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What Is a SIM Card?

R. Kayne
R. Kayne

A SIM card is the portable memory chip that serves as the “brain” of your cell phone. Its main function is to connect to your carrier’s wireless network, while also holding your phone number, address book, settings, and text messages.

The “SIM” in SIM card stands for “Subscriber Identity Module.” Essentially, it identifies which cell phone user is using a particular device and allows you to access your phone’s communication features, so that you can make calls, send SMS messages, and use mobile internet services like 4G.

Did You Know?

Globally, there are over 7 billion devices that use SIM cards to connect to cellular networks.

A SIM card connects your phone to your carrier's wireless network, allowing you to make calls, send SMS messages, and use 4G.
A SIM card connects your phone to your carrier's wireless network, allowing you to make calls, send SMS messages, and use 4G.

You may have wondered what the long code printed on your SIM card's microchip is all about. That code contains information about the carrier, country of origin, and a unique user ID. It’s also how a phone bill can be attributed to a particular device, based on usage. If a particular user hasn’t paid his or her phone bill, the carrier can stop service to the device.

SIM cards are tied to a particular service provider (carrier) and can only be used with a service plan from that carrier, either with a long-term contract or on a prepaid or month-to-month basis.

Prepaid SIM cards are a good option for people who don’t want to be tied to one carrier with a long-term contract. They are especially useful for frequent travelers who want to use their phone abroad without paying international roaming charges.

SIM Cards, Then and Now

GSM vs. CDMA: What's the Difference?

The SIM card is the "brain" of your phone, storing your phone number, address book, and identifying information.
The SIM card is the "brain" of your phone, storing your phone number, address book, and identifying information.

The history of the SIM card is linked to the development of the GSM (Global System for Mobile Communications) network, which is the global standard for telecommunications. It’s the main network used around the world, especially in Europe, Asia, and Africa. Your SIM card is what allows your phone to connect with a GSM network.

Phones on the GSM network (such as T-Mobile and AT&T) always contain SIM cards, which can be inserted directly into other GSM phones.

The United States also has the CDMA (Code-Division Multiple Access) network, which is mainly used by Verizon and Sprint.

A SIM card often comes pre-cut, so that it can be used as a Mini, Micro, or Nano SIM.
A SIM card often comes pre-cut, so that it can be used as a Mini, Micro, or Nano SIM.

Historically, phones that operated on the CDMA network saved the phone number and other identifying information to the handset itself. While arguably less convenient for users, CDMA handsets have often been heavily subsidized, giving users less incentive to switch phones frequently. As technology changes, however, cell phone providers have upgraded to Long Term Evolution (LTE), which is based on GSM technology. This means that some type of SIM card is likely to be required for devices that use this network.

An increasing number of smartphones support both GSM and CDMA, making it easier to switch networks while keeping the same device.

Why Do SIM Cards Come in So Many Different Sizes?

When SIM cards were first introduced in 1991, they were huge -- about the size of a credit card! Thankfully, they have been getting smaller and smaller as technology develops. Depending on the age of your device, you may have a Standard, Micro, or Nano SIM inside your phone.

Full SIM:

The original SIM of the 1990s was rectangular and roughly the size of a credit card.

Size: 3.37 inches by 2.13 inches (85.6 mm by 54 mm)
Standard (Mini) SIM:

Significantly smaler than the Full SIM, Standard (Mini) SIM cards were used in older mobile phones, such as the iPhone 3G and flip phones.

Size: 0.98 inches by 0.59 inches (25 mm by 15 mm)
Micro SIM :

Micro SIMs are very similar to Standard (Mini) SIMs. The size of the contact is the same, but with less plastic casing around the edges. In fact, Standard (Mini) SIMs can be cut to turn them into Micro SIMs. The Micro SIM became the accepted size with the introduction of the iPhone 4 in 2010, and other phone models quickly followed suit.

Size: 0.59 inches by 0.47 inches (15 mm by 12 mm)
Nano SIM :

Released in 2012, the Nano SIM is the most common size of SIM card in smartphones since the iPhone 5.

Size: 0.48 inches by 0.35 inches (12.3 mm by 8.9 mm)
Embedded SIM (eSIM) :

The latest version of SIM card technology comes embedded in the device and is the tiniest of the lot. You’ll find it in the latest iPhone and Google Pixel models.

