What is a SIM Card?
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A SIM card or Subscriber Identity Module is a portable memory chip used in some models of cellular telephones. The SIM card makes it easy to switch to a new phone by simply sliding the SIM out of the old phone and into the new one. The SIM holds personal identity information, cell phone number, phone book, text messages and other data. It can be thought of as a mini hard disk that automatically activates the phone into which it is inserted.
A SIM card can come in very handy. For example, let's say your phone runs out of battery power at a friend's house. Assuming you both have SIM-based phones, you can remove the SIM card from your phone and slide it into your friend's phone to make your call. Your carrier processes the call as if it were made from your phone, so it won't count against your friend's minutes.
If you upgrade your phone there's no hassle involved. The SIM card is all you need. Just slide it into the new phone and you're good to go. You can even keep multiple phones for different purposes. An inexpensive phone in the glove compartment, for example, for emergency use, one phone for work and another for home. Just slide your SIM card into whatever phone you wish to use.
High-end cell phones can be very attractive and somewhat pricey. If you invest in an expensive phone you might want to keep it awhile. Using a SIM card, it is even possible to switch carriers and continue to use the same phone. The new carrier will simply issue you their own SIM card. The phone must be unlocked, however, and operate on the new carrier's frequency or band.
A SIM card provides an even bigger advantage for international travelers -- simply take your phone with you and buy a local SIM card with minutes. For example, a traveler from the U.S. staying in the U.K. can purchase a SIM card across the pond. Now the phone can be used to call throughout England without paying international roaming charges from the carrier back home.
SIM cards are used with carriers that operate on the Global System for Mobile Communication (GSM) network. The competing network is Code Division Multiple Access (CDMA), a technology created by U.S. company Qualcomm. As of fall 2005, CDMA cell phones and CDMA carriers do not support SIM cards in most parts of the world, though this is changing. A CDMA SIM card called the R-UIM (Re-Useable Identification Module) was made available in China in 2002, and will eventually be available worldwide. Expectations for the future include a cell phone market that supports both SIM (GSM) and R-UIM (CDMA) cards by default.
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102
i'm on a two-year contract with AT&T that doesn't expire for another 16 months. i recently won a free $300 Verizon phone, so i'm wondering if Verizon phones have SIM card slots. - anon51135
101
how can i clean a vodaphone simcard for samsung mobile? - anon49459
99
What does SIM card stand for? Please explain. - anon49086
98
my sim card blocked itself and i don't want a new number. =( - anon48765
96
I just dropped my phone in water and my sim card doesn't work. can I buy a new sim card with the same number? I've had it forever and dont want the hassle of giving my new number to everyone. - anon48406
95
I use a RoamForce SIM card for international calls and blackberry data. - anon46583
94
is there a sim card on my L7c motorola phone? - anon45996
93
can i text using a sim card on my phone? - anon45525
92
Hello. Where is the simcard on a virgin mobile AudioVox model phone? I opened up the back of the phone where the battery is located but I don't see anything like what is being described. - anon45021
91
what is meant By LAPU balance or USSD balance regarding talk time in the telecom industry? - anon44434
89
I have a "MagicJack" which works fantastic. GoogleVoice now offers a free service to forward any of your phone numbers to your MagicJack number. Could I buy SIM card for the sole purpose of switching my existing number to the SIM card? If so, I could use the Google service to forward my existing number to the newly assigned MagicJack number - wow, what a deal. - wkoeller
87
I now use a Motorola W376g cell phone, which has a camera and a sim card. I had a nice photo taken, but I was so thrilled to have such a nice photo on my cell phone that I did not press the key under the word "Store". That photo is very important to me, and I feel like an idiot for making such a stupid mistake. Is the photo gone for good, or is it on the sim card? If it is on the sim card, how do I access it? (Yes, I have looked in the multimedia-pictures section of my camera, and the photo is *not* there.)
(I also seem to have lost another photo. In that case, I did press the key under the word "store", but I did not click on store only on the next screen. Is that photo gone forever as well?) Thank you. I feel like an idiot! - anon43239
86
can i use an att sim card with verizon wireless phone (the Alias 2) please answer! - anon42660
85
sim card cloning is possible? if yes please suggest software or site ID. - anon41689
84
How do I get my photos out of my old Verizon wireless LG phone? I'd like to either transfer the photos to my computer hard drive if possible.
