Tekelec has promoted a former Lucent Technologies executive as its new CEO.

Ron de Lange joined the Morrisville-based telecommunications technology company in 2005 and has been "the primary architect of the company's product strategy." He replaces interim CEO Krish Prabhu, who took the job in January after Frank Plastina abruptly resigned after 5 years as CEO.

De Lange, 52, takes over as Tekelec goes through a key transition. The company, which makes software and other technology used by mobile-phone carriers, has seen sales slow and is shifting its focus to the next generation of wireless networks that carry more data and video.