GSM Technology

GSM Technology
GSM (Global System for Mobile Communications) leads the world as the fastest growing, most reliable and advanced digital technology available in the marketplace today. GSM provides integrated voice mail, high-speed data, fax, paging and short message services capabilities. GSM customers enjoy secure communications, and GSM offers unparalleled call privacy and fraud prevention. As members of the GSM Global Network, GSM subscribers can use their phones at home, across town, across the continent, or around the world (except for with country specific SIM cards). GSM operates on the multiple spectrum frequency bands used around the world - 1900MHZ, which is used in North America and 900MHz and 1800 MHz for other locations. Different mobile phone networks operate at different frequencies, which means that if you wish to use your mobile phone outside your home country, you generally need a handset that supports multiple frequency bands. Make sure that the celluar phone you are interested in is compatible with the GSM band of the country you will use it in.
As a general Guideline:

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. WE believe eventually GSM will be the only cell phone standard in the world.

The GSM network provides the best digital wireless voice quality in the world today.