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Pioneers in IP Voice Solutions Team to Make FMC a Reality for Network Operators around the World

WESTFORD, Mass. and BARCELONA, Spain, February 14, 2007 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, and ip.access, the creator of cellular picocell and femtocell technologies, announced today at the 3GSM World Congress in Barcelona, Spain that the two companies have entered into a partnership. Sonus, which recently unveiled its strategy to create new cost-efficient solutions designed to deliver fixed-mobile service over GSM spectrum, will work together with ip.access, which will provide in-building picocell and femtocell solutions. For ip.access, this relationship validates the Company's IP Multimedia Subsystem (IMS) roadmap and allows ip.access to work closely with a leading provider of wireless and wireline IP-voice and multimedia infrastructure solutions.

“This relationship with Sonus has significant benefits for our customers. Working with Sonus broadens the attractiveness of both organisations' offerings as it creates an end-to-end IMS-based solution that brings together fixed and mobile voice in an office environment,” said Stephen Mallinson, CEO of ip.access. “ip.access is committed to making picocell technology available to operators globally. Sonus is a highly-regarded player in the IMS space and we are consequently thrilled to be working closely with them to offer what we believe could be the holy grail of the convergence story.”

“Sonus recognizes a strong opportunity to reshape the communications landscape and help our customers take advantage of the recently released GSM spectrum to arm consumers with a whole new level of custom services,” said Steve Edwards, chief marketing officer, Sonus Networks. “This partnership with ip.access, a leader in this rapidly evolving industry, is a critical step for executing on our vision and being one of the first companies to deliver an actionable FMC solution for today's single mode handsets.”

Additional information regarding Sonus' recently announced strategy for delivering on the promise of LP GSM can be found in the press release entitled, “Sonus Networks Unveils Strategy to Help Network Operators Capitalize on Low Powered GSM Business Opportunity” issued February 13, 2007. Sonus will be exhibiting its industry leading solutions at the 3GSM World Congress, one of the wireless industry's largest tradeshows, at Booth D46, Hall 2, Level 1. Additional information on the 3GSM World Congress can be found at http://3gsmworldcongress.com.

About ip.access

Based in Cambridge, UK, ip.access ltd (www.ipaccess.com) is a leading manufacturer of cost-effective picocell and femtocell infrastructure solutions for GSM, GPRS, EDGE and 3G. These solutions bring IP and cellular technologies together and solve in-building access problems for mobile operators, opening up new revenue streams while defending existing business.

Oyster 3G™ is the home access femtocell that dramatically increases 3G cell capacity and coverage; improves quality of experience; and drives down costs. Oyster 3G is ready for today's mobile networks and tomorrow's IMS infrastructure.

nanoGSM picocell provides GSM, GPRS and EDGE coverage and capacity for offices, shops and using satellite backhaul passenger aircraft, ships and in remote rural areas.

With over 18 live networks around the world and many more being deployed, ip.access is the partner of choice for operators competing in the new converged marketplace.

ip.access counts Scottish Equity Partners, Intel Capital, Rothschild Gestion, Amadeus Capital Partners and Motorola among its shareholders.

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 Westford, 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 Item 1A “Risk Factors” of Sonus' Quarterly Report on Form 10-Q dated May 8, 2006, 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: 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 and uncertainties associated with the Company's announced review of its historical stock option grants and accounting, including any potential impact on the Company's financial statements or results, any tax liabilities or penalties, the Company's inability to timely report with the Securities and Exchange Commission, the Company's potential inability to meet NASDAQ requirements for continued listing, potential investigations, regulatory actions or litigation arising out of the review or any restatement; 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.

The product information in this press release is for informational purposes only and is subject to change at Sonus' sole discretion without notice. Sonus has no obligation or commitment to develop or deliver any product or future release, upgrade, feature, enhancement or function described in this release. The information is provided “AS IS,” with all faults, and without any warranties whatsoever, express or implied, including, but not limited to, warranties of merchantability, performance, or fitness for a particular purpose.

Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.