FOR PURPOSES OF SECTIONS 1273 AND 1275 OF THE INTERNAL  REVENUE  CODE,  THE
AMOUNT OF ORIGINAL  ISSUE  DISCOUNT  WITH  RESPECT TO EACH  $1,000 OF  PRINCIPAL
AMOUNT OF THIS SECURITY IS $220.59, THE ISSUE DATE IS DECEMBER 19, 2000, AND THE
YIELD TO MATURITY IS 1.25% PER ANNUM.

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY  TRUST  COMPANY  TO THE  COMPANY  OR ITS  AGENT FOR  REGISTRATION  OF
TRANSFER,  EXCHANGE OR PAYMENT,  AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO.  OR IN SUCH  OTHER  NAME  AS IS  REQUESTED  BY AN  AUTHORIZED
REPRESENTATIVE  OF THE DEPOSITORY  TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO  CEDE  & CO.  OR TO  SUCH  OTHER  ENTITY  AS IS  REQUESTED  BY AN  AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY),  ANY TRANSFER,  PLEDGE OR OTHER
USE HEREOF FOR VALUE OR  OTHERWISE  BY OR TO ANY  PERSON IS  WRONGFUL  SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

     THIS  SECURITY IS A GLOBAL  SECURITY  WITHIN THE  MEANING OF THE  INDENTURE
HEREINAFTER  REFERRED  TO AND IS  REGISTERED  IN THE NAME OF A  DEPOSITARY  OR A
NOMINEE THEREOF.  THIS SECURITY IS EXCHANGEABLE FOR SECURITIES REGISTERED IN THE
NAME OF A PERSON  OTHER THAN THE  DEPOSITARY  OR ITS NOMINEE ONLY IN THE LIMITED
CIRCUMSTANCES  DESCRIBED IN THE INDENTURE AND,  UNLESS AND UNTIL IT IS EXCHANGED
IN WHOLE OR IN PART FOR SECURITIES IN DEFINITIVE  FORM, THIS SECURITY MAY NOT BE
TRANSFERRED  EXCEPT AS A WHOLE BY THE  DEPOSITARY TO A NOMINEE OF THE DEPOSITARY
OR BY A NOMINEE OF THE  DEPOSITARY TO THE  DEPOSITARY OR ANOTHER  NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR
A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.



<PAGE>

                                      -2-

Certificate Number R-[  ]

Number of Zero Coupon  Convertible  Debentures due December 19, 2020 represented
hereby:  400,000 (representing  $400,000,000.00 in aggregate principal amount at
maturity)

Unless this  certificate  is presented by an  authorized  representative  of The
Depository Trust Company (55 Water Street,  New York, New York) ("DTC"),  to the
Company (as defined below) or its agent for  registration of transfer,  exchange
or payment,  and any certificate  issued is registered in the name of Cede & Co.
or such other name as is requested by an authorized  representative  of DTC (and
any payment is made to Cede & Co. or to such other  entity as is requested by an
authorized  representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR  OTHERWISE BY OR TO ANY PERSON IS WRONGFUL  inasmuch as the  registered
owner hereof, Cede & Co., has an interest herein.

Unless  and  until  it is  exchanged  in  whole  or in part  for  securities  in
definitive  registered form, this certificate may not be transferred except as a
whole  by DTC to a  nominee  of DTC  or by a  nominee  of DTC to DTC or  another
nominee of DTC or by DTC or any such  nominee  to a  successor  Depository  or a
nominee of such successor Depository.


                               COMCAST CORPORATION


                             ZERO COUPON CONVERTIBLE
                         DEBENTURE DUE DECEMBER 19, 2020
                              (each a "Debenture")

                                                           CUSIP 200300 BH 3

Issue Price:  $779.41 per $1,000.00 principal amount at maturity
Maturity Amount:  $1,000.00

     COMCAST  CORPORATION,  a corporation  duly organized and existing under the
laws of the  Commonwealth  of Pennsylvania  (herein called the "Company",  which
term includes any successor corporation under the Indenture hereinafter referred
to), for value received, hereby promises to pay to

     Cede & Co.  or its registered assigns,

     the Maturity Amount

in any coin or currency of the United  States of America  which,  at the time of
payment is legal  tender for public and private  debts,  upon  presentation  and
surrender of this Debenture, on the 19th day of December, 2020, at the office or
agency of the Company in New York,  New York.  The "Maturity  Amount" will equal
$1,000.00  per Debenture  unless the Company  elects to pay cash interest on the
Debentures  following a Tax Event,  in which case the Maturity Amount will equal
the  Restated  Principal  Amount (as  defined on the  reverse  hereof).  No cash
interest will be payable on the  Debentures  unless the Company  elects to do so
following  a Tax  Event as  described  on the  reverse  hereof.  Original  Issue
Discount  will accrue as  specified  on the reverse  hereof.  This  Debenture is
convertible  to the Class A Special  Common  Stock of the Company and subject to
additional  provisions,  in  each  case  as  specified  on the  reverse  hereof.
Capitalized  terms used on the face hereof without  definition  have the meaning
specified on the reverse hereof.

<PAGE>

                                      -3-

THE  PROVISIONS OF THIS  DEBENTURE ARE CONTINUED ON THE REVERSE  HEREOF AND SUCH
CONTINUED PROVISIONS SHALL FOR ALL PURPOSES HAVE THE SAME EFFECT AS THOUGH FULLY
SET FORTH AT THIS PLACE.

     This  Debenture  shall not be entitled to any benefit  under the  Indenture
referred to on the reverse  hereof or any  indenture  supplemental  thereto,  or
become  valid or  obligatory  for any  purpose  until  the  Trustee  under  said
Indenture,  or a  successor  trustee  thereunder,  shall have signed the form of
certificate of authentication appearing hereon.

                                  *    *    *

<PAGE>

                                      -4-

     IN WITNESS  WHEREOF,  COMCAST  CORPORATION has caused this instrument to be
duly executed under its corporate seal.

Dated:


                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Debentures of the series
referred to on the reverse hereof.

THE BANK OF NEW YORK,
   as Trustee,


By:  _____________________________
          Authorized Officer

                                              COMCAST CORPORATION


                                              By:  _____________________________
                                                   Title:

                                              Attest:


                                              By:  _____________________________
                                                   Title:


<PAGE>

                                      -5-

                             [Reverse of Debenture]

                             ZERO COUPON CONVERTIBLE
                         DEBENTURE DUE DECEMBER 19, 2020

General
-------

     This  Debenture is one of a duly  authorized  issue of  debentures,  notes,
bonds or other  evidences  of  indebtedness  of the Company  (herein  called the
"Securities") of the series  hereinafter  specified,  all issued or to be issued
under an  indenture  dated as of June 15, 1999 (herein  called the  "Indenture")
executed  between the Company and The Bank of New York, as successor in interest
to Bank of Montreal  Trust  Company,  a New York  banking  corporation  with its
principal offices in New York, New York (hereinafter  called the "Trustee"),  to
which indenture and all supplemental  indentures  reference is hereby made for a
specification  of  the  rights  and  limitations  of  rights  thereunder  of the
registered holders of the Debentures,  the rights and obligations  thereunder of
the Company and the rights,  duties and immunities thereunder of the Trustee and
the terms  upon  which the  Debentures  are,  and are to be,  authenticated  and
delivered.  The terms of the  Indenture  are hereby  incorporated  by  reference
herein.  The  Securities  may be issued in one or more series,  which  different
series  may be issued in  various  aggregate  principal  amounts,  may mature at
different  times,  may bear interest (if any) at different rates, may be subject
to different  redemption  or repayment  provisions  (if any),  may be subject to
different  sinking,  purchase or analogous funds (if any) and may otherwise vary
as provided in the Indenture.  This  Debenture is one of a series  designated as
Zero Coupon Convertible Debentures due December 19, 2020 (hereinafter called the
"Debentures") of the Company,  each Debenture  representing  $1,000.00 principal
amount at maturity,  limited in aggregate  number to  1,285,000  Debentures  (or
$1,285,000,000   in  aggregate   principal  amount  at  maturity)  or  1,477,750
Debentures (or  $1,477,750,000 in aggregate  principal amount at maturity if the
underwriter's  over-allotment  option is exercised in full). The Debentures will
be issued in  denominations  of $1,000 principal amount at maturity and integral
multiples thereof.

