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I was really excited about buying an unlocked iPhone 4S. And then I read this: The unlocked iPhone will not work with CDMA carriers such as Verizon Wireless or

by e28eta 15y ago

I was really excited about buying an unlocked iPhone 4S. And then I read this: The unlocked iPhone will not work with CDMA carriers such as Verizon Wireless or Sprint. [1] Until an unlocked phone means I can switch between the major US carriers, it doesn't mean anything for me. I don't travel internationally, and when I do I'll hopefully be able to jailbreak and unlock. [1] http://store.apple.com/us/browse/home/shop_iphone/family/iphone/iphone4s http://store.apple.com/us/browse/home/shop_iphone/family/iph...

ansible 15y ago
Verizon / Sprint use a completely different cellular technology than AT&T and T-Mobile. (Most acronyms have been intentionally left out for simplification) There are two distinct hardware versions of the iPhone 4S (and other phones like the Samsung Galaxy S 2) that need to work with the different sets of carriers. The situation will kinda/sorta be fixed with the next generation of technology, because most of the major carriers are adopting LTE, but there will still be issues with global roaming.
- riblack3 15y ago
  I believe the 4S did away with distinct models for GSM and CDMA. The cellular chip it uses can handle both, much like the Galaxy Nexus. (Unsure as to why the Nexus supports T-Mobile's AWS bands and the iPhone doesn't though, maybe the antennae.) I would speculate that the reason carrier unlocked phones do not work with CDMA is related to their agreement with Verizon (and/or Sprint).
  - ansible 15y ago
    Well, I'm slightly surprised at that, but if anyone can do it, Qualcomm can. As for 3G bands, it is common enough to make a 3G system that supports 3 frequency bands. Supporting 4 is difficult, and 5 bands usually entails significant performance compromises. So since the carriers aren't all on the same bands, you usually have to pick and choose. The iPhone 4 previously had design issues with its antenna system anyway. They fixed it, or at least people don't complain about it anymore. But major fixes (like supporting an additional frequency band) might not be possible without significant re-design.
- rsynnott 15y ago
  There's only one version of the iPhone 4S (it does CDMA and GSM/UMTS/HSDPA), but the two large US CDMA carriers do not generally allow phones they didn't sell on their networks.
cstejerean 15y ago
Don't count on jailbreak and unlock. Jailbreaking is easy, but unlocking a phone with a new baseband will prove quite challenging.

by e28eta 15y ago

ansible 15y ago

Verizon / Sprint use a completely different cellular technology than AT&T and T-Mobile. (Most acronyms have been intentionally left out for simplification) There are two distinct hardware versions of the iPhone 4S (and other phones like the Samsung Galaxy S 2) that need to work with the different sets of carriers. The situation will kinda/sorta be fixed with the next generation of technology, because most of the major carriers are adopting LTE, but there will still be issues with global roaming.

riblack3 15y ago
I believe the 4S did away with distinct models for GSM and CDMA. The cellular chip it uses can handle both, much like the Galaxy Nexus. (Unsure as to why the Nexus supports T-Mobile's AWS bands and the iPhone doesn't though, maybe the antennae.) I would speculate that the reason carrier unlocked phones do not work with CDMA is related to their agreement with Verizon (and/or Sprint).
- ansible 15y ago
  Well, I'm slightly surprised at that, but if anyone can do it, Qualcomm can. As for 3G bands, it is common enough to make a 3G system that supports 3 frequency bands. Supporting 4 is difficult, and 5 bands usually entails significant performance compromises. So since the carriers aren't all on the same bands, you usually have to pick and choose. The iPhone 4 previously had design issues with its antenna system anyway. They fixed it, or at least people don't complain about it anymore. But major fixes (like supporting an additional frequency band) might not be possible without significant re-design.
rsynnott 15y ago
There's only one version of the iPhone 4S (it does CDMA and GSM/UMTS/HSDPA), but the two large US CDMA carriers do not generally allow phones they didn't sell on their networks.

cstejerean 15y ago

Don't count on jailbreak and unlock. Jailbreaking is easy, but unlocking a phone with a new baseband will prove quite challenging.