TAX SHARING AGREEMENT

                                  BY AND AMONG

                                   AT&T CORP.,

                            LUCENT TECHNOLOGIES INC.

                                       AND

                                 NCR CORPORATION


                                   DATED AS OF
                                FEBRUARY 1, 1996
                 AND AMENDED AND RESTATED AS OF MARCH 29, 1996





                                TABLE OF CONTENTS

ARTICLE I  DEFINITIONS

   1.1
ADJUSTMENT...................................................  1
   1.2.
AGREEMENT....................................................  1
   1.3.  AT&T TAX
ADJUSTMENT..........................................  2
   1.4.  AT&T TAX
BENEFIT.............................................  2
   1.5.
CONSOLIDATION................................................  2
   1.6.  CONSOLIDATED
RETURN..........................................  2
   1.7.  CONTROLLING
PARTY............................................  2
   1.8.  CORRELATIVE
ADJUSTMENT.......................................  2
   1.9.  DISPUTED
ADJUSTMENT..........................................  3
   1.10. FINAL
DETERMINATION..........................................  3
   1.11. INDEPENDENT THIRD
PARTY......................................  3
   1.12. INDEMNIFIED
PARTY............................................  4
   1.13. INDEMNIFYING
PARTY...........................................  4
   1.14. INITIAL
DETERMINATION........................................  4
   1.15. INTERESTED
PARTY.............................................  4
   1.16. INTERESTED PARTY
NOTICE......................................  4
   1.17. NCR TAX
ADJUSTMENT...........................................  4
   1.18. NCR TAX
BENEFIT..............................................  4
   1.19. LUCENT TAX
ADJUSTMENT........................................  5
   1.20. LUCENT TAX
BENEFIT...........................................  5
   1.21. NON-LINE OF BUSINESS
ADJUSTMENT..............................  5
   1.22. RESTRUCTURING
ADJUSTMENT.....................................  5
   1.23.
RETURN.......................................................  5
   1.24. SEPARATE
RETURN..............................................  6
   1.25. SEPARATION
AGREEMENT.........................................  6
   1.26. SIGNIFICANT
OBLIGATION.......................................  6
   1.27.
TAX..........................................................  6
   1.28. TAX
ADJUSTMENTS..............................................  6
   1.29. TAX
BENEFITS.................................................  6
   1.30. TAX
CONTEST..................................................  6
   1.31. TAXING
AUTHORITY.............................................  7
   1.32. ULTIMATE
DETERMINATION.......................................  7






 ARTICLE II  TAX ADJUSTMENTS/BENEFITS


  2.1. IN
GENERAL....................................................  7
  2.2. TAX ADJUSTMENTS AND
BENEFITS..................................  8
  2.3. RESTRUCTURING
ADJUSTMENTS.....................................  9
  2.4. NON-LINE OF BUSINESS
ADJUSTMENTS.............................. 11

ARTICLE III TAX CONTESTS

  3.1. NOTIFICATION OF TAX
CONTESTS.................................. 14
  3.2. TAX CONTEST SETTLEMENT
RIGHTS................................. 14
  3.3. TAX CONTEST
PARTICIPATION..................................... 15
  3.4. TAX CONTEST
WAIVER............................................ 16
  3.5. TAX CONTEST DISPUTE
RESOLUTION................................ 17

ARTICLE IV  PROCEDURE AND PAYMENT

  4.1.
PROCEDURE..................................................... 20
  4.2.
PAYMENT....................................................... 21
  4.3.
INTEREST...................................................... 21

ARTICLE V  OTHER TAX MATTERS

  5.1. TAX POLICIES AND PROCEDURES DURING CONSOLIDATION
 ............. 22
  5.2.
COOPERATION................................................... 23
  5.3. FILING OF
RETURNS............................................. 23

ARTICLE VI  MISCELLANEOUS

  6.1. GOVERNING
LAW................................................. 24
  6.2.
AFFILIATES.................................................... 24
  6.3. INCORPORATION OF SEPARATION AGREEMENT PROVISIONS
 ............. 24
  6.4.
NOTICES....................................................... 24
  6.5. CONFLICTING OR INCONSISTENT
PROVISIONS........................ 25
  6.6.
DURATION...................................................... 25
  6.7.
AMENDMENT..................................................... 25
  6.8. TAX ALLOCATION
AGREEMENTS..................................... 26






                              TAX SHARING AGREEMENT

                  THIS TAX SHARING  AGREEMENT,  dated as of February 1, 1996, is
by and among AT&T, Lucent and NCR.  Capitalized terms used herein shall have the
respective  meanings  assigned  to  them  in  the  Separation  Agreement  unless
otherwise defined in Article I hereof.

                  WHEREAS,  AT&T,  Lucent and NCR have  executed the  Separation
Agreement  pursuant to which AT&T's  existing  businesses will be separated into
three independent businesses; and

                  WHEREAS,  it is  appropriate  and  desirable  to set forth the
principles  and  responsibilities  of the  parties to this  Agreement  regarding
future  Adjustments  with respect to Taxes,  Tax Contests and other  related Tax
matters.

                  NOW,  THEREFORE,  the parties,  intending to be
legally bound,
agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

                  For the purpose of this  Agreement the  following  terms shall
have the following meanings:

                  1.1.  ADJUSTMENT  means the deemed  increase  or
decrease in a
Tax,  determined on an  issue-by-issue or
transaction-by-transaction  basis, as
appropriate, and using the assumptions set forth in the next sentence, resulting
from an adjustment  made or proposed by a Taxing  Authority  with respect to any
amount reflected or required to be reflected on any Return relating to such Tax.
For  purposes  of  determining  such deemed  increase or decrease in a Tax,  the
following  assumptions  will be used:  (a) in the case of any  income  Tax,  the
highest  marginal  Tax  rate or,  in the  case of any  other  Tax,  the  highest
applicable  Tax rate,  in each case in effect  with  respect to that Tax for the
Taxable  period or any  portion of the  Taxable  period to which the  adjustment
relates;  and (b) such determination shall be made without regard to whether any
actual increase or decrease in such Tax will in fact be realized with respect to
the Return to which such adjustment relates.

                  1.2. AGREEMENT means this Tax Sharing Agreement,
including any
schedules, exhibits and appendices attached hereto.




                  1.3. AT&T TAX  ADJUSTMENT  means,  with respect to any Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  increase  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to  the  AT&T  Services  Business;  provided,  however,  that  any
Adjustment  comprising a  Restructuring  Adjustment  shall not be  considered in
determining the amount of any AT&T Tax Adjustment.

                  1.4.  AT&T TAX  BENEFIT  means,  with  respect to any  Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  decrease  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to  the  AT&T  Services  Business;  provided,  however,  that  any
Adjustment  comprising a  Restructuring  Adjustment  shall not be  considered in
determining the amount of any AT&T Tax Benefit.

                  1.5.  CONSOLIDATION means, as appropriate,  any Taxable period
or any portion of a Taxable  period  during which (a) one or more members of the
Lucent  Group are  members of an AT&T  Consolidated  Return;  or (b) one or more
members of the NCR Group are members of an AT&T Consolidated Return.

                  1.6.  CONSOLIDATED  RETURN means, as appropriate,  (a) for any
Taxable  period or any portion of a Taxable period ending or deemed to end on or
prior to the  Distribution  Date,  any  consolidated  or  combined  Return  that
includes one or more members of the AT&T Group and/or one or more members of the
Lucent  Group;  and (b) for any  Taxable  period,  or any  portion  of a Taxable
period,  beginning or deemed to begin after the Distribution  Date and ending or
deemed to end on or prior to the date of the NCR Distribution,  any consolidated
or combined  Return that includes one or more members of the AT&T Services Group
and/or one or more members of the NCR Group.

                  1.7.  CONTROLLING  PARTY means AT&T or any other member of the
AT&T  Services  Group,  Lucent or any other member of the Lucent Group or NCR or
any other member of the NCR Group, as the case may be, that filed or, if no such
Return has been filed, was required to file, a Return that is the subject of any
Tax Contest,  or any successor and/or assign of any of the foregoing;  provided,
however,  that in the case of any Consolidated  Return, the Person that actually
filed such  Consolidated  Return (or any successor and/or assign of such Person)
will be the Controlling Party.

