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                                                                   Exhibit 10.06

                          CONCORD COMMUNICATIONS, INC.
                                 1997 STOCK PLAN

 (AS AMENDED ON MARCH 12, 1998, MARCH 1, 1999, MAY 15, 1999 AND MARCH 8, 2000)

      1. PURPOSE; TERMINATION OF PRIOR PLAN. The purpose of the 1997 Stock Plan
(the "Plan") is to encourage key employees of Concord Communications, Inc. (the
"Company") and of any present or future parent or subsidiary of the Company
(collectively, "Related Corporations") and other individuals who render services
to the Company or a Related Corporation, by providing opportunities to
participate in the ownership of the Company and its future growth through (a)
the grant of options which qualify as "incentive stock options" ("ISOs") under
Section 422(b) of the Internal Revenue Code of 1986, as amended (the "Code");
(b) the grant of options which do not qualify as ISOs ("Non-Qualified Options");
(c) awards of stock in the Company ("Awards"); and (d) opportunities to make
direct purchases of stock in the Company ("Purchases"). Both ISOs and
Non-Qualified Options are referred to hereafter individually as an "Option" and
collectively as "Options." Options, Awards and authorizations to make Purchases
are referred to hereafter collectively as "Stock Rights." As used herein, the
terms "parent" and "subsidiary" mean "parent corporation" and "subsidiary
corporation," respectively, as those terms are defined in Section 424 of the
Code. The Company's 1995 Stock Plan (the "1995 Stock Plan") is terminated
effective as of October 16, 1997 and henceforth, the Company shall make no
grants under the 1995 Stock Plan. The 1995 Stock Plan shall, however, continue
to govern all options, awards and other grants granted and outstanding under the
1995 Stock Plan.

      2.    ADMINISTRATION OF THE PLAN.

                  A. BOARD OR COMMITTEE ADMINISTRATION. The Plan shall be
            administered by the Board of Directors of the Company (the "Board")
            or, subject to paragraph 2(D) (relating to compliance with Section
            162(m) of the Code), by a committee appointed by the Board of two or
            more of its members (the "Committee"). Hereinafter, all references
            in this Plan to the "Committee" shall mean the Board if no Committee
            has been appointed. Subject to ratification of the grant or
            authorization of each Stock Right by the Board (if so required by
            applicable state law), and subject to the terms of the Plan, the
            Committee shall have the authority to (i) determine to whom (from
            among the class of employees eligible under paragraph 3 to receive
            ISOs) ISOs shall be granted, and to whom (from among the class of
            individuals and entities eligible under paragraph 3 to receive
            Non-Qualified Options and Awards and to make Purchases)
            Non-Qualified Options, Awards and authorizations to make Purchases
            may be granted; (ii) determine the time or times at which Options or
            Awards shall be granted or Purchases made; (iii) determine the
            purchase price of shares subject to each Option or Purchase, which
            prices shall not be less than the minimum price specified in
            paragraph 6; (iv) determine whether each Option granted shall be an
            ISO or a Non-Qualified Option; (v) determine (subject to paragraph
            7) the time or times when each Option shall become exercisable and
            the duration of the exercise period; (vi) determine whether
            restrictions such as repurchase options are to be
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            imposed on shares subject to Options, Awards and Purchases and the
            nature of such restrictions, if any; and (vii) interpret the Plan
            and prescribe and rescind rules and regulations relating to it. If
            the Committee determines to issue a Non-Qualified Option, it shall
            take whatever actions it deems necessary, under Section 422 of the
            Code and the regulations promulgated thereunder, to ensure that such
            Option is not treated as an ISO. The interpretation and construction
            by the Committee of any provisions of the Plan or of any Stock Right
            granted under it shall be final unless otherwise determined by the
            Board. The Committee may from time to time adopt such rules and
            regulations for carrying out the Plan as it may deem best. No member
            of the Board or of the Committee shall be liable for any action or
            determination made in good faith with respect to the Plan or any
            Stock Right granted under it.

