Document:

CORRECTED PURCHASE MONEY MORTGAGE NOTE

      FOR VALUE RECEIVED, the undersigned (collectively, the "Maker") hereby
promise to pay to the order of AMBIENT CORPORATION, of 1033 Beacon Street,
Brookline, MA 02446-5654, or at such other place, or to such other party or
parties, as the holder of this note (the "Note") may from time to time
designate, the principal sum of ONE MILLION NINE HUNDRED NINETY DOLLARS
($1,990,000.00), with no interest computed thereon, together with charges
thereon made as follows: One installment of the principal amount hereof and any
charges thereon shall be due and payable on April 5, 2011 (unless sooner due and
payable).

      This Note is secured by (i) the Mortgage and Security Agreement dated of
even date herewith by and between Linda J. Isaacson and Mark S. Isaacson, as
Trustees of the Rashi Realty Trust dated February 22, 1991, in favor of holder
encumbering property located at 38 Jordan Drive, Brookline, Massachusetts and
recorded in the Norfolk County Registry District of the Land Court and (ii) the
Mortgage dated of even date herewith by Linda J. Isaacson, in favor of holder
encumbering property located at 250 Ocean Avenue, Lawrence, New York and
recorded in the Nassau County Land Records (the Mortgage and Security Agreement
and the Mortgage are hereinafter collectively referred to as the "Mortgage").

      If not sooner paid, the entire outstanding principal balance of this Note,
plus all accrued and unpaid, late fees, costs and expenses hereunder, shall be
due and payable on April 5, 2011 except as herein set forth ("Maturity Date").
After the third (3rd) anniversary of this note (April 5, 2004), if Ambient
Corporation or its successors ceases to do business, is liquidated under the
Bankruptcy Laws of the United States or Mark Isaacson is no longer employed by
Ambient Corporation, then the maturity date shall be twelve (12) months from the
date of that event. Any payment received by the holder hereof more than ten (10)
days after it is due shall be subject to a late charge of five per cent (5%) of
the amount due.

      The aggregate amount outstanding hereunder and each payment hereon shall
be recorded in the books and records of the holder, and the aggregate amount
reflected on such books and records as outstanding at any time shall be
conclusive evidence of the aggregate amount owing and unpaid hereunder as of
such time.

      All payments by Maker hereunder shall be applied first to late charges,
then to the balance on account of the principal of this Note. If an Event of
Default (as hereinafter defined) occurs, the holder hereof may apply payments in
such manner and order as it deems appropriate.

<PAGE>

      Maker promises to pay, in addition to said principal sums, all taxes,
costs, expenses, disbursements and assessments which may be levied against the
holder hereof upon this Note or the indebtedness evidenced hereby (the "Loan
Indebtedness"), or upon any collateral securing this Note, and together with all
costs of collection including reasonable attorneys' fees incurred by the holder
hereof on the Loan Indebtedness to (1) collect the Loan Indebtedness due
hereunder from any party liable for the payment of the Loan Indebtedness whether
as maker, endorser, guarantor, surety or otherwise (the "Parties") and realize
its rights under this Note, (2) enforce, foreclose and realize its rights under
this Note or any other security document, and (3) defend and protect the
validity of this Note or any other security document in connection with any
litigation or controversy arising from or connected therewith. Said costs,
expenses and reasonable attorneys' fees enumerated above shall expressly include
but not be limited to those as may be incurred by the holder hereof to collect
the Loan Indebtedness due hereunder from any of the Makers after judgment in
favor of the holder hereof by any court of competent jurisdiction, including
those incurred by the holder hereof to foreclose any judgment lien, right of
power of sale, or to realize upon any collateral or to otherwise obtain payment
and satisfaction of such judgment from any of the Parties. Maker's obligation to
pay such costs and reasonable attorneys' fees of the holder hereof in connection
with the protecting, enforcing or realizing of the rights and remedies above
described shall exist whether or not proceedings are instituted or legal
appearances made in any court of competent jurisdiction on behalf of the holder
hereof.

