CHELMSFORD, Mass., May 6, 2005 – Sonus Networks (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced that it has scheduled a conference call for Monday, May 9, 2005, at 5:00 pm Eastern to announce its Q1 fiscal 2005 financial results. Financial results are expected to be issued after the close of the market on Monday, May 9, 2005.

Date: Monday, May 9, 2005
Time: 5:00 pm Eastern

To listen via telephone:

Dial-in number: (888) 673-1412 or (212) 346-6534

To listen via the Internet

Sonus will host a live webcast of the conference call. To access the webcast, visit www.sonusnet.com, Corporate, Investor Relations.

Replay:

A telephone playback of the call will be available following the conference and can be accessed by calling (800) 633-8284 or (402) 977 9140. The reservation number for the replay is 21245825. The telephone playback will be available through Monday, May 23, 2005.

A replay of the webcast will be also available on the Sonus Networks Investor Relations site through Tuesday, May 9, 2006. To access the replay of the webcast, visit http://www.sonusnet.com , Corporate, Investor Relations.

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 ArchitectureTM (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, 2004 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. 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, 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.