Last month, in a further blaze of publicity, Qwest launched the world's first uncompressed Internet telephony service.

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Ms Prestage had been talking to Mr McGuigan on an internet telephony service just an hour before he was killed.

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But Internet service providers who want to bundle telephony to their customers using the public Internet will have to invest heavily in bandwidth if quality is to be acceptable.

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Sometimes described as a 2.5G technology because it acts as a bridge between mobile telephony and the full-fledged mobile Internet, the service has spawned a whole new style of phone usage, particularly among Japan's youth (see accompanying story).

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And while many mobile services don't come with international calling, using the Skype service you can make international calls without paying hefty long distance fees, although there will be Internet telephony charges.

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