It is impossible to guarantee that the US telecomms infrastructure will not fail on New Year's Eve 1999, because of the sheer size of the country's network.
During today's live global Y2K debate over the Web, Michael Powell, a commissioner at the US Federal Communications Commission, admitted he was concerned about the ability of the country's 1,400 independent operators to fight the bug effectively.
"We're not without concerns," he said. "There are 1,400 small companies out there and we are working to find out how we can reach out to them."
Around 20 of the US' largest operators claim they have completed their inventory work, and have carried out impact analysis. Many are spending between $2 billion and $3 billion on the problem, and are working to be compliant by the second quarter of next year.
Powell also raised concerns over the safety of international carriers. He said: "The UK, Canada and the US are forging ahead but what about emerging nations?"
Telecomms users should quiz their suppliers about their relationships with overseas telcos, he urged.
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