     The  Debentures  are senior  unsecured  obligations of the Company and rank
equal  in  right of  payment  with all  existing  and  future  senior  unsecured
indebtedness  of the Company and senior in right of payment to all  existing and
future subordinated indebtedness of the Company.

     The Maturity Amount, the Redemption Price, the Repurchase Price, the Change
in Control  Purchase  Price and  interest,  if any,  on the  Debentures  will be
payable at the office or agency the Company  maintains  for such purpose  within
The City and  State of New York or, at the  Company's  option,  payment  of cash
interest may be made by check mailed to the holders of the  Debentures  at their
respective  addresses  set  forth in the  register  of  holders  of  Debentures;
provided  that all cash  payments  with respect to  Debentures  to a holder of a
minimum of $100,000  principal  amount at maturity of  Debentures  who has given
written wire transfer instructions,  on or prior to the relevant Record Date, to
the paying agent,  will be made by wire transfer of immediately  available funds
to the accounts  specified by such holders.  Until  otherwise  designated by the
Company,  the  Company's  office or agency in New York will be the office of the
Trustee maintained for such purpose.

Interest
--------

     No cash  interest  will be payable  on the  Debentures  unless the  Company
elects to do so  following  a Tax Event as  described  below.  If the  principal
amount  hereof  or any  portion  of such  principal  amount is not paid when due
(whether upon acceleration  pursuant to Section 4.01 of the Indenture,  upon the
date set for payment of the Redemption Price pursuant hereto,  upon the date set
for payment of Change in Control Purchase Price pursuant  hereto,  upon the date
set for  payment  of the  Repurchase  Price  pursuant  hereto or upon the stated
maturity of this  Debenture)  or if  interest  due hereon or any portion of such
interest is not paid when due in accordance herewith, then in each such case the
overdue amount shall, to the extent  permitted by law, bear interest at the rate
of 2.5% per annum,  compounded  semi-annually,  which interest shall accrue from
the date such overdue

<PAGE>

                                      -6-

amount was originally due to the date payment of such amount, including interest
thereon,  has been made or duly provided for. All such interest shall be payable
as set forth in the Indenture.  The accrual of such interest on overdue  amounts
shall be in lieu of, and not in addition to, the  continued  accrual of Original
Issue Discount.

     Original  Issue  Discount (the  difference  between the Issue Price and the
principal  amount at maturity of the  Debenture),  in the period  during which a
Debenture remains outstanding,  shall accrue at 1.25% per annum, on a semiannual
bond  equivalent  basis using a 360-day year composed of twelve  30-day  months,
from the Issue Date of this Debenture.

Redemption
----------

     The  Debentures are redeemable for cash at the option of the Company at any
time on or after December 19, 2005,  upon not less than 15 nor more than 60 days
notice by mail to holders of  Debentures,  for a price  equal to the Issue Price
per Debenture plus accrued  Original Issue Discount at a rate of 1.25% per annum
compounded  semi-annually to the date of redemption (the "Redemption Price"), on
the basis of a 360-day year consisting of twelve 30-day months.  The date of any
such redemption is known as the "Redemption Date".

     The table below shows  Redemption  Prices of the Debentures at December 19,
2005,  at each  following  December  19 prior to  maturity  and at  maturity  on
December  19,  2020.  The prices  reflect the accrued  Original  Issue  Discount
calculated  through  each date.  The  Redemption  Price of a Debenture  redeemed
between these dates will include an additional  amount reflecting the additional
Original  Issue  Discount  accrued since the  immediately  preceding date in the
table to the actual Redemption Date.

                                                 Accrued Original    Redemption
Redemption Date                  Issue Price     Issue Discount      Price
---------------                  -----------     ----------------    ----------
December 19, 2005..............   $779.41             $50.11          $829.52
December 19, 2006..............    779.41              60.51           839.92
December 19, 2007..............    779.41              71.04           850.45
December 19, 2008..............    779.41              81.70           861.11
December 19, 2009..............    779.41              92.50           871.91
December 19, 2010..............    779.41             103.43           882.84
December 19, 2011..............    779.41             114.50           893.91
December 19, 2012..............    779.41             125.71           905.12
December 19, 2013..............    779.41             137.06           916.47
December 19, 2014..............    779.41             148.55           927.96
December 19, 2015..............    779.41             160.19           939.60
December 19, 2016..............    779.41             171.97           951.38
December 19, 2017..............    779.41             183.90           963.31
December 19, 2018..............    779.41             195.98           975.39
December 19, 2019..............    779.41             208.21           987.62
December 19, 2020..............    779.41             220.59         1,000.00


     From and after the date a Tax Event  occurs and the  Company  elects to pay
cash interest at 1.25% per annum on the Debentures  instead of accruing Original
Issue  Discount,  the  principal  amount  for  redemption  will be the  Restated
Principal Amount (as defined below).

     If the Company  redeems fewer than all of the outstanding  Debentures,  the
Trustee will select the Debentures to be redeemed by lot, on a pro rata basis or
by another method the Trustee considers fair and appropriate.


<PAGE>

                                      -7-

     If the  Trustee  selects a portion of a  holder's  Debentures  for  partial
redemption  and the  holder  converts  a  portion  of the same  Debentures,  the
converted portion will be deemed to be from the portion selected for redemption.
Each Debenture will be redeemed in whole.

Conversion
----------

     Holders may convert each  Debenture  into 14.2566 shares of Class A Special
Common Stock of the Company (the "Class A Special  Common Stock") so long as the
conditions  described  below are met, at any time until the close of business on
the last Business Day prior to December 19, 2020. If a Debenture has been called
for  redemption,  the holder will be entitled to convert the Debenture until the
close of business on the Business Day immediately preceding the Redemption Date.
A Holder may convert fewer than all of its  Debentures so long as the Debentures
converted are a multiple of $1,000 principal amount at maturity.

