What is a SIM Card?

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  • Originally Written By: R. Kayne
  • Revised By: Patti Kate
  • Edited By: Niki Foster
  • Last Modified Date: 13 October 2019
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A Subscriber Identity Module (SIM) card is a portable memory chip used mostly in cell phones that operate on the Global System for Mobile Communications (GSM) network. These cards hold the personal information of the account holder, including his or her phone number, address book, text messages, and other data. When a user wants to change phones, he or she can usually easily remove the card from one handset and insert it into another. SIM cards are convenient and popular with many users, and are a key part of developing cell phone technology.

Activating a SIM Card

Since all of a user's data is tied to the SIM card, only it needs to be activated when the person opens an account with a cell phone service provider (also called a carrier). Each card has a unique number printed on the microchip, which the carrier needs to activate it. In most cases, the phone's owner can go either to the carrier's website and enter this number in the appropriate tool or call the service provider directly from another phone to get it turned on. SIM cards are tied to a particular carrier and can only be used with a service plan from that carrier.


Swapping Handsets

One of the biggest advantages of SIM cards is that they can easily be removed from one mobile phone and used in any other compatible phone to make a call. This means that, if the user wants to buy a new handset, he or she can activate it quickly by inserting his or her old SIM card. The user's phone number and personal information is carried on the card, so there's no need to do anything else to transfer this information. Most phone applications (apps) are stored in the phone's memory or secure digital (SD) card, however, so they will not be transferred to the new handset.

Some cell phone carriers lock their handsets; this means they will only work with SIM cards from that carrier. This is especially common in the US, where service providers sell the handsets at a discount in exchange for the consumer signing a long-term contract for service. Handsets can be unlocked with the right code, however, although the exact process varies by manufacturer and model. Any SIM card can be used with an unlocked phone. Phones without a card, or with one that is not compatible, can typically only be used for emergency calls.

Pre-Paid SIMs

Pre-paid SIM cards are also available, allowing a phone that's locked to the pre-paid carrier's network or an unlocked phone to be used without a long-term contract. This type of card is useful for people who don't want to be tied to one carrier, or who want to try out a service provider before committing. It's especially useful for international travelers, who can purchase a local SIM card to use their phone abroad. This allows the user to keep the same phone — with the apps and other settings that are stored in it — without paying international roaming charges from the carrier back home. It also gives the traveler a local phone number, making it less expensive for people to call the traveler from within the same country.

SIM Cards Sizes

SIM cards are made in three different sizes to accommodate different devices. Most phones use mini-SIM or micro-SIM cards, which are quite small — the mini is 25 mm by 15 mm (0.98 in by 0.59), and the micro is 15 mm by 12 mm (0.59 in by 0.47 in). Full-sized cards are much larger, 85.6 mm by 53.98 mm (3.37 in by 2.13 in), and are too big for most phones. All cards are only 0.76 mm (0.03 in) thick, however, and the microchip contacts are in the same arrangement. This means that, with the proper adapter, the smaller cards can be used in devices designed for larger ones.


A SIM card offers security for both the user's data and his or her calls. The cards can be locked, meaning that only someone who has the correct personal identification number (PIN) can use the card. If the phone is stolen, the thief cannot use a locked SIM or get any information off of it without the PIN.

In addition, the card has a secret authentication code and an encryption key that protect the phone's transmissions. Although it is possible to "clone" a cell phone on the GSM network and thus steal service, it's much more difficult than it is to clone a phone on the competing Code Division Multiple Access (CDMA) network. 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.

Other Cell Phone Technologies

Phones that operate on the CDMA network do not use SIM cards; instead, most save the phone number and other identifying information in the handset itself. While this can be less convenient for users, CDMA is most common in the US, where handsets are usually heavily subsidized and users may have less incentive to switch phones frequently. In addition, some carriers, mostly in Asia, do use their own removable card format, called a Re-Useable Identification Module (RUIM).

