Sonus Networks Schedules Conference Call for Fourth Quarter and Full Year 2009 Financial Results

WESTFORD, MA, February 2, 2010 – Sonus Networks, Inc. (Nasdaq: SONS), providing network transformation through IP communications technology, today announced that it will release financial results for the fourth quarter and full year 2009 after the close of the market on Thursday, February 25, 2010, and will host a conference call with financial analysts and investors at 4:45 p.m. ET that day.

Conference Call Details

Date: Thursday, February 25, 2010
Time: 4:45 p.m. ET.

To listen live via telephone

Dial-in number: 800-913-1647
International Callers: +1 212-231-2907

To listen via internet

Sonus will host a live webcast of the conference call. To access the webcast, visit sonus.net, About Us, Investor Relations.

Replay Information

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 +1 402-977-9140. The reservation number for the replay is 21458243 and will be available until March 11, 2010.

A replay of the webcast will be also available on the Sonus Networks Investor Relations website. To access the replay of the webcast, visit sonus.net, About Us, Investor Relations, Webcast Archive.

About Sonus Networks

Sonus Networks, Inc., providing network transformation through IP communications technology, is leading the evolution of communications networks to support the multi-device demands of today’s digital lifestyle. Sonus solutions and services enable fixed, mobile and cable operators to gain network awareness and new multi-media capabilities essential to retaining and expanding their subscriber base. Through standards-based interoperable solutions and services, Sonus extends the investments made in traditional networks by enabling operators to seamlessly migrate to next generation technology and deliver the secure, reliable, scalable and cost-effective network needed to grow their business. For more information, visit sonus.net.

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. For a discussion of the risks and uncertainties which could cause actual results to differ from those contained in the forward-looking statements, see “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2008 and Quarterly Report on Form 10-Q for the quarters ended March 31, 2009, June 30, 2009 and September 30, 2009.

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

For more information, please contact:

Lucy Millington
978-614-8240
lmillington@sonusnet.com

Beth Panfil
978-614-8034
bpanfil@sonusnet.com