WESTFORD, Mass. and SWINDON, UK, November 19, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider IP-voice infrastructure solutions, today announced it had been selected by BT Conferencing to develop scalable customer conferencing solutions. BT Conferencing is a market leader in business communications solutions, including audio, video and web conferencing.

Deployment of the Sonus platform within BT Conferencing's global infrastructure will allow for existing customer reservationless solutions to be expanded and scaled to meet demand, whilst retaining their existing call access numbers. New customers will benefit from the improved scalability that the solution provides using a single set of access numbers for their reservationless service. By simplifying the experience, BT Conferencing aims to encourage customers to utilize the service more frequently.

"We chose Sonus Networks to help us rollout this new service because of the Company's proven track record. This solution is an important additional feature to our conferencing and collaboration portfolio and we expect an enthusiastic response from our customers," said Aaron McCormack, CEO, BT Conferencing.

In addition to enabling this new service, the Sonus platform provides BT Conferencing with improved flexibility, a future-proof foundation and additional resilience by ensuring that in the unlikely event of network problems, calls can be serviced from alternate locations.

"Sonus is excited to be partnering with BT Conferencing to deliver feature-rich voice services to business users throughout the UK," said Hassan Ahmed, president, chairman and CEO, Sonus Networks. "By deploying a Sonus-powered conferencing service, BT Conferencing will be able to offer a more robust end user experience, while reaping the benefits of improved operational efficiencies."

By leveraging Sonus' complete IP-voice infrastructure, including the GSX™ 9000 Open Services Switch and the PSX^™ Call Routing Server, BT Conferencing will empower its customers with the ability to work seamlessly between traditional analogue and IP environments, which is critical as bridge and network technologies evolve.

While the initial platform will be deployed in Boston, MA, USA BT anticipates the deployment of this service globally, over the next 12 months.

About BT Conferencing

BT Conferencing was established more than 20 years ago and is now a leading global provider of audio, video and web collaboration services. Year on year growth has seen the company out-perform the conferencing industry expectation and with its extensive global portfolio, is now the number one conferencing provider in the UK and Europe with current reach in over 54 countries. BT Conferencing is based in the USA, EMEA and Asia Pacific and specialises in the delivery of reliable, robust and innovative conferencing solutions and product hardware to some of the largest companies in the world. The company offers tailor-made solutions to customers, whether they are small SMEs or major global businesses. www.bt.com/conferencing.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of IP-voice 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 for the period ended September 30, 2007, 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 restatement of its historical stock option granting practices and accounting including regulatory actions or litigation; 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.

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.