A popular myth in UK goes like this: If you are heading to the U.S., go with any tri-band phone. In fact, most retailers and customer service people advise you to travel with a tri-band phone for worldwide compatibility. This is not necessarily true because the U.S. also has the 850 MHz band — which is not covered by most UK and European handsets.
Like their dual-band counterparts, tri-band handsets can be misleading, especially if you purchase the phone in the U.S. It could mean 850/ 900/ 1900 MHz or 900/ 1800/ 1900 MHz or 850/ 1800/ 1900 MHz. Now that the U.S. is using two frequencies for GSM service, some phones are being sold as tri-band phones, which feature both U.S. GSM frequencies and only one of the international frequencies. Of the two international frequencies, 900 MHz and 1800 MHz, unfortunately the 1800 MHz band is less commonly used in the rest of the world. This makes these tri-band phones not as useful as a tri-band phone with both international frequencies while travelling outside the U.S.
The bottom line is if you’re buying a tri-band phone, make sure you understand which three bands it includes.
For full international compatibility, you need a handset that is quad-band (850, 900, 1800, and 1900 MHz). The quad-band phone enables access to the 850-MHZ frequency as well. Networks that operate on the 850 MHz band are not so common outside of the U.S. other than for some in Southern and Central American countries.
If you are a frequent international traveller, you are better off buying a quad-band phone. You can find quad-band phones at most retailers in UK.
If you are buying a quad-band phone from a carrier, ensure all bands are enabled. Some carriers disable one or more bands, especially when their networks are not operating on those bands.
If multiband phones employ different frequencies within the same technology, then multimode phones utilise frequencies among different technologies. In other words, multimode phones combine two or more technologies into a phone. For instance, a multimode phone can use 800 MHz AMPS and 800 MHz CDMA.
Multimode phones are valuable in enabling roaming, especially in the U.S. There are too many networks in the U.S., and they are fragmented throughout the landscape with too many rivals.
Dual-mode phones support more than one technology. For example, a handset that supports 800 MHz CDMA and 800 MHz AMPS is a dual-mode phone. You can also have phones that support dual-band/ dual-mode. Dual-mode phones let you access different technologies in the same or different geographic regions, essentially giving your phone a wider coverage area.
Almost every single 3G phone sold in UK is actually a dual-mode WCDMA/ GSM phone.
If you’re buying a dual-mode phone, make sure you understand which bands and technologies it includes. Dual-mode phones are sometimes known as bi-mode phones as well.
You can find tri-mode phones usually in the U.S. They support three different technologies. The combination can be 800 MHz AMPS, 800/ 1900 MHz CDMA, and 1900 MHz GSM.
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