As technology changes, however, more cell phone providers are upgrading to 3GPP Long Term Evolution (LTE), which is based on GSM technology. This means that some sort of SIM card is likely to be required for devices that use this network.


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Discuss this Article

Post 210

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

Post 207

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

Post 206

Does a SIM card save photos?

Post 205

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?

Post 202

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

Post 201

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?

Post 200

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?

Post 199

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.

Post 195

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

Post 194

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

Post 193

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?

Post 192

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

Post 188

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.

Post 187

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.

Post 186

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!

Post 185

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

Post 184

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.

Post 183

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?

Post 182

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.

Post 181

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?

Post 180

where can i get a double memory card.

Post 179

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?

Post 177

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?

Post 176

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

Post 175

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?

Post 172

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?

Post 171

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

Post 170

what we have to do to buy a sim card?

Post 168

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?

Post 167

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

Post 166

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

Post 165

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.

Post 164

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!

Post 161

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

Post 160

Can a SIM card be duplicated? --Zbat

Post 159

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

Karley Boisvert
Post 158

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

Post 157

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.

Post 155

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?

Post 154

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?

Post 152

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?

Post 151

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

Post 149

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?

Post 148

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

Post 147

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

Post 146

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.

Post 145

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?

Post 144

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?

Post 143

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

Post 142

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?

Post 141

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

Post 140

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?

Post 139

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?

Post 138

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

Post 137

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?

Post 135

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?

Post 134

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

Post 133

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.

Post 131

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!!!!

Post 130

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?

Post 129

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?

Post 128

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?

Post 127

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

Post 126

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.

Post 124

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.

Post 123

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?

Post 122

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

Post 121

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.

Post 120

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?

Post 119

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.

Post 118

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

Post 116

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

Post 114

Sim cards are a joke.

Post 113

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?

Post 112

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?

Post 111

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

Post 108

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.

Post 107

which carriers in the US use SIM cards?

Post 106

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?

Post 105

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??

Post 104

SIM - Subscriber Identity Module.

CDMA - Code Division Multiple Access.

Post 103

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.

Post 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.

Post 101

how can i clean a vodaphone simcard for samsung mobile?

Post 99

What does SIM card stand for? Please explain.

Post 98

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

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

Post 95

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

Post 94

is there a sim card on my L7c motorola phone?

Post 93

can i text using a sim card on my phone?

Post 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.

Post 91

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

Post 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.

Post 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!

Post 86

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

Post 85

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

Post 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.

Post 82

how do i save my stuff in to my simcard?

Post 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?

Post 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.

Post 79

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

Post 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.

Post 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.

Post 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?

Post 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.

Post 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?

Post 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.

Post 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?

Post 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!

Post 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?

Post 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

Post 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.

Post 65

Can a sim card work on my sidekick? lx

Post 64

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

Post 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.

Post 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?

Post 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?

Post 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.

Post 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...

Post 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?

Post 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 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!

Post 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?

Post 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.

Post 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?

Post 51

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

Post 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 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..!!!!

Post 48

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

Post 47

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

Post 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?

Post 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 :)

Post 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.

Post 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?

Post 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?

Post 41

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

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

Post 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!

Post 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

Post 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.)

Post 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.

Post 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?

Post 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?

Post 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?

Post 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.

Post 31

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

Post 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.

Post 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.

Post 28

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

Post 27

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

Post 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 !!


Post 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?

Post 23

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

Post 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.

Post 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?

Post 20

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

Post 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

Post 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?

Post 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.

Post 16

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

Post 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!

Post 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 (:

Post 13

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...

Post 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?

Post 10

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

Post 9

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

Post 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

Post 7

why is it called re-useable identification?

Is there any phone that supports the two networks?

Post 6

what are the processes of making a sim card?

Post 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?

Post 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.
Post 3

Where is the Sim card in a verizon chocolate phone?

Post 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.

Post 1

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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