Size: 0.24 inches by 0.20 inches (6 mm by 5 mm)

These days, many SIM cards are pre-cut so that you can easily pop out the size you need for your device. There are also adaptors that can be used to make Nano SIMs suitable for older phones designed to hold Standard SIMs. It’s also possible to “trim” down Standard SIM cards to fit the Micro SiM slot on more up-to-date phones, although this can potentially destroy the SIM card.

However, if you get a new phone designed for a different size SIM, it’s easy to port your number to a new SIM card. All you need is a PAC code from your carrier.

If you find yourself temporarily without a SIM card, or one that isn’t compatible with your cell phone, you will still be able to use your phone to make emergency calls, and possibly use certain features such as the camera or apps over WiFi.

Upgrading Your Phone, Swapping Your SIM

One of the biggest advantages of SIM cards is how easily they can be removed from one cell phone and inserted into another, compatible handset.

This makes it very straightforward to activate a new phone by inserting your existing SIM card. Your phone number and personal information is stored on the SIM card, so there's no need to do anything else to transfer this information. However, it’s important to note that most apps are actually stored in the phone's memory or secure digital (SD) card, so they won’t automatically be transferred to the new handset by simply swapping the SIM card.

It used to be incredibly common (especially in the U.S.) for carriers to lock their handsets, so that they would only work with SIM cards provided by that carrier. Service providers would often give customers a discount on their handset in exchange for signing a long-term contract. Handsets can be unlocked with the right code, however, although the exact process varies by manufacturer and model.

It is now standard practice for phones to be sold unlocked, or for the carrier to unlock them at the end of a contract period.

SIM Cards and Security

SIM cards can be locked using a personal identification number (PIN), so that only someone who has the PIN can use the card. If the phone is stolen, it will be unusable without the PIN.

In addition, the SIM card has an authentication code and an encryption key that protect the phone's transmissions. Because of the way the encryption information is transmitted to the carrier, it's usually necessary to have physical access to the SIM card in order to copy it.

The Future of SIM Cards

The future of SIM card technology has already begun to make the tangible “card” obsolete, instead replacing it with a chip embedded on the device's circuit board that carries out the functions of the Nano SIM, and more. The eSIM is an example of this futuristic technology that allows users to switch carriers without having to get a new SIM card. The iPhone 11 and the Google Pixel 4 already use eSIM technology, in additional to having a Nano SIM.

Many of the latest smartphones also feature

Dual Sim

technology, which allows you to insert two SIM cards into the same devices (or have one eSIM and one Nano SIM), allowing the same device to serve two different phone numbers, either on the same network or on two different networks. Dual SIM handsets are particularly popular with people who use the same device for both personal and business use, and want to keep their calls and phone bills separate, or international travelers who have a domestic SIM and a foreign SIM.

Discussion Comments


I purchased a freedompop sim card and was able to get free sim only service, $0/month. It works okay so far in Arizona.


Why would you use a sim card in your car media?


Does a SIM card save photos?


There is a sticker blocking the spot where a sim card should be. Can I remove this sticker and install my sim card from another phone?


My wife has an old LG VX5400. She cannot let go of this due to pics that are dear to her. Is there a sim card in this phone that can be recovered and reload pics onto a computer for safe keeping? I'm willing if this is possible? Help! Aloha, jo


We have purchased two Samsung Android phones. We had two Samsung flip-top phones. Our question: is all of our "info" stored on the phones or the sim cards, and can we retrieve it using new sim cards or not?


I have a Samsung Prevail through boost and would like to switch to straight talk because of coverage issues. Is it possible to do so and keep same phone number?


I have a samsung mobile and I am using an old bsnl sim to open the internet but it was not opening and showing a connection error, so how can I use the gprs on my phone? I have all internet settings so give me a solution.


Why does a sim card's corner look like a folded corner?


How do you erase an assigned number to a pre-paid SIM card?


I am not tech savvy AT ALL so I am confused all around. I just two days ago decided to buy two prepaid

phones from Straight Talk: the Samsung Galaxy Precedent-Androids with the unlimited phone plan cards for $45. Now I'm reading bad reviews on the phone and would like to get an unlocked phone. What do I need besides the phone itself? And can I use the Straight Talk phone card on an unlocked phone since it is non refundable?


Does a sim card have storage memory? If it does, then how big can it be?


I have a samsung b2100 and I would like to know why my deleted texts are not being saved to the sim card. Is it not the default setting in this phone? I can't find any way to check this out in the settings, but then I am a complete technophobe. My sim card is a Vodafone card.

