Verizon and Sprint customers have the option of buying a "world phone" that uses CDMA in the U.S. and GSM abroad.

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"Trends in worldwide CDMA continue to be positive, though the U.S. market was a bit softer in April in our recent checks, " Hoffman wrote in a research note Tuesday.

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Last week Verizon announced that the new Samsung Galaxy S III smartphone will soon work on GSM networks around the world, not just the CDMA networks similar to the one Verizon operates in the U.S. With the far broader coverage of GSM, this was great news for world travelers with the Android phone.

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Korean makers LGand Samsung--making CDMA phones with Qualcomm's chips--began bombing the U.S. with far cheaper models, undercutting Qualcomm's handset business.

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The iPhone 4S will be a world phone that can switch between different network standards, both CDMA and GSM, and will be available through all three major U.S. carriers as well as through Apple itself.

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Earlier standards wars mean Europe has phones that work on a system called GSM, while U.S. phones run on GSM, plus TDMA and CDMA. Before the new standard, wireless data had still other incompatible designs and only 700, 000 users in the U.S. "Diplomacy is harder than technology, " says Rossman.

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In terms of cellular access technology, U.S. carriers can be divided into two basic camps: CDMA and GSM.

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