Intrado Selects Sonus Networks to Provide Softswitching Technology for VoIP E9-1-1 Solution; Industry Leading E9-1-1 Provider Chooses Sonus for Reliability, Scalability.

CHELMSFORD, Mass. -- Sonus Networks (NASDAQ: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced that Intrado Inc., (NASDAQ: TRDO), a global provider of integrated data and telecommunications solutions, will utilize technology from Sonus Networks to support the delivery of VoIP E9-1-1 calls using the Intrado(R) V9-1-1(SM) Mobility Service. Intrado, a leading provider of critical emergency and Enhanced 9-1-1 services, is expanding its network coverage to support its VoIP service provider customers in meeting the functional requirements of the recent Federal Communications Commission ruling, which mandates E9-1-1 capabilities for VoIP service offerings.

"Clearly the market has stated that 9-1-1 is essential to VoIP service," said Stephen Meer, Intrado co-founder and chief technology officer. "Sonus' architecture supports the reliable delivery of such a critical service."

Intrado will use a full suite of Sonus products to support the V9-1-1 Mobility Service. In particular Sonus will manage traffic between VoIP networks, offering carriers both the security and point of demarcation functionality critical to delivering emergency services.

Sonus' distributed, standards-based architecture allows Intrado to scale its network as the demand for consumer VoIP services continues to increase. The Sonus architecture also facilitates the rapid integration and deployment of new next generation services as Intrado continues to expand its roster of next generation emergency services. In addition, because Sonus' platform was designed for 99.999% network availability, service providers and consumers can rely on Sonus' superior performance.

"IP-based communication is beginning to reach a stage in its adoption curve where many mainstream consumers are replacing their primary telephone service with a VoIP-based offering," said Hassan Ahmed, chairman and CEO, Sonus Networks. "As the migration continues, Sonus Networks is dedicated to working with industry leaders like Intrado to ensure that consumers can continue to leverage the cost-savings and service enhancements enabled by VoIP, without sacrificing access to emergency functions and other traditional services associated with legacy networks."

In May 2005, the Federal Communications Commission issued a ruling requiring VoIP service providers to supply E9-1-1 emergency calling capabilities to their customers as a mandatory feature of the service. With the addition of the Sonus network architecture to the Intrado VoIP 9-1-1 product suite, E9-1-1 calls can be routed within the existing 911 network and the static or mobile caller's address and location information delivered to the appropriate Public Safety Answering Point (PSAP).

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its Open Services Architecture(TM) (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking and tandem switching, residential and business access, network border switching and enhanced services. Sonus' 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 Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events 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 the "Risk Factors" section of Sonus' Annual Report on Form 10-K dated March 15, 2005 and the "Cautionary Statements" section of Sonus' Quarterly Report on Form 10-Q, dated May 9, 2005, both filed with the SEC, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. In addition, any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks. Open Services Architecture, GSX9000 and Insignus are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.