The revolving door of executives at Sonus Networks Inc. (Nasdaq: SONS) keeps spinning as Jocelyn Philbrook, the company’s VP of corporate marketing and investor relations is set to leave the company, Light Reading has learned.

Sonus confirmed Philbrook’s planned departure, which was part of one of new CEO Richard Nottenberg’s first decisions as head of the company. Nottenberg split the marketing and investor relations roles into two separate positions, thus eliminating Philbrook’s job.

Nottenberg, former CTO of Motorola Inc. (NYSE: MOT), was appointed CEO of Sonus in May replacing Hassan Ahmed who stayed on as Chairman. (See Ex-Moto CTO Tabbed to Run Sonus.) The new standalone position in charge of corporate marketing will report to him while the new director of investor relations will report to the CFO.

Since the start of 2007, the company has seen its CTO, CFO, chief marketing officer, and a sales VP leave. (See Sonus Has New CTO, Sonus Hires Gaynor, Sonus Realigns, and Sonus Sees Sales Shakeup.)

The move also comes while Sonus deals with a completely separate drama with its largest, most vocal investor, Legatum Capital.

Fearing a hostile takeover bid from the Dubai-based investment firm, Sonus adopted a "poison pill" stockholder rights plan last week to make itself harder to acquire. (See Sonus Preps Poison Pill and Sonus Engages With Legatum.) Legatum said today it has no interest in buying Sonus.

Sonus shares are down $0.07 (1.99%) to $3.45 in late afternoon trading on Monday. The company's stock is down about 40 percent, year-to-date.

— Raymond McConville, Reporter, and Ray Le Maistre, International News Editor, Light Reading