CDMA Meaning: What CDMA Networks Are and Why They Matter for Your Phone

If you’re shopping for a new-to-you used phone or trying to figure out if your current device is compatible with a different wireless provider, it’s important to know some key terms. With some used phones, you might see the term “CDMA” thrown around — this stands for Code Division Multiple Access, and it has a big impact on how the device functions in daily usage.

CDMA phones were once a hot commodity, but has technological innovation made these devices relics of the past? Or is there still a use for CDMA technology today?

CDMA: Code Division Multiple Access

CDMA networks are a form of radio and mobile communication technology that enables multiple people to use their cell phones on the same frequency band. CDMA prevents interference from concurrent voice calls and allows devices to communicate with cell towers.

There have been many types of multiple access technologies used for mobile phones over the years, providing consumers a way to share network infrastructure without interrupting each other’s communications. CDMA is a form of spread-spectrum technology, which means that each call’s data is encoded using a unique key, and the network spreads out these encoded calls over a range of frequencies. The device receiving the call decodes the signal using this same key.

CDMA networks were originally created for military comms in World War II. The technology is so efficient and secure that companies leveraged it decades later as the foundation for mobile data networks.

CDMA and GSM Networks: The Race for Mobile Dominance

GSM networks were CDMA’s top competitor. Short for Global System for Mobile Communications, GSM technology shares some common aspects with CDMA networks, like the ability for frequency bands to handle many different calls at the same time. That said, there are also some significant differences that set them apart.

GSM networks made their debut in 1991. By 2006, GSM phones were the universal standard, with over 2 billion users. By the mid-2010s, GSM technology had left CDMA in the dust, with a 90%+ market share and networks in over 200 countries. What made GSM networks so appealing compared to CDMA technology?

Data Issues With CDMA Phones

One major differentiator was the fact that CDMA networks were great for voice calls but struggled mightily with the introduction of data plans on cell phones. While CDMA typically couldn’t handle both voice and data at the same time, GSM networks can maintain simultaneous voice and data communications. As smartphones became the norm, GSM technology naturally surpassed CDMA networks due to this data difference.

Network Locks for CDMA Carriers

Wireless network locks were another major issue for CDMA technology. GSM users can switch cellular networks — for example, from T-Mobile to Verizon’s network — by swapping out their SIM cards. However, CDMA carriers had network locks built into the phones. Therefore, if you wanted to switch carriers with a CDMA phone, you would have to switch mobile devices, too.

GSM Becomes the True “Global System for Mobile” Communications

In Europe, GSM became the common standard for mobile networks. As other countries started adopting the technology, various GSM carriers set up roaming agreements that allowed their users to make calls and transmit data all over the world.

From SIM Cards to Unique Carriers: How GSM and CDMA Fought for Supremacy

Two major issues made it all but inevitable that GSM networks would win the mobile frequency band wars: SIM cards and carrier loyalty. In the U.S., four of the largest wireless carriers were split between CDMA and GSM. While Verizon and Sprint (which today is part of T-Mobile) exclusively used CDMA technology, AT&T and T-Mobile opted for GSM networks.

This schism caused confusion and more than a few headaches for consumers. Users were frustrated by how difficult it was to switch networks at all, not to mention switching from CDMA to GSM or vice versa. After all, CDMA phones didn’t work on GSM networks, and GSM phones didn’t work on CDMA technology. It became apparent that one of these technologies would become the standard while the other slipped into obsolescence.

One of the reverberating effects of the CDMA vs. GSM battle is how much easier it is to switch networks today. Now, some wireless carriers still “lock” their devices, but they must unlock it if you meet a few basic conditions. For instance, you must have fully paid off the phone and had service on it for a designated time period (usually 60-90 days). But in general, it’s incredibly simple to switch networks today in a post-CDMA world.

SIM cards played a big role in GSM’s eventual victory, as the presence or absence of these cards became a key difference between the competing networks. CDMA devices didn’t have SIM cards — as we mentioned earlier, the phones were irrevocably tied to the carrier’s network using unique code numbers. Thanks to GSM phones’ usage of removable SIM cards, users could switch devices and wireless providers with ease by simply popping out their cards and inserting them into their new phones.

Over the years, Verizon and Sprint eventually shifted their operations to GSM tech, and today, CDMA technology is essentially dead. Or is it?

Is CDMA Still in Use?

