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WESTFORD, Mass., July 11, 2002 - Sonus Networks, Inc. (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today reported its financial results for the second quarter ended June 30, 2002.

Revenues for the second quarter of fiscal 2002 were $21.3 million compared with $52.6 million in the same period last year. Adjusted net loss for the second quarter of fiscal 2002 was $10.5 million or $0.06 per share compared with adjusted net income for the second quarter of fiscal 2001 of $1.2 million or $0.01 per share. Actual net loss for the second quarter of fiscal 2002 was $17.8 million or $0.09 per share compared with an actual net loss for the second quarter of fiscal 2001 of $51.4 million or $0.30 per share.

Revenues for the first six months of fiscal 2002 were $42.5 million compared with $94.1 million in the same period last year. Adjusted net loss for the first six months of fiscal 2002 was $23.2 million or $0.12 per share compared with adjusted net income for the first six months of fiscal 2001 of $1.3 million or $0.01 per share. Actual net loss for the first six months of fiscal 2002 was $34.0 million or $0.18 per share compared with an actual net loss for the first six months of fiscal 2001 of $133.9 million or $0.80 per share.

A reconciliation of adjusted to actual net income (loss) for the periods is as follows:

"The telecommunications market remains very challenging, and continues to impact our financial results," said Hassan Ahmed, president and CEO, Sonus Networks. "During this period, we have been focused on managing our business and finances with precision and extending our market leadership. Today's announcement of Deutsche Telekom, the largest PTT in Europe, as our newest customer further validates the packet voice market, and is an important endorsement of Sonus and our packet voice solutions."

Concurrent with this release, Sonus announced that Deutsche Telekom's T-Systems International division has chosen Sonus to build out its next-generation VoIP network to provide multi-national corporations with enhanced voice services (see today's press release "T-Systems International Selects Sonus Networks to Provide Packet Voice Infrastructure and Services"). T-Systems will leverage the Sonus-based network to deliver services such as global voice VPN (virtual private network) and sophisticated call center routing facilities, with additional services to follow.

In May, Sonus announced that KDDI, one of the largest carriers in Japan, selected Sonus to provide packet voice infrastructure solutions to support the delivery of voice over IP (VoIP) services over KDDI's broadband network. By deploying Sonus' industry-leading media gateway, softswitch and management solutions, KDDI will be able to cost-effectively deliver a range of SIP-based voice services over its high-speed fiber optic infrastructure.

During the quarter, Sonus unveiled its SMARRT^TM Cable solution, a next-generation packet voice solution specifically geared to the requirements of cable operators (MSOs). Building on packet technology already proven in carrier voice networks, Sonus' SMARRT Cable solution is designed for carrier-grade reliability, voice quality and features, and delivers voice services in a cost-effective and flexible PacketCable^TM architecture.

To further drive the implementation of VoIP in broadband cable networks, Sonus and Motorola, Inc. Broadband Communications Sector are collaborating to create a comprehensive packet voice solution available for broadband network operators. The Motorola/Sonus end-to-end packet voice solution draws upon the extensive capabilities of two industry leaders - Motorola providing advanced IP access network solutions and Sonus providing telco-grade packet voice infrastructure products.

Also in the quarter, Sonus was named the worldwide market share leader for carrier-class packet voice equipment for the seventh consecutive quarter. Leading industry research firms In-Stat/MDR, Infonetics Research and Synergy Research Group issued first quarter 2002 market share reports confirming Sonus' continued leadership position in a number of market segments. Also in May, the Aberdeen Group released a report citing Sonus' deployment with Japanese carrier Fusion Communications as one of the most significant VoIP deployments of 2001.

Today, Sonus announced that it has been named as a defendant in a securities class action lawsuit (Steinberg v. Sonus Networks, Inc., et al., 02 CV 11315 D. Mass) alleging that the company made false and misleading statements about its products and business. Sonus has not yet filed a response to the complaint. The company believes that the claims are without merit and that it has substantial legal and factual defenses, which it intends to pursue vigorously.

Sonus Networks, Inc., is a leading provider of packet voice infrastructure products for the new public network. With its Open Services Architecture^TM (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 Sonus' Quarterly Report on Form 10-Q, dated May 10, 2002 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 emerging 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.

SMARRT 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.