Sonus Showcases IP-Based Voice Applications Design for the Japanese Market at VON Japan

TOKYO, Japan and CHELMSFORD, Mass., July 19, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, announced today that at VON Japan (Booth V-001), the Company will be showcasing IP-based voice applications that enable Japanese consumers greater levels of customization and personalization in their communications experience. Delivered over a Sonus IP Multimedia Subsystem (IMS)-ready architecture and built with Sonus' IMS application development tools, including the Sonus IMX™ Multimedia Application Platform, these new applications demonstrate how a Sonus-based network can help network operators globally deliver the types of applications and services that promote customer acquisition and retention in their unique markets.

“The Asia-Pacific market has typically been on the leading edge of the adoption curve when it comes to new applications and features for enhancing the communications experience. By deploying a Sonus-based IMS-ready architecture, network operators can dramatically reduce the cost and complexity of introducing new services to market, promoting new levels of experimentation and innovation,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “In addition, Sonus' standards-based development methodology allows network operators to easily customize the applications with localization features, such as localization of the user interface.”

Sonus, which currently supports over 49 international signaling variants and integrates localization features such as language translations, helps to enable network operators from around the world leverage the benefits of IP-based voice solutions. Sonus' focus on meeting the regionally-specific demands of global network operators, in particular those in Japan, has helped the company achieve its worldwide market share leadership position. In Japan specifically, according to Synergy Research Group's report on Q1 market share results, Sonus currently owns nearly 46% of the total service provider VoIP infrastructure market, 6x its nearest competitor, and in the high density gateway category, Sonus leads the industry with nearly 87% of the total market.

Applications being demonstrated at this year's VON Japan, Sonus Booth V-001, include:

• Parental Controls: An IMX-based application that allows parents to use a Web portal to define and enforce the policy of how their children's cell phones are used, including restricting calls to and from specific numbers, setting the time-of-day the phone can be used, minutes used, etc.
• “WebWalls”: An interactive application that allows users with mobile phones to communicate in real-time with Web-connected screens or advertisements.
• Ring Back Tone: A service that enables subscribers to replace the traditional “ringback” tone callers hear with a unique personalized message, music clips, movie lines, sound effects, etc.
• Click-to-Dial Infrastructure: A set of capabilities that enable Web-based services with click-to-dial capabilities. This capability could be used by Web merchants to connect buyer and seller without needing to reveal either party's phone numbers.

“Today's communication networks reach global audiences. In an area as richly diverse as Asia-Pacific, the ability to rapidly and cost-efficiently tailor new applications to various regions is key to widespread adoption,” said Takayuki Oshima, Managing Director, Sonus Networks Japan. “Voice services have evolved rapidly in Japan, taking the nation to greater heights as a trailblazer in this field and becoming one of the world's most sophisticated telecommunications markets. Sonus is honored and privileged to be a predominant supplier to the leading operators in this region. We look forward to growing and sustaining our foothold in this challenging market by providing world-class products and services.”

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 comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus 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, dated March 14, 2006, and Quarterly Report on Form 10-Q, dated May 5, 2006, both 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: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. 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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