CHELMSFORD, Mass., July 16, 2004 – Sonus Networks (Nasdaq: SONSE) has scheduled a conference call for Monday, July 19, 2004, at 5:30 pm Eastern regarding its financial results, its re-examination of prior periods and to provide an update on its business.

Date: Monday, July 19, 2004
Time: 5:30 pm Eastern

To listen via telephone:

Dial-in number: +1-888-722-1081 or +1-212-676-5260

To listen via the Internet:

Sonus will host a live webcast of the conference call. To access the webcast, visit the Sonus Networks Investor Relations site at http://www.sonusnet.com.

Replay:

A telephone playback of the call will be available following the conference and can be accessed by calling +1-402-977-9140. The access code for the replay is 21202963. The telephone playback will be available through Monday, August 2, 2004.

The webcast will be available on the Sonus Networks Investor Relations site through July 19, 2005. To access the replay of the webcast, visit the Investor Relations site at http://www.sonusnet.com.

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 (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.

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