I am trying to get some texts I deleted in error and thought that a sim recovery kit would work for me but it didn't. It only found 15 messages and none of them were deleted ones. Does anyone know? Thanks so much.


I have a Blackberry 8330 that has no SIM card slot -- only a MicroSD card slot. Is it possible to convert or add a sim card slot? please help.


My SIM card has been broken in half and so now i can't use my phone. If i order a new phone on the same mobile provider, is there any way of keeping my existing mobile number? I have looked up PAC codes but am not sure if this is necessary to obtain if i'm not switching mobile providers. Can't seem to find the answer on the web!


GPS Tracking Systems are now being designed with SIM cards to transmit data in real-time.


I tried to change the sim care in one net10 phone to another net10 phone and it said sim rejected, so changing the sim from one phone to another don't work.


I'd like to know if all hi-end phones(including Blackberry) have a dual sim or would i need to look for that make?


Very good article. I think I will sign up after this. But this should clear the confusion of a lot of people. You deserve a pat on the back.

P.S. Should I get the LG Xenon, Pantech Laser, LG Vu, or the Samsung Eternity. I have enough to buy any of those but can't decide.


i have a new iphone 4 but i do not want to purchase the new data plan if i have an old att plan but not with a smart phone. can i just switch the sim card?


where can i get a double memory card.


I will be traveling to Germany and have a samsung/ verizon cell phone. I would like to be able to make calls to US and within Germany while I'm there and from here. What do you recommend?


well i punched my phone and broke the screen and i want to switch to a different phone and i have a two year contract. will it work?


This straight talk cell phone service is trying to tell me their sim card won't work on any other sim card gsm phone.


I have a Cellular phone (NOKIA-Model 3230) using a SIM card. now I moved to other country (in a short time) for job, with mobile system operated by 3G CDMA. Could I connect to the network of entire country (I took roaming service in my home country)? And by what way?


Want to purchase a motorola i9. thank God i did not. Was told my sim card will not work in this phone and I would have to get a new sim card to run it. Is this true?


is it possible that an SIM card is consuming the power?

I have had a GSM SIM card and for a few days i am feeling that my mobile phone battery required charging more frequently, earlier i was charging the mobile battery once in two days, now i have to re-charge twice in a day.

i have replaced the original new battery in my hand set but the result was the same.

i thought my mobile hand set has some problems. i have procured a new hand set but still the result is the same. can someone explain what is happening and how i can solve this problem? --SCandal, India


what we have to do to buy a sim card?


why we can't use a sim card as a memory card.

if we increase the sim card memory to 10MB there will be fast access of internet, so why can't we increase the memory capacity up to 10MB?


Can I use a watch phone on my t-mobile account?


i got a china iphone (kingston) and will it work in the USA with a verizon sim? please i need help. thanks in advance.


Verizon and Sprint do not use sim cards. If you can't find a spot to put the card in the phone, usually behind the battery, it means it doesn't take one.


i have a tmobile htc hd2 but i am using my at&t sim card. i have already unlocked it but how do i make the internet work! Please help!


What is the total memory of a SIM card? How much memory does it have in Mb? Does anybody know?


Can a SIM card be duplicated? --Zbat


can i use a verizon sim card in an att go phone? phone says it is restricted.

Karley Boisvert

I accidentally, permanently locked myself out of my LG Breeze. if I get a new SIM card will my phone still work?


I have a Nokia 2860 from Corr Wireless Network that has a working sim card. I am wanting to buy the Samsung T401G from the net10 that has a sim card. I would like to know if my sim card from the nokia will work in the samsung? Thanks in advance.


I got a new phone recently and the screen broke. Since i didn't have insurance i have to wait until i can upgrade, but i can't stand being with no phone, so if i purchase a prepaid phone will the sim card work on it? what else do i have to do?


I brought a 1.3 Inch touchscreen watch mobile phone from ebay and it said that i can't use a 3g or cmda card. Why is that?


i have a china phone model DONOD MTK6225. i tried accessing the internet but it says "gprs not subscribed". please help me. I'm using a globe phone number here in the philippines. any nokia or Sony ericsson phone that is similar to my phone features and settings?


My Samsung GT-S5560 is saving sms in sim memory not in phone memory. Please help.


i had a sim card from my old phone, and i now use that in my new blackberry. the new blackberry came with a new sim card. if i put that sim card in another phone, does that mean i have two functioning phones with two sim cards?


Would text messages go back or return to sender if my cell phone is off? Thank you.


