The Canadian company said on Wednesday Genband is acting as the stalking horse bidder, setting the floor price for the assets at an auction supervised by the bankruptcy court.
The purchase price is subject to balance sheet and other adjustments estimated at about $100 million.
The offer by Texas-based Genband includes the North America, Caribbean and Latin America and Asia Carrier VoIP and Application Solutions business. It also includes an agreement for the sale of substantially all of the assets of the Europe, Middle East and Africa portion of its CVAS business.
Nortel expects to seek U.S. and Canadian court approvals for the bidding procedures, including a bid deadline and tentative auction date, next month.
It said a significant amount of the employees in the operations being sold would retain their jobs with Genband.
Nortel, once North America's biggest telecommunications equipment company, filed for bankruptcy protection last January. Rather than attempting to restructure, it is auctioning off its assets in an attempt to pay back debtholders.
Earlier this month, bankruptcy courts cleared the way for Ciena Corp (CIEN.O) to acquire Nortel's optical networking and carrier ethernet business for $769 million, after fighting off a legal challenge by Nokia Siemens Networks.
Network equipment maker Ciena said it expects the deal -- which will double its size and increase its debt load -- to close in the first quarter of 2010.
Ciena trumped an offer by Nokia Siemens and its financial partner, One Equity Partners, with an auction-winning bid of $530 million in cash and $239 million in convertible securities.
Last month, Sweden's Ericsson (ERICb.ST) won an auction for Nortel's wireless assets, including the CDMA wireless technology used in North America and in the emerging LTE high-speed wireless technology.
The case is Nortel Networks Inc, et al, No. 09-10138 in the U.S. Bankruptcy Court for the District of Delaware.
(Reporting by Santosh Nadgir in Bangalore and Scott Anderson in Toronto; editing by John Wallace)