Carrier Interoperability

[zorb58]

I have wondered this for an extremely long time but this quote from a recent article on the Lumia 929 really got me thinking again: "The leaker has also noted that the device is unlocked, like most of Verizon?s devices, and that putting an AT&T or T-Mobile SIM into the device allowed it to work on those networks."

Can somebody please fully explain how carrier interoperability works? As a hypothetical, let's say I want to buy an AT&T Lumia 920 and use it on Verizon. Why or why would this not be possible?

 

[rdubmu]

The 920 will not work on Verizon. Number one it doesn't support CDMA network.

For example of the Verizon iPhone 5s will work on at&t and T-Mobile but not spirint.

The reason why is because the SIM card part of iPhone is unlocked and the Verizon 5s supports GSM networks including all bands of LTE for both At&t and T-Mobile. The CDMA part is locked.

The Sprint iPhone 5s is the same as the Verizon iPhone except it is all locked down on both the GSM Sim card side and CDMA PART.



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[zorb58]

I see. Now, Nokia's website says that the 920 does work on WCDMA networks. Is this a global model it is listing, or does the "W" change things?

 

[palandri]

I see. Now, Nokia's website says that the 920 does work on WCDMA networks. Is this a global model it is listing, or does the "W" change things?

No, WCDMA evolved from GSM, and CDMA2000 evolved from CDMA. Verizon and Sprint do not want non-carrier branded phones on their network. AT&T & T-Mobile will accept unbranded unlocked GSM phones on their network.

http://www.gsma.com/aboutus/gsm-technology/gsm

 

[zorb58]

Okay it makes sense now... American carriers blow.

 

[berty6294]

Okay it makes sense now... American carriers blow.

Amen. I'm on the Big Evil Verizon.

 

[hopmedic]

The biggest reason that Verizon phones work on other networks but others don't work on Verizon's network is because most Verizon phones (all now?) are "world" phones, having both the CDMA radios to use on their home network, and GSM radios, allowing them to work on other networks. Used to be that they wouldn't unlock the phone unless you called them and told them that you were traveling abroad, and would need your phone unlocked. Now, since they are using the LTE band that they are, one of the conditions of the lease of that band was that they can't lock phones to their network that use that band. So while you see people advertising 822, 928, and 8x on ebay as unlocked, the fact is that ALL Verizon LTE phones, by definition, are unlocked from the carrier.

 

[rdubmu]

The biggest reason that Verizon phones work on other networks but others don't work on Verizon's network is because most Verizon phones (all now?) are "world" phones, having both the CDMA radios to use on their home network, and GSM radios, allowing them to work on other networks. Used to be that they wouldn't unlock the phone unless you called them and told them that you were traveling abroad, and would need your phone unlocked. Now, since they are using the LTE band that they are, one of the conditions of the lease of that band was that they can't lock phones to their network that use that band. So while you see people advertising 822, 928, and 8x on ebay as unlocked, the fact is that ALL Verizon LTE phones, by definition, are unlocked from the carrier.

Why do Sprint lock their phones than ?

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[hopmedic]

No idea. I was only a Sprint customer for a few weeks because their coverage where I live is so bad, so I never bothered looking much into them. I don't even know if any of their phones are world phones (having GSM as well as CDMA radios).

 

[inteller]

I can't wait until carriers go VoLTE and dump all the CDMA/GSM crap. CDMA is really holding convergence back.

 

[rdubmu]

I can't wait until carriers go VoLTE and dump all the CDMA/GSM crap. CDMA is really holding convergence back.

Yeah but at least here in the statee CDMA is a superior voice network. I remember in the late 90's and early 00's Verizon was the only network you got service in an elevator.

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