                  B. COMMITTEE ACTIONS. The Committee may select one of its
            members as its chairman, and shall hold meetings at such time and
            places as it may determine. A majority of the Committee shall
            constitute a quorum and acts of a majority of the members of the
            Committee at a meeting at which a quorum is present, or acts reduced
            to or approved in writing by all the members of the Committee (if
            consistent with applicable state law), shall be the valid acts of
            the Committee. From time to time the Board may increase the size of
            the Committee and appoint additional members thereof, remove members
            (with or without cause) and appoint new members in substitution
            therefor, fill vacancies however caused, or remove all members of
            the Committee and thereafter directly administer the Plan.

                  C. GRANT OF STOCK RIGHTS TO BOARD MEMBERS. Notwithstanding the
            provisions of paragraph 2.A., no Stock Rights shall be granted to
            any person who is, at the time of the proposed grant, a member of
            the Board unless such grant is approved by a majority vote of the
            disinterested members of the Board. All grants of Stock Rights to
            members of the Board shall in all respects be made in accordance
            with the provisions of this Plan applicable to other eligible
            persons. Members of the Board who either (i) are eligible to receive
            grants of Stock Rights pursuant to the Plan or (ii) have been
            granted Stock Rights may vote on any matters affecting the
            administration of the Plan or the grant of any Stock Rights pursuant
            to the Plan, except that no such member shall act upon the granting
            to himself or herself of Stock Rights, but any such member may be
            counted in determining the existence of a quorum at any meeting of
            the Board during which action is taken with respect to the granting
            to such member of Stock Rights. Notwithstanding any other provision
            of this paragraph 2, in the event the Company registers any class of
            any equity security pursuant to Section 12 of the Securities
            Exchange Act of 1934, as amended (the "Exchange Act"), any grants to
            members of the Board of Options made at any time from the effective
            date of such registration until six months after the termination of
            such registration shall be made only by the Board; provided,
            however, that if a majority of the Board is eligible to participate
            in the Plan or in any other stock option or other stock plan
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            of the Company or any of its affiliates, or has been so eligible at
            any time within the preceding year, any grant to directors of
            Options must be made by, or only in accordance with the
            recommendation of, a Committee consisting of three or more persons,
            who may but need not be members of the Board or employees of the
            Company, appointed by the Board but having full authority to act in
            the matter, none of whom is eligible to participate in this Plan or
            any other stock option or other stock plan of the Company or any of
            its affiliates, or has been eligible at any time within the
            preceding year. The requirements imposed by the preceding sentence
            shall also apply with respect to grants to officers who are not also
            members of the Board. Once appointed, the Committee shall continue
            to serve until otherwise directed by the Board.

                  D. PERFORMANCE-BASED COMPENSATION. The Board, in its
            discretion, may take such action as may be necessary to ensure that
            Stock Rights granted under the Plan qualify as "qualified
            performance-based compensation" within the meaning of Section 162(m)
            of the Code and applicable regulations promulgated thereunder
            ("Performance-Based Compensation"). Such action may include, in the
            Board's discretion, some or all of the following (i) if the Board
            determines that Stock Rights granted under the Plan generally shall
            constitute Performance-Based Compensation, the Plan shall be
            administered, to the extent required for such Stock Rights to
            constitute Performance-Based Compensation, by a Committee consisting
            solely of two or more "outside directors" (as defined in applicable
            regulations promulgated under Section 162(m) of the Code), (ii) if
            any Non-Qualified Options with an exercise price less than the fair
            market value per share of Common Stock are granted under the Plan
            and the Board determines that such Options should constitute
            Performance-Based Compensation, such options shall be made
            exercisable only upon the attainment of a pre-established, objective
            performance goal established by the Committee, and such grant shall
            be submitted for, and shall be contingent upon shareholder approval
            and (iii) Stock Rights granted under the Plan may be subject to such
            other terms and conditions as are necessary for compensation
            recognized in connection with the exercise or disposition of such
            Stock Right or the disposition of Common Stock acquired pursuant to
            such Stock Right, to constitute Performance-Based Compensation.

