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What are Phone Bands (GSM, CDMA) and

What is the difference between GSM vs CDMD... 

In this article, we are going to discuss the two popular technologies that provide multiple accessibilities to a channel GSM and CDMA. The basic difference between GSM and CDMA is that GSM is specific to a SIM card that is used with the mobile phone. We take a closer look at some of the differences between GSM and CDMA networks and how they matter to us as a consumer.

When consumers think about mobile network providers, their primary concern is with regards to coverage, quality, support, pricing, and other factors but when you pick a network carrier, you also make the choice between a GSM network or a CDMA network, at least in the US.

You have probably come across these terms in the past when picking a mobile phone, or when first joining, or switching, network carriers, but what do they mean and what is the difference between the two? We find out, as we take a closer look at GSM vs CDMA and what it signifies for us as consumers.

What is the difference between GSM vs CDMD


CDMA vs GSM Explained

What is GSM?

GSM (Global System for Mobile Communication) is a time-division technology that breaks the transmission signal into separate time slots for each device (CDMA is a code-division meaning that the users are separated by a specific digital code.). GSM was first created in Europe by the Telecommunications Standards Institute during the early ’80s. This European Institute formed a group called Groupe Speciale Mobile (also abbreviated as GSM) to create a digital mobile communication system. The main purpose was to develop a better network for the whole European continent with a more effective technical solution for wireless communication.

GSM stands for Global System for Mobile Communication and is now considered the standard for communication globally, particularly in Asia and Europe, with its availability in over 210 countries worldwide. With the first introduction of the SIM cards in the ’90s, GSM phones have been characterized by having a SIM card that allows users to switch their phone number and personal information to any other unlocked GSM phone. As we already explained before, this is not possible with CDMA phones.

Although GSM technology is the most common technology around the world, the US is still working with both the CDMA network and GSM network. However, 2G GSM is going extinct in the country due to the arrival of the 5G network, which is the fifth (and latest) generation of cellular mobile communications. Talking about cellular frequency bands, many GSM mobile phones support three frequency bands (900/1,800/1,900 MHz or 850/1,800/1,900 MHz) or four bands (850/900/1,800/1,900 MHz).

Cell phones that support three bands are usually called tri-band phones, while other ones are commonly known as quad-band phones or world phones because you can make international trips and use the same smartphone.  


What is CDMA?

CDMA (Code-division Multiple Access) is a digital radio system that supports a mobile phone network. The system was developed by the Allied from World War II. CDMA gives users total access to the network spectrum. This allows more users to connect to the network at the same time. It securely encrypts the individual conversation of each user through a random digital sequence. Therefore, the voice call data is kept protected in a way that just those who participate in the call can receive the data.

CDMA, or code division multiple access, was a standard designed and patented by Qualcomm, but subsequently used as the basis for the CDMA2000 and WCDMA standards for 3G. However, because of its proprietary nature, CDMA hasn’t seen the global adoption that GSM has, with less than 18% of the networks around the world using CDMA, and is primarily found in the US, with Verizon Wireless and Sprint both using CDMA networks, as well as in South Korea and Russia.

In the past, mobile phones with CDMA network capability did not use SIM cards. Each device is designed specifically to work for a specific network provider only. It means that cell phones are linked to an operator and its network. Now, it changed because network providers operating on CDMA started to use SIM cards for their LTE coverage. If you decide to change the provider you can either buy a new mobile phone or ask to get your phone unlocked at your current provider. 

CDMA networks layer digitalized calls over one another, assigning unique codes to differentiate between them. Every call data is encoded with a different key, and the calls are then transmitted at the same time. The receivers each have a unique key as well, to split the combined signal into its individual calls.

What are Phone Bands GSM and CDMA


Lists of CDMA and GSM Carriers (USA)

As we already mentioned in the previous part, most of the world uses GSM networks. But there are places where CDMA networks still exist. Do you know if you are part of a CDMA carrier or a GSM carrier?

By now, you probably have an idea already and you can conclude what type of network you belong to. Below, you will find a list of GSM & CDMA carriers in the USA for you to double-check:

GSM Carriers in the US

  • AT&T
  • Broadpoint
  • DTC Wireless 
  • Indigo Wireless
  • T-Mobile

CDMA Carriers in the US

  • Verizon 
  • Sprint
  • U.S. Cellular
  • Cricket

Talking about frequency bands, AT & T uses 1900 MHz, 850 MHz, while T Mobile uses 1900 MHz, 1700/2100 MHz. On the other hand, Verizon and Sprint use the same frequency band which is 800 MHz, 1900 MHz.  


