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   &lt;div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "&gt;
   &lt;div align="center" style="font-size: 10pt; margin-top: 0pt"&gt;&lt;b&gt;&lt;/b&gt;
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   &lt;div align="left"&gt;
   &lt;/div&gt;
   &lt;div align="center" style="font-size: 10pt"&gt;&lt;b&gt;&lt;/b&gt;&lt;/div&gt;
   &lt;div align="center" style="font-size: 10pt"&gt;&lt;b&gt;&lt;/b&gt;&lt;/div&gt;
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   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;&lt;b&gt;1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES&lt;/b&gt;
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;&lt;i&gt;Basis of Presentation&lt;/i&gt;
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;The accompanying unaudited consolidated financial statements of ADTRAN&lt;sup style="font-size: 85%; vertical-align: text-top"&gt;&amp;#174;&lt;/sup&gt;, Inc. and its
   subsidiaries (ADTRAN)&amp;#160;have been prepared pursuant to the rules and regulations for reporting on
   Quarterly Reports on Form 10-Q. Accordingly, certain information and notes required by generally
   accepted accounting principles for complete financial statements are not included herein. The
   December&amp;#160;31, 2009 Consolidated Balance Sheet is derived from audited financial statements, but does
   not include all disclosures required by accounting principles generally accepted in the United
   States.
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;In the opinion of management, all adjustments necessary for a fair presentation of these interim
   statements have been included and are of a normal and recurring nature. The results of operations
   for an interim period are not necessarily indicative of the results for the full year. The interim
   statements should be read in conjunction with the financial statements and notes thereto included
   in ADTRAN&amp;#8217;s Annual Report on Form 10-K for the year ended December&amp;#160;31, 2009, filed on February&amp;#160;26,
   2010 with the SEC.
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;&lt;i&gt;Use of Estimates&lt;/i&gt;
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;The preparation of financial statements in conformity with accounting principles generally accepted
   in the United States of America requires management to make estimates and assumptions that affect
   the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities
   at the date of the financial statements, and the reported amounts of revenue and expense during the
   reporting period. Our more significant estimates include the allowance for doubtful accounts,
   obsolete and excess inventory reserves, warranty reserves, customer rebates, allowance for sales
   returns, determination of the deferred revenue components of multiple element sales agreements,
   estimated income tax contingencies, the fair value of stock-based compensation, and the evaluation
   of other-than-temporary declines in the value of investments. Actual amounts could differ
   significantly from these estimates.
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;&lt;i&gt;Recent Accounting Pronouncements&lt;/i&gt;
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;In October&amp;#160;2009, the Financial Accounting Standards Board (FASB)&amp;#160;issued Update No.&amp;#160;2009-13, which
   amends the Revenue Recognition topic of the FASB Accounting Standards Codification (Codification).
   This update provides amendments to the criteria in Subtopic 605-25 of the Codification for
   separating consideration in multiple-deliverable arrangements. As a result of those amendments,
   multiple-deliverable arrangements will be separated in more circumstances than under existing U.S.
   GAAP. The amendments establish a selling price hierarchy for determining the selling price of a
   deliverable and will replace the term fair value in the revenue allocation guidance with selling
   price to clarify that the allocation of revenue is based on entity-specific assumptions rather than
   assumptions of a marketplace participant. The amendments will also eliminate the residual method
   of allocation and require that arrangement consideration be allocated at the inception of the
   arrangement to all deliverables using the relative selling price method and will require that a
   vendor determine its best estimate of selling price in a manner that is consistent with that used
   to determine the price to sell the deliverable on a standalone basis. These amendments will be
   effective prospectively for revenue arrangements entered into or materially modified in fiscal
   years beginning on or after June&amp;#160;15, 2010, with early adoption permitted. We do not expect the
   adoption of this amendment will have a material impact on our consolidated results of operations or
   financial condition.
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;In October&amp;#160;2009, the FASB issued Update No.&amp;#160;2009-14, which amends the Software topic of the
   Codification. The amendments in this update change the accounting model for revenue arrangements
   that include both tangible products and software elements. Tangible products containing software
   components and non-software components that function together to deliver the tangible product&amp;#8217;s
   essential functionality is no longer within the scope of the software revenue guidance in Subtopic
   985-605 of the Codification. In addition, the amendments in this update require that hardware
   components of a tangible product containing software components always be excluded from the
   software revenue guidance. In that regard, the amendments provide additional guidance on how to
   determine which software, if any, relating to the tangible product also would be excluded from the
   scope of the software revenue guidance. The amendments also provide guidance on how a vendor
   should allocate arrangement consideration to deliverables in an arrangement that includes both
   tangible products and software. The amendments also provide further guidance on how to allocate
   arrangement consideration when an arrangement includes deliverables both included and excluded from
   the scope of the software revenue guidance. These amendments will be effective prospectively for
   revenue arrangements entered into or materially modified in fiscal years beginning on or after June
   15, 2010, with early adoption permitted. We do not expect the adoption of this amendment will have
   a material impact on our consolidated results of operations or financial condition.
   &lt;/div&gt;
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   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;During the six months ended June&amp;#160;30, 2010, we adopted the following accounting standards,
   which had no material effect on our consolidated results of operations or financial condition:
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;In January&amp;#160;2010, the FASB issued Update No.&amp;#160;2010-06, which amends the Fair Value Measurements and
   Disclosures topic of the Codification. The amendments in this update require new disclosures about
   transfers in and out of Level 1 and Level 2 fair value measurements and the activity in Level 3
   fair value measurements and, in addition, clarify existing disclosures required for levels of
   disaggregation and inputs and valuation techniques. These amendments will be effective for interim
   and annual reporting periods beginning after December&amp;#160;15, 2009, except for the disclosures about
   activity in Level 3 fair value measurements, which is effective for fiscal years beginning after
   December&amp;#160;15, 2010, and for interim periods within those fiscal years. We adopted this amendment
   for the period ended March&amp;#160;31, 2010, and we have provided the disclosures required for the period
   ended June&amp;#160;30, 2010.
   &lt;/div&gt;
   &lt;div align="justify" style="font-size: 10pt; margin-top: 10pt"&gt;In February&amp;#160;2010, the FASB issued Update No.&amp;#160;2010-09, which amends the Subsequent Events topic of
   the Codification. The amendments in this update require entities that are SEC filers to evaluate
   subsequent events through the date that the financial statements are issued. Additionally, SEC
   filers are no longer required to disclose the date through which subsequent events were evaluated.
   The amendments in this update were effective upon issuance. We adopted this amendment for the
   period ended March&amp;#160;31, 2010, and we have provided the disclosures required for the period ended
   June&amp;#160;30, 2010.
   &lt;/div&gt;
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 -Publisher AICPA
 -Name Accounting Principles Board Opinion (APB)
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