what is Dual bands cell phone

GSM cell phones use frequencies within four different frequency bands :

• 850 MHz   (824.2 - 848.8 MHz Tx;  869.2 - 893.8 MHz Rx)

• 900 MHz   (880-2 - 914.8 MHz Tx;  925.2 - 959.8 MHz Rx)

• 1800 MHz  (1710.2 - 1784.8 MHz Tx; 1805.2 - 1879.8 MHz Rx)

• 1900 MHz  (1850.2 - 1909.8 MHz Tx; 1930.2 - 1989.8 MHz Rx)

Although 850 and 900, and 1800 and 1900 are very close together, a phone that works in one frequency band unfortunately can not also work in the frequency band next to it unless added as a specific extra frequency band.  For comparison, when you have your FM radio tuned to a radio station at 98.1 MHz, there's no way you'll hear what is happening on another radio station at 98.3 MHz unless you retune your radio.

Dual bands cell phone is support 850/1900 mhz or 900/1800 mhz.  So the dual bands can not work in some place. Before you buy mobile phone ,please make sure the work net frequency in your country.