GSM vs CDMA: Main differences

Both are multiple access standards, which means that multiple calls can go through a single tower, but as you can see, the major difference between the two has to do with the way your data is converted into the radio waves that your phone broadcasts and receives. There are, of course, more practical considerations that matter more for us as a consumer, which you can find listed below:

  • SIM cards: Before the advent of 4G LTE, the obvious difference between GSM and CDMA devices was with regards to the SIM card. GSM handsets came with a SIM card slot, while CDMA phones did not. In other words, CDMA is a handset-based standard, with a phone number linked to a particular device. If you wanted to upgrade to another phone, you would have to get in touch with the network carrier, de-activate the old device and activate the new one. On the other hand, with GSM devices, the phone number is linked to the SIM card, so when switching devices, all you have to do is pop the SIM card into a new phone and you are good to go. (This is obviously without taking into consideration GSM devices being locked to network carriers, as seen in the US).
  • Network coverage: Network coverage doesn’t depend on whether it is a GSM or CDMA network, but rather on the infrastructure the carrier has in place. GSM networks are far more popular globally, but in the US, Verizon Wireless, a CDMA network, boasts the highest number of subscribers and broadest coverage in the country.
  • International roaming: In your home market, it doesn’t matter what kind of network it is, with the focus instead on the available coverage. However, when it comes to international roaming, GSM has the upper hand, with a lot more GSM networks around the world, along with roaming deals between these providers. With a GSM phone, you also have the advantage of picking up a local SIM card wherever you are, assuming that you have an unlocked device. You may not get full access to data connectivity, depending on the device and network compatibility though.

The Evolution of Mobile Communication Technologies


The Evolution of Mobile Communication Technologies

With the advent of 4G and the adoption of LTE and LTE-Advanced as the standard by the majority of network carriers worldwide, the debate of GSM vs CDMA matters less every day. You may have noticed that modern smartphones intended for CDMA networks also come with SIM card slots, to take advantage of the network’s 4G LTE capabilities.

With the move towards 5G, the choice between GSM and CDMA becomes even less relevant, as voice call technologies increasingly moved over to data network brands. Today, the argument is only a consideration as 2G and 3G networks are still used as the backbone of network voice technologies. Eventually, these bands will be repurposed and networks will move away from this older voice technology. For example, AT&T has already turned off its 2G GSM network and Verizon is set to shut down 2G and 3G CDMA comes to the end of 2019.

While GSM and CDMA handsets cannot be interchanged even now, and will never be cross-compatible, that won’t make a difference as we continue to make a push towards more advanced 4G and 5G networks. Unless international roaming is a factor, as far as your voice call and 3G data needs are concerned, both GSM and CDMA networks are equally good, with factors like availability, coverage, customer service, and price, more at play here.


GSM vs. CDMA: What Does the Future Hold?

As stated above, GSM and CDMA are only applicable to 2G and 3G networks. With the advent of 4G, all carriers around the world use the global LTE standard. GSM and CDMA only come into play as a fallback where there's poor or no LTE coverage. And as we enter the 5G era, the two network bands will continue to be less critical. For instance, major US carriers will start closing their 3G networks in early 2022.

LTE (Long Term Evolution) is the worldwide 4G wireless standard for all U.S. carriers, and AT&T, T-Mobile, and Verizon started integrating voice calling over 4G in 2014. Today, all carriers support voice over 4G and are in the process of installing 5G, which is intended as a single global standard called 5G-NR. If you are still using a 2G or 3G phone, consider upgrading and replacing it with a 4G or 5G phone. That’s because major carriers are in the process of aggressively sunsetting these old standards in favor of 4G LTE and 5G.

Verizon has already shut down its CDMA network. Following T-Mobile’s recent merger with Sprint, the combined company will likely retire Sprint’s older network by the end of 2021. AT&T has already shut down its 2G GSM network and said it will also shut down 3G GSM in February 2022. T-Mobile plans to shut down its 3G GSM in April 2022 and will terminate 2G GSM in December 2022. T-Mobile plans to shut down the 3G CDMA network used by some Sprint and Boost customers on January 1, 2022. Verizon will shut down its 3G CDMA network on December 31, 2022.


Does GSM vs CDMA still matter?

Yes, the voice networks of US wireless carriers still use two fundamentally different technologies GSM and CDMA. Sprint and Verizon use CDMA, while AT&T and T-Mobile along with most of the rest of the world use GSM.  

The good news is that phones are a bit more compatible and portable among carriers than they were a few years ago. But phone makers, like Apple, still tend to make multiple versions of their phones so you need to know which model you're buying before you can know if you can take it to another carrier.

