If you’ve tried to keep up with the latest smartphones and handheld devices, you probably know that there’s quite a bit of industry jargon. Especially when it comes to connection strength, you’ve probably heard tons of acronyms and insider terms, from LTE to 5G.
Two terms you’ve likely come across, especially if you have an older phone, are CDMA (Code Division Multiple Access) and GSM (Global System for Mobile Communications). GSM was initially introduced in Finland in 1991, while CDMA networks followed shortly after. For decades, these two competing standards defined how mobile phones connected to carrier networks around the world – and understanding the difference still matters if you’re shopping for a used or older device.
GSM has long dominated the global landscape, holding approximately 82% of worldwide market share and operating in more than 200 countries. CDMA, by contrast, accounts for less than 20% of global wireless networks and was largely concentrated in the United States, parts of Asia, and a handful of other markets. As of 2026, both technologies are firmly in their legacy period: AT&T shut down its 3G network in February 2022, T-Mobile shut down its 3G CDMA (Sprint) network in March 2022, and Verizon completed its 3G CDMA shutdown in December 2022. If your phone relies solely on one of these older networks, it is no longer able to make calls or access data.
Whether you’re looking to swap carriers and need an affordable device or you’re considering an upgrade but don’t want to pay retail prices, your prospective phone’s connectivity and capabilities still matter. That’s why it’s worth understanding what CDMA and GSM were, how they differed, and what their shutdown means for anyone still holding onto an older handset.
What is GSM?
GSM, or Global System for Mobile Communications, and CDMA came as part of the second generation of wireless technology, or the 2G era, which expanded greatly in the 1990s. Initially introduced in Finland in 1991, GSM promised a secure network connection, accessory and handset compatibility, and an extensive coverage area. Contrary to CDMA, GSM is a time division system, as opposed to a code division process.
Though this technology is much older than most people guess, it’s still in use to some degree worldwide. Even as global connectivity standards have improved – including widespread 4G LTE and continued 5G expansion – plenty of users still rely on legacy devices, especially in developing nations. Unlike CDMA phones and newer options like LTE (Long Term Evolution) and 5G, GSM devices are straightforward to spot because they rely on SIM cards.
After GSM replaced first-generation technology, including 1G NMT devices, it became a dominant industry standard – today holding approximately 82% of global market share compared to CDMA. GSM is available in more than 200 countries, while CDMA accounts for less than 20% of global wireless networks. GSM networks use a frequency band of 900, 1800, or 1900 MHz, and they are typically divided into cells, each of which is served by a base station, with a maximum cell site range of 120 km. GSM phones can roam internationally, meaning they can be used in any country with a GSM network.
It’s worth noting that although GSM came first, it also evolved faster. CDMA requires more processing power than GSM since it’s a full-on code-division system. As code division proved flexible and capable, new systems emerged from base GSM technology, such as “3G GSM,” wideband CDMA tech, or WCDMA – sometimes also referred to as UMTS, a Universal Mobile Telephone System. That said, the 3G era is now firmly behind us: AT&T shut down its 3G network in February 2022, T-Mobile shut down its 3G CDMA (formerly Sprint) network in March 2022, and Verizon ended its 3G CDMA network in December 2022.
What is CDMA?
CDMA, or Code Division Multiple Access, is a digital cellular technology that smartphones relied on primarily during the 2G and 3G eras. As the name suggests, Multiple Access refers to the band’s capacity to carry multiple signals on one transmission channel simultaneously, which helped boost available bandwidth for connected devices.
CDMA’s 1xRTT technology could provide speeds of up to 144 Kbps, and while faster CDMA variants existed, most major carriers chose to prioritize expanding their 4G LTE networks toward a global standard rather than continuing to invest in CDMA infrastructure.
Unlike GSM phones, CDMA phones traditionally did not utilize SIM cards and were typically locked into a carrier-specific plan. This made switching carriers far less convenient compared to GSM devices, which simply required swapping a SIM card. CDMA never achieved the same global adoption as GSM, which today holds approximately 82% of global market share and is available in more than 200 countries, while CDMA accounts for less than 20% of global wireless networks.
CDMA is now largely a thing of the past in the United States. AT&T shut down its 3G network in February 2022, T-Mobile shut down its acquired Sprint CDMA 3G network in March 2022, and Verizon officially ended its 3G CDMA network in December 2022. As a result, any devices that relied solely on CDMA networks are no longer able to connect to cellular service, and carriers have fully transitioned their customers to 4G LTE and 5G networks.
Which digital system is better?
You could ask this question on certain electronics and tech forums and stir up a lively debate about CDMA vs. GSM. While CDMA led to some meaningful advances, GSM ultimately dominated the global landscape, capturing approximately 82% of worldwide market share compared to CDMA’s less than 20%. GSM was available in more than 200 countries, and even back in 2007, it already held around 80-85% of the 2G market. Though each system still has its place in smartphone history, the truth is they’re both now fully retired technologies with well-documented limitations.
Since GSM’s introduction in Finland in 1991, it struggled with multiple access lines on one channel, leading to lower call quality and an infamous buzzing noise whenever GSM devices came too close to speakers. On the other hand, while CDMA’s 1xRTT technology offered speeds of up to 144 Kbps — faster than GSM’s slower GPRS data bandwidth — it still ran into significant speed limitations that couldn’t keep pace with the demands of modern video streaming, calling, and MMS. GSM also had a fixed maximum cell site range of 120 km, expanded from an older limit of 35 km, which gave it a broader geographic reach than many CDMA deployments.
