BBOOZE

So I do a fair amount of overseas travel and have never had an issue using my iphone and getting 3G speeds on the internet. I have also bought unlocked GSM phones and have not had an issu
e either. I'm in the UK now and the Desire HD is coming out next week and I'm wondering why I can't just buy it and use it fine when I come back to the US. Presumably if I were a UK resident and travelled to the US with this phone it would work fine just as I'm able to do with my US-based iphone in the UK. I understand every carrier and region uses its own frequencies but I don't understand why I'd be able to travel and get 3G speeds overseas but the concept of bring a phone over from another country but being stuck with 2G or Edge internet speeds doesn't click for me.

Can someone clear this up?

faugusztin

1) you have the GSM vs CDMA stuff
2) GSM runs on 850/1900 (USA) vs 900/1800 (everything except USA)
3) 3G - again diff frequencies - UMTS frequency bands - Wikipedia, the free encyclopedia

BBOOZE

But if I take my phone overseas I get 3G no problem. Every GSM or "world" phone (CDMA) I've taken overseas has gotten 3G no problem. So I ask again, why can't I simply buy a phone overseas and use it no problem here?

AndroidSPCS

You can. It should be no problem if the phone is unlocked, and you use T-mobile or AT&T. Depending on the specific brand / model 3G may be slower or only use EVDO, but you can certainly try it.

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MannyMel

A world phone uses both CDMA and GSM. Also you just have to find out what frequencies your phone works on. If it's tri-band or quad-band you have a better chance of it having a frequency you can use in the US and elsewhere.

Just make sure you know what you have and what is supported where you're going.

The same thing happens here: for example people that jailbreak an iphone to use on T-Mobile can't use the T-Mobile 3G network because the iPhone doesn't support the same bands. So its best to research what you plan on buying and the network it will be used on first.

Last edited by MannyMel; September 29th, 2010 at 04:21 PM.

faugusztin

Quad band makes it easier to work with standard GSM stuff in whole world, but HSPA stuff is problematic, phone must support both american and european frequencies. For example Desire Z and HD is a quad band phone, but HSPA is only european AFAIK.

So you can, but you need to buy a quad band phone and it must support european 3G frequencies.

Thefoodman52

In short- because in the UK, they're still lagging behind in the times with GSM, while we have 2 major carriers in the US plowing onwards with CDMA.