NEW YORK (AP) ¿ Nortel Networks, which has been operating under bankruptcy protection since January, has selected Avaya as the successful bidder for its segment that makes communications systems for businesses. Basking Ridge, N.J.-based Avaya Inc. will pay $900 million in cash for Nortel Enterprise Solutions and contribute $15 million to an employee retention program. Avaya had previously made a "stalking horse" bid of $475 million for the unit in a court-supervised bankruptcy auction. Canada-based Nortel Networks Corp. expects the deal to close in the fourth quarter. Canadian and U.S. court approvals will be sought at a joint hearing on Tuesday. The enterprise unit supplies landline phone systems and other communications equipment to businesses and large organizations around the world. In a statement, Joel Hackney, president of enterprise solutions, said it will be "business as usual" at the unit while it is absorbed by Avaya.