--- title: What is CDMA? description: CDMA is one of RedPocket Mobile’s wireless network options. CDMA plans work with GSM-unlocked and Verizon-compatible GSM devices—meaning the phone uses a SIM card and is not restricted to a single carrier. --- [Skip to content](https://help.redpocket.com/what-is-cdma#main-content) English Show submenu for translations [Submit a ticket](https://help.redpocket.com/kb-tickets/new?hsLang=en) ![3.svg\]](https://help.redpocket.com/hubfs/3.svg) Open main navigation Close main navigation - English Show submenu for translations - [Submit a ticket](https://help.redpocket.com/kb-tickets/new) - [Go to redpocket.com](https://www.redpocket.com/) [Go to redpocket.com](https://www.redpocket.com/) RedPocket Mobile - There are no suggestions because the search field is empty. 1. [Help Center](https://help.redpocket.com/?hsLang=en) 2. [Learn About Mobile](https://help.redpocket.com/learn-about-mobile?hsLang=en) 3. [About SIMs and Plans](https://help.redpocket.com/learn-about-mobile?hsLang=en#about-sims-and-plans) # What is CDMA? CDMA is one of RedPocket Mobile’s wireless network options. CDMA plans work with **GSM-unlocked** and **Verizon-compatible** devices, meaning the phone uses a SIM card and is not restricted to a single carrier.   ##### **Isn’t CDMA different from GSM?** Yes, but the difference matters less today than it used to. There are two main types of mobile technology: - **CDMA** (Code Division Multiple Access) - **GSM** (Global System for Mobile)   **GSM phones** store important calling information (like the phone number and wireless plan details) on a **SIM card**, which can be moved between compatible phones. For CDMA phones, this information is embedded in the device's hardware.  In the past, GSM also had a functional advantage: it allowed voice calls and mobile data to be used at the same time, while older CDMA phones could not. These limitations applied only to **2G and 3G**, which are now retired.   ##### **Why this difference matters less today** Modern phones use **4G LTE** and **5G**, which support voice and data at the same time. To support LTE, all carriers—including traditional CDMA carriers like Verizon—had to adopt SIM-based, GSM-compatible devices.   ##### **How this affects RedPocket mobile** Although this network is referred to as '**CDMA**', the devices used today are **GSM-compatible and SIM-based**. This is why RedPocket supports only GSM devices, even on networks that were historically known as CDMA.   ##### **How to check if your phone is GSM** Look for a **SIM card slot**, usually located on the side, top, or bottom of the phone, or underneath the phone's battery after removing the back cover. Quick Note: Apple iPhone models 14 and newer are eSIM-only. While these devices are GSM-compatible, they do not have a physical SIM card slot. Check your phone’s user manual or search online for your specific model’s SIM compatibility. If you’re still unsure, [contact support](http://redpocket.com/contact-us) for help. Additionally, please keep in mind that the phone must be **unlocked**.   ##### **Choosing a CDMA plan** If you’re interested in a CDMA calling plan, visit [redpocket.com/plans/plans-cdma](http://redpocket.com/plans/plans-cdma). Plans must be activated within **90 days** of purchase. 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