     Holders may surrender Debentures for conversion into Class A Special Common
Stock only if the Closing  Price of the Class A Special  Common Stock is greater
than 110% of the  Accreted  Conversion  Price per share for at least 20  Trading
Days  (as  defined  below)  of the 30  Trading  Days  prior to  conversion.  The
"Accreted  Conversion Price" as of any day will equal the sum of the Issue Price
of a Debenture plus the accrued Original Issue Discount for the Debenture,  with
that sum divided by the number of Class A Special  Common  shares  issuable upon
conversion  of a Debenture  on that day.  Even if the market  price  contingency
described  above  has  not  occurred,  the  Debentures  may be  surrendered  for
conversion:

     (i)  to the extent the Company has called the  Debentures  for  redemption;
          Debentures  called for redemption  may be  surrendered  for conversion
          from the date of notice of the redemption  until the close of business
          on the Redemption Date;

     (ii) if (a) the Company elect to make a  distribution  to all  stockholders
          that  would  result in an  adjustment  to the  conversion  rate  under
          subparagraph  (3)  or  (4)  of the  paragraph  below  relating  to the
          adjustment  of  the   Conversion   Rate  and  that,  in  the  case  of
          subparagraph  (4), has a per share value equal to more than 15% of the
          Closing  Price of the Class A Special  Common Stock on the Trading Day
          preceding  the  declaration  date  for  the  distribution  and (b) the
          Company  does  not  provide  that  holders  of  the   Debentures   may
          participate in the  distribution;  Debentures  may be surrendered  for
          conversion  at any time from and after  the  declaration  date for the
          distribution   until  the  Business  Day  immediately   prior  to  its
          ex-dividend date or until the Company  announces that the distribution
          will not take place; and

     (iii)if the Company is a party to a consolidation,  merger or binding share
          exchange  pursuant to which the Class A Special  Common  Stock will be
          converted into cash,  securities or other property;  Debentures may be
          surrendered  for  conversion at any time from and after the date which
          is 15 days prior to the anticipated  effective date of the transaction
          until 15 days after the actual  date of the  transaction  and,  at the
          effective time of the transaction, the right to convert the Debentures
          into Class A Special  Common  Stock  will be  changed  into a right to
          convert  them into the kind and  amount of cash,  securities  or other
          property  which the  holder  would  have  received  if the  holder had
          converted the Debentures immediately prior to the transaction.

     The "Closing Price" of any security on any date of determination  means the
closing sale price (or, if no Closing Price is reported,  the last reported sale
price)  of such  security  (regular  way) on the NYSE on such  date or,  if such
security is not listed for trading on the NYSE on any such date,  as reported in
the composite  transactions for the principal United States securities  exchange
on which such  security is so listed,  or if such security is not so listed on a
United  States  national or  regional  securities  exchange,  as reported by the
Nasdaq National Market, or if such security is not so reported,  the last quoted
bid price for such  security in the  over-the-counter  market as reported by the
National  Quotation  Bureau or similar  organization.  If no such  quotation  is
available


<PAGE>

                                      -8-

for any day, the Board of Directors  shall be entitled to determine  the Closing
Price on the basis of such quotations as it considers appropriate. To the extent
that trading of Reference  Shares regular way continues past 4:00 p.m., New York
City  time,  "Closing  Price"  shall be deemed to refer to the price at the time
that is then customary for determining the Trading Day's index levels for stocks
traded on the primary national securities exchange or automated quotation system
on which the Reference Shares are then traded or quoted.  All references to 4:00
p.m.,  New York City time,  in the  definition  of "Current  Market Value" shall
thereafter be deemed to refer to the then customary determination time.

     A  "Trading  Day" is defined as a day on which the  security,  the  Closing
Price of which is being  determined,  (a) is not  suspended  from trading on any
national or regional  securities  exchange or  association  or  over-the-counter
market at the close of business and (b) has traded at least once on the national
or regional securities  exchange or association or over-the-counter  market that
is the primary market for the trading of such security.

     The initial  Conversion  Rate is 14.2566  shares of Class A Special  Common
Stock for each Debenture, subject to adjustment as described below. Holders will
not receive any cash payment  representing  accrued Original Issue Discount upon
conversion of a Debenture.  Instead, upon conversion the Company will deliver to
holders a fixed  number of shares of Class A Special  Common  Stock and any cash
payment to account for fractional shares. The cash payment for fractional shares
will be based on the closing  price of the Class A Special  Common  Stock on the
Trading Day  immediately  prior to the  conversion  date.  Delivery of shares of
Class A Special  Common  Stock will be deemed to satisfy the  obligation  of the
Company to pay the principal amount of the Debenture, including accrued Original
Issue  Discount.  Accrued  Original  Issue  Discount will be deemed paid in full
rather than canceled, extinguished or forfeited. The Conversion Rate will not be
adjusted to account for the accrued Original Issue Discount.

     The  Conversion  Rate shall be adjusted from time to time by the Company as
follows:

          (1)  If  the  Company  shall  hereafter  pay  a  dividend  or  make  a
     distribution to all holders of the outstanding Class A Special Common Stock
     in shares of the Company's  Class A Special  Common  Stock,  Class A Common
     Stock, par value $1.00 per share ("Class A Common Stock") or Class B Common
     Stock,  par value $1.00 per share ("Class B Common  Stock" and,  along with
     the Class A Special Common Stock and the Class A Common Stock,  the "Common
     Stock"),  the  Conversion  Rate shall be  increased  so that the same shall
     equal the rate  determined by multiplying  the Conversion Rate in effect at
     the  opening  of  business  on the date  following  the date  fixed for the
     determination  of  stockholders  entitled to receive such dividend or other
     distribution by a fraction,  the numerator of which shall be the sum of the
     number  of  shares  of  Common   Stock  and  the  total  number  of  shares
     constituting  such  dividend  or other  distribution  made on all shares of
     Common Stock, and the denominator of which shall be the number of shares of
     Common  Stock  outstanding  at the close of  business on the date fixed for
     such determination, such increase to become effective immediately after the
     opening of business on the  Trading Day  following  the date fixed for such
     determination.  For the  purpose of this  subparagraph  (1),  the number of
     shares of Common  Stock at any time  outstanding  shall not include  shares
     held in the treasury of the Company.  The Company will not pay any dividend
     or make any  distribution on shares of Common Stock held in the treasury of
     the Company.  If any dividend or distribution of the type described in this
     subparagraph  (1) is declared but not so paid or made, the Conversion  Rate
     shall again be adjusted to the Conversion Rate that would then be in effect
     if such dividend or distribution had not been declared,  such adjustment to
     become effective immediately upon the withdrawal of the declaration;

          (2) If  outstanding  shares of Class A Special  Common  Stock shall be
     subdivided into a greater number of shares of Class A Special Common Stock,
     the Conversion Rate in effect at the opening of business on the Trading Day
     following the day upon which such  subdivision  becomes  effective shall be
     proportionately  increased,  and conversely,  in case outstanding shares of
     Class A Special  Com-


<PAGE>

                                      -9-

     mon Stock  shall be  combined  into a  smaller  number of shares of Class A
     Special  Common  Stock,  the  Conversion  Rate in effect at the  opening of
     business on the Trading Day following  the day upon which such  combination
     becomes  effective  shall be  proportionately  decreased,  such increase or
     decrease,  as the case may be, to become  effective  immediately  after the
     opening of business on the  Trading Day  following  the day upon which such
     subdivision or combination becomes effective;

