Exhibit 4.1











                              INSIGHT MIDWEST, L.P.

                                       and

                              INSIGHT CAPITAL, INC.

                                   As Issuers

                                       and

                              THE BANK OF NEW YORK

                             As Successor Trustee To

                        HARRIS TRUST COMPANY OF NEW YORK

                             -----------------------

                          SECOND SUPPLEMENTAL INDENTURE

                          Dated as of October 12, 2005

             (Supplemental to Indenture Dated as of October 1, 1999)

                              Series A and Series B
                          9 3/4% Senior Notes Due 2009









     SECOND SUPPLEMENTAL  INDENTURE,  dated as of October 12, 2005 (this "Second
Supplemental  Indenture")  among  Insight  Midwest,  L.P.,  a  Delaware  limited
partnership  (the  "Company"),  Insight  Capital,  Inc., a Delaware  corporation
("Insight Capital" and together with the Company,  the "Issuers"),  and The Bank
of New York, a New York  banking  corporation,  as  successor  trustee to Harris
Trust Company of New York (the "Trustee").

     WHEREAS,  the Issuers  executed  and  delivered  an  Indenture  dated as of
October  1,  1999  (as the same has been  amended  or  supplemented  to the date
hereof,  the  "Indenture")  between  the Issuers  and the  Trustee,  as trustee,
providing  for the issue of the  Issuers'  Series A and  Series B 9 3/4%  Senior
Notes Due 2009; and

     WHEREAS,  Section  9.02 of the  Indenture  provides  that  compliance  with
Section 4.15 of the Indenture may be waived with the consent of the Holders of a
majority in principal  amount of the then  outstanding  Notes voting as a single
class; and

     WHEREAS, pursuant to the Consent Solicitation Statement dated September 28,
2005,  as it has been  amended  or  supplemented  to the date  hereof  ("Consent
Solicitation  Statement"),  the Issuers have  solicited a waiver (the  "Waiver")
from the Record  Holders (as defined  herein)  with  respect to any  requirement
under the  Indenture  that the  Issuers  or any other  person may have to make a
Change of Control  Offer under  Section 4.15 of the Indenture as a result of the
execution and delivery of certain  agreements  and the  consummation  of certain
transactions in connection with the Merger (as defined herein);

     WHEREAS, in accordance with Section 9.02 of the Indenture, the Issuers have
received  the  written  consent of the Record  Holders of at least a majority in
principal  amount  of the  outstanding  Notes  voting  as a single  class to the
Waiver;

     WHEREAS,  pursuant to an Officers'  Certificate,  the Issuers have directed
the Trustee to enter into this Second Supplemental Indenture; and

     WHEREAS,  all  conditions  and  requirements  necessary to make this Second
Supplemental  Indenture a valid and binding  instrument in  accordance  with its
terms and the terms of the Indenture  have been  satisfied,  including,  without
limitation, the delivery to the Trustee of an Opinion of Counsel.

     NOW,  THEREFORE,  in  consideration  of the  premises  and  of  the  mutual
covenants  herein  contained,  the Issuers and the Trustee  hereby  covenant and
agree as follows:

     SECTION 1.  DEFINED  TERMS.  For all  purposes of this Second  Supplemental
Indenture, the following terms shall have the following meaning:

     "Carlyle"  means Carlyle  Partners III  Telecommunications,  L.P.,  Carlyle
Partners  IV  Telecommunications,  L.P.,  CP III  Coinvestment,  L.P.  and CP IV
Coinvestment, L.P., individually and collectively.

     "Consent Date" means 5:00 p.m., New York City time, on October 12, 2005, as
extended by the Issuers.

     "Consent  Payment" means the cash payment to be made on the Consent Payment
Date to the  Trustee  for the  benefit of the Record  Holders who consent to the
proposed Waiver on or prior to the Consent Date and do not withdraw such consent
prior to the Effective  Time in the amount,  and on the terms and subject to the
conditions, specified in the Consent Solicitation Statement.





     "Consent Payment Date" means a date promptly following  consummation of the
Merger and designated by the Issuers.

     "Continuing Investors" means Sidney R. Knafel,  Michael S. Willner,  Andrew
G. Knafel,  the Knafel Children  Trusts,  Thomas  Kempner,  James Marcus and any
other persons who become parties to the Exchange Agreement prior to consummation
of the Merger.

     "Effective Time" means 5:01 P.M., New York City time, on October 12, 2005.

     "Exchange  Agreement"  means the Exchange  Agreement,  dated as of July 28,
2005, by and among Insight,  Insight  Acquisition,  the Continuing Investors and
Carlyle, as the same may from time to time be amended, modified, supplemented or
restated.

     "Insight"   means  Insight   Communications   Company,   Inc.,  a  Delaware
corporation.

     "Insight   Acquisition"   means  Insight   Acquisition  Corp.,  a  Delaware
corporation.

     "Knafel  Children  Trusts"  means the Trust F/B/O Andrew G.  Knafel,  dated
September 13, 1978, the Trust F/B/O Douglas R. Knafel, dated September 13, 1978,
the Trust F/B/O Andrew G. Knafel and Douglas R. Knafel, dated July 16, 1976, and
the Trust F/B/O  Douglas R. Knafel,  dated  November 6, 1983,  individually  and
collectively.