      3. ELIGIBLE EMPLOYEES AND OTHERS. ISOs may be granted only to employees of
the Company or any Related Corporation. Non-Qualified Options, Awards and
authorizations to make Purchases may be granted to any employee, officer or
director (whether or not also an employee) or consultant of the Company or any
Related Corporation. The Committee may take into consideration a recipient's
individual circumstances in determining whether to grant a Stock Right. The
granting of any Stock Right to any individual or entity shall neither entitle
that individual or entity to, nor disqualify such individual or entity from,
participation in any other grant of Stock Rights.

      4. STOCK. The stock subject to Stock Rights shall be authorized but
unissued shares of Common Stock of the Company, par value $.01 per share (the
"Common Stock"), or shares of
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Common Stock reacquired by the Company in any manner. The aggregate number of
shares which may be issued pursuant to the Plan is 3,250,000, subject to
adjustment as provided in paragraph 13. If any Option granted under the Plan
shall expire or terminate for any reason without having been exercised in full
or shall cease for any reason to be exercisable in whole or in part or shall be
repurchased by the Company, the unpurchased shares of Common Stock subject to
such Option shall again be available for grants of Stock Rights under the Plan.

      No employee of the Company or any Related Corporation may be granted
Options to acquire, in the aggregate, more than 70% of the aggregate number of
shares of Common Stock which may be issued pursuant to the Plan during any
fiscal year of the Company. If any Option granted under the Plan shall expire or
terminate for any reason without having been exercised in full or shall cease
for any reason to be exercisable in whole or in part or shall be repurchased by
the Company, the shares subject to such Option shall be included in the
determination of the aggregate number of shares of Common Stock deemed to have
been granted to such employee under the Plan.

      5. GRANTING OF STOCK RIGHTS. Stock Rights may be granted under the Plan at
any time on or after October 16, 1997 and prior to October 15, 2007. The date of
grant of a Stock Right under the Plan will be the date specified by the
Committee at the time it grants the Stock Right; provided, however, that such
date shall not be prior to the date on which the Committee acts to approve the
grant.

      6.    MINIMUM OPTION PRICE; ISO LIMITATIONS.

                  A. PRICE FOR NON-QUALIFIED OPTIONS, AWARDS AND PURCHASES.
            Subject to paragraph 2(D) (relating to compliance with Section
            162(m) of the Code), the exercise price per share specified in the
            agreement relating to each Non-Qualified Option granted, and the
            purchase price per share of stock granted in any Award or authorized
            as a Purchase, under the Plan may be less than the fair market value
            of the Common Stock of the Company on the date of grant; provided
            that, in no event shall such exercise price or such purchase price
            be less than the lesser of (i) the book value per share of Common
            Stock as of the end of the fiscal year of the Company immediately
            preceding the date of such grant, or (ii) 50 percent of the fair
            market value per share of Common Stock on the date of such grant.

                  B. PRICE FOR ISOS. The exercise price per share specified in
            the agreement relating to each ISO granted under the Plan shall not
            be less than the fair market value per share of Common Stock on the
            date of such grant. In the case of an ISO to be granted to an
            employee owning stock possessing more than ten percent (10%) of the
            total combined voting power of all classes of stock of the Company
            or any Related Corporation, the price per share specified in the
            agreement relating to such ISO shall not be less than one hundred
            ten percent (110%) of the fair market value per share of Common
            Stock on the date of grant.
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            For purposes of determining stock ownership under this paragraph,
            the rules of Section 424(d) of the Code shall apply.

                  C. $100,000 ANNUAL LIMITATION ON ISO VESTING. Each eligible
            employee may be granted Options treated as ISOs only to the extent
            that, in the aggregate under this Plan and all incentive stock
            option plans of the Company and any Related Corporation, ISOs do not
            become exercisable for the first time by such employee during any
            calendar year with respect to stock having a fair market value
            (determined at the time the ISOs were granted) in excess of
            $100,000. The Company intends to designate any Options granted in
            excess of such limitation as Non-Qualified Options, and the Company
            shall issue separate certificates to the optionee with respect to
            Options that are Non-Qualified Options and Options that are ISOs.