Code Division Multiple Access played a significant role in the development of mobile communications, but for the most part, it’s irrelevant today. Verizon shut down its CDMA networks in 2022, while T-Mobile deactivated Sprint’s CDMA technology after their merger the same year. While CDMA remains in use in some small pockets of developing nations, most carriers around the world have shut down these legacy networks.

That said, CDMA does remain somewhat relevant today, as remnants of this technology still reverberate (mostly outside the U.S.). Specifically, GSM carriers use a 3G standard called the Universal Mobile Telecommunications System (UMTS) that uses wideband CDMA, a type of radio technology derived from legacy CDMA tech. However, UMTS today is largely used in China and is being slowly phased out over time.

Long story short? For most people in the United States and Europe, CDMA technology has become completely irrelevant.

How the CDMA vs. GSM Question Affects Buying Phones Today

While there are fewer and fewer CDMA devices in circulation today, they still pop up from time to time. If you’re buying or selling older used phones, you should still keep an eye out and avoid CDMA phones. To make sure a phone isn’t CDMA-based, look for terms like “unlocked” or “LTE-capable,” as these are surefire signs that a phone is GSM-based.

In addition, exercise caution with devices from the mid-2010s, especially if they were locked to the Verizon or Sprint networks. CDMA devices have essentially zero resale value today, so you’ll want to avoid buying them.

The Legacy of CDMA Technology

Both CDMA and GSM made significant impacts on today’s mobile phone technology — just because GSM won the war doesn’t mean CDMA didn’t have any lasting impacts. CDMA was a revolution for frequency efficiency, as it was the first widely adopted technology that allowed many users on the same frequency band, greatly increasing broader network capacity.

CDMA also made significant strides in network security. Before CDMA, it was far too easy to tap into a phone line and eavesdrop on calls. However, the spread-spectrum technology used by CDMA technology spread signals across wider phone bands, making these networks highly resistant to interference.

What Should You Do With CDMA Devices?

Overall, today’s typical smartphone user doesn’t need to know anything about CDMA. It’s a largely dead form of technology that was once a cornerstone of the wireless communication world. That said, even though there are few CDMA devices still in circulation, it’s still not all that unlikely to find one lying around collecting dust in the back of a drawer or in a box in your grandma’s attic. If you have one of these phones, what should you do with it?

Here at ecoATM, we gladly pay top dollar for high-quality used electronics. That said, it’s unlikely that we’ll offer any money for old CDMA devices, as there simply isn’t any market demand for these phones in today’s society. However, that doesn’t mean you should take your old phones to the landfill!

Recycle Your Old Phone With ecoATM

Whether your device runs on GSM, CDMA, or 5G, we’ll still recycle it on your behalf, even if we can’t resell it. We’ve already helped recycle over 50 million smartphones and tablets, and we’re well on our way to 100 million. When you recycle your old phone with ecoATM, you keep it out of the landfill, where it can leach toxic chemicals into the environment, potentially poisoning the air, soil, and water.

It couldn’t be much simpler to recycle your outdated CDMA devices with ecoATM. The first step is to get a pricing quote, and you can do this on our website or at your local ecoATM kiosk. With over 6,000 kiosks in the United States — located in popular retail stores like Kroger, Dollar General, Walmart, and more — your nearest ecoATM kiosk might be right around the corner, in a store you already shop at!

How It Works

If you use our online pricing tool, you just need to enter some details about the device so we can generate a quick quote. If you’d rather have it analyzed at the kiosk, simply connect it to the kiosk when you arrive. Our kiosk will perform an assessment of your phone and let you know whether we can offer you instant cash or if we’ll only accept the device for recycling.

Before you sell or recycle your phone at an ecoATM kiosk, you’ll need to take a few simple steps to prepare your device. First, make sure to back up all of your personal data — once you drop your phone off at an ecoATM kiosk, you won’t be able to access your photos, videos, app data, and more.

Then, you should perform a factory reset to restore your phone to its original factory settings and delete all of your data. If you have an Apple device, you’ll also need to turn off the “Find My” feature before bringing it to the kiosk. Make sure to log out of all your accounts, too.

You’ll also want to charge your device, as we offer more money for devices that turn on. In fact, we typically offer an average of $50 more for devices that power on than those that don’t! Finally, bring a valid form of state ID so we can verify your identity at the kiosk.

Once you’ve completed these steps, you’re ready to sell or recycle your device with ecoATM. Visit one of our 6,000+ kiosks today and see how good it can feel to help the environment and declutter your home at the same time!