Tri-band
The term tri- band for mobile phones means that they can transmit and receive on three different frequency bands . In most cases, such cell phones support the 900, 1800 and 1900 MHz bands. The first tri-band mobile phone in the world was the Motorola Timeport , which was launched in 1999.
In Europe , network operators use two frequency bands, the 900 MHz band and the 1800 MHz band. So that a mobile phone can be used in both frequency bands, it must have at least dual-band capabilities. In addition to Europe, dual-band 900/1800 MHz cell phones also work in large parts of Africa and the Asia / Pacific region because they use the same frequency spectrum .
Most network operators on the American continent use the 1900 MHz band. To be able to make calls here, the phone also needs support for this frequency band. The operators there are also increasingly using the so-called 850 MHz band. US cell phones are therefore often designed as dual band cell phones with 850/1900 MHz.
A mobile phone that can use all four frequency bands ( quad band ) is required for worldwide access to GSM networks .
In Japan , with Personal Digital Cellular , a digital cellular network was used, which in turn used other frequency bands.