How to Differentiate Between CDMA and GSM

Today, Mytour will guide you on how to check whether your phone uses a CDMA or GSM network. This information is crucial if you're looking to unlock your phone or use a specific carrier's SIM card on an unlocked device.

Consider your location. Unless you purchased your phone in the U.S. or Russia, it is most likely to use a GSM network.

• Although CDMA is one of the two primary networks in the U.S., only around 18 percent of mobile networks globally use CDMA.

You should know that most mobile phones now support LTE. Both CDMA and GSM are 3G networks, but phones on either network can also support 4G (LTE) as long as the device itself supports a 4G SIM card. This means that whether your phone is CDMA or GSM doesn't matter if you don't plan to switch networks.

• Similarly, whether your phone uses a SIM card or not is not a determining factor for distinguishing CDMA from GSM.

Check your current mobile carrier. In Vietnam, all major carriers including MobiFone, VinaPhone, Viettel, and VietnamMobile operate on GSM networks. If you purchase a phone from a carrier in Vietnam, it will almost certainly be a GSM version.

• Verizon in the USA operates on CDMA but also supports GSM.
• If you purchase an "unlocked" phone, it won't be tied to any particular carrier, making it hard to determine its network type.

Check the 'About' section in your settings. If you see an entry for MEID or ESN, your phone uses CDMA. If you see IMEI, it’s GSM. If both are present (like with Verizon phones), the device supports either CDMA or GSM.

• For iPhones — Open Settings, tap General, go to About and scroll to find MEID (or ESN) or IMEI.
• For Android — Open Settings, scroll down and tap System (only on Android Oreo), then tap About phone and select Status to find the MEID (or ESN) or IMEI.

Look at your phone's model number. If you still can't tell whether your phone uses CDMA or GSM, check the model number. This info can be found in the user manual or by navigating to the 'About' section in the settings. You can then search online to see which network the phone supports.

• For iPhones, go to Settings > General > About and check the number next to 'Model'. For Android users, go to Settings > System (on Android Oreo) > About phone to find the model number here.
• The iPhone model number is printed on the back of the phone, although it might be hard to see on darker colors like jet black or space gray.
• If you can't find the model number, visit the manufacturer's website to look up your phone type (e.g., iPhone 7, jet black, 128 GB). This will help narrow your search.

Try removing the SIM card and using the phone. While GSM and LTE phones require a SIM card, you can use a CDMA phone without one. If your phone works without a SIM card, it’s CDMA.

• The phone will default to 3G network.
• You can remove the SIM card from both iPhones and Android devices.

Call your current carrier. Reach out to your mobile carrier to ask whether your phone is CDMA or GSM. Most of the time, they will ask for your phone's IMEI or MEID number, as well as your name and other account details.

• Note that if your phone is unlocked and not tied to a specific carrier, contacting the carrier won't provide a solution. In this case, checking the model number is the best option.

• GSM phones are most commonly used in Europe and Asia, as they are convenient and often preferred by travelers.
• If you bring your phone to a carrier's service center, they can help determine whether it supports both networks. Some phones (like certain models from Verizon in the USA) support both CDMA and GSM through multiple SIM slots.

• If you can’t find the model number anywhere, take your phone to the manufacturer's service center (e.g., for iPhones, visit an Apple Store; for Samsung Galaxy, go to a Samsung distributor) where a technician can determine the model number and network type. This service is typically free of charge.