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Chicago, IL – June 22, 2004 – Sonus Networks (Nasdaq:SONSE), a leading provider of voice over IP (VoIP) infrastructure solutions, today announced that its InsignusTM Softswitch, featuring the ASX Access Server, now supports voice services on WiFi telephones. Sonus is demonstrating these capabilities in its exhibit at SUPERCOMM 2004.

The convergence of two industry trends is driving the adoption of voice over WiFi (VoWiFi). First, 2004 will be the year in which VoIP services start to achieve significant adoption among end-user subscribers. At the same time, WiFi is growing in popularity as the predominant access technology for businesses, residences and public areas. Delivering voice services over WiFi networks is a natural extension of the Sonus Networks Open Services ArchitectureTM (OSA), and can now be enabled by Sonus' ASX Access Server.

"We view the emergence of VoIP services for end users as a major industry theme in 2004, and this, coupled with the ubiquity of WiFi, offers exciting possibilities for delivering voice services over WiFi networks," said Michael O'Hara, vice president, marketing, Sonus Networks. "The ASX Access Server, with its robust SIP capabilities, is an ideal platform on which to offer these services, and we expect this to be an important disruptive technology in the years ahead."

In Sonus' booth #25204, the company is conducting live demonstrations of VoWiFi services using the Sonus ASX Access Server and the Pulver Innovations WiSIP handset. The WiSIPTM mobile IP phone is a next-generation intelligent IP communications device that brings SIP-based VoIP communications together with WiFi installations.

"VoIP is truly entering the mainstream of telecommunications, and we see WiFi as the next battleground," said Jeff Pulver, president and CEO, Pulver.com. "Companies and innovators that can usher in the convergence of VoIP and WiFi are ideally positioned to drive the adoption of voice services in wireless environments."

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 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, uncertainties regarding the timing of the Company’s completion of the audit and 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, uncertainties regarding the extent to which prior period financial statements will be restated, 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, 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.