          (3) If the Company  shall  issue  rights or warrants to all holders of
     its  outstanding  Common Stock  entitling them to subscribe for or purchase
     shares of Common  Stock at a price per share less than the  Current  Market
     Price  (as  defined  below)  on  the  date  fixed  for   determination   of
     stockholders  entitled to receive such rights or warrants,  the  Conversion
     Rate shall be adjusted so that the same shall equal the rate  determined by
     multiplying  the Conversion  Rate in effect  immediately  prior to the date
     fixed for determination of stockholders  entitled to receive such rights or
     warrants  by a  fraction,  the  numerator  of which  shall be the number of
     shares of Common Stock  outstanding on the date fixed for  determination of
     stockholders  entitled to receive  such  rights or warrants  plus the total
     number of  additional  shares of Common Stock offered for  subscription  or
     purchase,  and the  denominator  of which  shall be the number of shares of
     Common  Stock  outstanding  at the close of  business on the date fixed for
     determination  of stockholders  entitled to receive such rights or warrants
     plus the number of shares that the  aggregate  offering  price of the total
     number of shares so offered  would  purchase at such Current  Market Price.
     Such  adjustment  shall be  successively  made  whenever any such rights or
     warrants  are issued,  and shall  become  effective  immediately  after the
     opening  of  business  on the  Trading  Day  following  the date  fixed for
     determination of stockholders  entitled to receive such rights or warrants.
     To the  extent  that  shares of Common  Stock are not  delivered  after the
     expiration  of such  rights  or  warrants,  the  Conversion  Rate  shall be
     readjusted  to the  Conversion  Rate that  would  then be in effect had the
     adjustments  made upon the issuance of such rights or warrants been made on
     the basis of delivery of only the number of shares of Common Stock actually
     delivered.  If such rights or warrants  are not so issued,  the  Conversion
     Rate shall again be adjusted to be the  Conversion  Rate that would then be
     in effect if such date fixed for the determination of stockholders entitled
     to receive  such rights or  warrants  had not been  fixed.  In  determining
     whether any rights or warrants  entitle  the  holders to  subscribe  for or
     purchase shares of Common Stock at less than such Current Market Price, and
     in determining the aggregate offering price of such shares of Common Stock,
     there shall be taken into account any consideration received by the Company
     for  such  rights  or  warrants  and any  amount  payable  on  exercise  or
     conversion thereof, the value of such consideration, if other than cash, to
     be determined by the Board of Directors.

          (4) If the Company shall, by dividend or otherwise,  distribute to all
     holders  of its  Common  Stock  evidences  of its  indebtedness  or  assets
     (including securities,  but excluding any rights or warrants referred to in
     subparagraph  (3) hereof,  and excluding any dividend or  distribution  (x)
     paid exclusively in cash or (y) referred to in subparagraph (1) hereof (any
     of the foregoing hereinafter in this subparagraph (4) called the "Described
     Securities")),  then,  in each  such case  (unless  the  Company  elects to
     reserve such Securities for  distribution to the holders of Debentures upon
     the  conversion  of the  Debentures  so that  any  such  holder  converting
     Debentures will receive upon such conversion,  in addition to the shares of
     Class A Special  Common Stock to which such holder is entitled,  the amount
     and kind of such Described Securities which such holder would have received
     if such holder had converted  its  Debentures  into Class A Special  Common
     Stock  immediately prior to the Record Date hereof for such distribution of
     the Described Securities)),  the Conversion Rate shall be increased so that
     the  same  shall  be  equal  to the  rate  determined  by  multiplying  the
     Conversion  Rate  in  effect  on the  Record  Date  with  respect  to  such
     distribution  by a fraction,  the  numerator  of which shall be the Current
     Market  Price  per  share of the  Class A  Special  Common  Stock,  and the
     denominator  of which  shall be the Current  Market  Price per share of the
     Class A Special Common Stock on such Record Date less the fair market value
     (as  determined by the Board of  Directors,  whose  determination  shall be
     conclusive absent manifest error, and described in a certificate filed with
     the Trustee) on the Record Date of the portion of the Described  Securities
     so  distributed  applicable  to one share of Class A Special  Common Stock,
     such  in-


<PAGE>

                                      -10-

     crease to become effective  immediately prior to the opening of business on
     the day following  such Record Date;  provided,  however,  that if the then
     fair  market  value (as so  determined)  of the  portion  of the  Described
     Securities so distributed applicable to one share of Class A Special Common
     Stock is equal to or greater  than the Current  Market Price of the Class A
     Special  Common  Stock  on the  Record  Date,  in  lieu  of  the  foregoing
     adjustment,  adequate  provision  shall  be  made so that  each  holder  of
     Debentures  shall have the right to receive upon  conversion  the amount of
     Described  Securities  such  holder  would have  received  had such  holder
     converted   each  Debenture  on  the  Record  Date.  If  such  dividend  or
     distribution  is not so paid or made,  the  Conversion  Rate shall again be
     adjusted  to be the  Conversion  Rate that  would then be in effect if such
     dividend or distribution  had not been declared,  such adjustment to become
     effective  immediately upon the withdrawal of the dividend or distribution.
     If  the  Board  of  Directors  determines  the  fair  market  value  of any
     distribution  for  purposes of this  subparagraph  (4) by  reference to the
     actual or when issued trading market for any  securities,  it must in doing
     so  consider  the  prices  in such  market  over  the same  period  used in
     computing the Current Market Price of the Class A Special Common Stock.

          Rights or warrants  distributed by the Company to all holders of Class
     A Special  Common Stock  entitling the holders  thereof to subscribe for or
     purchase shares of the Company's  capital stock (either  initially or under
     certain circumstances), which rights or warrants, until the occurrence of a
     specified  event  or  events  ("Trigger  Event"):  (i)  are  deemed  to  be
     transferred with such shares of Class A Special Common Stock;  (ii) are not
     exercisable;  and (iii) are also issued in respect of future  issuances  of
     Class A Special Common Stock,  shall be deemed not to have been distributed
     for purposes of this subparagraph (and no adjustment to the Conversion Rate
     under this  subparagraph  will be  required)  until the  occurrence  of the
     earliest Trigger Event,  whereupon such rights and warrants shall be deemed
     to have been distributed and an appropriate adjustment (if any is required)
     to the Conversion  Rate shall be made under this  subparagraph  (4). If any
     such right or  warrant,  including  any such  existing  rights or  warrants
     distributed prior to the date of original  issuance of the Debentures,  are
     subject to events,  upon the  occurrence  of which such  rights or warrants
     become   exercisable  to  purchase  different   securities,   evidences  of
     indebtedness  or other assets,  then the date of the  occurrence of any and
     each such event shall be deemed to be the date of  distribution  and Record
     Date with  respect  to new  rights or  warrants  with  such  rights  (and a
     termination  or  expiration  of the  existing  rights or  warrants  without
     exercise by any of the holders thereof).  In addition,  in the event of any
     distribution (or deemed distribution) of rights or warrants, or any Trigger
     Event or other event (of the type described in the preceding sentence) with
     respect thereto that was counted for purposes of calculating a distribution
     amount  for  which  an  adjustment  to  the  Conversion   Rate  under  this
     subparagraph  was made, (a) in the case of any such rights or warrants that
     shall all have been redeemed or repurchased without exercise by any holders
     thereof, the Conversion Rate shall be readjusted upon such final redemption
     repurchase to give effect to such  distribution  or Trigger  Event,  as the
     case may be, as though it were a cash distribution,  equal to the per share
     redemption or repurchase  price  received by a holder or holders of Class A
     Special Common Stock with respect to such rights or warrants (assuming such
     holder had retained such rights or warrants),  made to all holders of Class
     A Special Common Stock as of the date of such redemption or repurchase, and
     (b) in the case of such rights or warrants  that shall have expired or been
     terminated  without  exercise by any holders  thereof,  the Conversion Rate
     shall be readjusted as if such rights and warrants had not been issued.

