For more information, please contact: Public Relations Beth Morrissey 978-589-8579 bmorrissey@sonusnet.com

Investor Relations Jocelyn Lynds (978) 589-8672 jlynds@sonusnet.com

New Entrants Deliver Variety of Enhanced Services, Network Infrastructure Solutions and Next-Generation Technologies; Partners From Canada, England and South Korea Expand OSPA's International Scope

WESTFORD, Mass., October 9, 2001 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that its Open Services Partner AllianceSM (OSPA) has added 11 new members.

Joining the OSPA are the following: ADTRAN Inc. of Huntsville, Ala.; Aperto Networks Inc. of Milpitas, Calif.; CosmoCom Inc. of Melville, N.Y.; CyberTel Inc. of Middletown, N.J.; Fastcomm Communications Corp. of Dulles, Va.; inPACT Technologies Ltd. of Denbighshire, England; jNetX LLC of Dallas, Texas; Kenetec Inc. of Naugatuck, Conn.; Mitel Networks of Ottawa, Canada; Polycom??, Inc. of Milpitas, Calif.; and Polypix Inc. of Seoul, South Korea.

Sonus' goal for the partner alliance is to assemble a comprehensive group of telecommunications providers that are committed to developing next-generation converged network solutions based on the Sonus platform. The latest entrants provide a wide array of enhanced services, network infrastructure solutions and next-generation technologies, reflecting the diversity of the program.

"In today's marketplace, carriers are looking for a place to identify the applications and services they need to get their next-generation networks up and running quickly," said Terri Griffin, vice president, marketing, Sonus Networks. "The OSPA serves as that kind of catalyst, and this latest group of partners demonstrates the breadth of solutions that are included in the OSPA. We look forward to working with each of the companies to meet our carrier customers' network needs.

The inclusion of new partners from Canada, England and South Korea also illustrates how the OSPA continues to expand around the globe. The OSPA has other partners based in Denmark, France, Germany, Ireland, Israel, Japan and Singapore. 

Companies joining the Sonus OSPA today offer the following solutions:

• ADTRAN is an established supplier of advanced transmission products for today's expansive telecommunications networks. ADTRAN's Total Access System includes Integrated Access Devices (IADs) offering both modular and fixed-port carrier class configurations. These IADs are ideal for T1 or DSL applications requiring data and analog voice support in a single compact platform. (www.adtran.com) 
• Aperto Networks develops multi-service fixed broadband wireless access systems that provide solutions to last-mile bottlenecks. Aperto Networks' point-to-multipoint PacketWave??? System consists of base station, subscriber units, subscriber management tools, and associated radios and antennas in a variety of frequency bands. The PacketWave system applies breakthrough technologies of OptimaLink???, RapidBurst???, and ServiceQ??? to address service provider needs for rapid network deployment, multi-service scalability, ease of installation and cost-effectiveness. (www.apertonet.com).
• CosmoCom provides IP-based call-center software that allows companies to deploy customer service representatives anywhere. CosmoCall Universe is a unified multimedia platform that can support remote call-center applications and scale up to 8,000 simultaneous customer service agents, 50,000 simultaneous calls and messages, and 500,000 call arrivals per hour for mission-critical service provider or enterprise applications. (www.cosmocom.com)
• CyberTel develops unified communications software that gives telecom providers the ability to provision device-, network-, topology- and media-independent services. The company's CyberCOMSC unified messaging product uses Session Initiation Protocol (SIP), allowing carriers to deploy additional services to their existing user base without additional acquisition costs. (www.cybertel.com)
• FastComm provides carrier-grade signaling protocol converters that bridge the gap between incompatible communications networks. The SignalPath 201 and 230 converters provide traditional and emerging carriers with the ability to provide long-distance services in foreign countries by converting their signaling protocols to the local country host's regional specific protocol. FastComm maintains and updates a database of country-specific signaling variants for over 80 countries. (www.fastcomm.com)
• inPACT markets a range of hardware-independent media servers to address the media requirements of VoIP networks. The inPACT Announcement Machine (iAM) is VoiceXML scriptable, and it supports various applications, including call answering services and bulk call receiving. The inPACT Voice Response Unit (iVRU) adds DTMF menu navigation, and the inPACT Voice Response Gateway (iVRg) adds an SQL database interface and the ability to record the media stream. (www.inpact-tech.co.uk)
• jNetX designs, develops and markets carrier-class evolutionary charging and application layer solutions for next-generation wireless and landline communication providers. Its products include a robust, standards-compliant application server platform, a service creation environment for rapid application creation and full-featured universal charging (voice, data, commerce, QoS) applications for prepaid account and card solutions. (www.jnetx.net) 
• Kenetec provides broadband access platforms that enable Integrated Communications Providers to deploy multimedia services over a converged network to businesses in multi-tenant units (MTUs). The company's EdgeXpress product family includes a service access unit, a service exchange platform and a service provisioning system for Services-oriented Building Area Networks (SBANs). EdgeXpress supports packetized and legacy voice, high-speed Internet access, video, and advanced IP services. (www.kenetec.com) 
• Mitel Networks has created a portfolio of IP phones, peripherals and applications that deliver next-generation services to the desktop. The company's March Networks 5055 SIP Phone is a full-featured business phone with speakerphone, 2x20 LCD alphanumeric display, URL- and IP-address dialing, and support for a long list of protocols, including IPv4, DNS, ICMP and RTP. (www.mitel.com)
• Polycom is a leader in endpoint voice and video communications, providing broadband solutions for corporations, schools, home offices and small businesses. Polycom markets the SoundPoint?? IP line of standards-based desktop phones, and the SoundStation?? IP, a conference phone based on the industry-leading line SoundStation audioconferencing products. The Polycom line supports leading VoIP platforms and multiple protocols. Its access products include the NetEngine integrated access devices that deliver connectivity across T1, ADSL, SDSL, G.SHDSL and VoDSL lines. Its interactive video communications solutions deliver conferencing services to the desktop and to all sizes of conference rooms. (www.polycom.com)
• Polypix provides a Web telephony suite called PIXEL , which consists of company-developed call server, control center, Internet call switch and browser plug-in products, along with an industry standard H.323 VoIP gateway, gatekeeper and Web server. Polypix also offers a wide range of enhanced services applications, including conferencing, Internet call waiting, IP PBX, videoconferencing, and a voice portal platform. (www.polypix.com)

About Sonus' OSPA

Founded on the combination of Sonus' Open Services Partner Alliance (OSPA) Program and the INIP PoweredSM Partner Program from the acquisition of telecom technologies, inc., the OSPA has gained significant industry momentum, with membership of more than 150 leading independent vendors. The OSPA provides a framework that offers service providers end-to-end packet-based network solutions using best-of-breed technologies and applications. The goal of the OSPA is to empower standards-based interoperability between applications, hardware vendors, and the Sonus product suite. An integral part of the Sonus OSPA, the Interoperability Laboratory in Richardson, Texas, is the first in the industry where product interoperability is verified, trial testing is performed, and complete solutions are ultimately produced. Additional information on the OSPA is available at http://ospa.sonusnet.com.

About Sonus Networks

Sonus Networks 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 market share 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. 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 August 13, 2001, 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 Company's ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change, integration risks relating to the acquisition of telecom technologies and manufacturing and sourcing risks.

Open Services Partner Alliance is a service mark of Sonus and Open Services Architecture is a trademark of Sonus. All other company and product names may be trademarks of the respective companies with which they are associated.