                  D. DETERMINATION OF FAIR MARKET VALUE. If, at the time an
            Option is granted under the Plan, the Company's Common Stock is
            publicly traded, "fair market value" shall be determined as of the
            date of grant or, if the prices or quotes discussed in this sentence
            are unavailable for such date, the last business day for which such
            prices or quotes are available prior to the date of grant and shall
            mean (i) the average (on that date) of the high and low prices of
            the Common Stock on the principal national securities exchange on
            which the Common Stock is traded, if the Common Stock is then traded
            on a national securities exchange; or (ii) the last reported sale
            price (on that date) of the Common Stock on the Nasdaq National
            Market, if the Common Stock is not then traded on a national
            securities exchange; or (iii) the closing bid price (or average of
            bid prices) last quoted (on that date) by an established quotation
            service for over-the-counter securities, if the Common Stock is not
            reported on the Nasdaq National Market. If the Common Stock is not
            publicly traded at the time an Option is granted under the Plan,
            "fair market value" shall mean the fair value of the Common Stock as
            determined by the Committee after taking into consideration all
            factors which it deems appropriate, including, without limitation,
            recent sale and offer prices of the Common Stock in private
            transactions negotiated at arm's length.

      7. OPTION DURATION. Subject to earlier termination as provided in
paragraphs 9 and 10 or in the agreement relating to such Option, each Option
shall expire on the date specified by the Committee, but not more than (i) ten
years from the date of grant in the case of Options generally and (ii) five
years from the date of grant in the case of ISOs granted to an employee owning
stock possessing more than ten percent (10%) of the total combined voting power
of all classes of stock of the Company or any Related Corporation, as determined
under paragraph 6(B). Subject to earlier termination as provided in paragraphs 9
and 10, the term of each ISO shall be the term set forth in the original
instrument granting such ISO, except with respect to any part of such ISO that
is converted into a Non-Qualified Option pursuant to paragraph 16.
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                                     - 6 -


      8. EXERCISE OF OPTION. Subject to the provisions of paragraphs 9 through
12, each Option granted under the Plan shall be exercisable as follows:

                  A. VESTING. The Option shall either be fully exercisable on
            the date of grant or shall become exercisable thereafter in such
            installments as the Committee may specify.

                  B. FULL VESTING OF INSTALLMENTS. Once an installment becomes
            exercisable, it shall remain exercisable until expiration or
            termination of the Option, unless otherwise specified by the
            Committee.

                  C. PARTIAL EXERCISE. Each Option or installment may be
            exercised at any time or from time to time, in whole or in part, for
            up to the total number of shares with respect to which it is then
            exercisable.

                  D. ACCELERATION OF VESTING. The Committee shall have the right
            to accelerate the date that any installment of any Option becomes
            exercisable; provided that the Committee shall not, without the
            consent of an optionee, accelerate the permitted exercise date of
            any installment of any Option granted to any employee as an ISO (and
            not previously converted into a Non-Qualified Option pursuant to
            paragraph 16) if such acceleration would violate the annual vesting
            limitation contained in Section 422(d) of the Code, as described in
            paragraph 6(C).

