EXHIBIT 10.1 (j)

                      ASSIGNMENT AND ASSUMPTION AGREEMENT

     This Assignment and Assumption Agreement (the "Assignment"), dated as
of January 3, 2002 (the "Effective Date"), is entered into by and between
AMSOUTH BANK OF ALABAMA (the "Assignor") and FIRST UNION NATIONAL BANK
(successor-in-interest to First Union National Bank of Tennessee) (the
"Assignee").

     1.   Definitions. Capitalized terms used but not defined herein shall
          have the meanings given to them in that certain First Amended and
          Restated Financing Agreement dated as of April 25, 1997 among
          ADTRAN, Inc., as borrower, State Industrial Development Authority,
          as issuer, and First Union National Bank (successor-in-interest to
          First Union National Bank of Tennessee), as bondholder (as amended,
          the "Financing Agreement").
     2.   Assignment and Assumption. As of the Effective Date, for an
          agreed consideration (which the Assignee has delivered to the
          Assignor prior to or concurrently with the execution hereof), the
          Assignor hereby irrevocably sells and assigns to the Assignee, and
          the Assignee hereby irrevocably purchases and assumes from the
          Assignor: (i) a 40% undivided participation interest in the Bond,
          the principal amount of such interest is $20,000,000 (the
          "Assignor's Participation"); (ii) to the extent of the Assignor's
          Participation, an undivided interest in all of the Bond Documents
          and the Collateral (as defined in the Participation Agreement, as
          hereinafter defined); and (iii) all of Assignor's right, title and
          interest in and to the Participant Account as defined in the
          Investment Agreement (the "Investment Agreement") dated April 25,
          1997 among First Union National Bank (successor-in-interest to
          First Union National Bank of Tennessee), ADTRAN, Inc. and AmSouth
          Bank of Alabama (collectively, the "Assigned Interest"). Such sale
          and assignment is without recourse to the Assignor and, except as
          expressly provided in this Agreement, without representation or
          warranty by the Assignor.
     3.   Representations and Warranties:

          3.1  Assignor: The Assignor represents and warrants that (i) it
               is the legal and beneficial owner of the Assigned Interest,
               (ii) the Assigned Interest is free and clear of any lien,
               encumbrance, option, right or other adverse claim, and (iii)
               it has full power and authority, and has taken all action
               necessary, to execute and deliver this Assignment and to
               consummate the transactions contemplated hereby.
          3.2  Assignee: The Assignee represents and warrants that (i) it
               has full power and authority, and has taken all action
               necessary, to execute and deliver this Assignment and to
               consummate the transactions contemplated hereby, and (ii) from
               and after the Effective Date, it shall, to the extent of the
               Assigned Interest, assume the rights and obligations of the
               Bondholder thereunder.

                                      29



     4.   Participant Account and Investment Agreement. The Assignor
          acknowledges and agrees that concurrently with the execution hereof
          the Participant Account (as defined in the Investment Agreement)
          and all amounts on deposit therein shall be transferred from
          Assignor to a deposit account maintained by the Company with
          Assignee, which deposit account shall be governed by and subject to
          a new investment agreement between the Company and Assignee in
          replacement of the Investment Agreement.
     5.   Payments. From and after the Effective Date, all payments from
          the Company in respect of the Assigned Interest (including payments
          of principal, interest, fees and other amounts) due and payable on
          or after the Effective Date shall be the sole property of the
          Assignee. As of the Effective Date $87,627.74 of the accrued and
          unpaid interest is owed to the Assignor in respect of the Assigned
          Interest. To the extent that such amount(s) are received by the
          Assignee from the Company, the Assignee shall promptly forward same
          to the Assignor.
     6.   Participation Agreement. That certain Participation Agreement
          dated as of April 25, 1997 between First Union Nation Bank
          (successor-in-interest to First Union National Bank of Tennessee)
          and AmSouth Bank of Alabama (the "Participation Agreement") is
          hereby terminated, as of the Effective Date, and except as
          otherwise provided in Paragraph 5 hereof, Assignor and Assignee
          represent and agree that neither has any claims, matured or
          unmatured, against the other arising from such Participation
          Agreement or the transactions described therein, or if any such
          claims exist, they are hereby waived and released.
     7.   General Provisions. This Assignment shall be binding upon, and
          inure to the benefit of, the parties hereto and their respective
          successors and assigns. This Assignment may be executed in any
          number of counterparts, which together shall constitute one
          instrument. Delivery of an executed counterpart of a signature page
          of this Assignment by telecopy shall be effective as delivery of a
          manually executed counterpart of this Assignment. This Assignment
          shall be governed by, and construed in accordance with, the law of
          the State of New Jersey.

The terms set forth in this Assignment are hereby agreed to:

                                                     ASSIGNOR:
                                                     AMSOUTH BANK OF ALABAMA
                                                     By: /s/ Nicholas Willis
                                                     -----------------------
                                                     Nicholas Willis
                                                     Commercial Banking Officer

                                                     ASSIGNEE:
                                                     FIRST UNION NATIONAL BANK
                                                     By: /s/ Robyn G. Beh
                                                     --------------------
                                                     Robyn G. Beh
                                                     Vice President

                                      30