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Any Problems with using GSM network in an area with dual CDMA/GSM networks.
saskat
Member

I have a confirmed as unlocked Verizon iPhone 4S. I will be traveling to an area in China that has both CDMA and GSM networks. My Hong Kong GSM sim card has full voice and data services. I do not want to connect to the CDMA network (and thus end up with Verizon roaming). Will this be an issue? Can CDMA be disabled or can GSM be selected as the only way to connect to service?

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
budone
Sr. Leader
Sr. Leader

I dont think so. I believe even with a GSM card, a VZW will will always look for a CDMA tower first.

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
saskat
Member

So I cannot count on being on the GSM network I want to be on and can't avoid Verizon roaming charges for voice and data? Looks like I would have to just bring my totally liberated basic Nokia for voice and forget about data except when I can be on Wifi.

If the above is the situation, then Verizon's unlock is only partly unlocked.

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
kaebfly
Leader

My understanding is that with a foriegn sim card in your phone it will not roam with VZW partners. It will roam on the network(s) that is associated with that simcard. I may be wrong, but that seems to be the whole point behind having the sim unlocked allowing you to choose to use a billing method other than VZW while traveling abroad.

Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
Not applicable

Hello Saskat, great question. I understand why you want to make sure you keep international roaming costs down. Kaebfly is correct. If your iPhone is unlocked and you insert another carrier SIM card into the phone, you will not be charged VZW roaming charges. You will be billed by that company or deduct from the prepaid minutes/data you purchased from them.

 

MarquiaF_VZW

Follow us on Twitter @VZWSupport

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
budone
Sr. Leader
Sr. Leader

MarquiaF_VZW wrote:

Hello Saskat, great question. I understand why you want to make sure you keep international roaming costs down. Kaebfly is correct. If your iPhone is unlocked and you insert another carrier SIM card into the phone, you will not be charged VZW roaming charges. You will be billed by that company or deduct from the prepaid minutes/data you purchased from them.

 

MarquiaF_VZW

Follow us on Twitter @VZWSupport

Marquia, the question is, if the phone is unlocked, you have a GSM SIM in the device, HOWEVER the area is serviced both by Vodaphone (CDMA) and a GSM provider, which provider takes precedent?

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
Not applicable

Budone, saskat asked if the phone would switch to CDMA and incur roaming charges, which seems to be the root cause for the post, unless there is another reason the user prefers GSM over CDMA. No, there is not a way to force the phone to pickup GSM only. Which carrier the phone picks up will be determined by the company you purchase the SIM card from and whichever network is stronger. I was in Bangkok last year and they use both CDMA and GSM. At the time, I did not have a global phone, but my friend did. I picked a low CDMA signal while his VZW BB Bold picked up a stronger GSM signal. He was using a VZW SIM.

 

MarquiaF_VZW

Follow us on Twitter @VZWSupport

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
saskat
Member

My sim card is a GSM. My question is whether the phone will default to Verizon's CDMA if that signal is stronger in a particular location

You say "Which carrier the phone picks up will be determined by the company you purchase the SIM card from AND whichever network is stronger."

It's still not clear to me from your statement what I can expect to happen. Does the Verizon CDMA automatically take over in such a case.

Nancy Lieff

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
saskat
Member

By the way, my sim is not Verizon's. It is a 3 Hong Kong subscription sim.

Nancy Lieff

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Re: Any Problems with using GSM network in an area with dual CDMA/GSM networks.
ChristinaB_VZW
Verizon Employee

Hi saskat,

I would like to clarify this for you once and for all. If you are using the SIM card of a carrier in Hong Kong and will be located in China, you will be billed from the carrier in Hong Kong and not Verizon Wireless. This is due to using the other carrier's SIM card, Depending on details of the SIM card from Hong Kong, you may want to consider getting a SIM card from the carrier in China. Your charges may be less, depending on the terms and conditions of the Hong Kong carrier. Please contact the carrier supplying you with the SIM card in order to obtain the details about the charges using the phone in China.

Thank you,

Christina B

VZW Support

Follow us on Twitter @VZWSupport

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