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CHELMSFORD, Mass., February 20, 2004 – Sonus Networks (Nasdaq: SONS) today announced that company executives will participate in the following financial conferences:

Goldman Sachs Technology Investment Symposium 2004

Phoenix, AZ
Tuesday, February 24, 2004, 2:10 pm MT
Speaker: Hassan Ahmed, president and CEO
Webcast Link: http://customer.nvglb.com/GOLD006/022304a_by/default.asp?entity=sonus

Raymond James & Associates 25th Annual Institutional Investors Conference

Orlando, FL
Tuesday, March 2, 2004, 9:50 am ET
Speaker: Bob Dye, vice president, strategic marketing
Webcast Link: http://www.wallstreetwebcasting.com/webcast/rjii04/sons

Interested investors can access live audio webcasts of the presentations on the Investor Relations section of the Sonus Networks website at www.sonusnet.com. Replays of the webcasts will be available 24 hours after the presentations. A full schedule of Sonus Networks’ investor activities is available on the Sonus Networks Investor Relations site.

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure solutions for wireline and wireless service providers. With its Open Services ArchitectureTM (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services. Sonus’ award-winning voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide. Sonus, founded in 1997, is headquartered in Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus 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 “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated November 10, 2003 and filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include, among others, unforeseen issues encountered in the completion of the Company’s independent investigation and the year-end audit, the continued adverse effect of developments in the telecommunications industry, Sonus’ ability to grow its customer base, dependence on new product offerings, market acceptance of its products, competition from large incumbent vendors, rapid technological and market change and manufacturing and sourcing risks. In addition, 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. Open Services Architecture, GSX9000 and Insignus are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.