Originally Posted by
Tourist in MSN
Many years ago I bought a 3G phone that was dual sim, the frequencies were for Asia or Europe, not North America. Phones and frequencies and standards are different now, but if you shop for a dual sim phone, I suggest you make sure the frequencies that the phone is wired for are the frequencies used by your provider.
That has gotten quite a bit better. Most unlocked phones I've found are "quad band" that I've found work well between US / Europe and Latin America -
https://en.wikipedia.org/wiki/GSM_frequency_bands
Some of these unlocked phones also enable both CDMA and GSM. Vendor pages such at this one also give clues of what US carriers work with which phones -
https://www.motorola.com/us/carrier-compatibility
The larger issue I've found is sometimes phones are sold with SIMs but were "locked" rather than "unlocked" - so now I am extra careful to make sure I start with an unlocked phone.