For more information, please contact:

NetVision Launches International Calls Program Using Sonus VoIP Infrastructure

Swindon, UK, December 15, 2004 - Sonus Networks, a leading supplier of service provider voice over IP (VoIP) infrastructure solutions and NetVision, Israel's largest Internet Service Provider, today announced that NetVision is deploying Sonus infrastructure to build a new network for international calls.

Sonus had provided NetVision with its GSX9000TM Open Services Switch and the InsignusTM Softswitch, to deliver a range of VoIP services and to enable callers to make international calls using the prefix 017. The program was launched on 15 November 2004

"NetVision pioneered Internet use in Israel and has since continued to work with new, innovative technologies. With the expansion of Netvision's business to international dialing services we are delighted to be helping them continue to offer a competitive edge," said Joop van Aard, vice president, sales, EMEA, Sonus Networks. "We are extremely pleased to be working with NetVision to expand their network and enhance their offerings to their customers."

"To ensure a high standard of quality is maintained when we expand our network to an international level, we needed a reliable and robust voice solution that is proven in the market," said Yuval Tzeiri, vice president of technology at NetVision. "Sonus' voice infrastructure solutions address our requirements for toll-quality voice and the capacity to handle large volumes of long-distance voice traffic. Moreover, Sonus has a significant reputation for deploying large-scale packet voice networks with the world's leading carriers, which made it the ideal partner for our network implementation."

About NetVision

NetVision was established in 1994 and is co-owned by Elron Electronic Industries and Discount Investment Corporation. The company pioneered the Internet market in Israel and has since grown to be Israel's largest provider of Internet services to both businesses and consumers. The company specializes in designing integrated Internet solutions to suit the needs of individual users. On November15th 2004, NetVision launched its international calls program. The services are available not only to its customers, but to all callers using the prefix 017.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of packet voice 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, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services. Sonus' award-winning 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. For more information, visit 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 November 9, 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, 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.