                  1.8.   CORRELATIVE   ADJUSTMENT  means,  in  the  case  of  an
Adjustment comprising either a Restructuring  Adjustment or Non-Line of Business
Adjustment,  the net present value of any future increases or decreases in a Tax
that would be realized,





using the  assumptions  set forth in the next  sentence,  by either  AT&T or any
other  member of the AT&T  Services  Group,  Lucent  or any other  member of the
Lucent Group or NCR or any other member of the NCR Group, as the case may be, in
one or more  Taxable  periods (or any  portion of a Taxable  period) but only if
such  increases or decreases (a) will take effect or begin to take effect in the
Taxable period or portion of a Taxable period immediately  following the Taxable
period or portion of a Taxable period in which the  Restructuring  Adjustment or
Non-Line  of  Business  Adjustment  to such Tax was  made;  and (b) are a direct
result of such an Adjustment to that Tax in the  immediately  preceding  Taxable
period or portion of such Taxable  period.  For purposes of determining  the net
present value of any such future  increases or decreases in a Tax, the following
assumptions will be used: (i) a discount rate equal to the sum of the Prime Rate
as of the  date  of the  Final  Determination  relating  to  such  Restructuring
Adjustment or Non-Line of Business Adjustment plus 3.5%; (ii) in the case of any
income Tax, the highest  marginal Tax rate or, in the case of any other Tax, the
highest applicable Tax rate, in each case in effect with respect to that Tax for
the Taxable period, or portion of the Taxable period, in which the Restructuring
Adjustment or Non-Line of Business  Adjustment was made; (iii) the depreciation,
amortization or credit rate or lives,  if applicable,  in effect for the Taxable
period, or portion of the Taxable period, in which the Restructuring  Adjustment
or Non- Line of Business  Adjustment was made; and (iv) such determination shall
be made without regard to whether any actual  increases or decreases in such Tax
will in fact be  realized  with  respect  to the  future  Returns  to which such
Correlative Adjustment relates.

                  1.9. DISPUTED ADJUSTMENT has the meaning set
forth in Section
3.4(b) hereof.

                  1.10.  FINAL  DETERMINATION  means (a) a  decision,  judgment,
decree or other order by any court of competent  jurisdiction,  which has become
final and is either no longer subject to appeal or for which a determination not
to appeal has been made; (b) a closing  agreement made under Section 7121 of the
Code or any comparable foreign, state, local, municipal or other Taxing statute;
(c) a final  disposition by any Taxing  Authority of a claim for refund;  or (d)
any other  written  agreement  relating  to an  Adjustment  between  any  Taxing
Authority  and any  Controlling  Party  the  execution  of which  is  final  and
prohibits  such  Taxing  Authority  or the  Controlling  Party from  seeking any
further legal or administrative remedies with respect to such Adjustment.

                  1.11.  INDEPENDENT  THIRD PARTY means a
nationally  recognized
law firm or any of the following  accounting firms or their
successors:  Arthur
Andersen  & Co.;  Ernst & Young;  KPMG Peat  Marwick & Main;
Deloitte & Touche;
Coopers & Lybrand; and Price Waterhouse & Co.






                  1.12. INDEMNIFIED PARTY has the meaning set
forth in Section
4.1 hereof.

                  1.13. INDEMNIFYING PARTY has the meaning set
forth in Section
4.1 hereof.

                  1.14. INITIAL DETERMINATION has the meaning set
forth in
Section 3.5(b)(i) hereof.

                  1.15.  INTERESTED  PARTY means AT&T or any other member of the
AT&T  Services  Group,  Lucent or any other member of the Lucent Group or NCR or
any other member of the NCR Group  (including any successor and/or assign of any
of each of the foregoing),  as the case may be, to the extent (a) such Person is
not the Controlling Party with respect to a Tax Contest; and (b) such Person (i)
may be liable for, or required to make, any indemnity payment,  reimbursement or
other payment  pursuant to the provisions of this Agreement with respect to such
Tax  Contest;  or  (ii)  may be  entitled  to  receive  any  indemnity  payment,
reimbursement or other payment pursuant to the provisions of this Agreement with
respect to such Tax Contest; provided,  however, that in no event shall a member
of either the AT&T  Services  Group,  the Lucent Group or the NCR Group,  as the
case may be, be an Interested  Party in a Tax Contest in which another member of
its Group is the Controlling Party with respect to the Tax Contest.

                  1.16. INTERESTED PARTY NOTICE has the meaning
set forth in
Section 3.4(b) hereof.

                  1.17.  NCR TAX ADJUSTMENT  means,  with respect to any Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  increase  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to the  NCR  Business;  provided,  however,  that  any  Adjustment
comprising a Restructuring Adjustment shall not be considered in determining the
amount of any NCR Tax Adjustment.

                  1.18.  NCR TAX  BENEFIT  means,  with  respect to any  Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  decrease  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to the  NCR  Business;  provided,  however,  that  any  Adjustment
comprising a Restructuring Adjustment shall not be considered in determining the
amount of any NCR Tax Benefit.






                  1.19. LUCENT TAX ADJUSTMENT means, with respect to any Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  increase  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to either the  Lucent  Assets or the  Lucent  Business;  provided,
however, that any Adjustment comprising a Restructuring  Adjustment shall not be
considered in determining the amount of any Lucent Tax Adjustment.

                  1.20.  LUCENT TAX BENEFIT  means,  with respect to any Taxable
period or portion of a Taxable period,  and as computed  separately with respect
to each  Tax,  the  net  decrease  in  each  such  Tax  equal  to the sum of all
Adjustments made pursuant to a Final Determination with respect to each such Tax
for each such  Taxable  period or portion of a Taxable  period  that are clearly
attributable  to either the  Lucent  Assets or the  Lucent  Business;  provided,
however, that any Adjustment comprising a Restructuring  Adjustment shall not be
considered in determining the amount of any Lucent Tax Benefit.

                  1.21.  NON-LINE OF BUSINESS  ADJUSTMENT means, with respect to
any Taxable period or portion of a Taxable  period,  and as computed  separately
with  respect to each Tax, the net increase or decrease in each such Tax, as the
case  may be,  equal  to the sum of all  Adjustments  made  pursuant  to a Final
Determination  with  respect  to each such Tax for each such  Taxable  period or
portion of a Taxable period other than (a) any Restructuring Adjustments and any
Correlative Adjustment attributable to such Restructuring  Adjustments;  (b) any
Tax Adjustments; and (c) any Tax Benefits.

                  1.22.  RESTRUCTURING  ADJUSTMENT  means,  with  respect to any
Taxable period or portion of a Taxable period,  and as computed  separately with
respect to each Tax,  the net increase or decrease in each such Tax, as the case
may  be,  equal  to  the  sum  of  all  Adjustments  made  pursuant  to a  Final
Determination  with respect to each such Tax for each Taxable  period or portion
of a  Taxable  period  that  are  attributable  to,  or  as  a  result  of,  any
transactions   undertaken  to  effectuate  the  separation  of  AT&T's  existing
businesses  into  three  independent   businesses  as  contemplated   under  the
Separation Agreement including,  but not limited to, any transactions undertaken
pursuant  to or relating  to the  Separation,  the IPO,  the  Distribution,  the
Non-U.S. Plan, the merger of RMC with and into AT&T and the NCR Distribution.

                  1.23.  RETURN  means  any  return,  report,  form  or  similar
statement or document (including,  without limitation, any related or supporting
information or schedule attached thereto and any information  return,  claim for
refund,  amended  return and  declaration  of estimated tax) that has been or is
required to be filed with any Taxing  Authority  or that has been or is required
to be furnished to any Taxing





Authority in connection with the determination,  assessment or
collection of any
Taxes  or  the  administration  of  any  laws,   regulations  or
administrative
requirements relating to any Taxes.

                  1.24. SEPARATE RETURN means any Return other
than a
Consolidated Return.

                  1.25. SEPARATION AGREEMENT means the Separation
and
Distribution Agreement, dated the date hereof, by and among AT&T
Corp., Lucent
Technologies Inc. and NCR Corporation.

                  1.26.   SIGNIFICANT  OBLIGATION  means,  in  the  case  of  an
Interested  Party,  and  with  respect  to any  Adjustment  comprising  either a
Restructuring  Adjustment  or Non- Line of  Business  Adjustment,  either  (a) a
Shared  Percentage that is greater than or equal to 30%; or (b) an obligation to
make or right to receive any indemnity  payment,  reimbursement or other payment
with  respect to any such  Adjustment  (including  the  effect of a  Correlative
Adjustment relating thereto) pursuant to the terms of this Agreement that (i) in
the case of any federal  income Tax is greater than $5 million,  and (ii) in the
case of any other Tax is greater than $1 million.

                  1.27.  TAX  (and,  with  correlative  meanings,   "Taxes"  and
"Taxable")    means,    without    limitation,    and   as   determined   on   a
jurisdiction-by-jurisdiction  basis, each foreign or U.S. federal,  state, local
or municipal income,  alternative or add-on minimum, gross receipts, sales, use,
ad  valorem,  transfer,  franchise,  profits,  license,  withholding,   payroll,
employment, excise, severance, stamp, occupation, premium, property or any other
tax,  custom,  tariff,  impost,  levy,  duty,  governmental  fee or  other  like
assessment  or charge of any kind  whatsoever,  together  with any  interest  or
penalty,  addition to tax or additional  amount related thereto,  imposed by any
Taxing Authority.

                  1.28. TAX ADJUSTMENTS  means any AT&T Tax Adjustment,  any NCR
Tax Adjustment or any Lucent Tax Adjustment, as the case may be.

                  1.29.  TAX BENEFITS  means any AT&T Tax  Benefit,  any NCR Tax
Benefit or any Lucent Tax Benefit, as the case may be.

                  1.30.  TAX  CONTEST  means,  without  limitation,  any  audit,
examination,  claim, suit, action or other proceeding relating to Taxes in which
an Adjustment to Taxes may be proposed,  collected or assessed and in respect of
which an indemnity  payment,  reimbursement or other payment may be sought under
this Agreement.