I closed my Verizon account and now have an ATT account with a Samsung phone. The old phone did not have a SIM card, so this method is not an option.
- verlapacheco
82
how do i save my stuff in to my simcard? - barrios13
81
i got an ATT phone. i put my sim card in to the motorola racer phone and it says locked. how did i unlock the motorola to use my sim card in there? is that possible? - anon40736
80
If you want to use your sim in a phone of another carrier, the phone of the other carrier needs to be unlocked to work. - anon40459
79
I have the same question as no 63. I try it. it will not take it. what am i doing so wrong? - anon40335
78
I have a SAMSUNG phone with Verizon service. If I understand correctly, I cannot use (put) a SIM card in this phone. I want to keep this phone. I will be in Europe (Belgium, Italy and France) for about 3 weeks and need a cell phone. What would you recommend that I do re phone, sim card(s?), charger etc. that would be the most economical way.(ie. buy an inexpensive phone for trip that takes a SIM card? rent a phone?)I will not be using the phone to call the United States. I am really ignorant on this subject so I appreciate any info. Thank you. - anon39352
77
sim cards are a pain in the butt! All the things that they are good for i can do without. No sim card would be fine with me. - anon38432
76
My daughter, in error, deleted some very important text messages. She has a motorola Razr cell. Is there any way that the deleted texts can be retrieved? - chris32450
74
I have a SIM card already, but I owe them lots of money. So I want to get a new sim card and do a pay as you go. Would that be possible? Also what kind of information do they ask when you want to activate a new sim card. - anon35471
72
i currently have a sprint/nextel phone that has a sim card. i want to get a new phone, but many that i look at don't have a sim card. can/how do i transfer my sim card to a phone that doesn't use one? - lilhoneybr
71
Ok, so my big enormous moose of a bloodhound ate my hubby's new phone. Literally put a tooth mark right through the battery. So since his contract is not up until November, to get a new phone I went and bought a go phone from walmart. Since it is the same network and takes a sim card as well. When I went to checkout the clerk said that there is a "possibility" that since we have a paid plan and this is a pre-paid phone that inserting my hubby's sim card it could "blowup". Of course this scares the dickens out of me. Does anyone know if this is true. I have used both types of phones before and interchanged my sims as well. But is there something new on the phones that could cause me a problem? Thanks. - anon34549
70
is there anyway to lock a sim card so it can't be used in another phone? also can my phone be locked so that no other sim card will work in it? - anon34301
69
I am in the process of buying an A008 T-Mobile PDA phone that has a dual sim card slot. I want to use the 2nd slot for pre-paid internet service. Is this possible and can you recommend a good inexpensive provider. Thank You! - kabrock
68
I have service through Cincinnati Bell. I want to buy a phone that is offered through AT&T. Can I just put my SIM card in and use this other phone? - vjnapier
67
i got a new iphone and want to give my old 2g to my mom. she has a pre-paid phone and when i insert that sim into the iphone and try to set up the number onto the phone through itunes it will not work. i think it's because iphones have to have the internet and since her sim is pre-paid it is not allowed. is there any way around this? any app or anything i can do? Thanks - anon31318
66
verizon and sprint are CDMA. they don't use Sim Cards, unless it's a phone that's compatible with oversees travel. they have ones that give you service access abroad. otherwise, they use ESN numbers to assign your account to your phone, so it's not as easy as AT&T and such where you just swap your card to swap your phone. - anon30908
65
Can a sim card work on my sidekick? lx
- anon29931
64
can i use the sim card from a nokia 6085 to nextel I530? - anon27846
63
Can I take the SIM card from my AT&T phone and put it in a T-Mobile phone that also uses a SIM card? Will it work? I don't plan on switching carriers but I will be without a phone for 2 weeks and needed to know if I can do this as a backup until I get my phone back. - nrbrown
62
Can I have a sim card for two phones? By this I mean like having two phones for the same line in the house? I'd like to have it so my spouse and I could answer the same phone number if need be. Would our cell phone company charge us for two phones or do they usually charge for per phone number? - anonymoose
61
Theoretically, if i have a SIM card, would i then be able to put that into an iphone, even though i do not have AT&T?Also, does Verizon have any phone that use SIM cards or is it possible to have Verizon put your number/plan onto a SIM card? - skiqueen618
60
My old Tracfone doesn't have a sim card & works fine in my area. I wanted to update to a newer Tracfone but can't find one without the sim card. Can you remove the sim card & still operate the phone? The phones with sim cards will not work in my area. - anon24781
59
NO anon711 you need to use your old sim card it will work just fine if you have the old sim card to put in it and IF it is broken the sim card it will not work my mom and my sister both have nokia cellphones and my sister just got a very new one and when she put that simchip in it worked like new... - michael27
58
I desire to access old sim cards as well as unused sim cards both for regular services and secure phones. When accessing these cards, are there security measures that should be taken? It is ok to just cut them up? If sim cards are not destroyed can another user merely insert them and be able to acquire services?