      Notwithstanding anything in this instrument to the contrary, it is
specifically understood and agreed that the obligations of Linda J. Isaacson,
Mark S. Isaacson, Trustee, and Linda J. Isaacson, Trustee, hereunder shall be
limited to the extent of their interest in the real and personal property
encumbered and secured by the Mortgage. Nothing herein shall be construed as
applying to any party other than Linda J. Isaacson, Mark S. Isaacson, Trustee,
and Linda J. Isaacson, Trustee. In addition to the obligations set forth herein
and in the Mortgage, Mark S. Isaacson shall be personally liable for the
principal and Loan Indebtedness under this Note and holder shall have the right
of full recourse in connection therewith.

      The following shall constitute an event of default ("Event of Default")
hereunder: Makers' failure to pay any sum due on this Note when due or failure
to perform any other obligation of Maker hereunder or under the Mortgage by
Maker of even date herewith.

      At the option of the holder hereof, the entire principal and Loan
Indebtedness thereon shall at once become due and payable without notice or
demand upon the occurrence at any time of any Event of Default, and the holder
hereof may proceed to exercise any rights it has under this Note or any security
document or at law, in equity or otherwise. Failure to exercise this option to
accelerate shall not constitute a waiver of the right to exercise the same in
the event of any subsequent Event of Default.

                                      -2-
<PAGE>

     Maker may at any time prepay this Note at any time in whole or in part,
without penalty or premium. In the event of any partial prepayment, payments
under this Note shall be adjusted accordingly.

      Any notice to Maker provided for in this Note shall be given by mailing
such notice by prepaid, first class mail addressed to: 1033 Beacon Street,
Brookline, MA 02446-5654 or to such other address as Maker may designate by
notice to the holder hereof. Any notice to the holder hereof shall be given by
mailing such notice by prepaid, first class mail, return receipt requested, at
the address stated in the first paragraph of this Note, or at such other person
or address as may have been designated by notice to Maker. Notice shall be
deemed given when mailed in accordance with this paragraph.

      All references to "holder hereof," the "Maker" or the "Parties" shall
apply to their respective heirs, successors and assigns. This Note may be sold,
transferred, assigned or pledged by the holder hereof from time to time without
notice to, or consent of, Maker.

      To the extent allowed by law, Maker and each endorser or guarantor of this
Note hereby waive presentment, protest, demand, diligence, notice of dishonor
and of nonpayment, and waive and renounce all rights to the benefits or any
statute of limitations and any moratorium, appraisement, exemption and homestead
now provided or which may hereafter be provided by any federal or state statute,
both as to itself personally and as to all of its or their property, whether
real or personal, against the enforcement and collection of the obligations
evidenced by this Note and any and all extensions, renewals and modifications.

      If the proceeds from an insurance policy are paid to the holder pursuant
to the Mortgage, the holder, at its option, may apply all or part of such
proceeds to the outstanding principal balance due hereunder, interest thereon
and other obligations of the Maker hereunder, except as otherwise provided in
the Mortgage.

                                      -3-
<PAGE>

     This Note shall be governed by and construed in accordance with the laws of
the State of New York. The Maker consents to the jurisdiction of the appropriate
court within the State of New York. with respect to any disputes arising out of
the enforcement of this Note.

     This Note is intended to replace a Note dated April 5, 2001, to correct
errors in said Note.

     IN WITNESS WHEREOF, the undersigned have caused their names to be set this
___ day of April, 2001.