      9. TERMINATION OF EMPLOYMENT. Unless otherwise specified in the agreement
relating to such ISO, if an ISO optionee ceases to be employed by the Company
and all Related Corporations other than by reason of death or disability as
defined in paragraph 10, no further installments of his or her ISOs shall become
exercisable, and his or her ISOs shall terminate after the passage of 60 days
from the date of termination of his or her employment, but in no event later
than on the specified expiration dates of such ISOs, except to the extent that
such ISOs (or unexercised installments thereof) have been converted into
Non-Qualified Options pursuant to paragraph 16. For purposes of this paragraph
9, a leave of absence with the written approval of the Committee shall not be
considered an interruption of employment under the Plan, provided that such
written approval contractually obligates the Company or any Related Corporation
to continue the employment of the employee after the approved period of absence.
Employment shall also be considered as continuing uninterrupted during any other
bona fide leave of absence (such as those attributable to illness, military
obligations or governmental service) provided that the period of such leave does
not exceed 90 days or, if longer, any period during which such optionee's right
to reemployment is guaranteed by statute or by contract. A bona fide leave of
absence with the written approval of the Committee shall not be considered an
interruption of employment under this paragraph 9, provided that such written
approval contractually obligates the Company or any Related Corporation to
continue the employment of the optionee after the approved period of absence.
ISOs granted under the Plan shall not be affected by any change of employment
within or among the Company and Related Corporations, so long as the optionee
continues to be an employee of the Company or any Related Corporation. Nothing
in the Plan
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                                     - 7 -


shall be deemed to give any grantee of any Stock Right the right to be retained
in employment or other service by the Company or any Related Corporation for any
period of time.

      10.   DEATH; DISABILITY.

                  A. DEATH. If an ISO optionee ceases to be employed by the
            Company and all Related Corporations by reason of his or her death,
            any ISO owned by such optionee may be exercised, to the extent
            otherwise exercisable on the date of death, by the estate, personal
            representative or beneficiary who has acquired the ISO by will or by
            the laws of descent and distribution, at any time prior to the
            earlier of (i) the specified expiration date of the ISO or (ii) 180
            days from the date of the optionee's death.

                  B. DISABILITY. If an ISO optionee ceases to be employed by the
            Company and all Related Corporations by reason of his or her
            disability, such optionee shall have the right to exercise any ISO
            held by him or her on the date of termination of employment, for the
            number of shares for which he or she could have exercised it on that
            date, at any time prior to the earlier of (i) the specified
            expiration date of the ISO or (ii) 180 days from the date of the
            termination of the optionee's employment. For the purposes of the
            Plan, the term "disability" shall mean "permanent and total
            disability" as defined in Section 22(e)(3) of the Code or any
            successor statute.

      11. ASSIGNABILITY. No ISO shall be assignable or transferable by the
optionee except by will or by the laws of descent and distribution, and during
the lifetime of the optionee shall be exercisable only by such optionee. Stock
Rights other than ISOs shall be transferable to the extent set forth in the
agreement relating to such Stock Right.

      12. TERMS AND CONDITIONS OF OPTIONS. Options shall be evidenced by
instruments (which need not be identical) in such forms as the Committee may
from time to time approve. Such instruments shall conform to the terms and
conditions set forth in paragraphs 6 through 11 hereof and may contain such
other provisions as the Committee deems advisable which are not inconsistent
with the Plan, including restrictions applicable to shares of Common Stock
issuable upon exercise of Options. The Committee may specify that any
Non-Qualified Option shall be subject to the restrictions set forth herein with
respect to ISOs, or to such other termination and cancellation provisions as the
Committee may determine. The Committee may from time to time confer authority
and responsibility on one or more of its own members and/or one or more officers
of the Company to execute and deliver such instruments. The proper officers of
the Company are authorized and directed to take any and all action necessary or
advisable from time to time to carry out the terms of such instruments.

      13. ADJUSTMENTS. Upon the occurrence of any of the following events, an
optionee's rights with respect to Options granted to such optionee hereunder
shall be adjusted as hereinafter provided, unless otherwise specifically
provided in the written agreement between the optionee and the Company relating
to such Option:
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                                     - 8 -


                  A. STOCK DIVIDENDS AND STOCK SPLITS. If the shares of Common
            Stock shall be subdivided or combined into a greater or smaller
            number of shares or if the Company shall issue any shares of Common
            Stock as a stock dividend on its outstanding Common Stock, the
            number of shares of Common Stock deliverable upon the exercise of
            Options shall be appropriately increased or decreased
            proportionately, and appropriate adjustments shall be made in the
            purchase price per share to reflect such subdivision, combination or
            stock dividend.

