Sonus Networks Provides Update On Nasdaq Listing Status

CHELMSFORD, Mass., August 5, 2004 – Sonus Networks (Nasdaq: SONSE) today announced it has received written notification from Nasdaq that the Company has met all the requirements necessary for continued listing on the Nasdaq National Market. Accordingly, the Nasdaq Listing Qualifications Panel has withdrawn its prior delisting decision dated July 28, 2004 and determined to continue the listing of the Company’s securities on the Nasdaq National Market.

Sonus also announced that the Company plans to file a Form 12b-25 (Notification of Late Filing) with the Securities and Exchange Commission (SEC) reporting that it will be unable to file its Quarterly Report on Form 10-Q for the quarter ended June 30, 2004 by the August 9, 2004 due date. The delay in filing Sonus’ second quarter Form 10-Q is the result of the extended time Sonus spent in completing its recent detailed financial review and restating its historical financial results. The Company completed its financial review and on July 28, 2004 reported financial results for the quarter and fiscal year ended December 31, 2003 and the quarter ended March 31, 2004.

The Company also will request an exception to Nasdaq’s filing requirements under Nasdaq Marketplace Rule 4310(c)(14) extending the date by which it must file its Quarterly Report on Form 10-Q for the quarter ended June 30, 2004. The Company will request an extension to August 30, 2004 and will make every effort to complete its filing by that date. At the Company’s request, to minimize disruption, the “E” will not be removed from Sonus’ trading symbol during the period that the Company is in compliance with the Nasdaq listing requirements. The Company’s stock will continue trading under the symbol “SONSE” pending the filing of its Form 10-Q for the second quarter. Sonus’ stock will be subject to delisting if Nasdaq does not grant the extension requested or Sonus does not file its Form 10-Q by any extended date granted by Nasdaq.

“Prior to the filing of our fiscal 2003 Form 10-K/A and Form 10-Q for the first quarter of 2004 last Wednesday, we dedicated ourselves to completing the complex review and preparation of our historical financial statements to bring our filings current,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “We are now working diligently to prepare our 10-Q filing for the second quarter and will complete this process as soon as possible.”

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 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 “Risk Factors” section of Sonus’ Annual Report on Form 10-K/A dated July 28, 2004 and filed with the SEC, and the “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated July 28, 2004 and filed with the SEC, which identify 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 Quarterly Report on Form 10-Q for the quarter ended June 30, 2004, the possibility that Sonus may be delisted from Nasdaq and risks associated with the pending securities litigation and SEC investigation. 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.