CHELMSFORD, Mass., February 9, 2006 - Sonus Networks (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced that it has scheduled a conference call for Monday, March 13, 2006, at 4:45 pm Eastern time to discuss its Q4 and FY2005 financial results. Financial results are expected to be issued after the close of the market on Monday, March 13, 2006.

Date: Monday, March 13, 2006
Time: 4:45 pm Eastern
To listen via telephone:
Dial-in number: (800) 847 8131
International Callers: (212) 346 6565

To listen via the Internet:
Sonus will host a live webcast of the conference call. To access the webcast, visit www.sonusnet.com, Corporate, Investor Relations.

Replay:
A telephone playback of the call will be available following the conference and can be accessed by calling (800) 633 8284 or for international callers, please call (402) 977 9140. The reservation number for the replay is 21283493. The telephone playback will be available through Monday, March 27, 2006.

A replay of the webcast will be also available on the Sonus Networks Investor Relations site through Tuesday, March 13, 2007. To access the replay of the webcast, visit www.sonusnet.com, Corporate, Investor Relations.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus is headquartered in Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. Readers are referred to the “Risk Factors” section of Sonus' Annual Report on Form 10-K, dated March 15, 2005, and the “Cautionary Statements” section of Sonus' Quarterly Report on Form 10-Q, dated November 8, 2005, both filed with the SEC, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. Any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.