                  B. CONSOLIDATIONS OR MERGERS. If the Company is to be
            consolidated with or acquired by another entity in a merger or other
            reorganization in which the holders of the outstanding voting stock
            of the Company immediately preceding the consummation of such event,
            shall, immediately following such event, hold, as a group, less than
            a majority of the voting securities of the surviving or successor
            entity, or in the event of a sale of all or substantially all of the
            Company's assets or otherwise (each, an "Acquisition"), the
            Committee may take one or more of the following actions: (i) provide
            for the acceleration and/or termination of any time period relating
            to the exercise of the Options, (ii) provide for the purchase of the
            Options, upon the optionee's request, for the amount in cash that
            could have been received upon the exercise of the Options and sale
            of the shares obtained thereby, (iii) adjust the terms of the
            Options in a manner determined by the Committee, (iv) cause the
            Options to be assumed, or new rights substituted therefor, by
            another entity or (v) make such other provision as the Committee may
            consider equitable and in the best interests of the Company.

                  C. RECAPITALIZATION OR REORGANIZATION. In the event of a
            recapitalization or reorganization of the Company (other than a
            transaction described in subparagraph B above) pursuant to which
            securities of the Company or of another corporation are issued with
            respect to the outstanding shares of Common Stock, an optionee upon
            exercising an Option shall be entitled to receive for the purchase
            price paid upon such exercise the securities he or she would have
            received if he or she had exercised such Option prior to such
            recapitalization or reorganization.

                  D. MODIFICATION OF ISOS. Notwithstanding the foregoing, any
            adjustments made pursuant to subparagraphs A, B or C with respect to
            ISOs shall be made only after the Committee, after consulting with
            counsel for the Company, determines whether such adjustments would
            constitute a "modification" of such ISOs (as that term is defined in
            Section 424 of the Code) or would cause any adverse tax consequences
            for the holders of such ISOs. If the Committee determines that such
            adjustments made with respect to ISOs would constitute a
            modification of such ISOs or would cause adverse tax consequences to
            the holders, it may refrain from making such adjustments.
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                                     - 9 -


                  E. RESTRICTED SECURITIES. If any person or entity owning
            restricted Common Stock obtained by exercise of an Option made
            hereunder receives new or additional or different shares or
            securities ("New Securities") in connection with a transaction
            described in subparagraphs A, B or C above, as a result of owning
            such restricted Common Stock, such New Securities shall be subject
            to all of the conditions and restrictions applicable to the
            restricted Common Stock with respect to which such New Securities
            were issued.

                  F. ISSUANCES OF SECURITIES. Except as expressly provided
            herein, no issuance by the Company of shares of stock of any class,
            or securities convertible into shares of stock of any class, shall
            affect, and no adjustment by reason thereof shall be made with
            respect to, the number or price of shares subject to Options. No
            adjustments shall be made for dividends paid in cash or in property
            other than securities of the Company.

                  G. FRACTIONAL SHARES. No fractional shares shall be issued
            under the Plan. Any fractional shares which, but for this
            subparagraph G, would have been issued to an optionee pursuant to an
            Option, shall be deemed to have been issued and immediately sold to
            the Company for their fair market value, and the optionee shall
            receive from the Company cash in lieu of such fractional shares.

                  H. ADJUSTMENTS. Upon the happening of any of the events
            described in subparagraphs A, B or C above, the class and aggregate
            number of shares set forth in paragraph 4 hereof that are subject to
            Stock Rights which previously have been or subsequently may be
            granted under the Plan shall also be appropriately adjusted to
            reflect the events described in such subparagraphs. The Committee
            shall determine the specific adjustments to be made under this
            paragraph 13 and, subject to paragraph 2, its determination shall be
            conclusive.