                                    --------------------------------------------
                                    LINDA J. ISAACSON, individually

                                    --------------------------------------------
                                    MARK S. ISAACSON, individually

                                    --------------------------------------------
                                    LINDA J.  ISAACSON,  AS  TRUSTEE  OF THE
                                    RASHI  REALTY TRUST DATED FEBRUARY 22, 1991

                                    --------------------------------------------
                                    MARK S.  ISAACSON,  AS  TRUSTEE  OF THE
                                    RASHI  REALTY TRUST DATED FEBRUARY 22, 1991

                                      -4-<PAGE>

                                                                     EXHIBIT 4.1
                                                                     -----------

                              AMENDED AND RESTATED

               3COM CORPORATION 1984 EMPLOYEE STOCK PURCHASE PLAN

     1.  Purpose. The 3Com Corporation 1984 Employee Stock Purchase Plan (the
         -------
"Prior Plan") was established to provide eligible employees of 3Com Corporation
("3Com") and any current or future subsidiary corporation(s) of 3Com
(collectively referred to as the "Company") with an opportunity, through payroll
deductions, to acquire common stock of 3Com. The Prior Plan has been amended
from time to time. On September 28, 1995, the Board of Directors of 3Com (the
"Board") amended and restated the Prior Plan as amended in order to make various
changes to the Prior Plan considered beneficial for continuing to carry out the
purposes of such plan, all in the form set forth herein (the "Plan"). For
purposes of the Plan, a parent corporation and a subsidiary corporation shall be
as defined in sections 424(e) and 424(f) of the Internal Revenue Code of 1986,
as amended (the "Code"). The Company intends that the Plan shall qualify as an
"employee stock purchase plan" under section 423 of the Code (including any
future amendments or replacements of such section), and the Plan shall be so
construed. Any term not expressly defined in the Plan but defined for purposes
of section 423 of the Code shall have the same definition herein. Because an
eligible employee who participates in the Plan (a "Participant") may withdraw
the Participant's accumulated payroll deductions and terminate participation in
the Plan or any Offering (as defined below) therein at any time during an
Offering Period (as defined below), the Participant is, in effect, given an
option which may or may not be exercised during any Offering Period.

     2.  Share Reserve. The maximum number of shares which may be issued under
         -------------
the Plan shall be 31,200,000 shares of 3Com's authorized but unissued common
stock (the "Shares"). In the event that any option granted under the Plan (an
"Option") for any reason expires or is terminated, the Shares allocable to the
unexercised portion of such Option may again be subjected to an Option.

     3.  Administration. The Plan shall be administered by the Board and/or by a
         --------------
duly appointed committee of the Board having such powers as shall be specified
by the Board. Any subsequent references to the Board shall also mean the
committee if it has been appointed. All questions of interpretation of the Plan
or of any Options shall be determined by the Board and shall be final and
binding upon all persons having an interest in the Plan and/or any Option.
Subject to the provisions of the Plan, the Board shall determine all of the
relevant terms and conditions of Options granted pursuant to the Plan; provided,
however, that all Participants granted Options pursuant to the Plan shall have
the same rights and privileges within the meaning of section 423(b)(5) of the
Code. All expenses incurred in connection with the administration of the Plan
shall be paid by the Company.

     4.  Eligibility. Any regular employee of the Company is eligible to
         -----------
participate in the Plan and any Offering (as hereinafter defined) under the Plan
except the following:

         (a)  employees who are customarily employed by the Company for less
than twenty (20) hours a week;
<PAGE>

          (b)  employees who own or hold options to purchase or who, as a result
of participation in the Plan, would own or hold options to purchase stock of the
Company possessing five percent (5%) or more of the total combined voting power
or value of all classes of stock of the Company within the meaning of section
423(b)(3) of the Code; and

          (c)  with respect to participation in the Additional Chipcom Offering
described in paragraph 5(a) below, employees who were not employed by the
Company or Chipcom Corporation ("Chipcom") as of October 2, 1995.

