CDMA & GSM Capability.

If I purchase an iPhone 6, 6 Plus or SE, with say, Verizon service which is CDMA, can I later switch to a GSM Network on the same phone. In other words are the phones fully compatible with both systems and not dedicated to the one used at time of purchase.

iPhone SE, iOS 9.3.1

Posted on Apr 4, 2016 9:01 AM

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25 replies

Jul 3, 2017 3:02 AM in response to Lawrence Finch

GSM and CDMA are both networks.

LTE is short for Long Term Evolution and is a 4G wireless broadband technology developed to achieve high-speed data. 4G is the fourth generation of technology, following 2G and 3G.

CDMA is a code division system. Code

division turned out to be a more powerful and flexible technology, so "GSM" is actually a CDMA technology, called WCDMA (wideband CDMA) or UMTS (Universal Mobile Telephone System).h Both GSM and CDMA carriers use LTE TECHNOLOGY.

CDMA is in no way being "phased out ".

Jul 3, 2017 8:05 AM in response to Debra420

I'm sorry, but that is almost completely wrong in every respect. GSM is actually a TDMA (Time Division Multiple Access) technology, not CDMA (Code Division Multiple Access). UMTS is not part of GSM. The Wikipedia article is not the standard, but is reasonably accurate: https://en.wikipedia.org/wiki/GSM


Here is what it has to say: GSM is a second-generation (2G) standard employing time-division multiple-Access (TDMA) spectrum-sharing, issued by the European Telecommunications Standards Institute (ETSI). The GSM standard does not include the 3G Universal Mobile Telecommunications System (UMTS) code division multiple access (CDMA) technology nor the 4G LTE orthogonal frequency-division multiple access (OFDMA) technology standards issued by the 3GPP.[

[emphasis added]

Note that LTE is neither GSM, nor TDMA nor CDMA. Nor WCDMA, which is a 3G technology, not 4G, and is also being phased out along with CDMA. The name is also misleading, as it is not an extension of CDMA, but a totally different technology.

Apr 4, 2016 9:19 AM in response to czvet

Yes, and No.


A little explanation:

While all iPhones since the 4s have included both CDMA and GSM hardware which would allow them to be used on any carrier either GSM or CDMA based,


It's a regular practice of CDMA carriers to not activate iPhones not sold specifically for them on their networks.


So if you were to buy say an AT&T iPhone, Sprint and Verizon would in the past not activate it on their service at all.


Recently new legislation has made it so Verizon now will activate iPhone 6s and 6s Plus on their networks even if not sold specifically for them.


Not sure whether Sprint does this too.

Another issue to consider, is when buying an iPhone for a specific carrier or from a specific carrier store, the iPhone is locked to that carrier, and requires unlocking if you want to be able to use it with other GSM carriers. (CDMA is not unlockable, and a Verizon based iPhone can never be used with Sprint's CDMA service and vice versa) .

Unlocking can only ever be authorized by the carrier to which the iPhone is locked. So an AT&T locked iPhone can only be unlocked by AT&T.

In the U.S. the only source of unlocked iPhones is Apple themselves. If you buy an iPhone from them at full price, it will be unlocked, and can be used with any GSM carrier of your choice.

Buying an iPhone at a reduced price with a 2 year contract with a particular carrier means the iPhone will be locked to that carrier, and only that carrier can unlock it for use with other carriers.


Unlocked iPhones, either from Apple, or ones correctly unlocked by the carrier to which they were locked to , will never lock to another carrier.


If you buy a Verizon iPhone at full price from Apple it will be unlocked and usable with any GSM carrier. If you buy it at a reduced price from Verizon or Apple with a 2 year contract it may be locked to Verizon, and you will need to fulfill Verizon's requirements for unlocking.

Apr 4, 2016 9:19 AM in response to czvet

czvet wrote:


If I purchase an iPhone 6, 6 Plus or SE, with say, Verizon service which is CDMA, can I later switch to a GSM Network on the same phone. In other words are the phones fully compatible with both systems and not dedicated to the one used at time of purchase.

All Verizon iPhones are sold unlocked. They should be usable on any GSM/LTE network.


Some of Phil's information is a bit out of date were Verizon is concerned. Verizon will activate any unlocked iPhone 6/6+ or 6S/6S+ except those intended for sale in China. This includes phones original intended for use on Sprint. The iPhone SE is not yet on the list but I expect it will be shortly.

Apr 4, 2016 11:33 AM in response to IdrisSeabright

Meg St._Clair wrote:


Phil0124 wrote:


So what you are saying, is Sprint needs to unlock the GSM portion before Verizon will activate the CDMA portion on their network. Seems a little convoluted.

I think, more accurately, Sprint needs to unlock the LTE part of the device. Larry will correct me if I've got that wrong.

Correct, but also because Verizon will not accept a CDMA-only iPhone 6 or later.

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CDMA & GSM Capability.

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