Which phones are more compatible with GSM Vs CDMA?


AC Question


Maybe I don't really understand exactly what makes a phone compatible or not, but it seems like a lot of phones are more compatible with GSM ( At&T) then CDMA (Verzion). For example the new moto G. Looking at other phones as well its seems like there are more phones that can be gotten unlocked that are more compatible with At&T. Am I totally missing something or is this the case?


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Feb 12, 2012
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Re: Gsm Vs CDMA

Older phones had GSM radios or CDMA radios. They're different technology. (GSM IS TDMA - time division multiple access - each phone gets a time slot to talk to the tower, CDMA is code division multiple access - the center frequency of the signal from each phone changes according to an algorithm based partly on the phone's ESN).

Newer phones have both TDMA and CDMA radios, so they can be used for either system. There's either compatible or not compatible, there's no "more compatible".

You have to look at the phone's 2G specs. If it's GSM/CDMA, it's compatible with either one. If it's not, and you want AT&T, it has to be GSM.

gone down south

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Jul 24, 2012
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Re: Gsm Vs CDMA

GSM is a global standard, so every phone is released supporting it (different carriers use different radio frequencies so not every specific handset works everywhere, but that's not a concern to this question.)

CDMA is used by Verizon and Sprint in the US and a couple niche markets in other countries, and that's it. A carrier had to specifically decide to make a model for Verizon and Sprint, then go through a difficult process of changing everything internally to meet up with those carriers' rather irrational design demands.

In practice, the only CDMA handsets are mass market offerings by the largest manufacturers who focus on the US market, because the barriers to entry are too high otherwise.