- anon24009
57
I have a contract with searsconnect. Last year my phone burnt out while charging. Thank goodness the SIM Card was okay so I started to use it in another LG Camera phone. It was working great, until I changed my phone to Motorolla from Rogers. Now for some reason I can't seem to call my home phone #. Works great calling everywhere else, but I just can't call home. Called my carrier to fix the problem and they said they can't I'd have to go to rogers, what I wanna know is, could this be the phone that I'm using or the sim card, 'cause when I put my sim card back into the old LG, still couldn't call home. Please help! - anon22796
56
Do you know a Wonderful “do-it-yourself, Plug & Play” sim card for unlocking iPhone 3G to work for any network, any carrier, any SIM card? And also for unlocking Nokia, Motorola, SamSung,Blackberry…etc (lots of brands of mobile) which is locked?
- turbosim
55
Do you know "dual sim card"? which can help your present mobile becomes “dual sim” mobile in 1 minute. Special for the mobile is “Brand mobile phones” which have not dual sim function.
- turbosim
52
My phone broke, so could I go to a store and pick up a GO Phone, and slide the SIM card from my broken one into the new one. I would still be on my contract from my broken phone, right? - footballcraz
51
Virgin Mobile has a website -- find their phone number there and they'll give you instructions to activate your phone. - anon21666
49
my uncle gave me a cell phone he had but never used, and i don't know the number. its a virgin mobile phone, and i tried to click the $ sign but it wont go through. and i cant get to the phone number..how can i find out what the number is so i can put minutes on the phone? please help me..!!!! - anon21051
48
How do I download data (files, photos, etc) from my Blackberry Curve sim card to my laptop?? - dishmandu
47
can i use my cingular sim card in a t-mobile phone? - tray4real
46
i have a blackberry that is supposed to be unlocked. i don't have a carrier. can i put a tracfone sim card in it? would that make it work for now? - marye
45
hello i just wanted to know what exactly a gsm card is, where i can purchase one, how much do they cost, and can i use it in a newer model iphone? i would very much appreciate any answers you may provide :) - anon16287
44
Why does my Blackberry 8330 (Curve) sometimes says SIM card rejected, which is displayed at the top of my screen? This is becoming a hassle, and I have been satisfied with my phone until now. - anon15624
43
Do you have to have a carrier to use an unlocked phone? Can you use a regular phone card that you pick up at the store to call? Does it come with a number in which people call you by? - anon15477
42
I have a LG VX5300 cell phone. Is there any way to download/retrieve the memory, even deleted text messages from my phone to my home computer? - nessfarms
41
hi i have a nokia 6010 that someone gave me. Everything works on it I dont have any service on it. the phone was used in a different area. i know nothing about this phone like if it's prepaid or monthly plan. i would like to get it working so i can use it to make calls. thank you - anon14529
40
hi...i bought cellphone in hong kong the seller told me that its going to worked here in us...but when i got it....its not working...i have t-mobile and no network at all....cant received email or send msgs and cant call or received messages...so dont know what to do! its a nokia n95! - bratinella
39
I have a prepaid Virgin Mobile phone and am interested in getting a Blackberry or other PDA. I was looking at phones on EBay because I have no interest in signing a 2-year contract. I don't think my phone has a SIM card. How do I get a SIM card without having to buy a new phone with one? Thanks! - anon12722
38
I have Sprint service, & I want to get a Motorola v365 ( unlocked ). Will it work with Sprint??
