such as Google Contacts) cannot, either -- and some are quite confused [AKA: crash].

It would be quite helpful if the article made it clear where this number is stored, so a reader can use the correct terminology when trying to get the service provider to understand the problem. quota (talk) 20:06, 29 October 2014 (UTC)

Universal SIM by Apple
The Apple iPad Air2 uses a fixed, build in SIM card, called Universal SIM based on Apple Patents from 2010. It would be worthwile to identify differences to the eUICC projects by GSMA. http://www.teltarif.de/apple-universelle-sim-mobilfunkmarkt-netzbetreiber-ipad-air-2-iphone/news/57663.html joooo 7:36, 19 January 2015 (UTC)

Ki vis-à-vis Ki
What does Ki actually mean, mathematically? Pronounce it, for starters. kencf0618 (talk) 17:00, 21 February 2015 (UTC)

Dual-SIM section
I don't understand this sentence in the Multiple-SIM Devices section: "In the Western world dual-SIM devices are less common, and even less so with multiple-SIM phones, but are commonplace in developing markets such as..." In particular, the sub-clause, "and even less so with multiple-SIM phones". Perhaps the writer intended to refer to phones with more than two SIM cards, but this is not what it says. A dual-SIM device is by definition a multiple-SIM device, so the statement that a multiple-SIM device is less common than a dual-SIM device is logically invalid. I changed this around to improve the logic and syntax, and corrected the Western bias by describing where it is more common (i.e. developing world) before where it is less common (Western world). An enterprising editor may wish to draw from the references in the Dual SIM article to strengthen, clarify, and verify this section. --RealGrouchy (talk) 03:17, 12 August 2015 (UTC)

NFC-SIM section

 * We need one;
 * Is it just an extension of VAS?
 * There is no NFC hardware on the sim, it's just a secure way to store credit card numbers for offline use.
 * Where is the specification? — Preceding unsigned comment added by Tim@ (talk • contribs) 15:10, 11 September 2015 (UTC)

External links modified
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M2M search redirects here instead of the "Machine to machine" page.
I would change the redirection myself if I knew how. — Preceding unsigned comment added by DreamsOfGenies (talk • contribs) 22:58, 3 October 2016 (UTC)

Double SIM ?
I read in various articles about mobile phones that some of them have "double-SIM". What in the world is that ? --Jerome Potts (talk) 21:08, 10 November 2016 (UTC)

CPU
As far as I know, SIMs contain a CPU. Most of them seem to use an 8-bit AVR core although a number use the ARM7TDMI and ARM has introduced the SecurCore SC300 CPU cadenced at 25MHz. The SC has very granular memory management unlike existing cores. Since the CPUs run the Javacard machine, the fact that vendors describe SIMs as supporting 'Javacard Classic' means that their are ways to exit Javacard. Apparently R0=R1=$FFFF followed by bytecode $FF exits the machine but of course, you don't know what language it drops into.

Defcon 21 has a detailed explaination of how to develop Javacard applets. For their example, the applet could be signed by them but I am unsure how commercial SIMs decide if an applet is authentic and should be allowed to run. It seems very likely that their will be a master key. Android's master key was discovered and I'm prepared to bet that an appropriate SIM with known CPU could exit Javacard and download the entire ROM & RAM of said SIM. If someone discovers the master key, a SIM vector could infect everyone in someone's phonebook via SMS (applets are installed via SMS). The only positive use I can think of is to introduce MESH to aid communications during serious events. Otherwise, it would only be a method of calling a premium number an defrauding people - something that needs to be analysed as a risk.
 * Yes. Just like Minix OS used in all Intel SoC and chipsets, all SIM cards run what is called a COS, card operating system, written in C and assembler. See example code here https://github.com/kuriel07/YCOS. And it has nothing to do with Javacard. It is the firmware of the ucontroller, that does elementory files structure and all crypto algorithms. Valery Zapolodov (talk) 15:40, 7 May 2021 (UTC)

Proposed merge with Overlay SIM
Very closely related short article. Derek Andrews (talk) 11:40, 28 July 2017 (UTC)
 * I can support this. Came across the Overlay SIM article via the New Pages backlog - it's very short, and the information it contains would be more useful for people reading this article. -- Cheers, Alfie. (Say Hi!) 11:56, 23 January 2018 (UTC)
 * I also support this. Would make logical sense in the Formats section. = paul2520 (talk) 13:27, 24 January 2018 (UTC)
 * Support Overlay SIM doesn't need a separate article and would be better off merged into this artice. VibeScepter (talk) (contributions) 18:12, 2 April 2018 (UTC)
 * ✅ Klbrain (talk) 20:59, 24 November 2018 (UTC)

Volume of a SIM?
I find the table of SIM card sizes quite useful, except for the column "volume". Not only does it smell of WP:OR, I can't see why it would be important or even interesting to any reader. The word "volume" appears nowhere else in the article (nor in Talk, current or archived) and I can't guess at its importance. Does anybody care about SIM card volume? Shall I remove the column? &mdash; JohnFromPinckney (talk) 06:09, 12 October 2018 (UTC)
 * Having not heard any dissent or explanation I have removed the "Volume" column. I've also taken the opportunity to adjust the table toward MOS:ACCESS. &mdash; JohnFromPinckney (talk) 22:18, 18 October 2018 (UTC)

Requested move 24 January 2019

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this section. 

