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Sonus Networks to Request Review of Nasdaq Staff Determination

CHELMSFORD, Mass., March 30, 2004 – Sonus Networks (Nasdaq: SONS), a leading provider of voice over IP (VoIP) infrastructure solutions, today announced that consistent with the information provided in its press release on March 29, 2004, the Company has received a Nasdaq Staff Determination.  The letter indicates that because the Company has not timely filed its Form 10-K for the fiscal year ended December 31, 2003, it is not in compliance with the Nasdaq continued listing requirements set forth in Nasdaq Marketplace Rule 4310(c)(14).  As a result of the delinquency, Sonus Networks will begin trading under the symbol “SONSE” effective at the opening of business on Wednesday, March 31, 2004.

Sonus Networks will request a hearing with the Nasdaq Listing Qualifications Panel within seven days of the date of the Determination for continued listing on the Nasdaq National Market.  Sonus Networks’ securities will remain listed on the Nasdaq National Market pending the outcome of the hearing.  There can be no assurance that the Panel will grant a request for continued listing.  

As announced in its press release on March 29, 2004, Sonus Networks remains committed to accurate and transparent financial reporting and continues to conduct a detailed review of the timing of revenue recognized from customer transactions and of other financial statement accounts.  The Company is working diligently to complete its 2003 Form 10-K and to fully comply with all requirements for continued listing.

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 Architecture (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 contains 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 as a result of various risk factors, including, among others, the Company’s ability to maintain its listing on Nasdaq and to complete the audit and file its 2003 Form 10-K and future periodic reports, risks as to the SEC’s investigation of these or other 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 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.