I know about the sim cards, but not that much, Sprint uses CDMA,, right! help me out! thanks - engineer
37
? Verizon uses SIM cards, I thought. If your dog ruined your phone you can still remove the SIM and use it in any new phone. If you really don't have a SIM and it really is Verizon, go to any Verizon outlet with a new [Verizon] phone, or call them, and they will ask for a SN off the new phone and transfer service to it. After a short lag the new phone will be usable but the old one won't. (So if for example, someone wanted to use two phones with a single phone number, it won't work, cause they won't activate the new phone without deactivating the old one.) - anon12635
36
My dogs got ahold of my phone and i want a new one...
I have verizon and since there is no sim card is there a way i can get a new phone without having to update the contract. - anon12328
35
I successfully transferred my Sim card from an old Motorola phone, purchased from Rogers into a Blackberry Pearl. My friend has a Audiovox cell phone, purchased from Bell Mobility and he wants me to do the same thing. However I cannot find a sim card in his phone. Is there one? - anon12321
34
I stop using my SIM card for along time, when i used it again, the screen display insert SIM. Would the service provider lock the SIM if you would not use it for a long time? Would the service provider would unlock it if i want to? - lordpack
33
I purchased a Sony Ericsson Z710i off eBay, the phone worked great when I put in my SIM, after manually entering the MMS and Internet setting. The vibrate on the phone didn't work, so I returned it. They sent me another one, and it looked slightly newer, although, the same model. The problem with this phone, is it would not read my SIM card. AT&T SIMs worked, T-Mobile SIMs worked, but CellularOne, which is now owned by AT&T SIMs would not work at all. WHY? My old deactivated SIM, which has a different circuit print on the SIM itself even registered and allowed the phone to open simply saying "inactive SIM" Emergency Calls Only. Is there a difference with new and old SIMS? T-Mobile, CellularOne/AT&T all use the GSM network, including EDGE technology. Why would one model Z710i work for my SIM, and not the exact model but on a different phone, meanwhile, working for the other SIMs? Help? Any suggestions?
- anon11749
32
I have a 7 digit customer number (6971542)on my current SIM. My service provider will now migrate from 7 digit to 8 digit meaning my new number will be 76971542. I am wondering if my new number will work with my current SIM. - anon11114
31
I have a samsung phone and would like to extract deleted text messages, is it possible because of the sim card? - markaplus
30
The article says that you can swap SIM cards between phones but for that to work the phone you're swapping to has to be unlocked and have the same frequency/band. So what if your friend is on a different carrier or using another frequency/band? How would you know about the band/frequency? If your friend is using the same carrier, that's one thing, but all of us use something different. That kind of makes the SIM not so useful then, except for new phones of course. - anon10407
29
Hi I have a Verizon LG VX8300 phone and I dropped it in the ocean. It is drying right now and i want to know what to do or what is the best thing to do. I need to know where the "SIM" card is on this model. - joemcmahon
28
If I take my SIM card and my memory card out of my phone is there any personal information left on it? - anon9180
27
I need more information about the GSM Sim which you called R-UIM. Who can I talk to, is it now available anywhere? - anon9003
26
I have an old Motorola i860, I have pictures and text messages that I would like to save (the sender is no longer with us). They were on phone but the power died and now they are not on the simcard anymore. What happened ? Can I save them or are they gone forever too? Also I have more pics and texts on a broken Motorola V3m that has no SIM card can I somehow transfer them to my new phone ? please tell me how to do this, they are the only pictures and messages that I have left of her !!