      14. MEANS OF EXERCISING OPTIONS. An Option (or any part or installment
thereof) shall be exercised by giving written notice to the Company at its
principal office address, or to such transfer agent as the Company shall
designate. Such notice shall identify the Option being exercised and specify the
number of shares as to which such Option is being exercised, accompanied by full
payment of the purchase price therefor either (a) in United States dollars in
cash or by check, (b) at the discretion of the Committee, through delivery of
shares of Common Stock having a fair market value equal as of the date of the
exercise to the cash exercise price of the Option, (c) at the discretion of the
Committee, by delivery of the optionee's personal recourse note bearing interest
payable not less than annually at no less than 100% of the lowest applicable
Federal rate, as defined in Section 1274(d) of the Code, (d) at the discretion
of the Committee and consistent with applicable law, through the delivery of an
assignment to the Company of a sufficient amount of the proceeds from the sale
of the Common Stock acquired upon exercise of the Option and an authorization to
the broker or selling agent to pay that amount to the Company, which sale shall
be at the participant's direction at the time of exercise, or (e) at the
discretion of the Committee, by any combination of (a), (b), (c) and (d) above.
If the Committee exercises its discretion to permit payment of the exercise
price of an ISO by means of the methods set forth in
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                                     - 10 -


clauses (b), (c), (d) or (e) of the preceding sentence, such discretion shall be
exercised in writing at the time of the grant of the ISO in question. The holder
of an Option shall not have the rights of a shareholder with respect to the
shares covered by such Option until the date of issuance of a stock certificate
to such holder for such shares. Except as expressly provided above in paragraph
13 with respect to changes in capitalization and stock dividends, no adjustment
shall be made for dividends or similar rights for which the record date is
before the date such stock certificate is issued.

      15. TERM AND AMENDMENT OF PLAN. This Plan was adopted by the Board in July
1997 and by the stockholders of the Company on September 9, 1997. The Plan was
amended on March 12, 1998 to increase the number of shares authorized for
issuance under the Plan by 750,000 shares to 1,500,000, and such amendment was
approved by the stockholders of the Company at the Annual Meeting held on April
30, 1998. On March 1, 1999, the Board of Directors further amended the Plan to
increase the number of Shares authorized for issuance under the Plan by
1,000,000 shares to 2,500,000 shares and to make certain other minor
modifications, and such amendment was approved by the stockholders of the
Company at the Annual Meeting held on April 27, 1999. On May 15, 1999, the Board
of Directors further amended the Plan by adding Section 22 to the Plan. On March
8, 2000 the Board of Directors further amended the Plan to increase the number
of shares authorized for issuance under the Plan by 750,000 shares to 3,250,000,
subject to the approval of the amendment of the Plan by the stockholders of the
Company at the next Meeting of Stockholders. The Plan shall expire at the end of
the day on October 15, 2007 (except as to Options outstanding on that date).
Subject to the provisions of paragraph 5 above, Options may be granted under the
Plan prior to the date of stockholder approval of the Plan. The Board may
terminate or amend the Plan in any respect at any time, except that, without the
approval of the stockholders obtained within 12 months before or after the Board
adopts a resolution authorizing any of the following actions: (a) the total
number of shares that may be issued under the Plan may not be increased (except
by adjustment pursuant to paragraph 13); (b) the provisions of paragraph 3
regarding eligibility for grants of ISOs may not be modified; (c) the provisions
of paragraph 6(B) regarding the exercise price at which shares may be offered
pursuant to ISOs may not be modified (except by adjustment pursuant to paragraph
13); and (d) the expiration date of the Plan may not be extended. Except as
otherwise provided in this paragraph 15, in no event may action of the Board or
stockholders alter or impair the rights of a grantee, without such grantee's
consent, under any Stock Right previously granted to such grantee.