          No  adjustment of the  Conversion  Rate shall be made pursuant to this
     subparagraph  (4) in respect of rights or  warrants  distributed  or deemed
     distributed on any Trigger Event to the extent that such rights or warrants
     are actually  distributed,  or reserved by the Company for


<PAGE>

                                      -11-

     distribution  to holders of Debentures  upon  conversion by such holders of
     Debentures  to Class A Special  Common Stock.  If the Company  implements a
     stockholder  rights  plan,  the  Company  agrees that such rights plan will
     provide that upon conversion of the Debentures, the holders holding Class A
     Special Common Stock issued upon conversion shall receive the rights issued
     under  such  plan  in lieu  of the  Company  making  an  adjustment  of the
     Conversion Rate pursuant to this  subparagraph (4) unless there has already
     been an adjustment  of the  Conversion  Rate pursuant to this  subparagraph
     (4).

          For purposes of this  subparagraph (4) and  subparagraphs (1) and (3),
     any dividend or distribution to which this  subparagraph  (4) is applicable
     that also includes  shares of Class A Special  Common  Stock,  or rights or
     warrants  to  subscribe  for or purchase  shares of Class A Special  Common
     Stock  (or  both),  shall  be  deemed  instead  to  be  (A) a  dividend  or
     distribution of the evidences of indebtedness,  assets or shares of capital
     stock other than such shares of Class A Special  Common  Stock or rights or
     warrants (and any Conversion  Rate increase  required by this  subparagraph
     (4) with  respect  to such  dividend  or  distribution  shall then be made)
     immediately  followed by (B) a dividend or  distribution  of such shares of
     Class A Special  Common  Stock or such rights or warrants  (and any further
     Conversion Rate increase  required by subparagraphs (1) and (3) hereof with
     respect to such dividend or  distribution  shall then be made),  except (C)
     the Record Date of such dividend or  distribution  shall be  substituted as
     "the date fixed for the  determination of stockholders  entitled to receive
     such dividend or other distribution", "the date fixed for the determination
     of stockholders  entitled to receive such rights or warrants" and "the date
     fixed for such  determination"  within the meaning of subparagraphs (1) and
     (3), and (D) any shares of Class A Special  Common  Stock  included in such
     dividend or distribution  shall not be deemed  "outstanding at the close of
     business  on the date fixed for such  determination"  within the meaning of
     subparagraph (1) hereof.

          (5) If the  Company  shall  distribute  to  all or  substantially  all
     stockholders of the Company an all-cash distribution in an aggregate amount
     that,  together  with (a) any cash and the fair  market  value of any other
     consideration   payable  in  respect  of  a  tender   offer   described  in
     subparagraph (6) below  consummated  within the preceding 12 months and not
     triggering an adjustment in the Conversion  Rate and (b) all other all-cash
     distributions to all or substantially  all stockholders of the Company made
     within  the  preceding  12  months  not  triggering  an  adjustment  of the
     Conversion Rate pursuant to this  subparagraph (5), exceeds an amount equal
     to 12.5% of the  Current  Market  Value of all  outstanding  shares  of the
     Common Stock on the Trading Day immediately  preceding the day on which the
     Company  declared  the  distribution,  then the  Conversion  Rate  shall be
     increased so that the same shall equal the rate  determined by  multiplying
     the Conversion Rate in effect immediately prior to the close of business on
     such Record Date by a fraction, the numerator of which shall be the Current
     Market  Price  of the  Class A  Special  Common  Stock on the  Trading  Day
     immediately   preceding   the  day  on  which  the  Company   declared  the
     distribution,  and the  denominator  of which shall be the  Current  Market
     Price of the  Class A  Special  Common  Stock on the  Record  Date less the
     amount  of cash  so  distributed  (and  not  excluded  as  provided  below)
     applicable to one share of Class A Special  Common Stock,  such increase to
     be  effective  immediately  prior to the opening of business on the Trading
     Day following the Record Date;  provided,  however,  that if the portion of
     the cash so  distributed  applicable to one share of Class A Special Common
     Stock is equal to or greater  than the Current  Market Price of the Class A
     Special  Common  Stock  on the  Record  Date,  in  lieu  of  the  foregoing
     adjustment,  adequate  provision  shall  be  made so that  each  holder  of
     Debentures  shall have the right to receive upon  conversion  the amount of
     cash such  holder  would  have  received  had such  holder  converted  each
     Debenture on the Record Date.  If such dividend or  distribution  is not so
     paid or  made,  the  Conversion  Rate  shall  again be  adjusted  to be the
     Conversion  Rate  that  would  then  be  in  effect  if  such  dividend  or
     distribution  had not been  declared.  If any  adjustment is required to be
     made as set forth in this  subparagraph (5), such adjustment shall be based
     upon the  amount  by which  such  distribution  exceeds  the  amount of the
     distribution permitted to be excluded pursuant hereto.


<PAGE>

                                      -12-

          (6) If the Company shall purchase  shares of its Common Stock pursuant
     to a tender  offer made by the  Company or any of its  Subsidiaries  to the
     extent that the same involves aggregate consideration to all holders of its
     Common Stock that,  together with (a) any cash and the fair market value of
     any other  consideration  payable in respect of a tender offer described in
     this  subparagraph  (6) consummated  within the preceding 12 months and not
     triggering  an  adjustment  in the  Conversion  Rate  and (b) all  all-cash
     distributions to all or substantially  all stockholders of the Company made
     within  the  preceding  12  months  not  triggering  an  adjustment  of the
     Conversion Rate pursuant to subparagraph (5) above, exceeds an amount equal
     to 12.5% of the  Current  Market  Value of all  outstanding  shares  of the
     Common Stock on the Trading Day immediately  preceding the day on which the
     Company  declared  the  distribution,  then the  Conversion  Rate  shall be
     increased so that the same shall equal the rate  determined by  multiplying
     the Conversion Rate in effect immediately prior to the expiration time (the
     "Expiration  Time") of such tender  offer by a fraction,  the  numerator of
     which  shall  be the sum of (x) the  fair  market  value  of the  aggregate
     consideration payable to all holders of the Company's Common Stock based on
     the acceptance  (up to any maximum  specified in the terms of the tender or
     exchange  offer)  of all  shares  validly  tendered  or  exchanged  and not
     withdrawn as of the Expiration  Time (the shares deemed so accepted,  up to
     any such maximum,  being referred to as the "Purchased Shares") and (y) the
     product of the number of shares of Class A Special Common Stock outstanding
     (less any Purchased  Shares) at the Expiration  Time and the Current Market
     Price  of the  Class  A  Special  Common  Stock  on the  Trading  Day  next
     succeeding the Expiration  Time, and the  denominator of which shall be the
     number of shares of Common  Stock  outstanding  (including  any tendered or
     exchanged  shares) at the Expiration  Time multiplied by the Current Market
     Price of the Common Stock on the Trading Day next succeeding the Expiration
     Time, such increase to become effective immediately prior to the opening of
     business on the Trading Day following the  Expiration  Time. If the Company
     is  obligated  to purchase  shares  pursuant to any such tender or exchange
     offer,  but the Company is  permanently  prevented by  applicable  law from
     effecting  any such  purchases or all such  purchases  are  rescinded,  the
     Conversion  Rate shall  again be adjusted  to be the  Conversion  Rate that
     would then be in effect if such tender or exchange offer had not been made.

