EXHIBIT 12 1997 Form 10-K Southern New England Telecommunications Corporation Computation of Ratio of Earnings to Fixed Charges Dollars in Millions, For the Year Ended December 31, 1997 Income before income taxes $316.0 Add: Interest on indebtedness 89.0 Portion of rents representative of the interest factor 6.6 Earnings before fixed charges and income taxes (1) $411.6 Fixed charges Interest charges $ 93.6 Portion of rents representative of the interest factor 6.6 Fixed charges (2) $100.2 Ratio of earnings to fixed charges [(1) divided by (2)] 4.11