A friend gave me a motorola v 555 with no sim card. How can I activate it?


I have a Nokia and an LG. The SIM card does not fit into the nokia or vice versa and reading articles like the one above is a real disappointment because if one sim card won't fit into another, why then don't they say just that? a lot of crap for nothing.


My Blackberry Pearl has water damage and the screen will not work. I do not want to purchase a data plan, but liked my old phone. Can I buy another Blackberry Pearl (8100, or other) online and add my old SIM card or do I have to alert ATT?

In other words, will they need to activate the new phone, thus locking me into a new contract and data plan or can I simply purchase another phone until I am ready to commit to the higher priced plan?


Some mobile phones save deleted text messages to their removable sim cards by default. When that sim card is full, it will start overwriting the older deleted text messages with more recently deleted text messages. Others save it to an internal memory before it is completely deleted. Do all sim cards save deleted text messages by default or are they gone forever?


Can i put a go phone chip in my samsung slider?


I have a phone with a dual Sim Card capability. My question is, can it use two different networks at the same time with say two different tariffs from two suppliers? It also has a spaceholder for up to 8 megabytes of memory. Is this also a factor for operation?


where is the sim card n the samsung rant by sprint? i see the microsd card. is that the same as a sim card?


I have the motorola i465 and I can't receive calls, could it be a problem with my sim card? I live on the border with mexico, and I've already called several times to the customer care center, but I am still experiencing this troubles Do you think is it a problem with my sim card? I have three years with the same card and I've had to change the phone three times, but with the same sim card. So what do you think is going on?


I have an LG Shine CU720 and need to know if the SIM card will work in a Blackberry 7290. Both are AT&T phones. Do I have to purchase a separate data plan for the Blackberry?


i want to transfer my phone number to a CDMA phone like the htc droid eris. can i do that? and how?


We want to use a mobile phone just for the calendar and reminders, not for calls. Can we buy a SIM card and use it with phone service? If so, where can we get one?


if i bought a new phone on orange, but wanted to stay with 02 or some other carrier,could i take the sim card from my old phone and put it in my new one?


can i put an at&t sim card in a tmobile phone?


Verizon most certainly does use sim cards. The Blackberry Storm has a sim card. Verizon has other phones that also use them. However I do not know if they are the same size.


I have an lg ks360 and have topped up but the people have said that they will send it to me in 73 hours. I have now waited for two weeks and i haven't had my ten pounds. Please help me!!!!


I have a Tmobile account with a sim card,and now i have a phone from verizon. Can i use my Tmobile sim card in the verizon phone, and still retrieve the internet along with the rest of all my info?


I have an env touch and while i was trying to transfer my pictures from my phone to my memory card they somehow got deleted. is there any way i can get the pics back?


I got a used singular phone from my friend. I want to insert my at&t SIM card to this phone. what should I do? Do I need to call cingular/at&t?


I am Gaurang. I want to know why in the shape of the simcard there is a cut. It is not perfectly rectangular.


A tri band phone is not worth having in the U.S. To cover all areas in the U.S., you need a quad band phone.


i have lost my phone which includes the sim and i have changed numbers so many times i would like to know if i could get the same number on my new sim which they are both on telstra prepaid.


My phone got wet and I have been using my boyfriend's track phone and I just put my sim card in from my togo phone and it's locked out. what can I do?


my nokia phone said that the sim card was rejected. what do i do about that?


I am going to london next week (i live in australia) and just bought a UK sim card. Best thing is that this sim was already pre-registered and pre-activated.


i bought a samsung go phone and my sim cards locked to the samsung. i tried to put my sim card in my other phones but it won't work. can anyone help me?


Thanks for the quick and easy overview. I was searching for "swap sim cards swap phone numbers?" and found the answer easier than normal with your article.


i have a broken contract phone with at&t. can i just pick up a gophone and use my same sim?


is it possible to stick a SIM card from TMobile in a Verizon phone?


Sim cards are a joke.


I want a new phone, but i want to keep my same carrier. I want a new sim card also (one that doesn't have a 3g sim. I want to buy an unlocked phone online and it needs a gsm carrier without "3g" sim card. Can i ask the carrier for a new non 3g sim card?


