# Smartphone advice needed

**URL:** <https://boards.straightdope.com/t/smartphone-advice-needed/713951>\
**Category:** In My Humble Opinion\
**Created:** [March 1, 2015, 8:49pm UTC](https://boards.straightdope.com/t/smartphone-advice-needed/713951 "2015-03-01T20:49:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![race\_to\_the\_bottom](https://avatars.discourse-cdn.com/v4/letter/r/c4cdca/32.png) [@race\_to\_the\_bottom](https://boards.straightdope.com/u/race_to_the_bottom)\
**Post date:** [March 1, 2015, 8:49pm UTC](https://boards.straightdope.com/t/smartphone-advice-needed/713951/1 "2015-03-01T20:49:56Z")

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I have Verizon service which is a CDMA system, but I am traveling to Vietnam, and need a GSM phone to use there. I can get a prepaid SIM card to use at almost any shop there.

New unlocked GSM phones are available on Ebay, but they are “AT%T, T-mobile”. Does that mean anything? Does it mean they will only work on the AT&T, T-mobile networks even though they are “unlocked”? If that is not the case, why does the seller advertise them as “AT&T, T-mobile”?

I just want to make sure I don’t get to Vietnam, put a prepaid SIM card into it and it won’t work.

Link to phones here. [http://www.ebay.com/itm/5-3G-Unlocked-Android-AT-T-T-mobile-Cell-Phone-Smartphone-Straight-Talk-GSM-GPS-/371223681192?pt=LH\_DefaultDomain\_0&var=&hash=item566ea7d8a8](http://www.ebay.com/itm/5-3G-Unlocked-Android-AT-T-T-mobile-Cell-Phone-Smartphone-Straight-Talk-GSM-GPS-/371223681192?pt=LH_DefaultDomain_0&var=&hash=item566ea7d8a8)

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**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\
**Post date:** [March 1, 2015, 8:56pm UTC](https://boards.straightdope.com/t/smartphone-advice-needed/713951/2 "2015-03-01T20:56:37Z")

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> [@race\_to\_the\_bottom](#):
>
> I have Verizon service which is a CDMA system, but I am traveling to Vietnam, and need a GSM phone to use there. I can get a prepaid SIM card to use at almost any shop there.
> 
> New unlocked GSM phones are available on Ebay, but they are “AT%T, T-mobile”. Does that mean anything? Does it mean they will only work on the AT&T, T-mobile networks even though they are “unlocked”? If that is not the case, why does the seller advertise them as “AT&T, T-mobile”?

they’re usually listed as “AT&T, T-Mobile” when they can accept a SIM from either carrier and support the frequency bands held by those carriers. There’s no guarantee that a phone which supports those two carriers can be used in other countries operating on different bands. Some phones are “global” which means they do; I had a Verizon Windows Phone a while back (HTC Trophy) which was “global,” it used its CDMA radio here at home on VZW’s network, but came with a Vodafone SIM for use in Europe and elsewhere.

edit: for the phone you linked, these are the supported bands:

GSM850/900/1800/1900MHZ

so you’d need to find out what bands are used where you’re traveling to.

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**Author:** ![race\_to\_the\_bottom](https://avatars.discourse-cdn.com/v4/letter/r/c4cdca/32.png) [@race\_to\_the\_bottom](https://boards.straightdope.com/u/race_to_the_bottom)\
**Post date:** [March 1, 2015, 10:42pm UTC](https://boards.straightdope.com/t/smartphone-advice-needed/713951/3 "2015-03-01T22:42:55Z")

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Thanks.

Yes, I see. I also that they only operate in 2G, except in WCDMA. Not a good choice, then if I want 3G service.