In the US, different carriers use different technologies. For instance, AT&T uses GSM while Verizon uses CDMA.
If you’re looking for the differences between CDMA and GSM, you’ve come to the right place. We’ll also detail the different GSM carriers and those using CDMA, plus how to check which network band your phone uses.
CDMA and GSM Technologies
CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are frequency bands associated with the second and third generation of wireless technology (2G and 3G).
Under the hood, CDMA works in packet switching mode while GSM works in circuit switching mode. For you as an end-user, the most crucial distinction between the two is GSM allows you to make calls and use data at the same time while CDMA doesn’t.
Between the two, GSM is the most popular with a larger market share around the world. As such, GSM is more suitable for someone who travels frequently. Moreover, thanks to SIM cards, you can easily switch between different devices by simply porting over your card.
CDMA phones are compatible with 2G/3G CDMA networks, while GSM phones only work with 2G/3G GSM networks. So if you want to use your CDMA device on a GSM network, it won’t work.
As such, it’s essential to know what kind of technology your phone uses. Understanding the difference between CDMA and GSM comes in handy when you want to switch carriers. Of course, assuming you have an unlocked phone that isn’t tied to one specific carrier.
While phones did support one or the other in the early days, nowadays, most have both CDMA and GSM. However, the question of whether or not your phone supports one or the other, or both, largely depends on where you bought it. We’ll show you how to check whether your phone supports GSM, CDMA, or both bands later. But, first, here are the different GSM and CDMA carriers in the US.
GSM and CDMA Carriers
In the US, different carriers use different bands. The only GSM carriers are AT&T and T-Mobile. CDMA carriers include Sprint’s old 3G network (now owned by T-Mobile), US Cellular, and Verizon.
The network used also influences the frequency band supported by smartphones sold by respective carriers across the US. For instance, AT&T and T-Mobile only sell GSM-compatible phones. The only special case is Verizon, which despite having a CDMA network, sells phones that support both GSM and CDMA bands.
Does Your Phone Use CDMA or GSM? Here’s How to Check
There are five different ways of checking whether your phone uses GSM, CDMA, or supports both.
1. Does Your Phone Have a SIM Card Slot?
In the old days, one of the easiest ways to tell the type of band supported by a phone was whether it had a SIM card slot or not. GSM phones had a SIM card slot while CDMA phones didn’t. CDMA phones don’t need a SIM card since the phone number is linked to the device itself.
However, with the advent of 4G and 5G networks, many smartphones have SIM cards, so it’s no longer an efficient method. But if your device doesn’t have a SIM card slot, it uses CDMA. That said, the advent of eSIM changes things again, which is why checking for a SIM slot isn’t a reliable option.
2. Using the Settings App
You can also check by digging through the Settings app on an Android or iOS device.
On iOS, open the Settings app, tap General, and select About. On Android, open the Settings app, tap About phone, and select Status.
Keep in mind that precise steps will vary from device to device on Android due to the fragmented nature of the OS. In the About (iOS) or Status (Android) page, scroll down and check for a MEID, ESN, or IMEI number.
If your phone has a MEID or ESN number, it uses CDMA, and if it has IMEI, it uses GSM. If you see both, that means your phone supports both GSM and CDMA networks.
3. Where Did You Buy Your Device?
Devices bought directly from manufacturers commonly support both CDMA and GSM for better compatibility. So, for example, if you bought your phone direct from Samsung or Apple, chances are it supports both.
However, carrier-locked devices are usually associated with a particular network band. As previously stated, different carriers support different bands. Every wireless carrier sells devices that are compatible with its network band.
Smartphones from AT&T and T-Mobile are GSM-compatible since both carriers use GSM technology like most of the rest of the world. However, while Verizon is a CDMA carrier, it sells smartphones that support both GSM and CDMA. That means a Verizon unlocked smartphone can work on T-Mobile’s or AT&T’s GSM networks without issue.
Read More: Is My Phone Unlocked? Here’s How to Know
4. Check Your Phone Model Information
Another easy way to tell whether your iOS or Android device is a GSM or CDMA variant is by looking up the model number online. You can find your phone’s model number at the back or with the packaging box it shipped with. Once you have the model number, you can look it up online to determine whether your device supports GSM, CDMA, or both.
5. Refer to the Manufacturer’s Documentation
The paperwork that ships with your device also contains details about the network band supported by your device. However, you don’t need the paperwork if you know your specific device model, as you can look it up on the manufacturer’s website.
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.
