Dual-band

A dual-band mobile device supports voice and data communications conforming to one bearer technology, such as GSM, but on two different sets of frequencies. For example, to support additional mobile network operators or to provide additional capacity and coverage, many European and Asia/Pacific countries/markets have licensed deployment of GSM networks on both 900MHz and 1,800MHz spectrum. A dual-band GSM phone enables the user to roam automatically across networks on either frequency. Most GSM phones sold in these countries are dual-band. A tri-band phone is required to roam among operators in Asia/Pacific, Europe and North America, because GSM has been deployed in 1,900MHz spectrum in North America.