     "Current  Market  Price"  per  share of Common  Stock at any date  shall be
deemed  to be the  average  of the  daily  Closing  Prices  per share of Class A
Special  Common Stock for the ten  consecutive  Trading Days  preceding  the day
before the Record Date (or, if earlier,  the day before the related  ex-dividend
date) with respect to any  distribution,  issuance or other event requiring such
computation.  Notwithstanding  the  foregoing,  if the Company shall engage in a
transaction  described in subparagraphs (1) or (2) relating to the adjustment of
the Conversion Rate that treats  unequally the Class A Special Common Stock, the
Class A Common Stock or the Class B Common Stock (provided that distributions of
one class of Common Stock on all classes of Common  Stock,  or the same class of
Common  Stock all shares of such class of Common Stock shall not be deemed to be
unequal  treatment),  then the Current  Market Price of the Class A Common Stock
and the Class B Common Stock shall be adjusted in such manner (as  determined by
the Board of Directors,  whose determination shall be conclusive absent manifest
error,  and described in a certificate  filed with the Trustee) so as to reverse
the effect of such unequal treatment.

     "fair market value" shall mean the amount which a willing buyer would pay a
willing seller in an arm's-length transaction.

     "Record  Date" shall mean,  with respect to any dividend,  distribution  or
other  transaction or event in which the holders of Class A Special Common Stock
have the right to receive any cash, securities or other property or in which the
Class A Special Common Stock (or other applicable  security) is exchanged for or
converted into any combination of cash,  securities or other property,  the date
fixed  for  determination  of  stockholders   entitled  to  receive  such  cash,
securities  or other  property  (whether  such  date is  fixed  by the  Board of
Directors or by statute, contract or otherwise).


<PAGE>

                                      -13-

     The Company may make such increases in the Conversion  Rate, in addition to
those required by subparagraphs  (1) through (6) of the paragraph above relating
to the adjustment of the Conversion Rate as the Board of Directors  considers to
be  advisable  to avoid or diminish any income tax to holders of Class A Special
Common Stock or rights to purchase Class A Special  Common Stock  resulting from
any dividend or  distribution  of stock (or rights to acquire stock) or from any
event treated as such for income tax purposes.

     To the extent  permitted by  applicable  law, the Company from time to time
may  increase  the  Conversion  Rate by any amount for any period of time if the
period is at least  twenty (20) days,  the  increase is  irrevocable  during the
period  and the Board of  Directors  shall have made a  determination  that such
increase  would be in the best  interests  of the Company,  which  determination
shall be conclusive.  Whenever the Conversion Rate is increased  pursuant to the
preceding  sentence,  the  Company  shall  mail  to  holders  of  record  of the
Debentures a notice of the increase at least fifteen (15) days prior to the date
the  increased  Conversion  Rate takes  effect,  and such notice shall state the
increased Conversion Rate and the period during which it will be in effect.

     No  adjustment  in the  Conversion  Rate  shall  be  required  unless  such
adjustment would require an increase or decrease of at least one percent (1%) in
such  rate;  provided,  however,  that any  adjustments  that by  reason of this
paragraph  are not  required to be made shall be carried  forward and taken into
account in any  subsequent  adjustment.  All  calculations  under this Debenture
shall be made by the  Company  and shall be made to the  nearest  cent or to the
nearest  one-thousandth  (1/1000) of a share,  as the case may be. No adjustment
need be made for rights to purchase  Class A Special  Common Stock pursuant to a
Company  plan for  reinvestment  of  dividends  or  interest.  To the extent the
Debentures become convertible into cash,  assets,  property or securities (other
than capital stock of the Company),  no adjustment need be made thereafter as to
the cash, assets,  property or such securities.  Interest will not accrue on the
cash.

     If a holder submits its  Debentures  for  conversion  after the Company has
elected to exercise its option to pay cash interest instead of accruing Original
Issue  Discount  between a Record  Date and the  opening of business on the next
interest  payment date (except for  Debentures or portions of Debentures  called
for redemption on a redemption  date occurring  during the period from the close
of  business on a Record Date and ending on the opening of business on the first
Business Day after the next interest  payment date, or if this interest  payment
date is not a business day, the second  Business Day after the interest  payment
date),  the holder must pay funds equal to the interest payable on the converted
principal amount.

     To convert a Debenture,  a holder must (a)  complete and manually  sign the
Conversion Notice set forth below and deliver such notice to a Conversion Agent,
(b)  surrender  the  Debenture to a Conversion  Agent,  (c) furnish  appropriate
endorsements  and transfer  documents if required by a Registrar or a Conversion
Agent, and (d) pay any transfer or similar tax, if required.

Repurchase by the Company at the Option of the Holder
-----------------------------------------------------

     Holders may require the Company to  repurchase  the  Debentures on December
19, 2001,  December 19, 2003,  December 19, 2005, December 19, 2010 and December
19,  2015  (each,  a  "Repurchase   Date").  The  Company  must  repurchase  any
outstanding  Debenture for which the holder delivers a written repurchase notice
to the paying agent during the period  beginning at any time from the opening of
business on the date that is 20 Business  Days prior to the relevant  Repurchase
Date until the close of business on the fifth day prior to the Repurchase  Date.
If the repurchase  notice is given and withdrawn during the period,  the Company
shall not be obligated to repurchase the related Debentures.

     The repurchase price payable (the "Repurchase  Price") will be equal to the
Issue Price plus accrued  Original Issue Discount  through the Repurchase  Date.
The  Repurchase  Price of a  Debenture  as of each  Repurchase  Date  will be as
follows:


<PAGE>

                                      -14-

     $789.18 per Debenture on December 19, 2001;

     $809.10 per Debenture on December 19, 2003;

     $829.52 per Debenture on December 19, 2005;

     $882.84 per Debenture on December 19, 2010; and

     $939.60 per Debenture on December 19, 2015.

     The Company may pay the  Repurchase  Price for  repurchases on the December
19, 2001,  2003 and 2005  Repurchase  Dates in cash or shares of Class A Special
Common  Stock,  or a  combination  of cash and shares of Class A Special  Common
Stock.  The Company may pay the Repurchase Price for repurchases on the December
19, 2010 and 2015 Repurchase Dates in cash only.

     If the Company has  previously  exercised  its option to pay cash  interest
instead of accruing  Original Issue  Discount on the Debentures  following a Tax
Event, the Repurchase Price will be equal to the Restated  Principal Amount plus
the accrued and unpaid interest that accrued from the date the Company exercised
its option through the Repurchase Date.