                  1.31. TAXING AUTHORITY means any Governmental Authority or any
subdivision,  agency, commission or authority thereof, or any quasi-governmental
or  private  body  having  jurisdiction  over  the  assessment,   determination,
collection or other imposition of Taxes.

                  1.32. ULTIMATE DETERMINATION has the meaning set
forth in
Section 3.5(b)(iii) hereof.

                                   ARTICLE II
                            TAX ADJUSTMENTS/BENEFITS

                  2.1 IN GENERAL.  (a) In determining  Lucent's liability and/or
obligation  to make,  or  Lucent's  right to  receive,  any  indemnity  payment,
reimbursement  or other payment in respect of any Tax under this Agreement,  any
Taxable  period or portion of a Taxable  period that  includes the  Distribution
Date shall be deemed to  include  and end on such  Distribution  Date and Lucent
shall have no liability  and/or  obligation  to make,  or right to receive,  any
indemnity  payment,  reimbursement  or other payment in respect of any Tax under
this Agreement with respect to any Taxable period or portion of a Taxable period
that begins or is deemed to begin after the Distribution Date.

                  (b) In determining  NCR's liability and/or obligation to make,
or NCR's right to receive, any indemnity payment, reimbursement or other payment
in respect of any Tax under this  Agreement,  any Taxable period or portion of a
Taxable period that includes the date of the NCR Distribution shall be deemed to
include and end on such date and NCR shall have no liability  and/or  obligation
to make, or right to receive,  any  indemnity  payment,  reimbursement  or other
payment  under this  Agreement in respect of any Tax with respect to any Taxable
period or portion of a Taxable  period  that  begins or is deemed to begin after
the date of the NCR Distribution.

                  (c)  Any  Adjustment   relating  to  or  arising  out  of  the
employment  of employees or former  employees  the  Liabilities  with respect to
which are assumed by Lucent pursuant to Section 2.1(a) of the Employee  Benefits
Agreement shall be deemed to be Adjustments that are clearly attributable to the
Lucent  Business  and shall be deemed to  comprise  a Lucent Tax  Adjustment  or
Lucent Tax  Benefit,  as the case may be. All other  Adjustments  relating to or
arising out of the employment of employees or former  employees  shall be deemed
to be Adjustments  that are clearly  attributable to the AT&T Services  Business
and shall be deemed to comprise an AT&T Tax  Adjustment or AT&T Tax Benefit,  as
the case may be,  except to the  extent  that such  Adjustments  arise out of or
relate to the employment of such individuals by NCR, in which case they shall





be deemed to be Adjustments  that are clearly  attributable  to the NCR Business
and shall be deemed to comprise a NCR Tax Adjustment or NCR Tax Benefit, as the
case may be.

                  2.2. TAX ADJUSTMENTS AND BENEFITS.  (a) Lucent shall be liable
for, and shall  indemnify and hold harmless,  subject to Section 3.4 and Section
3.5  hereof,  any member of the AT&T  Services  Group  and/or the NCR Group,  as
appropriate,  against any and all Lucent Tax  Adjustments for any Taxable period
or  portion  of a Taxable  period  ending  or  deemed  to end on or  before  the
Distribution  Date, in each case with respect to any Return of any member of the
Lucent Group, the AT&T Services Group or the NCR Group. Lucent shall be entitled
to  receive,  and shall be paid,  subject to Section 3.4 and Section 3.5 hereof,
(i) by AT&T,  the amount of any Lucent Tax  Benefits  for any Taxable  period or
portion  of a  Taxable  period  ending  or  deemed  to  end  on  or  before  the
Distribution  Date with respect to any Return of any member of the AT&T Services
Group; and/or (ii) by NCR, the amount of any Lucent Tax Benefits for any Taxable
period or portion of a Taxable  period  ending or deemed to end on or before the
Distribution Date with respect to any Return of any member of the NCR Group.

                  (b) AT&T shall be liable  for,  and shall  indemnify  and hold
harmless, as appropriate, and subject to Section 3.4 and Section 3.5 hereof, (i)
any member of the Lucent Group against any and all AT&T Tax  Adjustments for any
Taxable  period or  portion  of a Taxable  period  ending or deemed to end on or
before the  Distribution  Date;  and/or (ii) any member of the NCR Group against
any and all AT&T Tax  Adjustments for any Taxable period or portion of a Taxable
period ending or deemed to end on or before the date of the NCR Distribution, in
each case with respect to any Return of any member of the Lucent Group, the AT&T
Services Group or the NCR Group. AT&T shall be entitled to receive, and shall be
paid,  subject to Section 3.4 and Section 3.5 hereof,  (i) by Lucent, the amount
of any AT&T Tax Benefits for any Taxable  period or portion of a Taxable  period
ending or deemed to end on or before the  Distribution  Date with respect to any
Return of any member of the Lucent Group;  and/or (ii) by NCR, the amount of any
AT&T Tax  Benefits  for any Taxable  period or any  portion of a Taxable  period
ending  or  deemed to end on or  before  the date of the NCR  Distribution  with
respect to any Return of any member of the NCR Group.

                  (c) NCR shall be liable for, and shall indemnify
and hold
harmless, as appropriate, and subject to Section 3.4 and Section
3.5 hereof, (i)
any member of the AT&T Services Group against any and all NCR Tax
Adjustments
for any Taxable period or portion of a Taxable period ending or
deemed to end on
or before the date of the NCR Distribution; and (ii) any member of
the Lucent
Group against any and all NCR Tax Adjustments for any Taxable
period or portion
of a Taxable period ending or deemed to end on or before the
Distribution Date,
in each case with respect to any Return of any member of the
Lucent Group, the
AT&T Services Group or the NCR Group. NCR





shall be  entitled  to  receive,  and shall be paid,  subject to Section 3.4 and
Section  3.5 hereof,  (i) by AT&T,  the amount of any NCR Tax  Benefits  for any
Taxable  period or  portion of a Taxable  period  ending or deemed to end on the
date of the NCR  Distribution  with  respect  to any Return of any member of the
AT&T Services Group;  and/or (ii) by Lucent,  the amount of any NCR Tax Benefits
for any Taxable period or portion of a Taxable period ending or deemed to end on
the  Distribution  Date with  respect  to any Return of any member of the Lucent
Group.

                  2.3.  RESTRUCTURING  ADJUSTMENTS.  (a) Lucent  shall be liable
for, and shall indemnify and hold harmless,  as  appropriate,  any member of the
AT&T Services Group and/or the NCR Group against  Lucent's  share, as determined
in Section  2.3(d) below,  of any  Restructuring  Adjustment the amount of which
increases a Tax for any Taxable  period or portion of a Taxable period ending or
deemed to end on or before the  Distribution  Date, in each case with respect to
any Return of any member of the Lucent Group, the AT&T Services Group or the NCR
Group.  Lucent  shall be  entitled  to  receive,  and shall be paid (i) by AT&T,
Lucent's  share,  as determined in Section  2.3(d) below,  of any  Restructuring
Adjustment the amount of which decreases a Tax for any Taxable period or portion
of a Taxable period ending or deemed to end on or before the  Distribution  Date
with respect to any Return of any member of the AT&T Services Group; and/or (ii)
by  NCR,  Lucent's  share,  as  determined  in  Section  2.3(d)  below,  of  any
Restructuring  Adjustment  the amount of which  decreases  a Tax for any Taxable
period or portion of a Taxable  period  ending or deemed to end on or before the
Distribution Date with respect to any Return of any member of the NCR Group.

                  (b) AT&T shall be liable  for,  and shall  indemnify  and hold
harmless,  as  appropriate,  (i) any member of the Lucent Group  against  AT&T's
share,  as determined in Section 2.3(d) below, of any  Restructuring  Adjustment
the  amount of which  increases  a Tax for any  Taxable  period or  portion of a
Taxable period ending or deemed to end on or before the  Distribution  Date; and
(ii) any member of the NCR Group against AT&T's share,  as determined in Section
2.3(d) below,  of any  Restructuring  Adjustment the amount of which increases a
Tax for any Taxable  period or portion of a Taxable  period  ending or deemed to
end on or before the date of the NCR Distribution,  in each case with respect to
any Return of any member of the Lucent Group, the AT&T Services Group or the NCR
Group.  AT&T  shall be  entitled  to  receive,  and shall be paid (i) by Lucent,
AT&T's  share,  as  determined in Section  2.3(d)  below,  of any  Restructuring
Adjustment the amount of which decreases a Tax for any Taxable period or portion
of a Taxable period ending or deemed to end on or before the  Distribution  Date
with  respect to any Return of any member of the Lucent  Group;  and/or  (ii) by
NCR, AT&T's share,  as determined in Section 2.3(d) below, of any  Restructuring
Adjustment the amount of which decreases a Tax for any Taxable period or portion
of a Taxable period ending or





deemed to end on or before the date of the NCR Distribution  with
respect to any
Return of any member of the NCR Group.

                  (c) NCR shall be liable  for,  and  shall  indemnify  and hold
harmless,  as  appropriate,  (i) any member of the Lucent  Group  against  NCR's
share,  as determined in Section 2.3(d) below, of any  Restructuring  Adjustment
the  amount of which  increases  a Tax for any  Taxable  period or  portion of a
Taxable period ending or deemed to end on or before the  Distribution  Date; and
(ii) any member of the AT&T Services Group against NCR's share, as determined in
Section  2.3(d)  below,  of any  Restructuring  Adjustment  the  amount of which
increases a Tax for any Taxable  period or portion of a Taxable period ending or
deemed to end on or before the date of the NCR  Distribution,  in each case with
respect to any Return of any member of the Lucent Group, the AT&T Services Group
or the NCR Group.  NCR shall be entitled  to  receive,  and shall be paid (i) by
Lucent, NCR's share, as determined in Section 2.3(d) below, of any Restructuring
Adjustment the amount of which decreases a Tax for any Taxable period or portion
of a Taxable period ending or deemed to end on or before the  Distribution  Date
with  respect to any Return of any member of the Lucent  Group;  and/or  (ii) by
AT&T,  NCR's share, as determined in Section 2.3(d) below, of any  Restructuring
Adjustment the amount of which decreases a Tax for any Taxable period or portion
of a Taxable  period  ending  or deemed to end on or before  the date of the NCR
Distribution  with  respect  to any  Return of any  member of the AT&T  Services
Group.

                  (d)  AT&T,  Lucent  and NCR  shall  share  the  amount  of any
Restructuring  Adjustment  if, and to the extent,  each such party is liable for
and/or has an obligation  to make, or has the right to receive,  as the case may
be, any indemnity  payment,  reimbursement or other payment with respect to such
Restructuring  Adjustment under this Agreement, in proportion to the Shared AT&T
Percentage,  the  Shared  Lucent  Percentage  and  the  Shared  NCR  Percentage,
respectively; provided, however, that in the event that there is any Correlative
Adjustment with respect to any such Restructuring Adjustment,  then AT&T, Lucent
and NCR shall share such  Restructuring  Adjustment in the  following  manner in
order to ensure that the party or parties  that will bear the burden or inure to
the  benefit  of  the  Correlative  Adjustment  in the  future  will  share  the
Restructuring  Adjustment  in  proportion  to each of  their  respective  Shared
Percentages after giving effect to such Correlative Adjustment:

                  (i)  first,  the amount of any such  Restructuring  Adjustment
shall  be  increased  or  decreased,  as  appropriate,  by  the  amount  of  the
Correlative Adjustment,  the net amount resulting from such increase or decrease
being hereinafter referred to as the "Net Restructuring Adjustment" for purposes
of this Section 2.3(d);





                  (ii)  second,  the  Net  Restructuring   Adjustment  shall  be
allocated  among  AT&T,  Lucent  and  NCR  in  proportion  to  the  Shared  AT&T
Percentage, the Shared Lucent Percentage and the Shared
NCR  Percentage,
respectively,  to the  extent  each  such  party is  liable  for  and/or  has an
obligation  to make,  or has the  right  to  receive,  as the  case may be,  any
indemnity  payment,   reimbursement  or  other  payment  with  respect  to  such
Restructuring Adjustment under this Agreement; and

                  (iii) finally,  with respect to a party to which a Correlative
Adjustment  is  attributable,  that  party's  share  of  the  Net  Restructuring
Adjustment as allocated  pursuant to paragraph  (ii) of this Section 2.3(d) will
be  increased  or  decreased,  as  appropriate,  by the  amount,  if any, of the
Correlative  Adjustment that is attributable to such party in order to arrive at
such party's share of the Restructuring Adjustment.

Notwithstanding  any  other  provision  of  this  Agreement  or  the  Separation
Agreement  to  the  contrary,  in  the  case  of  any  Adjustment  comprising  a
Restructuring Adjustment that relates to the Distribution and arises as a result
of the  acquisition of all or a portion of the Lucent stock and/or its assets by
any means  whatsoever by any Person other than an Affiliate of Lucent  following
such  Distribution,  then the  Shared  Lucent  Percentage  with  respect to such
Adjustment  shall be 100% and each of the Shared AT&T  Percentage and the Shared
NCR Percentage shall be 0%.

                  (e)  Following  the  determination  of a  party's  share  of a
Restructuring  Adjustment  pursuant  to Section  2.3(d)  above,  and  subject to
Section 3.4 and 3.5 hereof,  the Controlling Party that controls the Tax Contest
to  which  such  Restructuring  Adjustment  relates  shall  (i) be  entitled  to
reimbursement  from AT&T,  Lucent  and/or  NCR,  as the case may be, for each of
their respective  shares, if any, of any Restructuring  Adjustment the amount of
which increases a Tax; and (ii) reimburse  AT&T,  Lucent or NCR, as the case may
be, for each of their respective shares, if any, of any Restructuring Adjustment
the amount of which decreases a Tax.

                  2.4.  NON-LINE OF BUSINESS  ADJUSTMENTS.  (a) Lucent  shall be
liable for, and shall indemnify and hold harmless, as appropriate, any member of
the AT&T  Services  Group  and/or  the NCR  Group  against  Lucent's  share,  as
determined in Section 2.4(d) below,  of any Non-Line of Business  Adjustment the
amount of which  increases a Tax for any Taxable  period or portion of a Taxable
period ending or deemed to end on or before the Distribution  Date, in each case
with respect to any Return of any member of the Lucent Group,  the AT&T Services
Group or the NCR Group.  Lucent shall be entitled to receive,  and shall be paid
(i) by AT&T,  Lucent's  share,  as  determined in Section  2.4(d) below,  of any
Non-Line  of  Business  Adjustment  the amount of which  decreases a Tax for any
Taxable  period or  portion  of a Taxable  period  ending or deemed to end on or
before the Distribution Date with respect to any Return of any member of the





AT&T  Services  Group;  and/or (ii) by NCR,  Lucent's  share,  as  determined in
Section 2.4(d) below, of any Non-Line of Business Adjustment the amount of which
decreases a Tax for any Taxable  period or portion of a Taxable period ending or
deemed to end on or before the  Distribution  Date with respect to any Return of
any member of the NCR Group.

                  (b) AT&T shall be liable  for,  and shall  indemnify  and hold
harmless,  as  appropriate,  (i) any member of the Lucent Group  against  AT&T's
share,  as  determined  in Section  2.4(d)  below,  of any  Non-Line of Business
Adjustment the amount of which increases a Tax for any Taxable period or portion
of a Taxable period ending or deemed to end on or before the Distribution  Date;
and (ii) any member of the NCR Group  against  AT&T's  share,  as  determined in
Section 2.4(d) below, of any Non-Line of Business Adjustment the amount of which
increases a Tax for any Taxable  period or portion of a Taxable period ending or
deemed to end on or before the date of the NCR  Distribution,  in each case with
respect to any Return of any member of the Lucent Group, the AT&T Services Group
or the NCR Group.  AT&T shall be entitled  to receive,  and shall be paid (i) by
Lucent,  AT&T's share, as determined in Section 2.4(d) below, of any Non-Line of
Business  Adjustment the amount of which  decreases a Tax for any Taxable period
or  portion  of a Taxable  period  ending  or  deemed  to end on or  before  the
Distribution  Date with respect to any Return of any member of the Lucent Group;
and/or (ii) by NCR,  AT&T's share, as determined in Section 2.4(d) below, of any
Non-Line  of  Business  Adjustment  the amount of which  decreases a Tax for any
Taxable  period or  portion  of a Taxable  period  ending or deemed to end on or
before the date of the NCR Distribution with respect to any Return of any member
of the NCR Group.

                  (c) NCR shall be liable  for,  and  shall  indemnify  and hold
harmless,  as  appropriate,  (i) any member of the Lucent  Group  against  NCR's
share,  as  determined  in Section  2.4(d)  below,  of any  Non-Line of Business
Adjustment the amount of which increases a Tax for any Taxable period or portion
of a Taxable period ending or deemed to end on or before the Distribution  Date;
and  (ii)  any  member  of the AT&T  Services  Group  against  NCR's  share,  as
determined in Section 2.4(d) below,  of any Non-Line of Business  Adjustment the
amount of which  increases a Tax for any Taxable  period or portion of a Taxable
period ending or deemed to end on or before the date of the NCR Distribution, in
each case with respect to any Return of any member of the Lucent Group, the AT&T
Services Group or the NCR Group. NCR shall be entitled to receive,  and shall be
paid (i) by Lucent,  NCR's share,  as determined in Section 2.4(d) below, of any
Non-Line  of  Business  Adjustment  the amount of which  decreases a Tax for any
Taxable  period or  portion  of a Taxable  period  ending or deemed to end on or
before  the  Distribution  Date with  respect to any Return of any member of the
Lucent Group;  and/or (ii) by AT&T, NCR's share, as determined in Section 2.4(d)
below,  of any Non-Line of Business  Adjustment the amount of which  decreases a
Tax for any Taxable





period or portion of a Taxable  period  ending or deemed to end on or before the
date of the NCR  Distribution  with  respect  to any Return of any member of the
AT&T Services Group.