CDMA and GSM also led to differing amounts of carrier control over the consumer. Networks like T-Mobile and AT&T made switching SIM cards between devices much easier due to GSM standards. Verizon, by contrast, relied heavily on CDMA technology, which made it especially difficult for customers to switch devices or carriers freely. All three major U.S. carriers have since shut down their legacy 3G networks entirely — AT&T ended its 3G network in February 2022, T-Mobile shut down its Sprint CDMA 3G network in March 2022, and Verizon retired its 3G CDMA network in December 2022.
Modern digital systems like 4G LTE and 5G networks have rendered these old debates largely irrelevant. Switching devices, transferring carriers, and trying new plans is far easier today. While plans may come at a premium for perks like unlimited high-speed data, they offer customers significantly more freedom and flexibility than anything CDMA or GSM could ever provide.
Should you invest in a GSM or CDMA phone?
Even though both CDMA and GSM are on their way out for good, millions of individuals still use these legacy digital systems every day. Though more and more people continue to switch to modern bands and networks, people in countries with slower infrastructure development may not have consistent or reliable 4G or 5G connectivity.
However, the reality of using legacy networks is a little more complicated. Major U.S. carriers have fully shut down their 3G networks, with AT&T ending its 3G service in February 2022, T-Mobile shutting down Sprint’s legacy 3G CDMA network in March 2022, and Verizon closing its 3G CDMA network in December 2022. Some carriers have left basic 2G service intact in limited capacities, but for most users, 3G is definitively gone. This has created real pressure for anyone still holding onto older handsets, and the “Switch or lose service” warnings that carriers issued for years have now fully materialized for 3G users.
Beyond network shutdowns, smartphones from the CDMA and GSM era simply don’t hold up well anymore. If you’re still working with one of these older devices, you’ve likely noticed degraded battery performance, connectivity issues, and trouble with basic calling and messaging. App developers have also largely stopped supporting older operating systems, meaning you may struggle to run even everyday applications.
It’s worth noting that GSM was always the dominant global standard, holding roughly 82% of global market share compared to CDMA, and remaining available in more than 200 countries. CDMA, by contrast, never accounted for more than about 20% of global wireless networks. Regardless, both technologies are now largely obsolete in markets with modern infrastructure, as 4G LTE and 5G have taken over as the global standard.
If you want a smartphone that will perform reliably over the next several years without service interruptions or compatibility headaches, upgrading to a 4G or 5G device is the clear move. As of 2026, 5G has matured considerably and is now widely available across most major markets. While 4G LTE remains a safe and functional choice in many parts of the world, 5G coverage has expanded rapidly, and investing in a 5G-capable device is increasingly the smarter long-term decision rather than a premium splurge.
Depending on your budget, a certified refurbished device can be a practical way to save money while still getting a capable modern phone. Pre-owned 4G or 5G devices can often be found at a significant discount compared to the latest flagship models, making it easier to step away from legacy networks without breaking the bank.
Looking even further ahead, 6G development is already underway globally, though widespread consumer availability is not expected until the early 2030s at the earliest. That means a 5G device purchased today should remain relevant and well-supported for many years to come, making it a solid investment for anyone looking to future-proof their connectivity.
Gazelle can help you find your next upgrade.
Learning the ins and outs of smartphone technology is no small feat. Major carriers have already shut down their legacy 3G CDMA and GSM networks – AT&T ended its 3G network in February 2022, T-Mobile shut down Sprint’s 3G CDMA network in March 2022, and Verizon ended its 3G CDMA network in December 2022 – meaning older devices that relied on those networks are no longer functional. If you’re still holding onto an outdated smartphone, now is the time to upgrade.
Gazelle offers dozens of different refurbished and lightly used electronics, including the newest smartphones like the iPhone 16 Pro Max and the Galaxy S25 Ultra. Our certified pre-owned devices must pass a rigorous 30-point inspection, and we provide top-notch customer service to help you make the most of your new device. Plus, you get the satisfaction of knowing that buying renewed electronics helps to keep e-waste out of landfills. When you’re ready to find your next smartphone, look to Gazelle.
FAQs
What is the difference between CDMA and GSM?
GSM uses time division technology and relies on SIM cards, while CDMA uses code division technology and traditionally locked users to specific carriers without SIM cards. GSM dominated globally with 82% market share, while CDMA accounted for less than 20% of worldwide networks.
Are CDMA and GSM networks still active?
No. All major U.S. carriers shut down their 3G networks between 2022 and 2023. AT&T ended service in February 2022, T-Mobile in March 2022, and Verizon in December 2022. Devices relying solely on these networks can no longer make calls or access data.
Can CDMA phones be used on any carrier?
CDMA phones were traditionally locked to specific carriers and didn't use SIM cards, making switching difficult. GSM phones were far more flexible, allowing users to simply swap SIM cards to change carriers.
Should I still buy a GSM or CDMA phone?
No. Both technologies are obsolete. Upgrading to a 4G LTE or 5G device is strongly recommended for reliable service and long-term compatibility. Certified refurbished devices offer an affordable way to make the switch.
Which was better, CDMA or GSM?
GSM ultimately won out, capturing 82% of global market share and operating in over 200 countries. While CDMA offered some speed advantages early on, neither technology could meet modern demands, and both have since been replaced by 4G LTE and 5G.