AT&T and T-Mobile (and theirMVNOs) run on the GSM network technology while Sprint andVerizon (and their MVNOs) run on CDMA technology. GSM andCDMA are not cross compatible. The good thing is, most newerphones are now compatible across all carriers..
In respect to this, does AT&T use GSM or CDMA?
In the US, Sprint, Verizon, and US Cellular useCDMA. AT&T and T-Mobile use GSM. Most of therest of the world uses GSM. The global spread of GSMcame about because in 1987, Europe mandated the technology by law,and because GSM comes from an industryconsortium.
Subsequently, question is, is Virgin Mobile a GSM carrier? Virgin Mobile provides CDMA devices in the US,meaning phones don't work based on a SIM card, as opposed to GSMcarriers (e.g. AT&T and T-mobile). CDMA phonesusually have SIM slots, but they support only foreign GSMnetworks. You'd be better off buying a GSM iPhone 5 andunlocking it.
Then, does GSM unlocked work with AT&T?
All unlocked phones work on carriers thatuse GSM networks. Popular U.S. carriers that use GSMnetworks include AT&T, T-Mobile, Cricket, MetroPCS,Simple Mobile and Tracfone. Most foreign carriers also useGSM networks. You will need to use a SIM card from aGSM provider to get service for your unlockedphone.
Can Sprint phones work on AT&T?
There are only a few Sprint phones that willwork on AT&T. Sprint is CDMA network andAT&T is GSM network. There are a few phones thathave both radios but they are few. Most phones are notcompatible on both networks.
Related Question Answers
Can I use a GSM phone on a CDMA network?
Well GSM networks like US Mobile, T-Mobile, andAT&T use removable SIM cards. This means that unlockedphones from other American GSM carriers will work on USMobile's network. On the other hand, Verizon and Sprint areCDMA carriers. CDMA carriers don't use SIMcards and most CDMA phones are locked into theirnetwork.How do I know if my phone is a GSM or CDMA?
Check your phone's "About"settings. If you see an MEID or an ESN category, yourphone requires CDMA; if you see an IMEIcategory, your phone is GSM. If you see both (e.g.,Verizon phones), your phone supports both CDMAand GSM, and may be either one.Is 4g LTE CDMA or GSM?
In the U.S., AT&T and T-Mobile are GSMcarriers, while Sprint and Verizon are CDMA carriers. Also,swapping phones on GSM networks is easier becauseGSM-compatible phones use SIM cards. In terms of theirrelevance to 3G and 4G LTE bands and frequencies, the thingto know is that CDMA and GSM only use 3Gtechnology.Can you switch SIM cards between phones on AT&T?
Re: SIM card swap Having a new phone is always exciting! The greatnews is if you need a compatible SIM card, youcan visit a local AT&T Corporate Store to obtainone at no charge.What is a GSM SIM card?
GSM networks use TDMA, which stands for TimeDivision Multiple Access. In order for the network to know whichusers are connected to the network, each phone uses a subscriberidentification module card, or SIM card. SIMcards are one of the key features of GSMnetworks.Is CDMA better than GSM?
First, neither GSM or CDMA is technicallybetter; they ultimately provide the same service and thequality of a network depends on the carrier, not the cellularstandard used. Second, GSM phones can be unlocked and switchcarriers, whereas CDMA phones are locked to acarrier.Is LTE a GSM?
LTE (Long Term Evolution) is a wireless broadbandtechnology for communication of high speed data for mobile phones.The main difference between the technologies is that both CDMA& GSM can support cellular and data, whereas LTEcan only support data.What is a GSM unlocked phone?
Unlocked GSM phone means that it wouldn't belocked into a specific carrier network. On the upside it meansfreedom to choose your own GSM carrier that suits your needs(and wallet) best. On the down side several carrier-specificfeatures may not be available.Can you put any SIM card into an unlocked phone?
With an unlocked device, a GSM smartphonecan be reprovisioned and used on another network simply bypopping out the old SIM card and putting in a newone from the new carrier. The standard is not as widely usedas GSM. CDMA devices do not have SIMcards.Is Verizon going to GSM?
When will Verizon Wireless switch to GSMin the US? Verizon already has GSM as its basenetwork. As of January 1, 2020, CDMA is no longer going tobe supported OR EVEN FUNCTION on the Verizonnetwork.Can I bring an unlocked phone to AT&T?
BYOD (bring your own device) and BYOP(bring your own phone) mean you bring yourunlocked, compatible device to AT&T. Although youdidn't buy your device from AT&T, you canactivate your unlocked phone on an AT&Tplan.What is GSM unlocked vs fully unlocked?
An unlocked phone means you can use it withwhatever carrier your phone can connect to. An unlocked GSMphone can connect to GSM networks, like T-Mobile. A CDMAcapable phone can connect to CDMA networks, like Verizon. A fewphones can do either one.How do I know if my AT&T phone is unlocked?
Get the request number from your unlock requestconfirmation email, and your device IMEI. You'll need both tofind out the status of your device unlock request.Check your unlock status now, go toatt.com/unlockdevicestatus.What does GSM unlocked vs fully unlocked?
Factory Unlocked means that the phone isn'tattached to any cell phone service and can be used with anyservice that uses a SIM card. However - sometimes (in my experienceespecially in the US) you need to inform yourself wether ornot the internet (3G, 4G, etc) will work with yourcarrier.Can I use a GSM unlocked phone on Verizon?
US Mobile is a GSM carrier. In general, anunlocked GSM phone from AT&T and T-Mobile willwork on each other's networks. However, most, if not all, 4G LTEdevices from Verizon and Sprint are technically capable ofoperating on a GSM network, as LTE needs a SIM card tooperate.Does Virgin Mobile accept unlocked phones?
You can bring both of 'em to Virgin Mobile- all you need is a Virgin Mobile SIM card. Check if yourcurrent phone is compatible with our network. If yourphone isn't compatible, then we've got the phones youreally want. If your phone is currently locked, it needs tobe unlocked.What network does virgin run on?
The company was launched by Virgin Group in 1999as the world's first Mobile Virtual Network Operator (MVNO).As a virtual operator, Virgin Mobile does notmaintain its own network but instead has contracts to usethe EE network.Is Virgin Mobile going out of business?
The Virgin Mobile brand is being phasedout by parent company Optus, and it will stop selling phoneand internet services from June 15. Virgin Mobile storeswill close throughout June. You can stay on your existing plan forthe time being. If you're on a contract, it will continue asis.Is straight talk a GSM?
Straight Talk is an alternative carrier, orMobile Virtual Network Operator (MVNO), that offers prepaidwireless service through a partnership with TracFone and Wal-Mart.Straight Talk offers support for both CDMA and GSMdevices, as it piggybacks on the T-Mobile, Sprint, AT&T, andVerizon's networks. 
