4 ms·

Pardon my ignorance, but being in Europe means I've never used a 2G CDMA network - the iPhone4S supposedly works for both GSM and CDMA; if you don't get a SIM,

Pardon my ignorance, but being in Europe means I've never used a 2G CDMA network - the iPhone4S supposedly works for both GSM and CDMA; if you don't get a SIM, does the CDMA module only work if you bought the phone from a CDMA network operator, and not if you bought it from Apple directly?

kalleboo 15y ago
> does the CDMA module only work if you bought the phone from a CDMA network operator Yes. They program it with your subscriber number at purchase. Technically they could reprogram phones not sold by them with your subscriber number, but they don't (to force you to give them more money). There does exist a CDMA version of the SIM (RUIM? something like that). China Mobile uses it, and I think au/kddi do too. American carriers do not.
- Drbble 15y ago
  I am surprised they allows that. That sounds like a far more obvious antitrust violation than putting an IE icon on the Windows desktop.
  - a3camero 15y ago
    It gets worse in Canada. They carrier lock the phones to the brands. There's a big phone company called Telus that has a brand called Koodo and you can't swap phones between them even though it's actually the same network. All the joys of fake competition with none of the compatibility!
zred 15y ago
CDMA phones come with an ESN (http://www.mobileburn.com/definition.jsp?term=ESN http://www.mobileburn.com/definition.jsp?term=ESN). It's basically like your SIM card number, except that it doesn't change. CDMA carriers can activate a phone not sold by them by ESN. However, some carriers have decided that they would prefer you to buy a handset from them and refuse to activate devices that weren't sold by them. Sprint has a policy of not activating any ESN that comes from a phone they didn't sell. I'm not sure if that applies to the iPhone since a non-Sprint iPhone would really be the same device. Anyway, unlike SIM cards, you're more at the mercy of whether a carrier will activate it or not.
- sklnd 15y ago
  ESN is equivalent to IMEI in GSM/UMTS networks. IMEI is tied to equipment, and never changes, just like ESN. CDMA networks use IMSI to identify subscribers (as opposed to the equipment serial number) just like GSM/UMTS. IMSIs are provisioned on to the phone by the carrier with special software supplied by the phone manufacturer, instead of being supplied to the phone by the phone asking the SIM for it. There's no technical reason why CDMA networks can't use a removable card to store subscriber data, and indeed there are a few standards for doing so (RUIM and CSIM) and a few carriers that use them.

kalleboo 15y ago

> does the CDMA module only work if you bought the phone from a CDMA network operator Yes. They program it with your subscriber number at purchase. Technically they could reprogram phones not sold by them with your subscriber number, but they don't (to force you to give them more money). There does exist a CDMA version of the SIM (RUIM? something like that). China Mobile uses it, and I think au/kddi do too. American carriers do not.

Drbble 15y ago
I am surprised they allows that. That sounds like a far more obvious antitrust violation than putting an IE icon on the Windows desktop.
- a3camero 15y ago
  It gets worse in Canada. They carrier lock the phones to the brands. There's a big phone company called Telus that has a brand called Koodo and you can't swap phones between them even though it's actually the same network. All the joys of fake competition with none of the compatibility!

zred 15y ago

CDMA phones come with an ESN (http://www.mobileburn.com/definition.jsp?term=ESN http://www.mobileburn.com/definition.jsp?term=ESN). It's basically like your SIM card number, except that it doesn't change. CDMA carriers can activate a phone not sold by them by ESN. However, some carriers have decided that they would prefer you to buy a handset from them and refuse to activate devices that weren't sold by them. Sprint has a policy of not activating any ESN that comes from a phone they didn't sell. I'm not sure if that applies to the iPhone since a non-Sprint iPhone would really be the same device. Anyway, unlike SIM cards, you're more at the mercy of whether a carrier will activate it or not.

sklnd 15y ago
ESN is equivalent to IMEI in GSM/UMTS networks. IMEI is tied to equipment, and never changes, just like ESN. CDMA networks use IMSI to identify subscribers (as opposed to the equipment serial number) just like GSM/UMTS. IMSIs are provisioned on to the phone by the carrier with special software supplied by the phone manufacturer, instead of being supplied to the phone by the phone asking the SIM for it. There's no technical reason why CDMA networks can't use a removable card to store subscriber data, and indeed there are a few standards for doing so (RUIM and CSIM) and a few carriers that use them.