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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">UNITED STATES</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">SECURITIES AND EXCHANGE COMMISSION</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">WASHINGTON, D.C. 20549</font></b></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">FORM&nbsp;8-K</font></b></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">CURRENT REPORT</font></b></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">Pursuant to Section&nbsp;13 or 15(d)&nbsp;of the Securities Exchange Act of 1934</font></b></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Date of Report (Date of earliest event reported):<b> June&nbsp;21, 2013</b></font></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">SONUS NETWORKS,&nbsp;INC.</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Exact Name of Registrant as Specified in its Charter)</font></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">DELAWARE</font></b></p>    </td>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">001-34115</font></b></p>    </td>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">04-3387074</font></b></p>    </td>   </tr>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(State or Other Jurisdiction</font></p>    </td>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">of Incorporation)</font></p>    </td>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Identification No.)</font></p>    </td>   </tr>  </table>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">4 TECHNOLOGY PARK DRIVE, WESTFORD, MASSACHUSETTS 01886</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Address of Principal Executive Offices) (Zip Code)</font></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">(978) 614-8100</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Registrant&#146;s telephone number, including area code)</font></p>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Check the appropriate box below if the Form&nbsp;8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions ( <i>see</i> General Instruction A.2. below):</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;">&#160; Written communications pursuant to Rule&nbsp;425 under the Securities Act (17 CFR 230.425)</font></p>
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<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;">&#160; Soliciting material pursuant to Rule&nbsp;14a-12 under the Exchange Act (17 CFR 240.14a-12)</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;">&#160; Pre-commencement communications pursuant to Rule&nbsp;14d-2(b)&nbsp;under the Exchange Act (17 CFR 240.14d-2(b))</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;">&#160; Pre-commencement communications pursuant to Rule&nbsp;13e-4(c)&nbsp;under the Exchange Act (17 CFR 240.13e-4(c))</font></p>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt 4.5pt;text-indent:-4.5pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item 1.01.</font></b><b><font size="1" style="font-size:3.0pt;font-weight:bold;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></b><b><font size="2" style="font-size:10.0pt;font-weight:bold;">Entry into a Material Definitive Agreement.</font></b></p>
<p style="margin:0in 0in .0001pt 4.5pt;text-indent:-4.5pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">On June&nbsp;21, 2013, a committee of the Board of Directors of Sonus Networks,&nbsp;Inc. (the &#147;Company&#148;) approved and the Company entered into an amendment (the &#147;Amendment&#148;) to the Rights Agreement by and between the Company and American Stock Transfer&nbsp;&amp; Trust Company, LLC, as Rights Agent, dated as of June&nbsp;26, 2008, as amended by Amendment No.&nbsp;1 to Rights Agreement dated June&nbsp;10, 2011 (the &#147;Rights Agreement&#146;), to extend the expiration date of the rights contained therein to June 26, 2015.&#160; The Rights Agreement remains otherwise unmodified.</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">A copy of the Rights Agreement and a summary of its material terms were filed with the Securities and Exchange Commission on a Form&nbsp;8-K on June&nbsp;27, 2008.&#160; The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the Amendment, a copy of which is filed herewith as Exhibit&nbsp;4.3 and is incorporated herein by reference.</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">On June&nbsp;24, 2013, the Company issued a press release announcing the Amendment.&nbsp; A copy of the press release is included as Exhibit&nbsp;99.1 hereto.</font></p>
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<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item 3.03.</font></b><b><font size="1" style="font-size:3.0pt;font-weight:bold;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></b><b><font size="2" style="font-size:10.0pt;font-weight:bold;">Material Modification to Rights of Security Holders.</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Please see the disclosure set forth under &#147;Item 1.01. Entry into a Material Definitive Agreement,&#148; which is incorporated by reference into this Item 3.03.</font></p>
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<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item 9.01.</font></b><b><font size="1" style="font-size:3.0pt;font-weight:bold;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></b><b><font size="2" style="font-size:10.0pt;font-weight:bold;">Financial Statements and Exhibits.</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(d)</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>    </td>   </tr>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.1</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Rights   Agreement, dated as of June&nbsp;26, 2008, between the Company and American   Stock Transfer&nbsp;&amp; Trust Company, LLC, which includes as   Exhibit&nbsp;A thereto a Form&nbsp;of Certificate of Designation for the   Series&nbsp;A Junior Participating Preferred Stock, as Exhibit&nbsp;B thereto   the Form&nbsp;of Rights Certificate and as Exhibit&nbsp;C thereto a Summary   of Rights to Purchase Shares of Preferred Stock (incorporated herein by   reference from Exhibit&nbsp;4.1 of the Registrant&#146;s Current Report on   Form&nbsp;8-K, filed with the Securities and Exchange Commission on   June&nbsp;27, 2008).