      16. MODIFICATIONS OF ISOS; CONVERSION OF ISOS INTO NON-QUALIFIED OPTIONS.
Subject to paragraph 13(D), without the prior written consent of the holder of
an ISO, the Committee shall not alter the terms of such ISO (including the means
of exercising such ISO) if such alteration would constitute a modification
(within the meaning of Section 424(h)(3) of the Code). The Committee, at the
written request or with the written consent of any optionee, may in its
discretion take such actions as may be necessary to convert such optionee's ISOs
(or any installments or portions of installments thereof) that have not been
exercised on the date of conversion into Non-Qualified Options at any time prior
to the expiration of such ISOs, regardless of whether the optionee is an
employee of the Company or a Related Corporation at the time of such conversion.
Such actions may include, but shall not be limited to, extending the
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exercise period of such ISOs. At the time of such conversion, the Committee
(with the consent of the optionee) may impose such conditions on the exercise of
the resulting Non-Qualified Options as the Committee in its discretion may
determine, provided that such conditions shall not be inconsistent with this
Plan. Nothing in the Plan shall be deemed to give any optionee the right to have
such optionee's ISOs converted into Non-Qualified Options, and no such
conversion shall occur until and unless the Committee takes appropriate action.
Upon the taking of such action, the Company shall issue separate certificates to
the optionee with respect to Options that are Non-Qualified Options and Options
that are ISOs. The Committee, with the consent of the optionee, may also
terminate any portion of any ISO that has not been exercised at the time of such
conversion.

      17. APPLICATION OF FUNDS. The proceeds received by the Company from the
sale of shares pursuant to Options granted and Purchases authorized under the
Plan shall be used for general corporate purposes.

      18. NOTICE TO COMPANY OF DISQUALIFYING DISPOSITION. By accepting an ISO
granted under the Plan, each optionee agrees to notify the Company in writing
immediately after such optionee makes a Disqualifying Disposition (as described
in Sections 421, 422 and 424 of the Code and regulations thereunder) of any
stock acquired pursuant to the exercise of ISOs granted under the Plan. A
Disqualifying Disposition is generally any disposition occurring on or before
the later of (a) the date two years following the date the ISO was granted or
(b) the date one year following the date the ISO was exercised.

      19. WITHHOLDING OF ADDITIONAL INCOME TAXES. Upon the exercise of a
Non-Qualified Option, the transfer of a Non-Qualified Stock Option pursuant to
an arm's-length transaction, the grant of an Award, the making of a Purchase of
Common Stock for less than its fair market value, the making of a Disqualifying
Disposition (as defined in paragraph 18), the vesting or transfer of restricted
stock or securities acquired on the exercise of an Option hereunder, or the
making of a distribution or other payment with respect to such stock or
securities, the Company may withhold, or may require the grantee to pay,
additional withholding taxes in respect of amounts that constitute compensation
includible in gross income. The Committee in its discretion may condition (i)
the exercise of an Option, (ii) the transfer of a Non-Qualified Stock Option,
(iii) the grant of an Award, (iv) the making of a Purchase of Common Stock for
less than its fair market value, or (v) the vesting or transferability of
restricted stock or securities acquired by exercising an Option, on the
grantee's making satisfactory arrangement for such withholding. Such arrangement
may include payment by the grantee in cash or by check of the amount of the
withholding taxes or, at the discretion of the Committee, by the grantee's
delivery of previously held shares of Common Stock or the withholding from the
shares of Common Stock otherwise deliverable upon exercise of a Option shares
having an aggregate fair market value equal to the amount of such withholding
taxes.

      20. GOVERNMENTAL REGULATION. The Company's obligation to sell and deliver
shares of the Common Stock under this Plan is subject to the approval of any
governmental authority required in connection with the authorization, issuance
or sale of such shares. Government regulations may impose reporting or other
obligations on the Company with respect to the Plan.
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For example, the Company may be required to send tax information statements to
employees and former employees that exercise ISOs under the Plan, and the
Company may be required to file tax information returns reporting the income
received by grantees of Options in connection with the Plan.

      21. GOVERNING LAW. The validity and construction of the Plan and the
instruments evidencing Stock Rights shall be governed by the laws of the
Commonwealth of Massachusetts, or the laws of any jurisdiction in which the
Company or its successors in interest may be organized.

      22. REPRICING. Without the prior approval of the Company's stockholders,
Options issued under the Plan shall not be repriced, replaced or regranted
through cancellation or by lowering the Option exercise price of a previously
granted Option.