WESTFORD, Mass., February 11, 2004 – Sonus Networks (Nasdaq: SONS) today provided additional information regarding the delay in reporting its fourth quarter and full fiscal year financial results for the year ended December 31, 2003.  In connection with the year-end audit, Sonus Networks and its independent auditors have identified certain issues, practices and actions of certain employees relating to both the timing of revenue recognized from certain customer transactions and to certain other financial statement accounts, which may affect the Company’s 2003 financial statements and possibly financial statements for prior periods.

The revenue issues identified relate to the proper timing of recognizing revenue from certain customer transactions, and not whether the sales can be recorded as revenue.  For the customer transactions under review, the products have been delivered, customers are using the products in their networks and Sonus Networks has either received payment or is receiving payment for the products in the ordinary course. The Company is reassessing the proper periods in which revenue should be recognized for these transactions.  Revenue or deferred revenue in periods previously reported could increase, decrease or remain unchanged in those periods as a result of this reassessment. 

In response to the issues identified, the Company has taken the following steps:

• The Company is performing a detailed review of the revenue timing issues and practices and of certain other financial statement accounts
• The Audit Committee of Sonus Networks’ Board of Directors is conducting an independent investigation, employing the services of Hale and Dorr LLP and PricewaterhouseCoopers
• The Company has terminated certain non-executive employees
• Sonus Networks has notified the Securities and Exchange Commission of the Company’s independent investigation and is fully reporting the results of that ongoing investigation to the Commission

“We are deeply concerned and disappointed to have discovered that certain employees at Sonus Networks were engaged in behavior that violated our code of conduct and may have compromised the integrity of our financial reporting,” said Hassan Ahmed, president and CEO, Sonus Networks.  “The Company responded promptly by taking appropriate measures to address these matters. We assure our shareholders, customers and employees that our management and Board of Directors are committed to taking all necessary steps to complete our review in an expeditious and comprehensive manner, and to prevent such problems from occurring in the future.”

At this time, Sonus Networks cannot provide an anticipated date for the completion of its review or the year-end audit, or for the rescheduling of the release of its fourth quarter and fiscal year results for the year ended December 31, 2003.

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 Architecture (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 Westford, Massachusetts.

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.

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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.