cell phone in USA

Which frequencies are used in the US?

Originally, the US used only 1900 MHz for its GSM cell phone service.  In the last year or so, there has been a growing amount of GSM service on the 850 MHz band.  This type of service will usually be seen in rural areas, because the 850 MHz band has better range than the 1900 MHz band.  It can sometimes also found in city areas, particularly if the cell phone company has spare frequencies unused in the 850 MHz band, but no remaining frequencies to use in the 1900 MHz band.

Most of the 850 MHz service belongs to AT&T, and some to Cingular (these two companies are in the process of merging).  Although T-Mobile does not (as of July 04) have any of its own 850 MHz service, because it has roaming agreements with both AT&T and Cingular, even a T-mobile user might sometimes find themselves in an area where the only signal available is on 850 MHz.

Do you need both frequencies in the US?

This really depends on the areas in which you use your cell phone.  If you're in a major metropolitan area, you probably won't need the 850 MHz band, but if you travel to secondary areas regularly, you will find the extra coverage of the 850 MHz band to be valuable.

Looking into the future, it is probable we'll see increased use of 850 MHz to expand GSM's overall coverage into more of the country.

And then, looking further into the future, it is possible we'll see 1900 MHz coverage duplicating the 850 MHz coverage.

Bottom line :  If you travel out of the main cities, you'll definitely benefit from a phone that supports both 850 MHz and 1900 MHz.

So for USA client ,please select quad bands cellphone or tri bands cell phone.