     5.   Offerings
          ---------

          (a)  Offering Periods Beginning On or After October 1, 1999. Except as
               ------------------------------------------------------
otherwise set forth below, effective October 1, 1999, the Plan shall be
implemented by offerings (individually, an "Offering") of twenty-four (24)
months duration (an "Offering Period"). An Offering shall commence on April 1
and October 1 of each year and end on the second March 31 and September 30,
respectively, occurring thereafter. Notwithstanding the foregoing, the Board may
establish a different term for one or more of the Offerings and/or different
commencing and/or ending dates for such Offerings. An employee who becomes
eligible to participate in the Plan after such Offering but may participate in
any subsequent Offering provided such employee is still eligible to participate
in the Plan as of the commencement of any such subsequent Offering. Eligible
employees may not participate in more than one Offering at a time. The first day
of an Offering Period shall be the "Offering Date" for such Offering Period. In
the event the first and/or last day of an Offering Period is not a business day,
the Company shall specify the business day that will be deemed the first or last
day, as the case may be, of the Offering Period.

          (b)  Purchase Periods. Each Offering Period shall consist of four (4)
               ----------------
consecutive purchase period of six (6) months duration (a "Purchase Period").
The last day of each Purchase Period shall be the "Purchase Date" for such
Purchase Period. A Purchase Period commencing on April 1 shall end on the next
September 30. A Purchase Period commencing on October 1 shall end on the next
March 31. Notwithstanding the foregoing, the Board may establish a different
term for one or more Purchase Periods and/or different commencing dates and/or
Purchase Dates for such Purchase Periods. In the event the first and/or last day
of a Purchase Period is not a business day, the Company shall specify the
business day that will be deemed the first or last day, as the case may be, of
the Purchase Period.

          (c)  Governmental Approval; Shareholder Approval. Notwithstanding any
               -------------------------------------------
other provision of the Plan to the contrary, any Option granted pursuant to the
Plan shall be subject to (i) obtaining all necessary governmental approvals
and/or qualifications of the sale and/or issuance of the Options and/or the
Shares, and (ii) in the case of Options with an Offering Date after an amendment
to the Plan, obtaining any necessary approval of the shareholders of the Company
required in paragraph 17.

     6.   Participation in the Plan
          -------------------------

          (a)  Initial Participation. An eligible employee may elect to become a
Participant effective as of the first Offering Date after satisfying the
eligibility requirements set forth in

                                      -2-
<PAGE>

paragraph 4 above by delivering a subscription agreement authorizing payroll
deductions (a "Subscription Agreement") to the Company's Stock Administration
office not later than fifteen (15) calendar days, or such other period as the
Company may determine in its sole discretion, prior to such Offering Date. Such
Subscription Agreement shall state the eligible employee's election to
participate in the Plan and the rate at which payroll deductions shall be
accumulated. An eligible employee who does not deliver a Subscription Agreement
to the Company's Stock Administration office at least fifteen (15) calendar
days, or such period as the Company may determine in its sole discretion, prior
to the first Offering Date after becoming eligible to participate in the Plan,
shall not participate in the Plan for that Offering Period or for any subsequent
Offering Period unless such employee subsequently enrolls in the Plan by filing
a Subscription Agreement with the Company in accordance with this paragraph
6(a).

          (b)  Automatic Participation in Subsequent Offerings. A Participant
               -----------------------------------------------
shall automatically participate in each subsequent Offering Period until such
time as such Participant ceases to be eligible as provided in paragraph 4, the
Participant withdraws from the Plan pursuant to paragraph 10 below, or the
Participant terminates employment as provided in paragraph 11 below. A
Participant is not required to file an additional Subscription Agreement for
such Offering Periods in order to automatically participate therein. Unless
otherwise indicated in a subsequently filed Subscription Agreement, the rate at
which payroll deductions shall be accumulated with respect to any such
subsequent Offering Period shall equal the rate applicable to the immediately
preceding Offering Period.

