Understanding CDMA versus GSM

Person on refurbished tablet.

Understanding CDMA versus GSM

Need help deciding between two major US telecom standards? CDMA and GSM are both widely used by the top cellular networks globally. It might be a difficult choice to select between CDMA vs. GSM, as both have their very own distinct advantages. When searching for a mobile phone provider, you might have to determine which of these two technologies are the best fit for you and hopefully this guide will shed some light on the entire debate.


What is CDMA?

CDMA or Code Division Multiple Access is a technology that was developed by Qualcomm®. This network is currently the dominant system in North America and used for both Verizon® and Sprint®. CDMA was established before GSM in North America and consequently has a little more coverage than GSM. CDMA is for phone signal only and can only support 3G data speeds.The data portion of Verizon and Sprint devices is typically available at 4G LTE speeds which uses GSM. For this reason, many CDMA phones are both CDMA and GSM compatible.


Also, CDMA devices typically store account information and data (like your contact lists) directly on the cellular phones memory instead of a SIM Card (Subscriber Identity Module). CDMA phones are gradually catching up to GSM with R-UIM cards, but mobile phones that make use of this tech are still very rare in the US.


What is GSM?

GSM or Global System for Mobile communication was invented in 1987 by the GSM Association, a global organization specializing in developing this standard worldwide. GSM is a global standard backed by international carriers and this is the protocol that has matured more quickly and is stronger than CDMA. The GSM network is, for the most part, well established within North America, but may not be as far reaching as the CDMA network is today. GSM is catching up quickly however, but its EDGE technology is prone to interference. Many of the devices sold through AT&T and T-Mobile are GSM phones.


In GSM phones, your account information, contact list, and other personal data is stored on a SIM card. Once you get a brand-new mobile phone, you can just insert your SIM card into the new device and it'll work with your current account info and contact list. This portability is important for many people who plan to travel or change phones often.


Who wins the debate of GSM vs CDMA?

There is no obvious winner in the CDMA vs. GSM debate, it all depends upon your own individual needs. Do you frequent sparsely populated areas and prefer having the broader coverage of CDMA, do you live in a densely populated area or do you have thick concrete walls and prefer the stronger signal power of GSM? Which technology is the best for you?


What does unlocked really mean for me?

A device that is locked means that it will only work with one carrier whereas an unlocked pone will work with multiple carriers.A GSM unlocked phone means that it has a SIM card, and typically works with most GSM carriers like T-Mobile & AT&T, while a CDMA unlocked device may not have a SIM card and usually works with CDMA networks like Verizon & Sprint.


If you do not plan on switching carriers, then it is probably unnecessary to buy an unlocked device.However, purchasing an unlocked phone allows you to take the SIM card from your existing phone and put it into the new-to-you phone and be able to use it. The other benefit to owning an unlocked refurbished phone, is that you can buy a prepaid SIM card in the country you are traveling to, so you can temporarily use your device in that country because GSM networks are the most common type of network outside the US. It is still very important to check with your carrier on whether an unlocked device will work on their network. Certain models may not work within all the carrier’s bands and it is prudent to double check compatibility BEFORE you buy it.


No matter which choice you land on between CDMA and GSM, MyWiT® offers a variety of refurbished phones within each category. Our collection of refurbished smartphones are all tested and inspected by expert technicians and we ensure you’ll be 100% satisfied with your purchases or your money back (30-day money-back guarantee).

June 5, 2018
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