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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
    _______________________________________________________________________

                                    FORM 8-K

                                 CURRENT REPORT

     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

                                January 20, 2004

                Date of Report (Date of earliest event reported)
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                              SONUS NETWORKS, INC.
             (Exact Name of Registrant as Specified in its Charter)




         DELAWARE                     000-30229               04-3387074
         --------                     ---------               ----------
(State or Other Jurisdiction   (Commission File Number)     (IRS Employer
      of Incorporation)                                   Identification No.)


                 5 CARLISLE ROAD, WESTFORD, MASSACHUSETTS 01886
               (Address of Principal Executive Offices) (Zip Code)

                                 (978) 692-8999

              (Registrant's telephone number, including area code)

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Item 12. RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

     The information in this Current Report on Form 8-K and the exhibit attached
hereto shall not be deemed "filed" for purposes of Section 18 of the Securities
Exchange Act of 1934, as amended, or incorporated by reference in any filing
under the Securities Act of 1933, as amended, or the Exchange Act, except as
shall be expressly set forth by specific reference in such a filing.

     On January 20, 2004, Sonus Networks, Inc. issued a press release announcing
certain preliminary financial results for Q4 and fiscal year 2003, as well as a
delay in the release of its final Q4 and fiscal year 2003 financial results. A
copy of the press release is attached as Exhibit 99.1 hereto.



SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: January 21, 2004 SONUS NETWORKS, INC. By: /s/ Stephen J. Nill ------------------------------------------- Stephen J. Nill Chief Financial Officer, Vice President of Finance and Administration and Treasurer

Exhibit Index 99.1 Press release dated January 20, 2004.

                                                                   Exhibit 99.1

      SONUS NETWORKS DELAYS RELEASE OF ITS Q4 AND FY2003 FINANCIAL RESULTS

     Sonus Networks (Nasdaq: SONS) today postponed the release of its Q4 and
full year 2003 financial results pending the completion of its 2003 audit. Upon
completion of the audit, the Company will reschedule the conference call and
provide further details.

     Sonus Networks' business was strong in the quarter, achieving substantial
new business and a cash, cash equivalents and marketable securities balance at
December 31, 2003 exceeding $300 million.

     About Sonus Networks

     Sonus Networks, Inc., is a leading provider of packet voice 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, 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.

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

    CONTACT: Investor Relations:
             Sonus Networks
             Jocelyn Philbrook, 978-589-8672
             jphilbrook@sonusnet.com
             or
             Media Relations:
             Sonus Networks
             Beth Morrissey, 978-589-8579
             bmorrissey@sonusnet.com