WESTFORD, Mass. and DANVERS, Mass., August 19, 2003 – Sonus Networks (Nasdaq: SONS), a leading provider of carrier packet voice infrastructure solutions, and TÜV America Inc. today announced that Sonus has achieved ISO 9001:2000 certification. TÜV awarded Sonus ISO 9001:2000 certification on August 14, 2003. The scope of Sonus certification includes the design and development, manufacturing and test, and servicing of voice infrastructure products for the telecommunications industry.

Sonus Networks is committed to delivering high-quality, next-generation packet voice solutions. The implementation of an effective quality management system is critical in ensuring that the needs and expectations of our customers and stakeholders are identified and continuously achieved, said Brian Mistretta, quality systems manager, Sonus Networks. We are extremely proud to have been awarded ISO 9000 certification. This is a significant achievement for our company and it is testament to the efforts of every employee of Sonus Networks.

By adding ISO 9001:2000 quality management systems certification to its existing CUE product safety certification, Sonus Networks is taking a leading approach of combining numerous certifications demonstrating its commitment to its customers, the industry and itself while ensuring that quality and safety are top priorities, stated Calin Moldovean, management systems director, TÜV America Inc.

ISO 9000 is a generic system standard that specifies, in very broad terms, the necessary components of a quality management system. Rather than being specific to any one industry, it details the basic requirements of the quality function for all industries. ISO 9000s primary purpose is to provide organizations with useful internationally recognized models for operating a quality management system. ISO 9001:2000 is the most recent revision of the ISO 9000 standard, which replaces the previous ISO 9000:1994 standard effective December 15, 2003.

ISO 9000 was originally published in 1987 by the International Organization for Standardization, a worldwide federation of national standards bodies, headquartered in Geneva, Switzerland. The organization was founded in 1946 to develop a common set of standards for manufacturing, trade and communications. Today more than 90 countries are members, each with a representative. The representative for the United States is the American National Standards Institute (ANSI). Currently over 50,000 organizations in North America are certified to the ISO 9000 series of standards.

Earlier this year, Sonus became the first company to receive CUE Certification, a 3-in-1-product certification service offered by TÜV America for the Canadian, United States and European markets, the three most sought-after markets in the world. CUE is available for Machinery, Information Technology and Consumer Product customers, where TÜV America can simultaneously determine compliance to CSA/SCC (Canadian), UL/ANSI (United States) and EN/IEC (European) safety standards. Sonus GSX9000Ô Open Services Switch was CUE certified to Canadian CAN/CSA 22.2 No. 950-93, UL/ANSI 1950 3rd edition, and European EN 60950/A11:1997 standards.

About TUV America Inc. (Management Service Division)

TUV America Inc., Management Service Division, is an internationally recognized certification organization providing management system certification services as a leading ISO 9000 Registrar in North America, Asia and Europe. Headquartered in Danvers, Massachusetts, the organization maintains a full-time audit staff in over a dozen locations throughout North America offering a full suite of ISO Management System certifications including ISO 9000, ISO 14001, QS-9000, ISO/TS 16949, VDA 6.1, TE Supplement, AS9100, ISO 13485/13488, and EN 46000 certification services. Additionally, TÜV provides CE Marking assistance, mechanical/electrical product safety, electromagnetic compatibility (EMC), NRTL certification, SCC Certification Body services, and performs European Union Notified Body services for a variety of EU directives. Globally, TÜV has issued over 130,000 product and 12,000 quality management system certifications. For more information, visit www.TUVamerica.com.

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 ArchitectureÔ (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 Westford, 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 August 13, 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. These risk factors include, among others, the adverse effect of recent developments in the telecommunications industry, the weakened financial position of many service providers, Sonus ability to grow its customer base, dependence on new product offerings, market acceptance of its products, 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. GSX9000 and Open Services Architecture are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.