     "Merger"  means the proposed  merger of Insight  Acquisition  with and into
Insight as contemplated by the Merger Agreement.

     "Merger Agreement" means the Agreement and Plan of Merger, dated as of July
28, 2005, by and between Insight  Acquisition and Insight,  as the same may from
time to time be amended, modified, supplemented or restated.

     "Principals'  Agreement" means the Principals' Agreement,  dated as of July
28, 2005, by and among Sidney R. Knafel, Michael S. Willner and Carlyle, in each
case as the same may from time to time be  amended,  modified,  supplemented  or
restated.

     "Record Holder'' means each Holder of record as of the close of business in
New York City on September 26, 2005.

     "Securityholders  Agreement"  means  the  Securityholders  Agreement  to be
entered  into  concurrently  with the  consummation  of the  Merger by  Insight,
Carlyle,  the  Continuing  Investors  and each other  person who becomes a party
thereto  as  contemplated  thereunder,  as the  same  may  from  time to time be
amended, modified, supplemented or restated.

     "Termination Date" means the later of (A) the February 15, 2006 termination
date specified in Section 7.01(b)(i) of the Merger Agreement or (B) the date the
Merger  Agreement is  terminated,  but in no event later than the 60th day after
February 15, 2006.

     "Transactions"  means the  Merger  and the other  transactions  consummated
pursuant to the  Transaction  Agreements in  connection  with the closing of the
Merger.

     "Transaction   Agreements"  means  the  Merger   Agreement,   the  Exchange
Agreement,  the Voting Agreement, the Principals' Agreement, the Securityholders
Agreement and the other  agreements  and  instruments  executed and delivered in
connection therewith, in each case by the parties contemplated thereunder and as
the same may from time to time be amended, modified, supplemented or restated.





     "Voting  Agreement" means the Insight Voting Agreement dated as of July 28,
2005 between Insight Acquisition,  Sidney R. Knafel, Michael S. Willner,  Andrew
G. Knafel and the Knafel Children Trusts, in each case as the same may from time
to time be amended, modified, supplemented or restated.

Except as otherwise expressly provided or unless the context otherwise requires,
all  capitalized  terms defined herein shall have the meanings  assigned to them
herein.  All  capitalized  terms defined in the Indenture and not defined herein
shall have the meanings assigned to them in the Indenture.

     SECTION 2. WAIVER OF SECTION 4.15 OF  INDENTURE.  Subject to payment of the
Consent  Payment  on or before  the  Consent  Payment  Date by the Issuer to the
Trustee for the benefit of the Record Holders  entitled to such Consent  Payment
under  the  terms  and  subject  to the  conditions  set  forth  in the  Consent
Solicitation  Statement,  the  provisions  of Section 4.15 of the  Indenture are
hereby  waived in all respects as the same may relate to: (i) the  execution and
delivery of the Transaction  Agreements by the parties contemplated  thereunder,
and (ii) the  consummation  of the  Transactions  on or prior to the Termination
Date.

     SECTION 3. EFFECT ON ORIGINAL INDENTURE. This Second Supplemental Indenture
shall be  immediately  effective  at the  Effective  Time and form a part of the
Indenture  for all purposes  relating to the Notes and every holder of the Notes
heretofore  or  thereafter  authenticated  under the  Indenture as  supplemented
hereby,  shall be bound  hereby,  provided  that, in the event the Merger is not
consummated on or prior to the  Termination  Date and the Consent Payment is not
made to the Record Holders  entitled  thereto,  the Waiver and Section 2 of this
Second  Supplemental  Indenture  will have no further  effect.  The Indenture as
supplemented  by this Second  Supplemental  Indenture  is hereby in all respects
ratified and confirmed.

     SECTION 4. COUNTERPARTS. This Second Supplemental Indenture may be executed
in any number of  counterparts,  each of which  shall be an  original;  but such
counterparts shall together constitute but one and the same instrument.

     SECTION  5.  TRUSTEE  MAKES  NO  REPRESENTATIONS.   The  Trustee  makes  no
representations  as to the validity or sufficiency  of this Second  Supplemental
Indenture.  The  statements  and  recitals  herein are deemed to be those of the
Issuers and not of the Trustee.


                            [SIGNATURE PAGE FOLLOWS]




     IN WITNESS WHEREOF, the parties hereto have caused this Second Supplemental
Indenture to be duly executed, all as of the day and year first written above.


                                INSIGHT MIDWEST, L.P.
                                  By its General Partner,
                                  Insight Communications Company, L.P.
                                    By its General Partner,
                                    Insight Communications Company, Inc.

                                By: /s/ John Abbot
                                    -------------------------------------
                                    Name:   John Abbot
                                    Title:  Senior Vice President & Chief
                                            Financial Officer


                                INSIGHT CAPITAL, INC.


                                By: /s/ John Abbot
                                    -------------------------------------
                                    Name:   John Abbot
                                    Title:  Senior Vice President & Chief
                                            Financial Officer


                                THE BANK OF NEW YORK
                                as Trustee


                                By: /s/ Robert A. Massimillo
                                    -------------------------------------
                                    Name:   Robert A. Massimillo
                                    Title:  Vice President