Tax Event
---------

     The Company may pay cash interest on the Debentures from and after the date
a Tax Event (as  defined  below)  occurs  instead  of  accruing  Original  Issue
Discount.  The  principal  amount  will be  restated  (the  "Restated  Principal
Amount") and will be fixed in an amount calculated by adding the Issue Price and
the  Original  Issue  Discount  which had accrued up until the date on which the
Company  exercised the option to commence  paying cash  interest.  This Restated
Principal Amount will be the amount due at maturity.  If the Company elects this
option,  interest  will be based on a 360-day year  comprised  of twelve  30-day
months.  Interest will accrue from the option  exercise date and will be payable
semiannually on each June 19 and December 19.

     A "Tax  Event"  occurs  when  the  Company  receives  an  opinion  from  an
experienced independent tax counsel stating that, as a result of either:

     (i)  any amendment,  change or announced  prospective change in the laws or
          regulations of the United States or any of its political  subdivisions
          or taxing authorities of the United States; or

     (ii) any amendment,  change,  interpretation  or application of the laws or
          regulations  by any  legislative  body,  court,  government  agency or
          regulatory authority,

there is more than an insubstantial risk that interest, including Original Issue
Discount, payable on the Debentures either

     (i)  would not be deductible on a current accrual basis; or

     (ii) would not be deductible under any other method,

in whole or in part,  by the  Company  for  United  States  federal  income  tax
purposes.

     If interest is payable on a date that is not a Business  Day (as defined at
the end of this  paragraph),  payment will be made on the next Business Day (and
without any interest or other payment in respect of such de-


<PAGE>

                                      -15-

lay). However, if the next Business Day is in the next calendar year, payment of
interest will be made on the preceding Business Day. A "Business Day" means each
day except  Saturday,  Sunday and any day on which banking  institutions  in The
City of New York are authorized or required by law to close.

Change in Control
-----------------

     If the  Company  undergoes  a Change in  Control,  Holders  may require the
Company to purchase the  Debentures 35 Business Days after the Change in Control
(the  "Purchase  Date").  The  Company  will pay a purchase  price  equal to the
initial Issue Price plus accrued  Original Issue  Discount  through the Purchase
Date or, if the  Company  has  elected to pay cash  interest  on the  Debentures
following a Tax Event,  the  Restated  Principal  Amount plus accrued and unpaid
interest  through the Purchase  Date (the "Change in Control  Purchase  Price").
Holders may require the Company to purchase all or any part of the Debentures so
long as the principal  amount at maturity of the Debentures being purchased is a
multiple of $1,000.

     A "Change in Control" is defined as follows:

     (i)  any person or group (other than the Company,  its  Subsidiaries or any
          Permitted  Holder,  as  defined  below)  after the first  issuance  of
          Debentures becomes the beneficial owner of voting stock of the Company
          representing more than 50% of the total voting power of all classes of
          voting stock of the Company entitled to vote generally in the election
          of the members of the Board of Directors; or

     (ii) the Company  consolidates  with or merges into another  person  (other
          than a Subsidiary),  the Company sells,  conveys,  transfers or leases
          its  properties  and assets  substantially  as an entirety to a person
          (other than a  Subsidiary),  or any person  (other than a  Subsidiary)
          consolidates  with  or  merges  with  or  into  the  Company,  and the
          outstanding   common  stock  of  the  Company  is  reclassified  into,
          exchanged  for or  converted  into the  right  to  receive  any  other
          property or security;  provided that none of these  circumstances will
          be a Change in Control  if,  after a  transaction,  the  persons  that
          beneficially  owned the voting stock of the Company  immediately prior
          to  the  transaction  beneficially  own,  in  substantially  the  same
          proportion,  shares with a majority of the total  voting  power of all
          outstanding  voting  securities of the surviving or transferee  person
          that are entitled to vote  generally in the election of that  person's
          board of directors;

unless,  in each  case,  at least  80% of the  consideration,  other  than  cash
payments for fractional shares, in the transaction or transactions  constituting
the Change in Control,  consists of shares of voting  common stock of the person
that are, or upon issuance will be, traded on a national  securities exchange or
approved for trading on an established automated over-the-counter trading market
in the United States.

     A  "Permitted  Holder"  means  (i) Mr.  Brian L.  Roberts,  his  spouse  or
children, any trust for his benefit or the benefit of his spouse or children, or
any  corporation or partnership in which the direct and beneficial  owner of all
of the  equity  interest  is he or his spouse or  children  or any trust for the
benefit of him, his heirs, executors, administrators or personal representatives
upon his  death or upon his  incompetency  or  disability  for  purposes  of the
protection and management of his assets, and (ii) any person or group controlled
by each or any of the persons  referred to in clause (i).  For  purposes of this
definition  "beneficially  own," "beneficial  owner" and "beneficial  ownership"
shall have the  meaning as defined  pursuant  to Rules 13d-3 and 13d-5 under the
Exchange  Act  (except  that a  person  shall  be  deemed  to  have  "beneficial
ownership" of all securities that such person has the right to acquire,  whether
the right is exercisable immediately or only after the passage of time, upon the
happening of an event or otherwise).

     Holders  must  deliver a written  notice to the paying  agent  prior to the
close of business on the Business Day prior to the date on which the  Debentures
are to be repurchased to exercise the repurchase right upon a


<PAGE>

                                      -16-

Change in Control.  This  notice  must  specify  the  Debentures  submitted  for
repurchase.  Holders may withdraw the notice by  delivering a written  notice of
withdrawal to the paying agent before the same date.

     Within 15 Business Days after a Change in Control, the Company will publish
and mail to the Trustee and to each holder of the Debentures a written notice of
the  Change  in  Control  which  specifies  the  terms  and  conditions  and the
procedures  required for exercise of a Holder's  right to require the Company to
purchase its Debentures.

Events of Default; Remedies
---------------------------

     In case an Event of Default,  as defined in the Indenture,  shall occur and
be continuing,  the Maturity Amount of all Debentures then outstanding under the
Indenture may be declared,  or may become,  due and payable upon the  conditions
and in the manner and with the effect provided in the Indenture.

Calculations in Respect of the Debentures
-----------------------------------------

     The Company  will be  responsible  for making all  calculations  called for
under the Debentures. The Company must make all these calculations in good faith
and such calculations are final and binding on holders of the Debentures, absent
manifest error.  The Company will provide a schedule of its  calculations to the
Trustee  and  the  Trustee  is  entitled  to  rely  upon  the  accuracy  of such
calculations, without independent verification. The Trustee shall be entitled to
conclusively rely on the accuracy of the information and calculations  contained
in each Officers'  Certificate  delivered under this Debenture and shall have no
responsibility for verifying the accuracy thereof.