</font></p>    </td>   </tr>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.2</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment   No.&nbsp;1 dated as of June&nbsp;10, 2011 to Rights Agreement, dated as of   June&nbsp;26, 2008 between Sonus Networks, Inc. and American Stock   Transfer&nbsp;&amp; Trust Company, LLC (incorporated herein by reference from   Exhibit&nbsp;4.2 of the Registrant&#146;s Current Report on Form&nbsp;8-K, filed   with the Securities and Exchange Commission on June&nbsp;13, 2011).</font></p>    </td>   </tr>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.3</font></p>    </td>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment   No.&nbsp;2 dated as of June&nbsp;21, 2013 to Rights Agreement, first dated as   of June&nbsp;26, 2008 and as amended on June&nbsp;10, 2011, between Sonus   Networks,&nbsp;Inc. and American Stock Transfer&nbsp;&amp; Trust Company,   LLC.</font></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">99.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Press   Release issued by Sonus Networks,&nbsp;Inc. on June&nbsp;24, 2013.</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2<a name="PB_2_220401_7056"></a></font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
</div>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">SIGNATURE</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">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.</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
<tr>
<td width="50%" valign="top" style="padding:0in 0in 0in 0in;width:50.0%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>    </td>
<td width="43%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:43.34%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/   Jeffrey M. Snider</font></p>    </td>   </tr>
<tr>
<td width="50%" valign="top" style="padding:0in 0in 0in 0in;width:50.0%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name:</font></p>    </td>
<td width="43%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:43.34%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Jeffrey   M. Snider</font></p>    </td>   </tr>
<tr>
<td width="50%" valign="top" style="padding:0in 0in 0in 0in;width:50.0%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title:</font></p>    </td>
<td width="43%" valign="top" style="padding:0in 0in 0in 0in;width:43.34%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Senior   Vice President, Chief Administrative Officer, General Counsel and Secretary</font></p>    </td>   </tr>
<tr>
<td width="50%" valign="top" style="padding:0in 0in 0in 0in;width:50.0%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">DATED:   June&nbsp;24, 2013</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="43%" valign="top" style="padding:0in 0in 0in 0in;width:43.34%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3<a name="PB_3_220605_5335"></a></font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Exhibit&nbsp;Index</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
<tr>
<td width="8%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit<br>   No.</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="89%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:89.14%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>    </td>   </tr>
<tr>
<td width="8%" valign="bottom" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="89%" valign="bottom" style="padding:0in 0in 0in 0in;width:89.14%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Rights   Agreement, dated as of June&nbsp;26, 2008, between the Company and American   Stock Transfer&nbsp;&amp; Trust Company, LLC, which includes as   Exhibit&nbsp;A thereto a Form&nbsp;of Certificate of Designation for the   Series&nbsp;A Junior Participating Preferred Stock, as Exhibit&nbsp;B thereto   the Form&nbsp;of Rights Certificate and as Exhibit&nbsp;C thereto a Summary   of Rights to Purchase Shares of Preferred Stock (incorporated herein by   reference from Exhibit&nbsp;4.1 of the Registrant&#146;s Current Report on   Form&nbsp;8-K, filed with the Securities and Exchange Commission on June&nbsp;27,   2008).</font></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.2</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment   No.&nbsp;1 dated as of June&nbsp;10, 2011 to Rights Agreement, dated as of   June&nbsp;26, 2008 between Sonus Networks, Inc. and American Stock   Transfer&nbsp;&amp; Trust Company, LLC (incorporated herein by reference to   Exhibit&nbsp;4.2 of the Registrant&#146;s Current Report on Form&nbsp;8-K, filed   with the Securities and Exchange Commission on June&nbsp;13, 2011).</font></p>    </td>   </tr>
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<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.3</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Amendment   No.&nbsp;2 dated as of June&nbsp;21, 2013 to Rights Agreement, first dated as   of June&nbsp;26, 2008 and as amended on June&nbsp;10, 2011, between Sonus   Networks,&nbsp;Inc. and American Stock Transfer&nbsp;&amp; Trust Company,   LLC.</font></p>    </td>   </tr>
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<td width="8%" valign="top" style="padding:0in 0in 0in 0in;width:8.72%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
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<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">99.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="89%" valign="top" style="padding:0in 0in 0in 0in;width:89.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Press   Release issued by Sonus Networks,&nbsp;Inc. on June&nbsp;24, 2013.</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4<a name="PB_4_220630_5796"></a></font></p>
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{"company-data": {"conformed-name": "SONUS NETWORKS INC", "cik": "0001105472", "assigned-sic": "7373", "irs-number": "043387074", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-34115", "film-number": "13929844"}, "business-address": {"street1": "4 TECHNOLOGY PARK DRIVE", "city": "WESTFORD", "state": "MA", "zip": "01886", "phone": "9786148100"}, "mail-address": {"street1": "4 TECHNOLOGY PARK DRIVE", "city": "WESTFORD", "state": "MA", "zip": "01886"}}
UNITED STATES
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
Date of Report (Date of earliest event reported):
June 21, 2013
SONUS NETWORKS, INC.
