So what’s the difference? For the consumer, there isn’t much. Primarily, GSM is widely used globally while CDMA is more popular in the US. International travelers can more easily adapt their phones to foreign GSM networks. The other significant difference lies tucked in the phone itself, usually just under the battery. GSM phones store information on portable SIM cards, allowing you to keep all the settings and contacts from one phone and slip them all into another. You transfer all your data between phones simply by exchanging SIM cards. This is very convenient for upgrades, replacement phones, or if you just happen to like carrying different models depending on the occasion. CDMA stores that information in the phone itself and cannot save or transfer it between devices.
People wonder whether a choice between CDMA and GSM affects their coverage. Within their networks, the standards operate equally well. The difference lies in the reach of each network. Some regions of the country are within close reach of CDMA towers but far from GSM towers and vice versa. For those regions, it’s important to determine which carrier (i.e. which network) works best and to go with it. Coverage varies by region and availability, not network standard.
Only within the last year, really the last few months, have these network models become increasingly insignificant. These are 3G systems including (HSPA and HSPA+) we’ve been describing, but the next level, 4G networks, are popping up quickly. In fact as we begin to transition, 3G/4G Routers, phones and cell boosters are becoming increasingly common. Verizon has been rolling out its 4G LTE network, already in 140 markets and counting. AT&T has responded with its own 4G LTE network, currently operating in 5 cities. This “next-generation” standard improves data speeds so that you can download or stream as much music and video as you can muster, and do it instantly. 4G systems make smartphones worth it. So, CDMA and GSM are quickly becoming relics of the past. But, for those of us without an iPhone or Droid, they’re still significant and worth knowing more about.