George - gmac280
25
i have a sony ericsson v600i (prepaid) and my mom has just brought a nokia 6110 NAV (cap plan). i want to use the nokia, can i swap SIM cards. - put my prepaid sim card into the NOKIA? - anon8630
23
I have a motorola razr v3 cell phone. Can I get deleted text messages off of my sim card? If so, how? - bucready
22
I have cingular or at&t cell service. I really hated my phone so I went to the local Sam's Club and bought a togo phone which is AT&T. I did take the chip from my phone and put in the togo phone which is more modern than the one I had. Works fine. You can unlock Trac phones to do this too. - anon7408
21
i have a motorola phone that my mom bought for me. i don't know the pin number. so the phone locked. my boyfriend tried to unlock it got mad and broke the sim card. now my phone doesn't do anything. it just says insert sim. if i buy a prepaid sim card, will it still work? even if it was locked before it got broken? - anon6819
20
Does anyone have an answer for the tracfone/bluetooth problem by UF? - unclefred
19
I have a Tracfone and just bought a car with Bluetooth technology. My present phone does not work with bluetooth. Can I buy an unlocked phone and take the sim card from the tracfone and install it in the new phone and have it work in the car? Thanks, UF - anon6190
18
A friend who lives in Texas asked if he could use my sim card to unlock an extra cell phone he had. He stated that he was going to London for a few weeks & wanted to be able to use the phone while he was there & that the only way he could unlock this phone was if he used a sim card from a phone that used AT&T as the carrier. I felt a little uneasy so I told him no. Was this the right decision? Could he have charged calls to my number or would it have simply just unlocked his phone & nothing else? - knun
17
hi, i am considering purchasing an unlocked iphone from ebay and want to know: a) do i just go to T-mobile/cingular and purchase a SIM card and b) if not, do i just purchase a crappy phone with a SIM card in it and use that (and its corresponding services)? I am just trying to figure out the best way to get an iPhone and not use the ATT network. - anon5936
16
where is the SIM card in a virgin mobile 'shorty' (nokia) phone???? - anon5925
15
Thanks for explaining SIM Cards. Knowing I could, I have successfully copied my phone numbers to the SIM Card, and have ordered a new phone to replace my damaged one. When I move the SIM Card, I should be in business. Very useful! - FClark
14
i have a motorola from verizon, and there is this phone i want on ebay from T-mobile (it is unlocked). so is there anyway i could use the T-mobile phone, and use it on the verizon service? if anybody has an answer please let me know. please and thank you (: - anon5671
13
i have a simple verizon phone.. it doesnt have a card with it... and i wondered if there is a way to get a sim card or something from them that i could use in a sidekick, because i want a sidekick but i want verizon still instead of t-mobile... - anon5647
11
Hello. I just upgraded my cell phone that was brought over from Malaysia. Its the same company so it shouldn't have been a problem. i slid my old SIM CARD in and i could make calls. However, i could not top up my phone. Do you know what's wrong? - anon4772
10
i just brought a phone on ebay. I wanted to know what is a triband phone? - anon4659
9
Called my prepaid provider and they warned against inserting a new SIM card in the phone. Won't replacement cards work on prepaids? - anon4185
8
Hi, I am visiting the USA from England for a few months and brought my MOTOROLA V3i with me. I can send text messages but can't make calls. Can I buy a SIM from here to use in it and can you suggest which one I should go for? Thanks - anon3532
7
why is it called re-useable identification?
Is there any phone that supports the two networks? - anon3064
6
what are the processes of making a sim card? - anon3004
5
Can I use the sim card out of my CDMA phone ( if it has one) on my new nokia I just bought on ebay? - anon2537
4
To answer terence123:
Your SIM card should work in any GSM phone so if your sister's phones also use a SIM card they should theoretically work with your SIM card. One thing you need to be aware of is if she didn't get her phone from Cingular the phone could be locked. If it is locked you'll need to contact Cingular or the old carrier that the phone came from to have them help you unlock it. There are also resources online showing how to unlock phones.
To answer Anonymous: Since Verizon is a CDMA carrier (not GSM) their phones don't have a SIM card. SIM cards are used in GSM phones and R-UIM cards are used in CDMA phones (note: R-UIM equipped phones are currently only available in Asia). The chocolate phone you can buy from Verizon, Virgin Mobile, and Sprint is different than the SIM version you get from Cingular, T-Mobile, etc. See the wiseGeek article "What is the Difference Between GSM and CDMA?" for more info. - anon1655
3
Where is the Sim card in a verizon chocolate phone? - anon1336
2
I have a cingular account and a samsung phone. My sister has two newer phones that she wants to get rid of and wanted to know if I wanted them. Will my sim card work in any phone. - terence123
1
Hi, I purchased a used nokia 6103 thru EBay and I need to get a sim card for it. Should I get a new card or a preactivated card? - anon711
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Written by
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Last Modified: 03 November 2009
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