Why cant i buy a phone in the UK and use it in the US and vice versa?

[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]

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

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.

 

[MannyMel]

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?

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.

 

[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.