Editors' note: This article originally posted on April 8, 2012, and was updated on December 19, 2012. Open up your wallet today and there are no fewer than five smartphones you can buy running on quad ...

A phone that supports four different radio frequency bands. Different mobile phone networks around the world use different bands. A phone can only be used on a network if it supports the correct ...

In this edition of her advice column, CNET's Marguerite Reardon explains the differences between locked and unlocked phones and helps a reader figure out how to get an unlocked device. She also ...