Sonus Networks Achieves Milestone with Open Services Partner Alliance

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OSPA Doubles in First Year; Membership Swells to 34 Telecom Companies

WESTFORD, Mass., June 6, 2000 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure products for the new public network, today announced the addition of seven telecommunications vendors to the Sonus Open Services Partner Alliance™ (OSPA), expanding the membership to 34 companies. The new members of the OSPA include Cognitronics Corporation, iFace.com, MessageClick, Inc., Open Port Technology, Inc., Voyant Technologies, Inc., XACCT Technologies Inc. and Xybridge Technologies, Inc. The OSPA, launched in June of 1999, facilitates the rapid development and delivery of competitive services by carriers, application service providers and third-party independent service developers. 

"We’re truly thrilled with the market acceptance the OSPA has gained throughout the past year," said Gary Rogers, Sonus’ vice president of sales and marketing. "We have attracted 34 outstanding companies that offer a multitude of services to our carrier customers. By providing greater application choices through the Alliance, we are enabling service providers to build portfolios of innovative new services that will improve their competitive positions."

The most recent companies to join the Sonus OSPA bring a wide range of solutions to the market for enhanced data and voice services:

• Cognitronics Corporation provides carrier-class, network voice announcement systems, delivering the full range of network messages such as changed number, ANA, Class I and II features, flexible rate toll and TTY/TDD. The newly announced Cognitronics Exchange Series Media Resource Server operates seamlessly in both circuit switched and packet switched networks.
• iFace.com focuses on enhanced services for the converged voice and data network. Solutions encompass traditional telecom switching applications, Voice over Internet Protocol (VoIP), web initiated conference calls, and integrated circuit to packet switching with real-time billing, data and ATM networking technologies. 
• MessageClick, Inc. is a business-to-business Applications Service Provider (ASP) that offers global Internet-based unified communications services to a broad range of corporations, telephone companies, cable operators and major ISPs. MessageClick's Unified Communications solutions allow users to manage all of their voice, fax and e-mail communications by computer and over the telephone. 
• Open Port Technology, Inc. develops IP LaunchPad™, a carrier-class software platform that allows service providers to deliver enhanced IP services to their subscribers. IP LaunchPad offers the accountability, tracking and reliability of PSTN systems while taking advantage of the more efficient use of bandwidth, increased functionality, flexibility and reduced costs offered by IP networks. In addition to IP LaunchPad, Open Port offers a complete range of solutions for service providers, resellers, end users and third party developers.
• Voyant Technologies, Inc. is the leading platform provider for Intelligent Voice Applications. Voyant’s InnoVox platform is the most scalable in the market and can support nearly 100,000 subscribers, while meeting carrier-grade quality and reliability. Sitting on top of the open InnoVox platform is Voyant’s ReadiVoice application that sets the standard for totally automated conference calling, supports virtually unlimited capacity with 9,600 ports in one integrated system and empowers users with greater control over their communication experience.
• XACCT Technologies Inc. delivers software that allows network service providers to leverage the rapid growth of Internet services and data traffic to increase revenue opportunities. Network service providers use XACCTusage for comprehensive real-time data collection, data aggregation and automated user account provisioning to deploy new business models and higher margin enhanced services.
• Xybridge Technologies, Inc. provides a comprehensive family of carrier-class softswitch solutions for CLECs, ASPs, ITSPs, and OEMs. "One Solution. Universal Services."TM -- Only Xybridge delivers a complete, deployable, and integrated solution that encompasses carrier-grade IP Centrex, residential access, and long distance toll bypass services. The Xybridge Universal Services Suite accelerates service creation, reduces time to deployment, and provides carrier-grade fault tolerance with support for current and emerging IP telephony protocols, including MGCP, H.323, SIPBCP, Megaco, IPDC, IPST, and JAIN.

