A friend of mine is going to NYC. I'd like him to buy a contract free t-mobile iphone 6 for me cause they are cheaper in the US. I would like to use this phone with my european sim card provider. Is that possible?
When I've googled this I've seen some contradictory information on forums (can't post more than two links here cause I'm new) and in various websites. An apple customer rep told me: "As long as your preferred wireless provider is compatible with the T-Mobile GSM network, then it will work." What does compatible mean here? Is it a matter of frequencies and stuff that is fairly standardised? If I'd be able to connect to the local carriers network (ie. roam) with a t-mobile sim while travelling does that mean the network is compatible?
It seems like you might be able to discover if you're phone is useable in other countries for sure by looking at the per country coverage lists you'll find if you google "International Plans Calling Abroad Traveling T-Mobile".
The question "When I buy an iPhone 6 from the Apple website and select contract-free from T-Mobile, is the phone carrier unlocked?" that's already available on this page might be seen as an answer to this question. However clarifying what "compatible carriers" mean and wether information on where roaming is possible answers the question "are there compatible carriers in my country?" might be nice for other users, at least it'd be nice for me.
For LTE coverage info, I think you can compare supported LTE bands on the different models of iphones with LTE bands on networks in your country: