Pactolus Reaches Highest Level in Sonus' OSPA Through Deployment at Touch America; Touch America Running Live Calling Card Services on Pactolus and Sonus Solution

WESTFORD, Mass., and WESTBOROUGH, Mass., April 22, 2002 - Sonus Networks (Nasdaq: SONS) and Pactolus Communication Software Corporation today announced that Pactolus has achieved Platinum Partner standing in Sonus' Open Services Partner AllianceSM (OSPA). To attain Platinum status, companies' products must be deployed in a live, revenue-generating service provider network together with one or more Sonus solutions. Touch America (NYSE: TAA), a national broadband fiber-optic network and products and services company, has deployed a joint solution from Sonus and Pactolus, and is now delivering prepaid and postpaid calling card services to its customers over the Sonus/Pactolus VoIP (voice over IP) infrastructure.

"To deliver VoIP-based calling card services for business and residential users, we required a solution that would offer our customers the highest levels of voice quality and reliability at a competitive price," said Sharon Pavlicek, product manager for Touch America. "The comprehensive solution from Sonus and Pactolus addresses these requirements, and allows us to rapidly roll out the calling services on our 22,000-route-mile broadband network."

Touch America has rolled out Sonus' award-winning packet voice solutions, including the GSX9000 Open Services Switch, the Insignus Softswitch and the Sonus Insight Management System, as the foundation of the carrier's nationwide VoIP network. With the Sonus-based packet voice infrastructure, Touch America can provide a wide variety of next-generation, IP-based voice services.

Touch America's Business Anywhere Calling Card service for commercial customers and its Home Anywhere Calling Card service for residential customers uses Pactolus' SIPware' Prepaid Calling Card and SIPware Calling Card applications. These applications are proven to establish brand identity, add new subscribers, and generate revenue for service providers. The feature-rich SIPware Services solutions offer subscribers a range of benefits, including a self-service Web portal for service customization.

"With their successful implementation of Pactolus' calling card applications, Touch America has proven that SIP-based enhanced services are indeed ready for prime time," said Terri Griffin, vice president, marketing, Sonus Networks. "We are proud of what we've already accomplished together in the Touch America network, and we congratulate Pactolus for achieving the Platinum level in our OSPA."

"The combined Sonus and Pactolus solution has enabled Touch America to take advantage of the latest in next generation, SIP-based service architectures and deliver proven revenue generating services in their network," said Ken Osowski, vice president of product management and marketing for Pactolus. "This deployment by Touch America is yet another indication that SIP-based enhanced services are highly scalable and are gaining momentum in the market."

Sonus offers a full complement of packet voice solutions that have been designed to carrier standards, delivering toll-quality voice, system redundancy, and the capacity to handle extremely large call volumes. Sonus' voice infrastructure solutions offer a single platform that allows carriers to deliver a range of communications services including traditional long distance and local voice services, wholesale voice services, and enhanced services, such as unified communications, presence management, enhanced voicemail, voice portals and many others.

Pactolus provides a complete set of turnkey SIP-based services called SIPware Services, which allow service providers to get up and running quickly in a converged network infrastructure. Beyond the calling card services that Touch America is deploying, SIPware Services include conference calling and toll-free number services. SIPware Services, used in combination with high-end media gateways, include everything service providers need for deploying new services, adding subscribers, and generating revenues in a single, comprehensive solution.

About Sonus' OSPA

Sonus Networks' Open Services Partner Alliance program 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 family. An integral part of the Sonus OSPA, the OSPA Interoperability Laboratory is the first in the industry where product interoperability is verified, trial testing is performed and complete solutions are ultimately produced. To find additional information on the OSPA, including a list of all OSPA partners, log on to http://ospa.sonusnet.com.

About Pactolus Communication Software

Pactolus Communication Software Corporation (www.pactolus.com) is the leading provider of SIP-based enhanced service solutions for converged network infrastructure. The company is the first to bring sophisticated, third-party call control capabilities to SIP-based networks. The company's SIPware Services suite provides to carriers a comprehensive set of ready-to-deploy services including prepaid calling card, postpaid calling card, conference calling, 800 number services, and automated call distributor (ACD) functionality for deployment in SIP-based networks. Pactolus is a venture funded, privately held company headquartered in Westborough, Massachusetts.

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure products for the new public network. With its Open Services Architecture (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' 2001 Annual Report on Form 10-K, dated March 27, 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.

Open Services Partner Alliance is a service mark of Sonus Networks, and GSX9000, Insignus, Sonus Insight 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.