Can I use my new AT&T iPhone with T-Mobile?

Episode 1223 (15:26)

Evan from Los Angeles, CA
Apple iPhone 6s and 6s Plus

Evan bought an iPhone 6s Plus on the first day. He hears there's a different phone for AT&T, though. Leo says that's true. The AT&T iPhone is different, but only in that it has an extra band. Leo says that's not a bad thing as the AT&T model has a lower frequency to pass through walls. But can it work with other carriers? Leo says that nobody has really addressed it, but with all the bands that it has, it's a question an RF engineer might be able to answer. Leo's betting if he put the SIM in it, it should work in most cases.