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                                                                   EXHIBIT 10.06

                          CONCORD COMMUNICATIONS, INC.
                                 1997 STOCK PLAN
                (AS AMENDED ON MARCH 12, 1998 AND MARCH 1, 1999)

     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
          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

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          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 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.

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     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 Common Stock reacquired by the Company in any
manner. The aggregate number of shares which may be issued pursuant to the Plan
is 2,500,000, 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. 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

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          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.

     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


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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 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:

               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

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          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.

               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


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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
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, subject to approval of the amendment of the Plan by the
stockholders of the Company at the next Meeting of Stockholders. If the approval
of the amendment by the stockholders is not obtained prior to March 1, 2000, any
grants of ISOs under the Plan which include shares from the additional number of
shares authorized by the amendment made prior to that date but subsequent to the
date of the amendment will be rescinded. 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 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.

<PAGE>   8

     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. 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.