CHICAGO -- A glitch in MCI WorldCom Inc.'s data transmission network has partially disabled thousands of automated teller machines and restricted market trading of corn, soybeans and financial futures.
The problem began late last week and has caused extensive delays to nearly 30 percent of MCI WorldCom's global data network customers worldwide, company spokeswoman Linda Laughlin said Tuesday.
"Our network did not go down, but in some large metropolitan areas, customers couldn't get their traffic into a particular switch," Laughlin said. "Our technicians are still investigating what caused the problem and are working to identify all the service interruptions."
Laughlin said she did not know when service would be returned to normal.
The problems did not affect MCI WorldCom's long-distance telephone service.
MCI WorldCom was upgrading network software Thursday night when network customers began experiencing problems in cities including New York, Boston, Chicago, Los Angeles and San Francisco, Laughlin said.
ATMs nationwide -- and some outside the United States -- had intermittent trouble dispensing money because the disruption prevented the machines from communicating and determining a customer's balance. Some Internet services also became backlogged.
At the Chicago Board of Trade, the world's largest futures exchange, electronic trading terminals known as Project A shut down across the globe. The Project A electronic trading platform allows members to trade futures contracts linked to U.S. Treasuries, the Dow Jones industrial average, grains and other commodities.
The Board of Trade kept Project A terminals inside its Chicago offices running through a local network. Officials said they would add more terminals in the building Wednesday if the disruptions continued.
Board of Trade President Thomas Donovan on Tuesday issued a stinging rebuke of MCI WorldCom, saying company executives had assured him service would improve just two days before the disruption crippled Project A.
A similar service disruption occurred in an AT&T Corp. data network in April when that company attempted to upgrade its system. AT&T blamed software flaws for the disruption, which affected thousands of corporate customers nationwide.
MCI's stock fell $2.87 1/2 , or 3.7 percent, to $74.56 1/4 in late trading Tuesday on the Nasdaq stock exchange.