About Sonus’ OSPA

Launched in June 1999, the OSPA has gained significant industry momentum, with membership of 34 leading independent vendors offering subscriber-specified and user-provisioned services for the new public network. The OSPA gives carriers the flexibility to both develop and integrate "best-of-breed" applications, creating important new revenue streams. For participating partners, the OSPA provides open, published APIs, comprehensive developer tools, testing and support services, technology exchanges and co-marketing and sales activities. Equally important, the Alliance provides a unified customer/vendor forum for creating interoperable standards and technologies. Additional information on the OSPA is available at www.sonusnet.com/partners. 

About Cognitronics Corporation

Cognitronics Corporation (www.cognitronics.com) manufactures high-performance NEBS-compliant voice information systems for packet and circuit switched networks to serve all types of announcement and voice service applications, including fixed network messages, changed number, CLASS announcements, flexible toll rate and interactive voice response transactions. 

About iFace.com and Rare Medium Group, Inc. 

iFace.com is a wholly owned subsidiary of Rare Medium Group, Inc. (NASDAQ: RRRR). iFace.com brings companies and people profitably together by extending their reach through telephony applications and services. The company offers applications and services that enable web sites and service providers to apply flexible voice communications to rapidly changing customer and market requirements. Located in Kendall Park, NJ the company serves the telco and New Media marketplace. 

About MessageClick, Inc.

Founded in 1996, MessageClick provides Internet-based outsourced messaging services including fax, voice, wireless and unified messaging. MessageClick offers its services to corporations and service providers, which include cable operators, telephone companies, portals, and ISPs. MessageClick’s partners include Earthlink, Juno, AT&T, RCN, GTE and MindSpring. For more information, visit www.messageclick.com, or call 1-877-9-MCLICK. 

About Open Port Technology, Inc. 

Founded in 1993, Open Port Technology Inc. is a provider of Internet infrastructure messaging solutions. Open Port designs, develops and distributes IP LaunchPad, a carrier-class software platform that enables service providers to offer enhanced IP-based messaging services that connect to PSTN and wireless devices such as fax machines, telephones, voicemail systems, mobile phones and pagers. Open Port’s headquarters are located at 676 North St. Clair Street, Chicago, Illinois 60611. Additional information can be obtained by contacting Open Port by telephone (+1.312.867.5000), email (info@openport.com), or via the Internet (www.openport.com).

About Voyant Technologies, Inc. 

With more than 20 years of experience, Voyant Technologies, Inc. provides the leading platform and toolbox for intelligent voice applications. Voyant’s flexible, open InnoVox platform enables web-based applications, such as customer relationship management, multipoint internet conferencing, online education and enterprise resource planning. Enabling internet companies to deliver intelligent voice to their customers and helping telephony service providers integrate voice applications over the internet, Voyant’s mission is to embed voice into every web application. Due to its award-winning internet-based conferencing application, Voyant has more than 200 customers in 22 countries, including well-known telecommunications service providers, internet and Fortune 500 companies. For more information about Voyant Technologies, visit www.voyanttech.com or call 888-447-1087.

About XACCT Technologies Inc.

XACCT Technologies develops business infrastructure software that enables service providers to design and execute innovative, revenue-generating programs and services. XACCT markets its software directly and through network systems integrators and value-added resellers to service providers and Fortune 1000 companies. A privately held corporation, XACCT is funded by venture capital investors. More information is available at www.xacct.com.

About Xybridge Technologies, Inc. 

Xybridge Technologies, based in Richardson, Texas, is a leading provider of converged network softswitch solutions for service providers and OEMs. "One Solution. Universal Services."™ -- Only Xybridge delivers a complete, deployable, and integrated solution that encompasses carrier-grade IP Centrex, residential access, and long distance toll bypass services. The Xybridge Universal Services Suite is a scaleable service delivery platform that seamlessly bridges IP, PSTN and SS7 networks. The 100% Java architecture features the multi-protocol Universal Call Manager, Universal Service Framework, and Media Server, with open APIs for rapid service creation. Xybridge was founded in 1999 and is venture funded. The company maintains its web site at www.xybridge.com.

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 Sonus Networks’ Prospectus dated May 24, 2000.

Open Services Partner Alliance 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.