 On Mother's Day, Sunday, May 8, 1988, a fire broke out in the main switching room of the Hinsdale Central Office of the Illinois Bell telephone company.One of the largest switching systems in the state, the facility processed more than 3.5 million calls each day while serving 38,000 customers, including numerous businesses, hospitals, and Chicago's O'Hare and Midway Airports.Virtually the entire AT&T network of 4ESS toll tandems switches went in and out of service over and over again on January 15, 1990, disrupting long-distance service for the entire United States.