"These two tellers' machines at the Illinois State Bank, Quincy, Ill., are linked by telephone lines to the computer at Bank of St. Louis, more than 100 miles away. When a customer wishes to make a savings deposit, for example, the transaction keyed into one of these machines updates the depositor's account record stored in the computer within one-fourth of a second. Immediately, the savings passbook is updated with the amount of the deposit and any previously unposted dividends."