The result of the move request was: moved. (closed by non-admin page mover) feminist (talk) 08:33, 31 January 2019 (UTC)

Subscriber identity module → SIM card – Pretty much every publication I've read that talks about phones calls them SIM cards, and looking at the titles of the current citations used confirms this. For additional proof of it as a WP:COMMONNAME, some fairly recent links to usage in major tech publications: Wired, The Verge, Techcrunch, Ars Technica, Engadget, ZDNet, Mashable, PCMag. The reason the title should include "card" is because it is a natural disambiguation. Opencooper (talk) 06:29, 24 January 2019 (UTC)
 * Support In ictu oculi (talk) 09:12, 24 January 2019 (UTC)
 * Support. 62.165.227.102 (talk) 12:09, 24 January 2019 (UTC)
 * Support per commonname.--Staberinde (talk) 17:53, 24 January 2019 (UTC)


 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

In the US, the initialism BYOD is used instead of SIM-only
I haven't seen the term SIM-only here in the US. I've seen BYOD (for bring your own device) instead. It would be nice if the article mentioned this. (Of course, a source is needed for this; unfortunately, I don't have one.) I'll add that it seems odd to me that a provider would require a customer to agree to a contract for a SIM-only deal. I think BYOD contracts don't exist in the US; if this is accurate, perhaps this should be added to the article, too. -⁠-⁠184.248.207.170 (talk) 22:17, 2 May 2019 (UTC)

A Commons file used on this page has been nominated for speedy deletion
The following Wikimedia Commons file used on this page has been nominated for speedy deletion: You can see the reason for deletion at the file description page linked above. —Community Tech bot (talk) 00:22, 4 August 2019 (UTC)
 * SIM Card Types Movistar Colombia.jpg

A Commons file used on this page or its Wikidata item has been nominated for deletion
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 * Dual-SIM-eSIM.jpg

Location Area Identity
As non-expert the following statement about the LAI doesn't make much sense:

> When the device changes locations, it stores the new LAI to the SIM and sends it back to the operator network with its new location.

1) "with its new location" -> If "new location" refers to the LAI, which can be assumed, what does "it" refer to in "sends it back"?

2) The UE receives the LAI from the network I suppose (whether or not this is correct is missing in this section, but I wouldn't know from where else), so why would the UE send information back to the network that it received from the same network in the first place? Alestrix (talk) 09:47, 16 November 2022 (UTC)

Add a pure software SIM as a development?
In 2023, Onomondo launched SoftSIM, a 100% software-based SIM solution for Internet of Things devices. Instead of adding more hardware to embedded devices, SoftSIM is set to go beyond eSIMs by being downloaded from the cloud onto existing microcontrollers. It is initially being launched on SIMCom's A7672X series, Fibocom's MA510 modules, and Nordic Semiconductor's nRF9160 System-in-Package (SiP).
 * That is what SoftSIM is. It is a new form factor of SIM card. So, like 1FF, 2FF, 3FF, 4FF, MFF2, iSIM, and nuSIM mentioned in this article, it is a product to be sold but also a SIM form factor. In fact, it is a form factor without form, making it rather special and noteworthy, in my opinion.
 * Would it make sense for a subject matter expert to weigh in before you continue your crusade of e.g. deleting the Onomondo company stub? Mikeindenmark (talk) 08:26, 20 March 2023 (UTC)
 * That is what SoftSIM is. It is a new form factor of SIM card. So, like 1FF, 2FF, 3FF, 4FF, MFF2, iSIM, and nuSIM mentioned in this article, it is a product to be sold but also a SIM form factor. In fact, it is a form factor without form, making it rather special and noteworthy, in my opinion.
 * Would it make sense for a subject matter expert to weigh in before you continue your crusade of e.g. deleting the Onomondo company stub? Mikeindenmark (talk) 08:26, 20 March 2023 (UTC)
 * Would it make sense for a subject matter expert to weigh in before you continue your crusade of e.g. deleting the Onomondo company stub? Mikeindenmark (talk) 08:26, 20 March 2023 (UTC)