     7.   Purchase Price
          --------------

          (a)  Purchase Price. The purchase price at which Shares may be
               --------------
acquired in any Offering Period under the Plan shall be eighty-five percent
(85%) of the lesser of (a) the fair market value of the Shares on the Offering
Date of such Offering Period or (b) the fair market value of the Shares on the
Purchase Date of such Offering Period. For purposes of the Plan, the fair market
value of the Shares at any point in time shall be determined by the Board based
on such factors as the Board deems relevant; including, without limitation, the
mean of the bid and asked price of the Shares on the date in question as
reported by the National Association of Securities Dealers Automated Quotation
System.

          (b)  Automatic Transfer to Low Price Offering Period. To the extent
               -----------------------------------------------
permitted by any applicable laws, regulations, or stock exchange rules, if the
Fair Market Value of the common stock on any Exercise Date in an Offering Period
is lower than the Fair Market Value of the common stock on the Enrollment Date
of such Offering Period, then all participants in such Offering Period shall be
automatically withdrawn from such Offering Period immediately after the exercise
of their option on such Exercise Date and automatically re-enrolled in the
immediately following Offering Period as of the first day thereof.

     8.   Payment of Purchase Price; Payroll Deductions
          ---------------------------------------------

          (a)  Accumulation of Payroll Deductions. The purchase price of Shares
               ----------------------------------
to be acquired in an Offering Period shall be accumulated only by payroll
deductions over the Offering Period. Payroll deductions from a Participant's
compensation on each payday during the Offering

                                      -3-
<PAGE>

Period (i) shall not exceed ten percent (10%) of such Participant's base pay per
month reduced by any payroll deductions from such Participant's compensation to
purchase stock under any other plan of the Company intended to qualify as an
"employee stock purchase plan" under section 423 of the Code, and (ii) shall not
be less than one percent (1%) of the Participant's base pay per month. For
purposes hereof, a Participant's "base pay" from the Company is an aggregate
that (i) shall include all salaries and commissions, and (ii) shall not include
annual awards or incentive bonuses and any other payments not specifically
referenced in (i) above, except to the extent that the inclusion of any such
item with respect to all Participants on a non-discriminatory basis is
specifically approved by the Board. Payroll deductions shall commence on the
first payday following the first day of a Offering Period or as soon as
administratively feasible thereafter and shall continue to the end of such
Offering Period unless sooner altered or terminated as provided in the Plan.

          (b)  Election to Change Payroll Deduction Rate. A Participant may
               -----------------------------------------
decrease (but not increase) the rate of payroll deductions with respect to an
Offering Period only on or before and effective as of the date three (3) months
after the beginning of such Offering Period by filing an amended Subscription
Agreement with the Company. A Participant may increase or decrease the rate of
payroll deductions for any subsequent Offering Period by filing a new
Subscription Agreement with the Company not later than fifteen (15) calendar
days, or such other period as the Company may determine in its sole discretion,
prior to the beginning of such subsequent Offering Period.

          (c)  Participant Accounts. Individual accounts shall be maintained for
               --------------------
each Participant. All payroll deductions from a Participant's compensation shall
be credited to the Participant's account under the Plan and shall be deposited
with the general funds of the Company. No interest shall accrue on such payroll
deductions. All payroll deductions received or held by the Company may be used
by the Company for any corporate purpose.

     9.   Purchase of Shares
          ------------------

          (a)  Purchase. On the Purchase Date of each Offering Period, each
               --------
remaining Participant shall automatically purchase, subject to the limitations
set forth in paragraphs 9(b) and 9(c) below, that number of whole Shares arrived
at by dividing the total amount theretofore credited to the Participant's
account pursuant to paragraph 8(c) by the purchase price established for such
Offering Period pursuant to paragraph 7. Any cash balance remaining in the
Participant's Plan account shall be refunded to the Participant as soon as
practicable after the Purchase Date. In the event the cash to be returned to a
Participant pursuant to the preceding sentence is an amount less than the amount
necessary to purchase a whole Share, such amount shall continue to be credited
to the Participant's Plan account and shall be applied toward the purchase of
Shares in the immediately subsequent Offering Period. No Shares shall be
purchased in a given Offering Period on behalf of a Participant whose
participation in the Plan has terminated prior to the Purchase Date for such
Offering Period.

