Nortel has bought Pingtel, a subsidiary of enterprise mobility firm Bluesocket. Nortel hopes the open source IP PBX software/appliance division will have better luck moving forward.

Financial terms of the deal have not been disclosed, but Nortel will acquire the key assets of Pingtel from Bluesocket, Pingtel’s existing OEM relationship with Nortel will be brought in house and Pingtel employees will be integrated into Nortel’s Billerica, Mass. facility. Pingtel and Nortel have been working together for a while on SIP-based enterprise solutions

Pingtel’s sipX open source IP PBX software is highly regarded for its ability to scale to support up to 10,000 users; as an independent entity, Pingtel landed Amazon.com as its largest publicly announced customer. The Amazon.com installation reportedly supports over 5,000 users in a high-availability configuration.