AT&T's telephone network operated normally Tuesday after technicians replaced a faulty computer program that blocked millions of long-distance calls nationwide in the company's widest-ever outage.
No major problems were reported in Utah."We're seeing traffic starting to build up, and the network is operating flawlessly," spokeswoman Daisy Ottmann said.
American Telephone & Telegraph Co. said Monday's nine-hour outage was its most widespread ever, but the Martin Luther King Day holiday prevented it from being worse.
The company said it discovered the problem at mid-afternoon Monday and corrected it shortly before midnight. The problem was traced to the software, or program, that runs AT&T's computerized switching centers, Ottmann said.
She said the company installed a new version of the software.
AT&T said it still did not know exactly what went wrong but had all but eliminated sabotage or a computer virus as the cause.
About half of the long-distance callers on the AT&T network got a busy signal or a recording saying all circuits were busy, the company said.