                  (d)  AT&T,  Lucent  and NCR  shall  share  the  amount  of any
Non-Line of Business Adjustment if, and to the extent, each such party is liable
for and/or has an obligation  to make, or has the right to receive,  as the case
may be, any indemnity  payment,  reimbursement  or other payment with respect to
such Non-Line of Business Adjustment under this Agreement,  in proportion to the
Shared  AT&T  Percentage,  the  Shared  Lucent  Percentage  and the  Shared  NCR
Percentage, respectively; provided, however, that in the event that there is any
Correlative Adjustment with respect to any such Non-Line of Business Adjustment,
then AT&T,  Lucent and NCR shall share such  Non-Line of Business  Adjustment in
the following manner in order to ensure that the party or parties that will bear
the burden or inure to the benefit of the  Correlative  Adjustment in the future
will share the Non-Line of Business  Adjustment  in  proportion to each of their
respective   Shared   Percentages   after  giving  effect  to  such  Correlative
Adjustment:

                  (i)  first,  the  amount  of any  such  Non-Line  of  Business
Adjustment shall be increased or decreased, as appropriate, by the amount of the
Correlative Adjustment,  the net amount resulting from such increase or decrease
being hereinafter  referred to as the "Net Non-Line of Business  Adjustment" for
purposes of this Section 2.4(d);

                  (ii) second, the Net Non-Line of Business  Adjustment shall be
allocated  among  AT&T,  Lucent  and  NCR  in  proportion  to  the  Shared  AT&T
Percentage, the Shared Lucent Percentage and the Shared
NCR  Percentage,
respectively,  to the  extent  each  such  party is  liable  for  and/or  has an
obligation  to make,  or has the  right  to  receive,  as the  case may be,  any
indemnity payment,  reimbursement or other payment with respect to such Non-Line
of Business Adjustment under this Agreement; and

                  (iii) finally,  with respect to a party to which a Correlative
Adjustment is  attributable,  that party's share of the Net Non-Line of Business
Adjustment as allocated  pursuant to paragraph  (ii) of this Section 2.4(d) will
be  increased  or  decreased,  as  appropriate,  by the  amount,  if any, of the
Correlative  Adjustment that is attributable to such party in order to arrive at
such party's share of the Non-Line of Business Adjustment.

                  (e)  Following  the  determination  of a  party's  share  of a
Non-Line of Business Adjustment pursuant to Section 2.4(d) above, and subject to
Section 3.4 and 3.5 hereof,  the Controlling Party that controls the Tax Contest
to which such Non-Line of Business  Adjustment  relates shall (i) be entitled to
reimbursement from AT&T, Lucent





and/or NCR, as the case may be, for each of their respective  shares, if any, of
any  Non-Line of Business  Adjustment  the amount of which  increases a Tax; and
(ii)  reimburse  AT&T,  Lucent  or NCR,  as the case  may be,  for each of their
respective shares, if any, of any Non-Line of Business  Adjustment the amount of
which decreases a Tax.

                                   ARTICLE III
                                  TAX CONTESTS

                  3.1. NOTIFICATION OF TAX CONTESTS. The Controlling Party shall
promptly  notify  all  Interested  Parties  of (a) the  commencement  of any Tax
Contest  pursuant  to which such  Interested  Parties may be required to make or
entitled to receive an indemnity  payment,  reimbursement or other payment under
this  Agreement;  and (b) as required and  specified in Section 3.4 hereof,  any
Final  Determination made with respect to any Tax Contest pursuant to which such
Interested  Parties may be required to make or entitled to receive any indemnity
payment,  reimbursement or other payment under this Agreement.  The failure of a
Controlling  Party to promptly  notify any Interested  Party as specified in the
preceding  sentence shall not relieve any such Interested Party of any liability
and/or  obligation  which  it may  have  to the  Controlling  Party  under  this
Agreement  except to the extent that the Interested Party was prejudiced by such
failure,  and in no event shall such failure  relieve the Interested  Party from
any other liability or obligation which it may have to such Controlling Party.

                  3.2. TAX CONTEST  SETTLEMENT  RIGHTS.  The  Controlling  Party
shall  have the sole  right to  contest,  litigate,  compromise  and  settle any
Adjustment that is made or proposed in a Tax Contest without obtaining the prior
consent of any Interested Party;  provided,  however, that, unless waived by the
parties in writing, the Controlling Party shall, in connection with any proposed
or assessed  Adjustment  in a Tax Contest for which an  Interested  Party may be
required to make or entitled to receive an indemnity  payment,  reimbursement or
other payment under this Agreement (a) keep all such Interested Parties informed
in a  timely  manner  of all  actions  taken  or  proposed  to be  taken  by the
Controlling  Party;  and (b) provide all such Interested  Parties with copies of
any  correspondence  or filings  submitted  to any Taxing  Authority or judicial
authority, in each case in connection with any contest,  litigation,  compromise
or settlement relating to any such Adjustment in a Tax Contest. The failure of a
Controlling Party to take any action as specified in the preceding sentence with
respect to an Interested  Party shall not relieve any such  Interested  Party of
any liability and/or obligation which it may have to the Controlling Party under
this Agreement  except to the extent that the Interested Party was prejudiced by
such failure,  and in no event shall such failure  relieve the Interested  Party
from any other  liability or  obligation  which it may have to such  Controlling
Party. The Controlling Party may, in its sole discretion,  take into account any
suggestions made by





an Interested Party with respect to any such contest, litigation,  compromise or
settlement of any Adjustment in a Tax Contest.  All costs of any Tax Contest are
to be borne by the  Controlling  Party;  provided,  however,  that (x) any costs
related  to an  Interested  Party's  attendance  at any  meeting  with a  Taxing
Authority or hearing or  proceeding  before any judicial  authority  pursuant to
Section  3.3  hereof,  and (y) the costs of any  legal or other  representatives
retained by an  Interested  Party in  connection  with any Tax  Contest  that is
subject to the provisions of this  Agreement,  shall be borne by such Interested
Party.

                  3.3.  TAX  CONTEST  PARTICIPATION.  (a)  Unless  waived by the
parties in writing, the Controlling Party shall provide an Interested Party with
written notice  reasonably in advance of, and such  Interested  Party shall have
the right to attend,  any formally scheduled meetings with Taxing Authorities or
hearings or proceedings  before any judicial  authorities in connection with any
contest,  litigation,  compromise  or  settlement  of any  proposed  or assessed
Adjustment  comprising  any Tax Adjustment or Tax Benefit that is the subject of
any Tax Contest  pursuant to which such Interested Party may be required to make
or entitled to receive an  indemnity  payment,  reimbursement  or other  payment
under this Agreement. In addition,  unless waived by the parties in writing, the
Controlling  Party shall provide each such Interested Party with draft copies of
any  correspondence  or  filings to be  submitted  to any  Taxing  Authority  or
judicial  authority with respect to such Adjustments for such Interested Party's
review and  comment.  The  Controlling  Party shall  provide  such draft  copies
reasonably  in advance of the date that they are to be  submitted  to the Taxing
Authority  or judicial  authority  and the  Interested  Party shall  provide its
comments,  if any, with respect  thereto within in a reasonable time before such
submission.   The  failure  of  a  Controlling  Party  to  provide  any  notice,
correspondence  or filing as specified in this Section  3.3(a) to an  Interested
Party  shall not  relieve  any such  Interested  Party of any  liability  and/or
obligation  which it may have to the  Controlling  Party  under  this  Agreement
except to the extent that the  Interested  Party was prejudiced by such failure,
and in no event shall such failure  relieve the Interested  Party from any other
liability or obligation which it may have to such Controlling Party.

                  (b) Unless waived by the parties in writing,  the  Controlling
Party shall  provide an  Interested  Party with  written  notice  reasonably  in
advance  of, and such  Interested  Party  shall  have the right to  attend,  any
formally  scheduled  meetings with Taxing Authorities or hearings or proceedings
before any judicial  authorities  in  connection  with any contest,  litigation,
compromise or settlement of any proposed or assessed  Adjustment  comprising any
Restructuring  Adjustment or Non-Line of Business Adjustment that is the subject
of any Tax Contest  pursuant to which such  Interested  Party may be required to
make or entitled to receive an indemnity payment, reimbursement or other payment
under this  Agreement,  but only if the Interested  Party bears,  or in the good
faith judgment of the Controlling Party, may bear, a Significant Obligation with
respect to such Adjustment;  provided,  however, that the Controlling Party may,
in its sole





discretion,  permit an Interested Party that does not bear, or potentially bear,
such a Significant  Obligation  with respect to such an Adjustment  comprising a
Restructuring  Adjustment or Non-Line of Business  Adjustment to attend any such
meetings,  hearings or proceedings that relate to such Adjustment.  In addition,
unless  waived by the parties in writing,  the  Controlling  Party shall provide
each such Interested Party with draft copies of any correspondence or filings to
be submitted to any Taxing Authority or judicial  authority with respect to such
Adjustments  for such  Interested  Party's review and comment.  The  Controlling
Party shall  provide  such draft copies  reasonably  in advance of the date that
they are to be submitted to the Taxing  Authority or judicial  authority and the
Interested Party shall provide its comments, if any, with respect thereto within
in a reasonable time before such submission.  The failure of a Controlling Party
to provide any notice,  correspondence  or filing as  specified  in this Section
3.3(b) to an Interested Party shall not relieve any such Interested Party of any
liability  and/or  obligation  which it may have to the Controlling  Party under
this Agreement  except to the extent that the Interested Party was prejudiced by
such failure,  and in no event shall such failure  relieve the Interested  Party
from any other  liability or  obligation  which it may have to such  Controlling
Party.

                  3.4.  TAX  CONTEST  WAIVER.  (a) The
Controlling  Party shall
promptly  provide  written  notice,  sent postage prepaid by United States mail,
certified mail,  return receipt  requested,  to all Interested  Parties in a Tax
Contest (i) that a Final  Determination  has been made with  respect to such Tax
Contest; and (ii) enumerating the amount of the Interested Party's share of each
Adjustment  reflected in such Final  Determination  of the Tax Contest for which
such  Interested  Party  may be  required  to make or  entitled  to  receive  an
indemnity payment, reimbursement or other payment under this Agreement.

                  (b) Within ninety (90) days after an Interested Party receives
the notice described in Section 3.4(a) hereof from the Controlling  Party,  such
Interested  Party  shall  execute  a  written  statement  giving  notice  to the
Controlling Party (i) that the Interested Party agrees with each Adjustment (and
its share thereof)  enumerated in the notice  described in Section 3.4(a) hereof
except with respect to those  Adjustments  (and/or its shares  thereof) that, in
the good faith  judgment of the  Interested  Party,  it  disagrees  with and has
specifically  enumerated  its  disagreement  with,  including the amount of such
disagreement,  in the statement  (each such disagreed  Adjustment  (and/or share
thereof) hereinafter referred to as a "Disputed Adjustment");  and (ii) that the
Interested  Party thereby waives it right to a  determination  by an Independent
Third Party pursuant to the provisions of Section 3.5 hereof with respect to all
Adjustments  to which it  agrees  with its  share  (this  statement  hereinafter
referred to as the  "Interested  Party  Notice").  The failure of an  Interested
Party to provide the Interested Party Notice to the Controlling Party within the
ninety (90) day period  specified in the preceding  sentence  shall be deemed to
indicate that such Interested Party agrees with its share of all Adjustments





enumerated  in the  notice  described  in  Section  3.4(a)  hereof and that such
Interested  Party waives it right to a  determination  by an  Independent  Third
Party with respect to all such Adjustments (and its shares thereof)  pursuant to
Section 3.5 hereof.

                  (c) During the ninety  (90) day period  immediately  following
the  Controlling  Party's  receipt of the Interested  Party Notice  described in
Section 3.4(b) above,  the Controlling  Party and the Interested  Party shall in
good faith confer with each other to resolve any disagreement over each Disputed
Adjustment that was specifically  enumerated in such Interested Party Notice. At
the end of the  ninety  (90) day period  specified  in the  preceding  sentence,
unless otherwise  extended in writing by the mutual consent of the parties,  the
Interested  Party shall be deemed to agree with all  Disputed  Adjustments  that
were specifically  enumerated in the Interested Party Notice and waive its right
to a determination by an Independent  Third Party pursuant to Section 3.5 hereof
with respect to all such Disputed Adjustments unless, and to the extent, that at
any  time  during  such  ninety  (90)  day  (or  extended)  period,  either  the
Controlling  Party or the  Interested  Party has given the other  party  written
notice that it is seeking a determination by an Independent Third Party pursuant
to Section 3.5 hereof regarding the propriety of any such Disputed Adjustment.

                  (d)   Notwithstanding   anything  in  this  Agreement  to  the
contrary,  an Interested Party that does not have a Significant  Obligation with
respect  to an  Adjustment  comprising  either  a  Restructuring  Adjustment  or
Non-Line  of  Business  Adjustment  has  no  right  to  a  determination  by  an
Independent  Third  Party  under  section  3.5 hereof  with  respect to any such
Adjustment  comprising  a  Restructuring  Adjustment  or  Non-Line  of  Business
Adjustment.

                  3.5.  TAX CONTEST  DISPUTE  RESOLUTION.  (a) In the event that
either a  Controlling  Party or an  Interested  Party has given the other  party
written  notice as  required  in  Section  3.4(c)  hereof  that it is  seeking a
determination  by an  Independent  Third Party pursuant to this Section 3.5 with
respect to any Disputed  Adjustment  that was enumerated in an Interested  Party
Notice,  then the parties shall, within ten (10) days after a party has received
such  notice,   jointly  select  an   Independent   Third  Party  to  make  such
determination.  In the  event  that  the  parties  cannot  jointly  agree  on an
Independent  Third  Party to make such  determination  within  such ten (10) day
period,  then  the  Controlling  Party  and  the  Interested  Party  shall  each
immediately  select an Independent Third Party and the Independent Third Parties
so selected by the parties shall jointly  select,  within ten (10) days of their
selection, another Independent Third Party to make such determination.

                  (b) In making its  determination  as to the  propriety  of any
Disputed  Adjustment,  the Independent  Third Party selected pursuant to Section
3.5(a) above shall assume that the Interested  Party is not required or entitled
under applicable law to be a





member of any  Consolidated  Return.  In addition,  the Independent  Third Party
shall make its determination according to the following procedure:

                  (i) The  Independent  Third  Party shall  first  analyze  each
Disputed Adjustment for which a determination is sought pursuant to this Section
3.5 on a stand alone basis to determine  whether the actual outcome reached with
respect to such Disputed  Adjustment as reflected in the Final  Determination of
the Tax  Contest was fair and  appropriate  taking  into  account the  following
exclusive  criteria:  (A)  the  facts  relating  to  such  Adjustment;  (B)  the
applicable law, if any, with respect to such Adjustment; (C) the position of the
applicable Taxing Authority with respect to compromise, settlement or litigation
of such Adjustment;  (D) the strength of the factual and legal arguments made by
the Controlling Party in reaching the outcome with respect to such Adjustment as
reflected in the Final Determination of the Tax Contest; and (E) the strength of
the  factual  and legal  arguments  being made by the  Interested  Party for the
alternative  outcome being  asserted by such  Interested  Party  (including  the
availability of facts, information and documentation to support such alternative
outcome).  Based on this analysis,  the Independent  Third Party shall determine
what  is the  fair  and  appropriate  outcome  (hereinafter  referred  to as the
"Initial Determination") with respect to each such Disputed Adjustment.

                  (ii)  The   Interested   Party   shall  not  be   entitled  to
modification of its share of a Disputed Adjustment under this Section 3.5 if, as
the case may be,  either  (A) the amount  that  would be paid by the  Interested
Party under the Initial  Determination with respect to such Disputed  Adjustment
is 80% or more than the amount that would be paid by the  Interested  Party with
respect to such  Disputed  Adjustment  under the  actual  outcome  reached  with
respect to such Disputed Adjustment; or (B) the amount that would be received by
the  Interested  Party  under the  Initial  Determination  with  respect to such
Disputed  Adjustment is 120% or less than the amount that the  Interested  Party
would receive with respect to such Disputed  Adjustment under the actual outcome
reached with respected to such Disputed Adjustment.  The Independent Third Party
will provide notice to the  Controlling  Party and the  Interested  Party in the
event the Interested  Party is not entitled to  modification of its share of the
Disputed Adjustment pursuant to this paragraph (ii).

                  (iii) If the modification of an Interested  Party's share of a
Disputed  Adjustment  under  this  Section  3.5 is not  prohibited  pursuant  to
paragraph (ii) above,  then the Independent  Third Party shall determine what is
the fair and  appropriate  outcome  (hereinafter  referred  to as the  "Ultimate
Determination") to the Interested Party with respect to such Disputed Adjustment
in the context of the entire Tax Contest as it relates to the Interested  Party.
In making this  determination,  the  Independent  Third Party shall consider the
Disputed Adjustment as if it were raised in an independent audit of the





Interested Party by the appropriate  Taxing Authority and the Independent  Third
Party shall take into account and give appropriate weight in its sole discretion
to the following exclusive  criteria:  (A) the strength of the legal and factual
support for other potential,  non-frivolous  Adjustments with respect to matters
that were actually  raised and contested by the applicable  Taxing  Authority in
the Tax Contest for which the Interested Party could have been liable under this
Agreement but which were  eliminated  or reduced as a result of the  Controlling
Party   agreeing  to  the  Disputed   Adjustment   as  reflected  in  the  Final
Determination  of the Tax Contest;  (B) the effect of the actual outcome reached
with respect to the Disputed  Adjustment on other  Taxable  periods and on other
positions taken or proposed to be taken in Returns filed or proposed to be filed
by the Interested Party; (C) the realistic  possibility of avoiding  examination
of  potential,  non-frivolous  issues for which the  Interested  Party  could be
liable  under  this  Agreement  and that were  contemporaneously  identified  in
writings by the party or parties  during the course of the Tax Contest but which
had not been raised and contested by the applicable  Taxing Authority in the Tax
Contest;  and (D) the  benefits  to the  Interested  Party in  reaching  a Final
Determination,  and the strategy and  rationale  with respect to the  Interested
Party's Disputed  Adjustment that the Controlling Party had for agreeing to such
Disputed Adjustment in reaching the Final Determination,  in each case that were
contemporaneously  identified  in  writings  by the party or parties  during the
course of the Tax Contest.

                  (iv)  The   Interested   Party   shall  only  be  entitled  to
modification of its share of a Disputed Adjustment under this Section 3.5 if, as
the case may be,  either  (A) the amount  that  would be paid by the  Interested
Party under the Ultimate  Determination with respect to such Disputed Adjustment
is less than 80% of the amount that would be paid by the  Interested  Party with
respect to such  Disputed  Adjustment  under the  actual  outcome  reached  with
respect to such Disputed Adjustment; or (B) the amount that would be received by
the  Interested  Party under the  Ultimate  Determination  with  respect to such
Disputed  Adjustment is more than 120% of the amount that the  Interested  Party
would receive with respect to such Disputed  Adjustment under the actual outcome
reached with respected to such Disputed  Adjustment.  If an Interested  Party is
entitled  to  modification  of its share of any  Disputed  Adjustment  under the
preceding  sentence,  the amount the Interested Party is entitled to receive, or
is required to pay, as the case may be, with respect to such Disputed Adjustment
shall be equal to the  amount of the  Ultimate  Determination  of such  Disputed
Adjustment.  The Independent  Third Party will provide notice to the Controlling
Party and the Interested  Party stating whether the Interested Party is entitled
to  modification  of its  share  of the  Disputed  Adjustment  pursuant  to this
paragraph  (iv) and, if the Interested  Party is entitled to such  modification,
the amount as determined in the preceding  sentence that the Interested Party is
entitled to receive  from,  or required  to pay to, the  Controlling  Party with
respect to such Disputed Adjustment.





                  (c) Any  determination  made or notice given by an Independent
Third  Party  pursuant to this  Section  3.5 shall be (i) in writing;  (ii) made
within sixty (60) days following the selection of the Independent Third Party as
set forth in Section  3.5(a) of this  Agreement  unless such period is otherwise
extended by the mutual consent of the parties;  and (iii) final and binding upon
the parties.  The costs of any Independent Third Party retained pursuant to this
Section 3.5 shall be shared equally by the parties.  The  Controlling  Party and
the Interested Party shall provide the Independent  Third Party jointly selected
pursuant to Section 3.5(a) hereof with such  information or documentation as may
be  appropriate or necessary in order for such  Independent  Third Party to make
the determination requested of it. Upon issuance of an Independent Third Party's
notice under Section  3.5(b)(ii) or Section  3.5(b)(iv)  hereof, the Controlling
Party or the  Interested  Party,  as the case may be,  shall pay as specified in
Article IV of this Agreement,  the amount, if any, of the Disputed Adjustment to
the appropriate party.

                                   ARTICLE IV
                              PROCEDURE AND PAYMENT

                  4.1.  PROCEDURE.  (a) If an Interested Party has any liability
and/or  obligation  to make,  or the right to receive,  any  indemnity  payment,
reimbursement  or  other  payment  with  respect  to an  Adjustment  under  this
Agreement for which it does not have a right to a determination by an Interested
Third Party under Section 3.5 hereof,  then the amount of such Adjustment  shall
be immediately due and payable upon receipt by the Interested  Party of a notice
of Final  Determination  of a Tax Contest as required  and  specified in Section
3.4(a) hereof.

                  (b) If after  (i)  notice  of a Final  Determination  of a Tax
Contest as required and  specified in Section  3.4(a) hereof has been given by a
Controlling  Party  to an  Interested  Party;  and  (ii)  the  Interested  Party
receiving such notice has either:

                  (A) failed to provide the Interested Party Notice specified in
Section 3.4(b) hereof within the ninety (90) day period set forth in Section
3.4(b);

                  (B) provided the Interested  Party Notice specified in Section
3.4(b)  hereof  within the ninety (90) day period  specified  in Section  3.4(b)
agreeing  to all  Adjustments  (and  the  Interested  Party's  share of all such
Adjustments) and waiving the right to an Independent  Third Party  determination
pursuant  to Section 3.5 hereof with  respect to all such  Adjustments  (and the
Interested Party's share of such Adjustments);

                  (C) provided the Interested  Party Notice specified in Section
3.4(b)  hereof  within the ninety (90) day period  specified  in Section  3.4(b)
agreeing with some, but not





all,  Adjustments (and the Interested Party's share of such agreed  Adjustments)
and waiving the right to an Independent  Third Party  Determination  pursuant to
Section  3.5  hereof  with  respect  to all  such  agreed  Adjustments  (and the
Interested Party's share of such Adjustments); or

                  (D) provided the Interested  Party Notice specified in Section
3.4(b)  hereof  within the ninety (90) day period  specified  in Section  3.4(b)
specifically enumerating the Disputed Adjustments to which it does not agree and
for  which  the  notice  specified  in  either  Section  3.5(b)(ii)  or  Section
3.5(b)(iv) hereof relating to any such Disputed  Adjustment has been given by an
independent Third Party;

then the  amount  of any  Adjustment  agreed to or deemed to be agreed to by the
Interested  Party, or for which an Independent Third Party notice has been given
pursuant to either Section 3.5(b)(ii) or Section 3.5(b)(iv) hereof, as set forth
in each of clause  (A),  (B,  (C) or (D)  above,  shall be  immediately  due and
payable.

                  (c) Any Person entitled to any indemnification,  reimbursement
or other  payment  under  this  Agreement  with  respect  to the  amount  of any
Adjustment  that has become  immediately  due and payable under this Section 4.1
(the  "Indemnified  Party") shall notify in writing the Person against whom such
indemnification,  reimbursement  or other  payment is sought (the  "Indemnifying
Party") of its right to and the amount of such indemnification, reimbursement or
other payment;  provided,  however,  that the failure to notify the Indemnifying
Party  shall not  relieve  the  Indemnifying  Party  from any  liability  and/or
obligation  which  it  may  have  to an  Indemnified  Party  on  account  of the
provisions   contained  in  this  Agreement   except  to  the  extent  that  the
Indemnifying  Party was  prejudiced by such failure,  and in no event shall such
failure  relieve the  Indemnifying  Party from any other liability or obligation
which it may have to such Indemnified  Party. The Indemnifying  Party shall make
such indemnity payment,  reimbursement or other payment to the Indemnified Party
within  thirty (30) days of the receipt of the written  notice  specified in the
preceding sentence.

                  4.2. PAYMENT.  Any indemnity  payment,
reimbursement or other
payment required to be made pursuant to this Agreement by an
Indemnifying  Party
to an Indemnified Party shall be made, at the option of the
Indemnifying  Party,
by (a) certified  check payable to the order of the  Indemnified  Party;  or (b)
wire transfer of immediately  available  funds to such bank and/or other account
of the Indemnified  Party as from time to time the Indemnified  Party shall have
directed the Indemnifying Party, in writing.

                  4.3. INTEREST. Any indemnity payment,
reimbursement or other
payment required to be made by an Interested Party pursuant to
this Agreement
shall bear interest at the Prime Rate plus 2%, per annum, from the
date such
Interested Party





receives the notice of Final Determination made with respect to a Tax Contest as
provided in Section 3.4(a) hereof. Any indemnity payment, reimbursement or other
payment  required  to be made by a  Controlling  Party  to an  Interested  Party
pursuant to this  Agreement  shall bear  interest at the Prime Rate plus 2%, per
annum, from a date thirty (30) days after the date of a Final Determination made
with respect to a Tax Contest.

                                    ARTICLE V
                                OTHER TAX MATTERS

                  5.1. TAX POLICIES AND PROCEDURES DURING
CONSOLIDATION. It is
understood and agreed that during Consolidation:

                  (a) Members of the Lucent  Group and members of the NCR Group,
respectively,  shall each adopt and follow the Tax policies and procedures  that
have been  established by AT&T and  communicated to Lucent and NCR unless,  AT&T
shall otherwise  consent,  as provided herein. In the event that a member of the
Lucent  Group  and/or the NCR Group  desires to adopt and follow a Tax policy or
procedure that is different from that established by AT&T, Lucent and/or NCR, as
the case may be, shall,  in writing,  (i) request  AT&T's  consent to do so; and
(ii)  provide  AT&T with the  reasons  for the  request to adopt and follow such
different Tax policy or procedure. If AT&T determines in its good faith judgment
that it would be reasonable  and  appropriate  from the  perspective of the AT&T
Services Group for such member of the Lucent Group and/or the NCR Group to adopt
and follow  such  different  Tax policy or  procedure,  AT&T shall  provide  its
written consent thereto.

                  (b) AT&T shall provide to Lucent and NCR timely written notice
of any material proposed change in established Tax policies or procedures.

