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CHELMSFORD, Mass., July 28, 2004 – Sonus Networks, Inc. (Nasdaq: SONSE), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced that it is in the process of completing the preparation of its restated financial statements for fiscal years 2001, 2002 and the first three quarters of 2003, its Form 10K-A for the fiscal year ended December 31, 2003 and its Form 10-Q for the first quarter of 2004. The Company continues to work diligently to complete its filings as soon as possible. The Company has not filed its SEC periodic reports within the extended exception period granted by Nasdaq. Accordingly, the Company is seeking a further brief exception from the Nasdaq Listing Qualifications Panel for additional time to regain compliance with the Nasdaq filing requirements. There can be no assurance that the Panel will grant any additional exception.

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 Open Services ArchitectureTM (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking and tandem switching, residential and business access, network border switching and enhanced services. Sonus' 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 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 “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, uncertainties regarding the timing of the Company's completion of the filing of its Annual Report on Form 10-K/A for 2003 and future periodic reports, the possibility that Sonus may be delisted from Nasdaq, risks as to the litigation and SEC investigation with respect to the foregoing and related matters, unforeseen issues encountered in the completion of the audit and uncertainties regarding the extent to which prior period financial statements will be restated. 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, Insignus and Sonus Insight are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.