<PAGE>

                                                                  EXHIBIT 10.1.4

                               FOURTH AMENDMENT
                               -----------------

          THIS FOURTH AMENDMENT (this "Amendment") is made and entered into as
of September 30, 2000, by and among KNOLOGY HOLDINGS, INC., a Delaware
corporation, as Guarantor, certain Subsidiaries of the Guarantor identified on
the signature pages hereto (excluding KNOLOGY of Georgia, Inc.), as borrowers
(collectively, the "Borrowers"), the Lenders referred to in the Credit Agreement
defined below, and FIRST UNION NATIONAL BANK, as Administrative Agent for the
Lenders.

                             Statement of Purpose
                             --------------------

          The Lenders agreed to extend certain credit facilities to the
Borrowers pursuant to the Credit Agreement dated as of December 22, 1998 (as
amended, restated, supplemented or otherwise modified prior to the date hereof,
the "Credit Agreement") by and among the Borrowers, the Guarantor, the Lenders
and the Administrative Agent. All capitalized terms used and not defined in this
Amendment shall have the meanings assigned thereto in the Credit Agreement.

          The Borrowers have requested certain amendments to the financial
covenants contained in the Credit Agreement as set forth more fully below.

          Subject to the terms and conditions hereof, the Administrative Agent
and the Lenders are willing to agree to such amendments.

          NOW THEREFORE, for good and valuable consideration, the receipt and
adequacy of which is hereby acknowledged, the parties hereto agree as follows:

          1.  Amendments to Article IX.
              ------------------------

              a.  Section 9.4(a) is hereby amended by (i) deleting the number
              "157,000" opposite the date 9/30/00 in the table set forth therein
              and inserting the number "140,000" therefor and (ii) deleting the
              number "175,000" opposite the date 12/31/00 in the table set forth
              therein and inserting the number "147,000" therefor; and

              b.  Section 9.4(b) is hereby amended by (i) deleting the number
              "41.47" opposite the date 9/30/00 in the table set forth therein
              and inserting the number "41.00" therefor and (ii) deleting the
              number "41.78" opposite the date 12/31/00 in the table set forth
              therein and inserting the number "40.00" therefor.

              c.  Section 9.2 is hereby amended by adding the following proviso
              to the end of that Section, immediately following the number
              "1.00":

                  "; provided, however that for the fiscal quarters ending
                     --------
                  9/30/00 and 12/31/00, the ratio of (a) to (b) shall be no less
                  than 1.50 to 1.00"

<PAGE>

         2.   Consent.  The Lenders hereby consent to the exclusion of KNOLOGY
              -------
of Montgomery, Inc. (such Subsidiary was added as a Designated Borrower by the
Guarantor in May of 2000) as a Designated Borrower, as defined in the Credit
Agreement.

         3.    Conditions.  The effectiveness of this Amendment shall be
               ----------
conditioned upon (i) the delivery to the Administrative Agent of this Amendment
executed by the Administrative Agent, the Borrowers, the Guarantor and the
Required Lenders, (ii) the payment to the Administrative Agent of an amendment
fee equal to 0.25% of the Facility and (iii) the payment of any other fees and
expenses of the Administrative Agent or their counsel incurred through the
effective date of this Amendment.

         4.    Effect of Amendment.  Except as expressly amended hereby, the
               -------------------
Credit Agreement and Loan Documents shall be and remain in full force and
effect.  The amendment granted in this Amendment is specific and limited and
shall not constitute any further amendment of the Credit Agreement or a
modification, acceptance or waiver of any other provision of or default under
the Credit Agreement or any other document or instrument entered into in
connection therewith or a future modification, acceptance or waiver of the
provisions set forth therein.

         5.    Representations and Warranties/No Default.  By its execution
               -----------------------------------------
hereof, the Borrowers hereby certify that each of the representations and
warranties set forth in the Credit Agreement and the other Loan Documents is
true and correct as of the date hereof as if fully set forth herein (other than
representations and warranties which speak as of a specific date pursuant to the
Credit Agreement or any other Loan Document, which representations and
warranties shall have been true and correct as of such specific dates) and that
as of the date hereof (and after giving effect hereto) no Default or Event of
Default has occurred and is continuing.

         6.    Expenses.  The Borrowers shall pay all reasonable out-of-pocket
               --------
expenses of the Administrative Agent in connection with the preparation,
execution and delivery of this Amendment, including without limitation, the
reasonable fees and disbursements of counsel for the Administrative Agent.

         7.    Governing Law.  This Amendment shall be governed by and construed
               -------------
in accordance with the laws of the State of North Carolina, without reference to
the conflicts or choice of law provisions thereof.

         8.    Counterparts.  This Amendment may be executed in separate
               ------------
counterparts, each of which when executed and delivered is an original but all
of which taken together constitute one and the same instrument.


                            [Signature Pages Follow]

                                       2

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed under seal by their duly authorized officers, all as of the day and
year first written above.


[CORPORATE SEAL]              KNOLOGY OF COLUMBUS, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF MONTGOMERY, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF PANAMA CITY, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF AUGUSTA, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------



<PAGE>

[CORPORATE SEAL]              KNOLOGY OF CHARLESTON, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF SOUTH CAROLINA, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF ALABAMA, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF FLORIDA, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF HUNTSVILLE, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------



                           [Signature Pages Continue]



<PAGE>

[CORPORATE SEAL]              KNOLOGY OF BATON ROUGE, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF LOUISIANA, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              KNOLOGY OF TENNESSEE, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


[CORPORATE SEAL]              TTE, INC., as Borrower


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


                              By:
                                  ----------------------------------------------
                              Name:
                                    --------------------------------------------
                              Title:
                                    --------------------------------------------


                           [Signature Pages Continue]



<PAGE>

[CORPORATE SEAL]              KNOLOGY HOLDINGS, INC., as Guarantor


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------



                           [Signature Pages Continue]



<PAGE>

The undersigned hereby executes this Amendment solely to acknowledge and agree
to be bound by the amended provisions of Article IX, but in no way by becoming a
signatory hereto shall the undersigned become obligated for the repayment of the
Loans, Obligations or the payment of any other sum referred to herein or in any
Loan Document or incur any liability as a Borrower or Guarantor hereunder or
under any Loan Document or have any Obligation to pledge any of its assets
pursuant to the Loan Documents. Notwithstanding the foregoing, the parties
hereto agree that the occurrence of any event with regard to KNOLOGY of Georgia,
Inc. that would constitute a Default or Event of Default if such event occurred
with respect to any other Loan Party shall constitute a Default or Event of
Default, if applicable.


[CORPORATE SEAL]              KNOLOGY OF GEORGIA, INC.


                              By:  /s/ Robert K. Mills
                                  ----------------------------------------------
                              Name:    Robert K. Mills
                                    --------------------------------------------
                              Title:   Chief Financial Officer
                                    --------------------------------------------


                           [Signature Pages Continue]



<PAGE>

                              FIRST UNION NATIONAL BANK, as
                              Administrative Agent and Lender


                              By:   /s/ Mark L. Cook
                                  ----------------------------------------------
                              Name:    Mark L. Cook
                                    --------------------------------------------
                              Title:   Senior Vice President
                                    --------------------------------------------