Dion Joannou, president North America for Nortel, is leaving the telecommunications software and networking gear provider.

In a statement issued Wednesday evening, Nortel said Jonnaou was leaving “to pursue other personal interests.” His last day is Aug. 31.

No replacement was named.

Joannou had been with Nortel for 12 years. He was the company’s chief strategy officer before taking the North America post.

Nortel employs some 2,000 people in Research Triangle Park, N.C. That campus was part of Joannou’s area of responsibility.

"Throughout his 12 years at Nortel, Dion made many significant contributions in driving business momentum and played a critical role in developing Nortel’s Enterprise business," said Nortel Chief Executive Officer Mike Zafirovski. "We are sorry to see him go, and wish him much success in all his future endeavors. He has built a very talented team of executives who will continue to advance our business goals and deliver unparalleled service to our North American customers in the months and years ahead."

Since taking over as CEO in November of 2005, Zafirovski has replaced much of Nortel’s top management.