                  (c) AT&T shall establish all Return positions and make all Tax
elections  relating to a  Consolidated  Return.  Members of the Lucent Group and
members of the NCR Group shall take such Consolidated  Return positions and make
such Tax elections relating to a Consolidated  Return as may be taken or made by
AT&T,  or as  reasonably  requested by AT&T to be taken or made by any member of
the Lucent Group and/or any member of the NCR Group,  as the case may be, unless
AT&T shall  otherwise  consent,  as  provided  herein.  In the event that Lucent
and/or NCR determines that it would be reasonable and appropriate for any member
of the  Lucent  Group or any  member  of the NCR  Group,  respectively,  to take
positions or make elections relating to a Consolidated Return that are different
from those taken or made by AT&T (or reasonably  requested by AT&T of any member
of the Lucent Group or any member of the NCR Group),  Lucent  and/or NCR, as the
case may be, shall, in writing,





(i) request  AT&T's consent to do so; and (ii) provide AT&T with the reasons for
the request to take such different  positions or make such different  elections.
If AT&T  determines in its good faith  judgment that it would be reasonable  and
appropriate  from the  perspective of the AT&T Services Group for such member of
the Lucent Group and/or the NCR Group to take such  different  positions or make
such different elections, AT&T shall provide its written consent thereto.

                  5.2.  COOPERATION.   Except  as  otherwise  provided  in  this
Agreement,  and without limiting the provisions contained in Article VIII of the
Separation  Agreement  which are  incorporated  herein by reference  pursuant to
Section 6.3(a) hereof,  each member of the AT&T Services Group, the Lucent Group
and/or the NCR Group, as the case may be, shall, at their own expense, cooperate
with each other in the filing of, or any Tax Contest relating to, any Return and
any other  matters  relating to Taxes and, in  connection  therewith,  shall (i)
maintain  appropriate  books and records for any and all Taxable  periods or any
portion of a Taxable  period  that may be required  by AT&T's  record  retention
policies;  (ii)  provide to each other such  information  as may be necessary or
useful in the filing of, or any Tax Contest relating to, any such Return;  (iii)
execute and  deliver  such  consents,  elections,  powers of attorney  and other
documents that may be required or appropriate  for the proper filing of any such
Return or in conjunction with any Tax Contest  relating to any such Return;  and
(iv) make available for responding to inquiries of any other party or any Taxing
Authority,  appropriate  employees and officers of and advisors  retained by any
member of the AT&T Services  Group,  the Lucent Group,  or the NCR Group, as the
case may be.

                  5.3.  FILING  OF  RETURNS.   The  Person  that  would  be  the
Controlling Party with respect to any Tax Contest relating to a Return for which
any indemnity  payment,  reimbursement or other payment may be sought under this
Agreement  shall (a) prepare and file,  or cause to be prepared  and filed,  any
such Return within the time  prescribed  for filing such Return  (including  all
extensions of time for filing);  and (b) shall timely pay, or cause to be timely
paid,  the  amount  of any Tax  shown to be due and  owing  on any such  Return;
provided,  however,  that in the case of Taxes which are  Liabilities  of Lucent
pursuant to Section 2.3(a)(ii) of the Separation Agreement, if AT&T or any other
member of the AT&T Group is  required  pursuant to this  Agreement  to file such
Return  and pay the Taxes  shown as due  thereon,  Lucent  will pay to AT&T,  in
advance of the date on which AT&T must pay such  Taxes,  an amount  equal to the
amount of such Taxes which are Liabilities of Lucent. Such Person shall bear all
costs associated with preparing and filing, or causing to be prepared and filed,
any such  Return.  Except as  provided in Section  5.1(c)  hereof  (relating  to
Consolidated Returns), such Person shall establish all Return positions and make
all Tax elections relating to such Returns.





                                   ARTICLE VI
                                  MISCELLANEOUS

                  6.1.  GOVERNING  LAW.  To  the  extent  not  preempted  by any
applicable  foreign or U.S.  federal,  state,  or local Tax law, this  Agreement
shall be governed by and construed and  interpreted in accordance  with the laws
of the State of New York,  irrespective  of the choice of laws principles of the
State  of  New  York,  as  to  all  matters,   including  matters  of  validity,
construction, effect, performance and remedies.

                  6.2. AFFILIATES.  Each of the parties hereto shall cause to be
performed, and hereby guarantees the performance of, all actions, agreements and
obligations  set forth herein to be  performed  by any  Affiliate of such party;
provided,  however,  that for  purposes  of the  foregoing,  no Person  shall be
considered an Affiliate of a party if such Person is a member of another party's
Group.

                  6.3.  INCORPORATION OF SEPARATION  AGREEMENT  PROVISIONS.  The
following  provisions of the Separation Agreement are hereby incorporated herein
by reference,  and unless otherwise  expressly specified herein, such provisions
shall apply as if they are fully set forth  herein  (references  in this Section
6.3 to an "Article" shall mean Articles of the Separation Agreement):

                  (a) Article VIII (relating to Exchange of
Information and
Confidentiality); and

                  (b) Article XII (relating to Miscellaneous
Provisions, except as otherwise specified herein).

                  6.4.  NOTICES.  Except for any  notice or other  communication
required to be given by a Controlling  Party under this Agreement,  AT&T, Lucent
and NCR (or any other  Person  delegated  in writing  by each of the  foregoing)
shall  serve as the  single  point of  contact  to receive or give any notice or
other  communication  required or permitted to be given to any member of each of
their  respective  Groups under this  Agreement.  Unless  specifically  provided
otherwise  in this  Agreement,  all notices or other  communications  under this
Agreement  shall be in  writing  and  shall  deemed  to be duly  given  when (a)
delivered in person;  or (b) sent by  facsimile;  or (c) deposited in the United
States mail,  postage prepaid and sent certified mail, return receipt requested;
or (d) deposited in private express mail, postage prepaid, addressed as follows:

         If to any member of the AT&T Services Group, to:

                  AT&T Corp.




                  412 Mt. Kemble Avenue
                          Morristown, New Jersey 07960
                  Attn:  Vice President - Taxes and Tax Counsel
                            Facsimile: (201) 644-6823

         If to any member of the Lucent Group, to:

                  Lucent Technologies Inc.
                  600 Mountain Avenue
                          Murray Hill, New Jersey 07974
                  Attn:  Vice President - Taxes and Tax Counsel
                  Facsimile:

         If to any member of the NCR Group, to:

                  NCR Corporation
                  1700 S. Patterson Blvd.
                  Dayton, Ohio  45479
                  Attn:  Assistant Vice President & Director,
Corporate Taxes
                            Facsimile: (513) 445-6935

Any party may,  by written  notice to the other  parties,  change the address to
which such notices are to be given.

                  6.5. CONFLICTING OR INCONSISTENT PROVISIONS. In the event that
any provision or term of this Agreement  conflicts or is  inconsistent  with any
provision  or term of any other  agreement  between  or among  AT&T or any other
member of the AT&T Group,  Lucent or any other member of the Lucent Group and/or
NCR or any other member of the NCR Group, as the case may be, which is in effect
on or prior to the date hereof,  the provision or term of this  Agreement  shall
control and apply and the provision or term of any other agreement shall, to the
extent of such conflict or inconsistency, be inoperative and inapplicable.

                  6.6. DURATION. Notwithstanding anything in this
Agreement or
the Separation Agreement to the contrary, the provisions of this
Agreement shall
survive for the full period of all applicable statutes of
limitations (giving
effect to any waiver, mitigation or extension thereof).

                  6.7. AMENDMENT. Without limiting the provisions
contained in
Article XII of the Separation Agreement which are incorporated
herein by
reference pursuant to Section 6.3(b) hereof:





                  (a) The parties agree that any waiver,  amendment,  supplement
or modification of this Agreement that solely relates to and affects only two of
the three  parties  hereto  shall not  require  the  consent of the third  party
hereto.  Without  limiting the  foregoing,  effective  immediately  on notice to
Lucent,  without any further action  required by any member of the Lucent Group,
AT&T may assume any  Liability of any member of the NCR Group and all members of
the NCR Group shall thereupon automatically be released therefrom.

                  (b)  The  parties  acknowledge  that  the  provisions  of this
Agreement may not fully reflect all of their respective concerns with respect to
state and local Taxes.  Consequently,  the parties will cooperate in determining
whether to amend or supplement  this  Agreement no later than February 29, 1996.
To the  extent  no such  amendment  or  supplement  is  executed  on or prior to
February 29, 1996, the  provisions of this Agreement  shall remain in full force
and effect.

                  6.8. TAX  ALLOCATION  AGREEMENTS.  Lucent  hereby  assumes and
agrees  faithfully to perform and fulfill all obligations and other  Liabilities
of any member of the Lucent Group under the Federal Tax Allocation Agreement and
the State and Local Income Tax Allocation Agreement,  in accordance with each of
their respective terms.





                  IN WITNESS  WHEREOF,  the parties  hereto have caused this Tax
Sharing Agreement to be executed by their duly authorized
representatives.

AT&T CORP.

By: /s/
- ---------------------
Name:
Title:

LUCENT TECHNOLOGIES INC.

By: /s/
- ---------------------
Name:
Title:

NCR CORPORATION

By: /s/
- ---------------------
Name:
Title: