Although GSM is the big gorilla in the global market not everyone has jumped on the GSM train. An alternative cellular standard known as Code Division Multiple Access, or CDMA, is used by many carriers around the world. It is most popular in the United States and Russia. However, it’s also used in some Asian and African countries, often alongside competing GSM carriers. It's really easy to swap phones on a GSM network versus CDMA. This is because GSM phones use removable SIM cards to store information about the user on the GSM network, while CDMA phones do not. Instead, CDMA networks use information on the carrier's server side to verify the same type of data that GSM phones have stored in their SIM cards. This means that the SIM cards on GSM networks are interchangeable. Such an easy exchange is simply not possible with most CDMA phones, even if they do have removable SIM cards. Instead, you typically need your carrier's permission to perform such a swap. Since GSM and CDMA are incompatible with one another, you can't use a Sprint phone on a T-Mobile network, or a Verizon phone with AT&T.
LTE entered the market things have gotten a bit easier. The
reason being that in order to access LTE and fast data speed, you need a
SIM card no matter if you’re using CDMA or GSM. All LTE networks in the
U.S. are using GSM technology, as CDMA Technology is too old to handle
LTE speeds. Due to this, newer Verizon and Sprint phones all use a SIM
card and will, therefore, work on GSM networks. Something else to
consider when looking at the differences between CDMA and GSM is
that all GSM networks support making phone calls while using data. This
you can be out and about on a phone call but still use your navigation
browse the internet. Such capability is not supported on most CDMA
Seeing as all new phones aren’t using CDMA, it raises the
CDMA will disappear once old CDMA phones aren’t active anymore? With an
average cycle of replacing devices, pretty much all CDMA devices will be
gone by 2020. Currently, just a fraction of Verizon and Sprint’s
customers are utilizing the CDMA, as they’re mainly on LTE. Time will
tell if and when Verizon and Sprint will get rid of CDMA altogether.
With that being said acquiring wholesale CDMA cell phones is still
critical to have in your inventory for your customers as the technology
is still being used sporadically throughout the globe garnishing
anywhere between 20-25% market share.