Southern New England Telecommunications Corp has had its ratings put under review for possible downgrade by Standard and Poor’s Corp, which said it may cut the Hartford phone company’s double-A long-term debt and A-1-plus commercial paper ratings.About $1,000m of aggregate debt is affected. The action is in rsponse to the company’s proposal to buy those cellular telephone properties from Nynex Corp and Bell Atlantic Corp for a total $450m and to finance the acquisitions with debt, a move that will lead to a significant weakening in the company’s credit quality. Business fundamentals of the company remain solid, but the potential that a financially weaker parent will need to increase dividends from its telephone subsidiary may also result in a downgrade of Southern New England Telephone Co’s debt rating, the New York agency said.