(Exact Name of Registrant as Specified in its Charter)
DELAWARE
001-34115
04-3387074
(State or Other Jurisdiction
(Commission File Number)
(IRS Employer
of Incorporation)
Identification No.)
4 TECHNOLOGY PARK DRIVE, WESTFORD, MASSACHUSETTS 01886
(Address of Principal Executive Offices) (Zip Code)
(978) 614-8100
(Registrant's telephone number, including area code)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (
see
General Instruction A.2. below):
o
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
o
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
o
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
o
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Item 1.01.
Entry into a Material Definitive Agreement.
On June 21, 2013, a committee of the Board of Directors of Sonus Networks, Inc. (the "Company") approved and the Company entered into an amendment (the "Amendment") to the Rights Agreement by and between the Company and American Stock Transfer & Trust Company, LLC, as Rights Agent, dated as of June 26, 2008, as amended by Amendment No. 1 to Rights Agreement dated June 10, 2011 (the "Rights Agreement'), to extend the expiration date of the rights contained therein to June 26, 2015.  The Rights Agreement remains otherwise unmodified.
A copy of the Rights Agreement and a summary of its material terms were filed with the Securities and Exchange Commission on a Form 8-K on June 27, 2008.  The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the Amendment, a copy of which is filed herewith as Exhibit 4.3 and is incorporated herein by reference.
On June 24, 2013, the Company issued a press release announcing the Amendment.  A copy of the press release is included as Exhibit 99.1 hereto.
Item 3.03.
Material Modification to Rights of Security Holders.
Please see the disclosure set forth under "Item 1.01. Entry into a Material Definitive Agreement," which is incorporated by reference into this Item 3.03.
Item 9.01.
Financial Statements and Exhibits.
(d)
Exhibit
No.
Description
4.1
Rights   Agreement, dated as of June 26, 2008, between the Company and American   Stock Transfer & Trust Company, LLC, which includes as   Exhibit A thereto a Form of Certificate of Designation for the   Series A Junior Participating Preferred Stock, as Exhibit B thereto   the Form of Rights Certificate and as Exhibit C thereto a Summary   of Rights to Purchase Shares of Preferred Stock (incorporated herein by   reference from Exhibit 4.1 of the Registrant's Current Report on   Form 8-K, filed with the Securities and Exchange Commission on   June 27, 2008).
4.2
Amendment   No. 1 dated as of June 10, 2011 to Rights Agreement, dated as of   June 26, 2008 between Sonus Networks, Inc. and American Stock   Transfer & Trust Company, LLC (incorporated herein by reference from   Exhibit 4.2 of the Registrant's Current Report on Form 8-K, filed   with the Securities and Exchange Commission on June 13, 2011).
4.3
Amendment   No. 2 dated as of June 21, 2013 to Rights Agreement, first dated as   of June 26, 2008 and as amended on June 10, 2011, between Sonus   Networks, Inc. and American Stock Transfer & Trust Company,   LLC.
99.1
Press   Release issued by Sonus Networks, Inc. on June 24, 2013.
2
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.
By:
/s/   Jeffrey M. Snider
Name:
Jeffrey   M. Snider
Title:
Senior   Vice President, Chief Administrative Officer, General Counsel and Secretary
DATED:   June 24, 2013
3
Exhibit Index
Exhibit
No.
Description
4.1
Rights   Agreement, dated as of June 26, 2008, between the Company and American   Stock Transfer & Trust Company, LLC, which includes as   Exhibit A thereto a Form of Certificate of Designation for the   Series A Junior Participating Preferred Stock, as Exhibit B thereto   the Form of Rights Certificate and as Exhibit C thereto a Summary   of Rights to Purchase Shares of Preferred Stock (incorporated herein by   reference from Exhibit 4.1 of the Registrant's Current Report on   Form 8-K, filed with the Securities and Exchange Commission on June 27,   2008).
4.2
Amendment   No. 1 dated as of June 10, 2011 to Rights Agreement, dated as of   June 26, 2008 between Sonus Networks, Inc. and American Stock   Transfer & Trust Company, LLC (incorporated herein by reference to   Exhibit 4.2 of the Registrant's Current Report on Form 8-K, filed   with the Securities and Exchange Commission on June 13, 2011).
4.3
Amendment   No. 2 dated as of June 21, 2013 to Rights Agreement, first dated as   of June 26, 2008 and as amended on June 10, 2011, between Sonus   Networks, Inc. and American Stock Transfer & Trust Company,   LLC.
99.1
Press   Release issued by Sonus Networks, Inc. on June 24, 2013.
4