MORRISVILLE, N.C. — Tekelec’s board of directors has increased its membership to eight from seven and added Michael Ressner, a retired Nortel executive, to the post.

Ressner joined the board as of Nov. 28.

A former financial and operations executive at Nortel, Ressner is an adviser to the College of Management at North Carolina State University. He also has worked at NSCU as an adjunct professor of finance. Ressner already is a board member at Arsenal Digital Solutions, Entrust, Exide Technologies and Magellan Health Services.

Frank Plastina, chief executive at Tekelec, also is a former Nortel executive.