          (b)  Share Limitation. Subject to the adjustments set forth in
               ----------------
paragraph 13 below, no Participant shall be entitled to purchase more than 4,000
Shares in a single Offering.

                                      -4-
<PAGE>

          (c)  Fair Market Value Limitation. Notwithstanding any other provision
               ----------------------------
of the Plan, no Participant shall be entitled to purchase Shares under the Plan
(or any other employee stock purchase plan which is intended to meet the
requirements of section 423 of the Code sponsored by 3Com or a parent
corporation or subsidiary corporation of 3Com) at a rate which exceeds $25,000
in fair market value (or such other limit as may be imposed by section 423 of
the Code) for each calendar year in which the Participant participates in the
Plan or any other employee stock purchase plan described in this sentence, as
determined in accordance with section 423(b)(8) of the Code.

          (d)  Pro Rata Allocation. In the event the number of Shares which
               -------------------
might be purchased by all Participants in the Plan exceeds the number of Shares
available in the Plan, the Company shall make a pro rata allocation of the
remaining Shares in as uniform a manner as shall be practicable and as the
Company shall determine to be equitable.

          (e)  Rights as a Shareholder and Employee. A Participant shall have no
               ------------------------------------
rights as a shareholder by virtue of the Participant's participation in the Plan
until the date of issuance of a stock certificate(s) for the Shares being
purchased pursuant to the exercise of the Participant's Option. No adjustment
shall be made for dividends or distributions or other rights for which the
record date is prior to the date such stock certificate(s) are issued. Nothing
herein shall confer upon a Participant any right to continue in the employ of
the Company or interfere in any way with any right of the Company to terminate
the Participant's employment at any time.

          (f)  The Company may, from time to time, establish or change (i)
limitations on the frequency and/or number of changes in the amount withheld
during an Offering, (ii) an exchange ratio applicable to amounts withheld in a
currency other than U.S. dollars, (iii) procedures for permitting unequal
percentages of payroll withholding from a Participant's compensation in order to
accommodate the Company's established payroll procedures or mistakes or delays
in following those procedures when processing Participants' withholding
elections, and (iv) such other limitations or procedures as deemed advisable by
the Company in the Company's sole discretion which are consistent with the Plan
and section 423 of the Code.

          (g)  Any portion of a Participant's Option remaining unexercised after
the end of the Offering Period to which such right relates shall expire
immediately upon the end of such period.

     10.  Withdrawal
          ----------

          (a)  Withdrawal From the Plan. A Participant may withdraw from the
               ------------------------
Plan by signing and delivering to the Company's payroll office, a written notice
of withdrawal on a form provided by the Company for such purpose. Such
withdrawal may be elected at any time, and if prior to the end of an Offering
Period shall be effective for that Offering Period. A Participant is prohibited
from again participating in an Offering upon withdrawal from the Plan during
such Offering. A Participant who elects to withdraw from the Plan may again
participate in the Plan by filing a new Subscription Agreement in the same
manner as set forth in paragraph 6(a) above for initial participation in the
Plan. The Company may impose, from time to time, a requirement that the notice
of withdrawal be on file with the Company for a reasonable period of time prior
to the effectiveness of the Participant's withdrawal from the Plan.

                                      -5-
<PAGE>

          (b)  Return of Payroll Deductions. Upon withdrawal from the Plan, the
               ----------------------------
accumulated payroll deductions credited to a withdrawing Participant's account
shall be returned to the Participant and the Participant's interest in the Plan
shall terminate. No interest shall accrue on the payroll deductions of a
Participant.