If you use your sim card in a friend's phone, what number will show up to the person you're calling? And is there a way of changing the number on your sim card when using a different phone?


hello, this is my second post in the same page, not sure what happened to the first post. just wanted to thank every one for providing this good information on sim and mobiles. i would request someone to post some details on mobile imei numbers.

i was using a china made mobile and recently my mobile got banned because the government here says my mobile does not have imei number. As a lay man who is into the business of packers and movers in bangalore, i don't have much knowledge on these topics. --KGP


We have an ATT phone that has died. We don't want to continue the two year contract with ATT and don't want to renew our ATT contract just yet.

Can we put the ATT sim into a cheap ATT goPhone until we continue our ATT contract? Thanks.


which carriers in the US use SIM cards?


i have an att go phone and my sim card won't work in certain phones. how do i make it work? is there a way?


I have an AT&T LG Xenon. Could i use the same sim card that i already have in an unlocked phone from, for example: Tmobile??


SIM - Subscriber Identity Module.

CDMA - Code Division Multiple Access.


My phone was stolen and not even a week later my mom went in to get a new sim free of charge. the woman said it had to be processed and formatted for insurance. so my question is, how long will this take? it's already been a week so i want to know the waiting period without going in every two days and asking.


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.


how can i clean a vodaphone simcard for samsung mobile?


What does SIM card stand for? Please explain.


my sim card blocked itself and i don't want a new number. =(


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 don't want the hassle of giving my new number to everyone.


I use a RoamForce SIM card for international calls and blackberry data.


is there a sim card on my L7c motorola phone?


can i text using a sim card on my phone?


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.


what is meant By LAPU balance or USSD balance regarding talk time in the telecom industry?


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.


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!


can i use an att sim card with verizon wireless phone (the Alias 2) please answer!


sim card cloning is possible? if yes please suggest software or site ID.


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.


how do i save my stuff in to my simcard?


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?


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.


I have the same question as no 63. I try it. it will not take it. what am i doing so wrong?


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.


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.


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?


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.


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?


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.


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?


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!


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?


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


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.


Can a sim card work on my sidekick? lx


can i use the sim card from a nokia 6085 to nextel I530?


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.


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?


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?


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.


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...


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?


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 want to 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!


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?


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.


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?


Virgin Mobile has a website -- find their phone number there and they'll give you instructions to activate your phone.


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 won't go through. and i can't get to the phone can i find out what the number is so i can put minutes on the phone? please help me..!!!!


How do I download data (files, photos, etc) from my Blackberry Curve sim card to my laptop??


can i use my cingular sim card in a t-mobile phone?


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?


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 :)


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.


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?


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?


hi i have a nokia 6010 that someone gave me. Everything works on it I don't 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


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....can't received email or send msgs and can't call or received don't know what to do! its a nokia n95!


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!


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


? 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.)


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.


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?


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?


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?


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.


I have a samsung phone and would like to extract deleted text messages, is it possible because of the sim card?


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.


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.


If I take my SIM card and my memory card out of my phone is there any personal information left on it?


I need more information about the GSM Sim which you called R-UIM. Who can I talk to, is it now available anywhere?


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 !!



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?


I have a motorola razr v3 cell phone. Can I get deleted text messages off of my sim card? If so, how?


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.


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?


Does anyone have an answer for the tracfone/bluetooth problem by UF?


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


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?


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.


where is the SIM card in a virgin mobile 'shorty' (nokia) phone????


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!


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 (:


i have a simple verizon phone.. it doesn't 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...


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?


i just brought a phone on ebay. I wanted to know what is a triband phone?


Called my prepaid provider and they warned against inserting a new SIM card in the phone. Won't replacement cards work on prepaids?


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


why is it called re-useable identification?

Is there any phone that supports the two networks?


what are the processes of making a sim card?


Can I use the sim card out of my CDMA phone ( if it has one) on my new nokia I just bought on ebay?


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.


Where is the Sim card in a verizon chocolate phone?


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.


Hi, I purchased a used nokia 6103 through EBay and I need to get a sim card for it. Should I get a new card or a preactivated card?

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    • A SIM card connects your phone to your carrier's wireless network, allowing you to make calls, send SMS messages, and use 4G.
      A SIM card connects your phone to your carrier's wireless network, allowing you to make calls, send SMS messages, and use 4G.
    • The SIM card is the "brain" of your phone, storing your phone number, address book, and identifying information.
      The SIM card is the "brain" of your phone, storing your phone number, address book, and identifying information.
    • A SIM card often comes pre-cut, so that it can be used as a Mini, Micro, or Nano SIM.
      A SIM card often comes pre-cut, so that it can be used as a Mini, Micro, or Nano SIM.