CHELMSFORD, Mass., July 19, 2004 – Sonus Networks, Inc. (Nasdaq: SONSE), a leading supplier of voice over IP (VoIP) infrastructure solutions to service providers, today provided an update on its previously announced financial review. Sonus Networks has completed the detailed review of its financial statements for fiscal years 2003, 2002 and 2001. Additionally, the Audit Committee of Sonus’ Board of Directors has completed its internal investigation.

As a result of the financial review, Sonus will restate its consolidated financial results for fiscal 2001 and 2002, and the first three quarters of fiscal 2003. As previously reported, the primary impact of the restatements is the adjustment to the timing of revenue recognition and certain other financial statement accounts. Principal adjustments to revenue relate to the timing of revenue where the revenue has been deferred and recognized in subsequent periods. In addition, other material restatements include adjustments to purchase accounting, impairments, accruals and deferred compensation.

Sonus expects to file its 2003 Form 10-K/A and Q1 2004 Form 10-Q with the SEC within approximately a week. Sonus has requested an additional exception from the Nasdaq Listing Qualifications Panel for additional time to regain compliance with the Nasdaq filing requirements.

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.