Company spokesman Dave Johnson said the switch, used to direct Internet traffic, began "blinking on and off" at 4 a.m. PDT. For the next 90 minutes, about half of allWorldNet subscribers couldn't read e-mail or use personalized Web pages, he said.
Some customers still couldn't access personalized Web pages nearly three hours after the faulty switch was taken offline and Internet traffic was rerouted to other parts of AT&T's network. "We're putting the finishing touches on that problem now," Johnson said.
The Web access provider launched an investigation to determine why the switch began, as Johnson puts it, "blinking on and off" between working and not working. He wouldn't speculate on a possible cause.
AT&T WorldNet uses digital subscriber lines (DSL), whichare the most popular method to deliver broadband access to homes and offices.
The provider has a relatively small number of subscribers but is among thein the country, providing downloads at nearly twice the industry average, according to a recent survey.