maggie6812 :
I want to upgrade from my Razr V3 flip phone to a more up to date phone. 4G or android. Was told that a 3G sim card would not work in a 4G or Android phone. I am kind of getting the impression at this website that it will? Could you clarify this for me?
Your SIM card should not really matter - it's merely a container for authentication to your network. I would suggest checking the radio of your phone at GSMArena and asking your carrier what frequencies they operate on.
From there, you just have to find a phone that matches up, since it's the phone radios that really matter on network compatibility, as far as I understand. Perhaps there's some limitation your provider puts in place, ultimately, you should rely on their technical advice for the last word.
EX: I have some experience with similar matters myself. I'm a Canadian, and my carrier of choice is Mobilicity. They operate on an uncommon frequency here (only one other company in Canada uses it, Wind Mobile).
The frequency they use is AWS (1700mhz/2100mhz). Use the numbers, the names are variable. It's also known as WCDMA IV, but again, the numbers won't lie. Anyhow, that means I cannot buy a phone from the other carriers (Telus, etc) because they will not receive the frequency correctly.
Sort of like an AM/FM radio tuned to the wrong station. I have to get one that has those bands, and so I went with a Nexus 4.
Just illustrative. I think this is what you're referring to?
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