CDMA vs GSM vs LTE: The Differences & What You Need to Know

CDMA vs GSM vs LTE Labels

US Mobile provides service on the leading GSM, CDMA, and LTE networks in the US. But what are GSM and CDMA, and how do they affect your phone, service, and coverage? 

What is CDMA vs. GSM vs. LTE?

GSM and CDMA are different technologies that phones use to connect. They were both developed in the early nineties for 2G connectivity. But engineers couldn’t agree on which one was the best. So, in the US, the FCC settled on a “dual-mode” route that required either GSM or CDMA. That’s why we have 2 different technologies. 

Europeans, though, agreed on GSM, as did the rest of the world. That’s why GSM is the de-facto system for the rest of the world. 

For 3G, carriers only improved the original GSM and CDMA technology. So the duality remained.

Fortunately, engineers agreed on a new cellular system for 4G connectivity. And that’s LTE. Carriers designed LTE for data. But it’s been working so well that they are replacing everything else with it. For example, they’ve introduced VoIP solutions like VoLTe to replace traditional calls.

Do all the carriers agreeing on LTE mean it will easier to switch phones between carriers?

You would think so. But, no.

Most new phones use LTE only for data and rely on GSM or CDMA for voice and texts. So you’re stuck with choosing between a CDMA and GSM phone if you want voice. However, most of Verizon and Sprint’s customers are on LTE. They’re working on VoLTE to solve the voice-over CDMA problem so they can phase out 3G as early as 2019.

Moreover, the four carriers provide LTE on different frequency bands. They sell phones that only work on their frequencies, making it difficult to switch.

Many phone companies are also making phones that support CDMA, GSM, LTE on most bands. iPhones 6 and beyond, Google Pixels, Samsung S7s, and beyond.

As WhistleOut states that US Mobile supports both GSM and CDMA devices with their Super LTE and GSM sim card. 

What you NEED to know about CDMA vs. GSM vs. LTE

Call Quality on CDMA vs. GSM

Whether you use a CDMA or GSM network, it does not matter. What matters is the coverage from the CDMA and GSM networks. Luckily, US Mobile has excellent cellular coverage using the best GSM and CDMA networks in the US.

CDMA vs. GSM phones

Switching GSM phones between different networks is easier than with CDMA phones. That’s because all GSM phones use removable SIM cards. You can put a SIM from one phone into a newer one, and all your info like phone number and plan will go to the new phone.

CDMA phones didn’t use SIMs. They used embedded serial numbers to identify their users to carriers. This meant three things:

  • You couldn’t switch phones easily. You had to tell your carrier that you have a new phone so they can link the serial number of the new phone to your account.
  • This gives carriers more control over their phone choices. And, more often than not, they didn’t accept new phones unless you bought them through them.
  • Since there was no way to insert a SIM card, you could not take your phone with you to a GSM carrier.

LTE phones need SIM cards. And, since LTE provides the fastest data, most newer phones also have LTE capabilities. Thus, most newer phones also take SIM cards. Does that mean you can switch phones between carriers? It will be easier, but you still have to make sure your phone has different frequency bands. Or buy phones that support CDMA, GSM, and LTE on most bands.

Or find a carrier who provides service on GSM, CDMA, and LTE networks, lets you bring any phone and helps you figure out the best network for your phone (seriously, just ask us, and we’ll help), and provides great service and coverage with that 🙂

  1. I want to purchase the Galaxy Note 9 – International version. It allows for two SIM cards, which enables me to use one phone for business and personal, instead of carrying two physical phones.

    I want to use it with Verizon in the US. It does not have CDMA, but does have 3G and 4G LTE. Based on what I read on your site, data should not be a problem. But what about voice calls? Does Verizon use LTE for voice calls or do they still use CDMA?

    Some of the websites selling the international version say it will not work on Verizon, but I am sure that is because the international version is GSM/3G/4G LTE and not CDMA/3G/4G LTE.

    I spoke with a rep at Samsung who said that voice would automatically be downgraded to 3G but I’m still not sure that answers my question.

    Verizon says it will, as long as it has two physical SIMs and not an eSIM (software SIM, whatever that is)

    I guess the bottom line is, will this phone work on the Verizon network? Will I be able to make calls and use data?

  2. I am going (maybe moving permanently) to Lagos, Nigeria. I was given a Boost Mobile Samsung Galaxy S6 that was purchased on Amazon for me. I see that it can be an LTE CDMA or GSM phone. it’s locked to Boost Mobile and I don’t have it activated.
    I know there are GSM carriers in Nigeria but I am confused. I did try to see if the local Verizon phone store could accommodate this phone and they said they could not do anything for me.
    Reading your info, it looks like maybe they could have helped me out, maybe even with an international cell plan.
    The phone has a phone number of 808-371-9648 in setup and an IME xxxxxxxxxxxxxxxx.
    Do you have any suggestions
    Thank you

  3. I have two tracfones, one is LTE, the other GSM. Can I put the GSM SIM card in the LTE phone? The LTE is Verizon and I have no service. The GSM is AT&T and supports our area. I like the LTE phone better because it has more upgrades. Thank you.

    1. Hi Sheryle,

      To get the offer you have to get Super LTE service on an iPhone XS, iPhone XS Max or iPhone XR. All the best!

  4. I want to use my Kyocera duraforce Pro which is on CDMA I want to use it on gsm what can I do I love this phone please help me

    1. Hi Vance,

      We can understand why you love that phone so much 🙂 If your phone is unlocked, and not in a payment contract you could potentially bring it to our Super LTE network. We could send you a Starter Kit for free to see if it works.

      Just reach out to us at [email protected], or on chat and we’ll be happy to send one over for you to test.

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