     11.  Termination of Employment. Termination of a Participant's employment
          -------------------------
with the Company for any reason, including retirement or death, or the failure
of a Participant to remain an eligible employee, shall terminate the
Participant's participation in the Plan immediately. Upon such termination, the
payroll deductions credited to the Participant's account shall be returned to
the Participant (or in the case of the Participant's death, to the Participant's
legal representative) and all of the Participant's rights under the Plan shall
terminate. A Participant whose participation has been so terminated may again
become eligible to participate in the Plan by again satisfying the requirements
of paragraphs 4 and 6.

     12.  Repayment of Payroll Deductions Without Interest.  In the event a
          ------------------------------------------------
Participant's interest in the Plan is terminated, the Company shall deliver to
the Participant (or in the case of the Participant's death or incapacity, to the
Participant's legal representative) the payroll deductions credited to the
Participant's account.  No interest shall accrue on the payroll deductions of a
Participant.

     13.  Capital Changes.  In the event of changes in the common stock of the
          ---------------
Company due to a stock split, reverse stock split, stock dividend, combination,
reclassification or like change in the Company's capitalization, or in the event
of any merger, sale or reorganization, appropriate adjustments shall be made by
the Company in (a) the number and class of Shares of stock subject to the Plan
and to any outstanding Option, (b) the purchase price per Share of any
outstanding Option and (c) the Share limitation set forth in paragraph 9(b)
above.

     14.  Nonassignability.  Only the Participant may elect to exercise the
          ----------------
Participant's Option during the Participant's lifetime, and no rights or
accumulated payroll deductions of any Participant under the Plan may be pledged,
assigned or transferred for any reason, except by will or the laws of descent
and distribution, and any such attempt may be treated by the Company as an
election by the Participant to withdraw from the Plan.

     15.  Reports.  Each Participant shall receive after the last day of each
          -------
Offering Period a report of the Participant's account setting forth the total
payroll deductions accumulated, the number of Shares purchased and the remaining
cash balance to be carried over and/or refunded pursuant to paragraph 9(a)
above, if any.

     16.  Plan Term.  This Plan shall continue until terminated by the Board
          ---------
or until all of the Shares reserved for issuance under the Plan have been
issued.

     17.  Amendment or Termination of the Plan.  The Board may at any time amend
          ------------------------------------
or terminate the Plan, except that such termination cannot affect Options
previously granted under the Plan except as otherwise permitted by the Plan, nor
may any amendment make any change in an Option previously granted under the Plan
which would adversely affect the right of any Participant except as otherwise
permitted by the Plan, nor may any amendment be made without approval of the

                                      -6-
<PAGE>

shareholders of the Company within twelve (12) months of the adoption of such
amendment if such amendment would authorize the sale of more shares than are
authorized for issuance under the Plan or would change the designation of
corporations whose employees may be offered Options under the Plan.
Notwithstanding any other provision of the Plan to the contrary, in the event of
an amendment to the Plan which affects the rights or privileges of Options to be
offered under the Plan, each Participant with an outstanding Option shall have
the right to exercise such outstanding Option on the effective date of the
amendment and to participate in the Plan for the remaining term of such
outstanding Option pursuant to the terms and conditions of the Plan as amended.
If in accordance with the preceding sentence a Participant elects to exercise
such outstanding Option and to commence participation in the Plan as amended on
the effective date of such amendment, the Participant shall be deemed to have
received a new Option on such effective date, and such effective date shall be
deemed the Offering Date for such Option.

     18.  Clawback.  The Board may, in its discretion and, to the extent
          --------
necessary or desireable, modify or amend the Plan to reduce or eliminate an
unfavorable accounting consequence including, but not limited to: (i) altering
the Purchase Price for an Offering Period including an Offering Period underway
at the time of the change in Purchase Price; (ii) shortening any Offering Period
so that Offering Period ends on a new Exercise Date, including an Offering
Period underway at the time of the Board action; and (iii) allocating shares.

     Such modifications or amendments shall not require stockholder approval or
the consent of any Plan participants.

                                      -7-

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