Carrier-Class Packet Voice Switch Passes Rigorous NEBS Tests for Performance, Quality and Safety

WESTFORD, Mass., May 31, 2000 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure products for the new public network, today confirmed that the GSX9000™ Open Services Switch successfully completed the most rigorous set of performance and safety tests collectively known as Network Equipment-Building System (NEBS). The GSX9000 meets all NEBS Level 3 physical and environmental requirements for telecommunications equipment used in central offices, and can be deployed into both new and existing carrier networks. NEBS Level 3 represents the most stringent and comprehensive level of testing and provides the highest assurance of product operability. 

NEBS certification, originally developed by Bellcore (now Telcordia Technologies), is a rigid and extensive set of tests that evaluate performance and quality of network equipment, as well as environmental and safety levels. Network equipment is also tested for flammability, Zone-4 earthquake vibrations, thermal shock, changing temperatures, mechanical shock, and electrostatic discharge. 

"Our carrier customers demand that the network equipment they buy be held at the highest levels of safety and accountability," said Mike Hluchyj, founder and chief technical officer, Sonus Networks. "We designed the GSX9000 from the ground up to comply with NEBS Level 3 standards and this certification assures them that the GSX9000 meets those criteria.

The GSX9000 Open Services Switch is the central component of the Sonus Networks Open Services Architecture™. The GSX9000 was designed specifically to match the needs of public network service providers for redundancy, voice quality, interoperability, and scalability. Leading carriers such as Global Crossing, Williams Communications, Intermedia Communications, Z-Tel Technologies and Cybertel are deploying the GSX9000 to enhance their competitive positions through the reduction of operating costs and the development of revenue streams generated by new service applications.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice infrastructure products for the new public network. Sonus’ solutions enable service providers to deploy an integrated network capable of carrying both voice and data traffic, and to deliver a range of innovative, new services. The Sonus Open Services Architecture (OSA) and award-winning Packet Telephony suite cut the time-to-market for competitive new service products, allowing carriers and third-party developers to expand marketshare and build important new revenue streams. Its highly scalable products fully interoperate with and extend the life and utility of today’s public network. Sonus embodies in its management and staff decades of experience in developing carrier-class voice, data and multimedia solutions for implementation in the world’s largest networks. Sonus, founded in 1997, is headquartered in Westford, Massachusetts. 

This press release may contain forward-looking statements relating to future events or future financial performance that involve risks and uncertainties. These statements are made pursuant to the safe harbor provisions of Section 21E of the Securities Exchange Act of 1934. These statements are only predictions and actual results could differ materially from those anticipated in these statements based upon a number of factors including those risk factors identified in the Company's Prospectus dated May 24, 2000.

GSX9000 and Open Services Architecture are trademarks of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.