Modifications
-------------

     To the extent permitted by, and as provided in the Indenture, modifications
or alterations of the Indenture,  or of any indenture  supplemental thereto, and
of the  rights  and  obligations  of the  Company  and  of  the  holders  of the
Securities,  may be made by the  Company  with the consent of the holders of not
less  than  a  majority  of  the  principal  amount  (for  the  purposes  of the
Debentures,  the principal  amount of the Debentures for consenting  holders and
all holders shall be calculated by reference to the principal amount at maturity
of such  Debentures) of the Securities then  Outstanding of each series affected
thereby;  provided,  however,  that no such modification or alteration shall (i)
change the stated  maturity of the Principal of, or any sinking fund  obligation
or any  installment  of interest  on, such  holder's  Security;  (ii) reduce the
Principal thereof or the rate of interest  thereon,  or any premium payable with
respect  thereto;  (iii) change any place of payment  where,  or the currency in
which,  any  Security or any premium or the  interest  thereon is payable;  (iv)
change the provisions for calculating the optional  redemption price,  including
the definitions  relating  thereto;  (v) make any change to Section 4.07 or 4.10
(except to include other  provisions  subject to Section 4.10);  (vi) reduce the
percentage in principal amount of outstanding  Securities of the relevant series
the consent of whose  holders is required for any such  supplemental  indenture,
for any  waiver  of  compliance  with any  provisions  of the  Indenture  or any
defaults and their  consequences  provided for in the Indenture;  (vii) alter or
impair the right to convert any Security at the rate and upon the terms provided
in Article 12; (viii) waive a default in the payment of Principal of or interest
on any Security of such holder (except  pursuant to a rescission of acceleration
pursuant to Section 4.01); (ix) adversely affect the rights of such holder under
any mandatory  redemption or repurchase  provision or any right of redemption or
repurchase  at the option of such holder;  (x) modify any of the  provisions  of
Section 7.02,  except to increase any such percentage or to provide that certain
other  provisions  of the  Indenture  cannot be modified  or waived  without the
consent of the holder of each outstanding  Security  affected  thereby;  or (xi)
change or waive any provision that,  pursuant to a board resolution or indenture
supplemental  hereto establishing the terms of one or more series of Securities,
is prohibited to be so changed or waived.


<PAGE>

                                      -17-

     It is also  provided  in the  Indenture  that the  holders of a majority in
aggregate   principal  amount  (the  principal  amount  of  the  Debentures  for
consenting  holders and all holders  shall be  calculated  by  reference  to the
principal  amount  at  maturity  of  such  Debentures)  of the  Debentures  then
Outstanding  may  on  behalf  of  the  holders  of  all  the  Debentures   under
circumstances  specified in the  Indenture,  waive a past Event of Default under
the Indenture and its consequences, except a default in the payment of Principal
of or interest on the  Debentures.  Any such  consent or waiver by the holder of
this  Debenture  shall be  conclusive  and binding upon such holder and upon all
future  holders of this  Debenture and of any Debenture or Debentures  issued in
exchange or substitution herefor, irrespective of whether or not any notation of
such consent or waiver is made in this Debenture.

Miscellaneous
-------------

     No reference  herein to the Indenture and no provision of this Debenture or
of the Indenture  shall alter or impair the obligation of the Company,  which is
absolute  and  unconditional,  to pay the  principal  of,  premium,  if any,  or
interest on this Debenture at the place,  at the respective  times, at the rate,
and in the coin or currency herein prescribed.

     The Indenture permits both covenant  defeasance and legal defeasance of the
Debentures pursuant to Article 9 of the Indenture.

     The Indenture  contains  provisions setting forth certain conditions to the
institution of  proceedings  by holders of the  Debentures  with respect to this
Debenture and the Indenture and the enforcement of remedies under this Debenture
and the Indenture,  including, without limitation, the appointment of a receiver
or trustee.  However,  no reference  herein to the Indenture and no provision of
this  Debenture or the Indenture  shall impair or affect the right of any holder
of any Debenture to receive  payment of the principal of,  premium,  if any, and
interest on such  Debenture on or after the respective  dates  expressed in this
Debenture,  or to institute  suit for the  enforcement of any such payment on or
after such respective dates and any such right or such enforcement thereof shall
not require the consent of any other such holder.

     The transfer of this  Debenture is  registrable  by the  registered  holder
hereof, in person or by his attorney duly authorized in writing, on the books of
the  Company to be kept for that  purpose at the office or agency of the Company
in New York,  New York,  upon surrender and  cancellation  of this Debenture and
upon  presentation  of a duly  executed  written  instrument  of  transfer,  and
thereupon a new Debenture or Debentures of authorized denominations for the same
aggregate  principal  amount will be issued to the  transferee or transferees in
exchange herefor;  and this Debenture may be in like manner exchanged for one or
more  Debentures of other  authorized  denominations  but of the same  aggregate
principal  amount,  all in the  manner  and  subject  to the  conditions  in the
Indenture  contained and without payment of any service or other charge,  except
for any stamp or other tax or governmental charge in connection therewith. Prior
to due presentment of this Debenture for registration or transfer,  the Company,
the Trustee, any paying agent and any Debenture registrar may deem and treat the
person in whose name this  Debenture is registered as the absolute  owner hereof
for the purpose of receiving  payment hereof or on account hereof or of interest
hereon (subject to the provisions of the first paragraph on the face hereof) and
for all other purposes.

     No  recourse  shall be had for the payment of  Principal  of or interest on
this  Debenture  or for any claim  based  hereon or  otherwise  in any manner in
respect  hereof,  or in  respect  of  the  Indenture,  against  any  subsidiary,
incorporator,  stockholder, officer, director or employee, as such past, present
or future, of the Company or any subsidiary, incorporator, stockholder, officer,
director or employee,  as such, past,  present or future,  of any predecessor or
successor  corporation,  whether by virtue of any  constitutional  provision  or
statute or rule of law, or by the enforcement of any assessment or penalty or in
any other manner,  all such liability being expressly waived and released by the
acceptance hereof and as part of the consideration for the issue hereof.


<PAGE>

                                      -18-

     The  Indenture  and this  Debenture  shall be deemed to be a contract  made
under the laws of the State of New York, and for all purposes shall be construed
in  accordance  with  the laws of said  jurisdiction,  except  that the  rights,
duties,  obligations,  immunities  and  limitations  of  rights  of the  Trustee
pursuant to the Indenture  and the Debenture  shall be governed by and construed
in accordance with the laws of the State of New York.

     All  capitalized  terms used in this  Debenture and not  otherwise  defined
herein shall have the meanings ascribed to them in the Indenture.



<PAGE>

                                      -19-

     The following  abbreviations,  when used in the  inscription on the face of
this  Debenture,  shall be  construed  as though  they were  written out in full
according to applicable laws or regulations:

TEN COM- as tenants in common            UNIF GIFT MIN ACT-.....Custodian......
TEN ENT- as tenants by the entireties                      (Cust)       (Minor)
JT TEN - as joint tenants with right of  under Uniform Gifts to Minors Act______
         survivorship and not as                                         (State)
         tenants in common

     Additional abbreviations may also be used though not in the above list.

                           ___________________________

     For Value Received,  ___________ hereby sell(s),  assign(s) and transfer(s)
unto

     PLEASE INSERT SOCIAL SECURITY OR OTHER
     IDENTIFYING NUMBER OF ASSIGNEE
     :                                     :
     :                                     :




     (PLEASE  PRINT OR  TYPEWRITE  NAME AND  ADDRESS,  INCLUDING  ZIP  CODE,  OF
ASSIGNEE)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

the within  Debenture and all rights  thereunder,  irrevocably  constituting and
appointing  _____________,  Attorney to transfer said  Debenture on the books of
the within named Company with full power of substitution in the premises.

Dated:

               NOTICE: THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH THE
                       NAME AS WRITTEN  UPON THE FACE OF THE  CERTIFICATE  IN
                       EVERY PARTICULAR,  WITHOUT ALTERATION OR ENLARGEMENT OR
                       ANY CHANGE WHATEVER.

               --------------------------------------
               Name: