Pingtel is the main developer behind sipXecs, an open-source IP-PBX platform that is based on Linux.

Nortel has acquired key assets of Pingtel from Bluesocket, Burlington, Mass. Financial terms of the deal were not disclosed. Pingtel employees will be integrated into Nortel's Billerica, Mass., office, according to a Nortel statement.

"The acquisition is another building block in Nortel's vision to be a software-centric company and the leading provider of unified communications solutions," said David Downing, general manager of Enterprise and SMB Communications Systems at Toronto-based Nortel.

The transaction brings Pingtel's existing OEM relationship in-house and will bring Pingtel's "critical" research and development resources into Nortel's fold, Downing said.

Bluesocket in a statement said it plans to invest proceeds from the sale into its wireless LAN business to bolster product development, sales and marketing activities.