ATT Inc, the biggest U.S. phone company, said on Tuesday that it would sell its wireline operations in Connecticut to regional telephone operator Frontier Communications for $2 billion in cash, to help fund network upgrades. Frontier shares rose more than 8 percent after it said the deal would boost its dividend payout ratio, generate savings and improve its adjusted free cash flow. ATT, which depends on wireless for growth, and has said it would look to sell non-strategic wireline assets. Citi analyst Michael Rollins said the addition of ATT customers would help boost Frontiers valuation.