Multi-band device

Type of mobile phone Motorola Timeport, the first tri-band mobile phone (1999) A dual band 4G+ router In telecommunications, a multi-band device (including (2) dual-band, (3) tri-band, (4) quad-band and (5) penta-band devices) is a communication device (especially a mobile phone) that supports multiple radio frequency bands. All devices which have more than one channel use multiple frequencies; a band however is a group of frequencies containing many channels. Mobile carriers use multiple bands, internationally, to communicate with their telecommunications infrastructure. Multiple bands in mobile devices support roaming between different regions where different standards are used for mobile telephone services. Where the bands are widely separated in frequency, parallel transmit and receive signal path circuits must be provided, which may impact the manufacturing cost of multi-band devices due to increased circuit complexity. The term quad-band describes a device that supports four frequency bands: the 850 and 1900 MHz bands, which are used in the Americas, and 900 / 1800, which are used in most other parts of the world. Most GSM/UMTS phones support all four bands, while most CDMA20