For instance, Apple sells two versions of the iPhone 7, 7 Plus, 8, 8 Plus and X. Unlocked versions of these phones that aren't sold through a carrier are compatible with all four US carriers. The iPhones sold through Verizon or Sprint can also be used on both CDMA and GSM networks, which means they are compatible with AT&T and T-Mobile. But iPhones sold through AT&T and T-Mobile don't include modems for CDMA, so they can't be used for voice service on Verizon or Sprint.

The bottom line is that you should check before you buy if you think there's a chance you'll be switching carriers.


What is 4G?

4G is the fourth generation of broadband cellular network technology and it evolved from 3G, which is the technology that was present in almost all mobile phones until now. Although 4G and LTE are not exactly the same, LTE is commonly marketed as 4G LTE. One of the main aspects of 4G is that you can reach a speed that is almost 10 times faster than 3G.

All the telecommunication companies currently count with a 4G connection even though its different coverage packages. With 4G, your mobile phone or any other device can browse the internet at a speed close to optical fiber. 4G has a lot of advantages and you will realize why users and telecommunication companies call it LTE. 

Advantages of 4G

  • While 3G connection can only reach 10Mb/s, with 4G users can browse on the internet at a 100Mb/s speed. So watching a video, downloading apps or just browsing on a website is faster. Some research says that 4G might reach up to 1 GB/s speed connection.
  • It works better in real-time. The delay in the connection is at least 70% minor than the 3G. You will never notice pauses in voice calls or in online games.
  • Just a few users know that 4G will drop the network congestion so the data will move faster (from the client to the server and back) making our connection more stable. In this way, a lot of users can be connected at the same time in the same zone.

Disadvantages of 4G

  • You can only use 4G if your cell phone is compatible with this technology.
  • There are some areas where 4G is still not available nowadays.
  • Despite that 4G has an excellent speed connection; it does not exceed the optical fiber. However, it is still the best way to browse on the internet using your mobile phone.
  • No matter how fast 4G mobile internet is, it still has a data limit in most cases. Users can consume content faster but not a greater amount.


What is LTE?

LTE (Long-Term Evolution) is a standard for wireless broadband communication for cell phones,data terminals and other devices , based on the GSM/EDGE and UMTS/HSPA technologies. 4G encompasses several types of connections, between them LTE. There is one conventional technology known as LTE Advanced, and it reaches up to 3GB/s. Unfortunately, there are just a few mobile phones that are compatible. You can find them in Russia or South Korea. Germany was one of the first countries that had LTE technology.

German telecommunications companies do not sell it as 4G, it is simply called LTE. Beyond this name, just having a mobile phone that can reach a high-speed connection almost comparable with an optical fiber is the best way of using the mobile internet nowadays. The only thing that you have to make sure is to have a compatible cell phone and live in a city with good coverage. It is important to mention that iPhones newer than the 5 and almost all Androids newer than the Samsung Galaxy S5 will be compatible with all major carriers’ 4G LTE bands.  


What is 5G?

The 5th generation of mobile technology is on its way and is believed to be finally rolled out in 2020. Some users get to know 5G already as the U.S. carriers launched their service in some cities. For example, Verizon’s network in Chicago and Minneapolis, also some parts of Atlanta, Denver, Detroit, Indianapolis, Phoenix, Providence, Rhode Island, St. Paul, Minnesota, and Washington, DC. The provider Sprint introduced 5G in parts of Atlanta, Chicago, Dallas-Fort Worth, Houston, and Kansas City. This next generation of mobile broadband will beat the latest 4G. Also, it possibly retires the 3G.

5G will not only provide a better data speed. It will play a significant role in the technology industries through the use of connected devices. From human’s interest in gaming to the AR/VR technology, a vital step in driverless cars and medical robots for the healthcare system. That’s what we call ‘The Internet Of Things (IoT)’.


What Is The Internet Of Things (IoT)?

It is the use of connected devices. From human’s interest in gaming to the AR/VR technology, a vital step in driverless cars and medical robots for the healthcare system.


How do I get my phone unlocked?

Depending on how you bought your phone, it may already be unlocked. For example, if you didn't buy your phone through a US carrier or you purchased it directly from Apple or on Amazon and either company indicated it was unlocked, you don't have to do anything.

Prior to the change, Verizon phones came unlocked out of the box.

Phones bought through AT&T, Sprint, T-Mobile, and Verizon (starting later this year) will have locks on them. And you'll need to find out what criteria needs to be satisfied before you can ask for a code to unlock it. 

Thanks to mobile unlocking companies like ours, you don’t have to remain tied to your network provider forever. We help people unlock their phones and switch service providers. But not all cell phone unlocking companies are made alike.

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