Dual-band - A dual-band phone operates at both the 900 MHz and 1800 MHz spectrum. Dual-band works in Europe, Africa, Asia, Australia, New Zealand and much of South America.

Tri-band - A tri-band phone operates on three frequency bands, 900 MHz, 1800 MHz and 1900 MHz, allowing you to use it in Europe, Africa, Asia, nearly all of North America, Australia and New Zealand.

Quad-band - A quad-band phone allows you to roam almost anywhere globally. It covers the 850 Mhz, 900 MHz, 1800 MHz and 1900 MHz frequency ranges. Many countries in South America only have 850 MHz GSM service while both 1900 MHZ and 850 MHz GSM services are supported in the USA. 99% of all countries use the GSM standard.

Will a 900MHz GSM phone work in the United States? - In most cases, no. 900MHz GSM services will work in Washington DC only. Since Washington DC is home to many foreign diplomats, special considerations have been given to the area. In the US, 1900 GSM service is available in most areas. Please be sure to check local carriers such as Voicestream or Cingular wireless to verify that there is coverage in your area.

Please refer to this website that lists the GSM frequencies for all countries: http://allworldcellphones.com/gsm-frequencies-list.htm

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