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                                                                     EXHIBIT 4.3

                          MISSION SYSTEMS, INCORPORATED

                        1996 EQUITY INCENTIVE STOCK PLAN

1.   PURPOSE.

This 1996 Equity Incentive Stock Plan (the "Plan") is intended to provide
incentives: (a) to officers and other employees of Mission Systems, Inc. (the
"Company"), and any present or future parent or subsidiary of the Company
(collectively, "Related Corporations"), by providing them with opportunities to
purchase stock in the Company pursuant to options granted hereunder, which
qualify as "incentive stock options"("ISOs") under Section 422(b) of the
Internal Revenue Code of 1986, as amended (the "Code"); (b) to directors,
officers, employees and consultants of the Company and Related Corporations by
providing them with opportunities to purchase stock in the Company pursuant to
options granted hereunder, which do not qualify as ISOs but as "nonqualified
options" ("NQs") and (c) to directors, officers, employees and consultants of
the Company and Related Corporations by providing them with awards of stock of
the Company "Awards" ). Both ISOs and NQs are referred to hereafter individually
as an "Option" and collectively as "Options". Options and Awards 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.

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 by a committee appointed by the Board (the "Committee")
     provided that, to the extent required by Rule 16b-3 promulgated under the
     Securities Exchange Act of 1934 or any successor provision ("Rule 16b-3"),
     with respect to specific grants of Stock Rights, the Plan shall be
     administered by a disinterested administrator or administrators within the
     meaning of Rule 16b-3. All references to this Plan to the Committee shall
     mean the Board if a Committee has not been appointed. Subject to
     ratification of the grant 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 the employees of the
     Company and Related Corporations (subject to paragraph 3) to whom ISOs
     shall be granted, and determine (subject to paragraph 3) to whom NQs and
     Awards may be granted, (ii) determine the time or times at which Options or
     Awards shall be granted (iii) determine the exercise price of shares
     subject to each Option, which price shall not be less than the minimum
     price specified in paragraph 6; (iv) determine whether each Option granted
     shall be an ISO or an NQ (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 in shares subject to Options and Awards and the
     nature of such restrictions, if any, (vii) interpret the

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     Plan and prescribe and rescind rules and regulations relating to it; and
     (viii) resolve any disputes relating to the Plan or any Stock Rights issued
     pursuant to the Plan. If the Committee determines to issue an NQ, it shall
     take whatever actions it deems necessary, under Section 422 of the Code and
     applicable regulations, to ensure that such Option is not treated as an
     ISO. The interpretation and construction by the Committee of any provision
     of the Plan or any Stock Grant 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 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 chairman and shall hold
     meetings at such times and places as it may determine. Acts by a majority
     of the members of the Committee, or acts reduced to, or approved in writing
     by a majority of the members of the Committee (if consistent with
     applicable state law), shall constitute the valid acts of the Committee.
     From time to time the Board may increase the size of the Committee and
     appoint additional members, remove members (with or without cause) and
     appoint members in substitution, fill vacancies however caused, or remove
     all members of the Committee and thereafter directly administer the Plan.

3.   ELIGIBLE EMPLOYEES AND OTHERS.

ISOs may be granted only to employees of the Company or any Related Corporation.
NQs and Awards may be granted to any employee, officer, 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 an ISO, an NQ, or an Award. Granting of any Stock
Right to any individual or entity shall neither entitle that individual or
entity to, or disqualify him, her, or it from, participation in any other grant
of Stock Rights.

4.   STOCK

The stock subject to Options and Awards shall be authorized but unissued shares
of Class B Common Non-Voting Stock of the Company, no par value 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 200,000, subject to adjustments as provided in paragraph 13. If any Stock
Right 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, the unpurchased shares subject to such Stock Right shall
again be available for grants of Stock Rights under the Plan.

5.   GRANTING OF STOCK RIGHTS.

Stock Rights may be granted under the Plan at any time after April 25, 1996 and
prior to December 31, 2005. The date of grant of a Stock Right under the plan
will be the date specified

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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.

     The exercise price per share specified in the agreement relating to each NQ
     granted under the Plan shall in no event be less than the minimum legal
     consideration required therefor under the laws of New Hampshire, or the
     laws of any jurisdiction in which the Company or its successors in interest
     may be organized.

     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 fair market value per
     share of Common Stock on the date of such grant. In the case of an ISO
     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
     ISOs were granted) in excess of $100,000. The Company intends to designate
     any Options granted in excess of such limitations as NQs.

     D.   DETERMINATION OF FAIR MARKET VALUE.

     If, at the time an Option is granted under the Plan, Company's stock is
     publicly traded, "fair market value" shall be determined as of the last
     business day for which the prices or discussed in this sentence are
     available prior to the date such Option is granted and shall mean (i) the
     average (on the 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 List, if the Common Sock is not then traded on a
     national securities exchange; or (iii) the closing bid price (or the
     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 List. However, if the Common
     Stock is not


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     publicly traded at the time an Option is granted under the Plan, "fair
     market value" shall be deemed to be 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, each Option
shall expire on the date specified by the Committee, but not more than (i) ten
(10) years from the date of grant in the case of Options generally, and (ii)
five (5) years from the date of grant in the case of ISOs granted to an employee
owning stock possessing more than then 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 an NQ 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 the 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 of exercise of
     any installment of any Option, provided that the Committee shall not,
     without the consent of the optionee, accelerate the exercise date of any
     installment of any Option granted to any employee as an ISO (and not
     previously converted into an NQ 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).

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9.       TERMINATION OF EMPLOYMENT.

                  A.       TERMINATION FOR CAUSE OR RESIGNATION.

                  If an ISO optionee resigns without the written permission of
                  the Company, or is terminated for cause during the vesting
                  period of any Option, any such Option shall terminate
                  immediately, to the extent not previously exercised. Further,
                  the Company shall have the fight, but not the obligation, to
                  purchase from the optionee all, or any portion of the shares
                  obtained pursuant to the Plan, at any reasonable price in
                  excess of the exercise price, as determined by the Board or
                  Committee.

                  B.       TERMINATION FOR OTHER THAN DEATH AND DISABILITY.

                  If an ISO optionee ceases to be employed by the Company and
                  all Related Corporations other than as defined in paragraph 9
                  (A) above, or by reason of death or disability as defined in
                  paragraph 10, no further installments of his ISOs shall become
                  exercisable, and his / her ISOs shall terminate after the
                  passage of five (5) business days from the date of termination
                  of his / her employment, but in no event later than on their
                  specified expiration dates, except to the extent that such ISO
                  (or unexercised installment thereof) have been converted into
                  NQs pursuant to paragraph 16. For the purposes of this
                  paragraph 9, employment shall be considered as continuing
                  uninterrupted during any 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 ninety (90) days, or, if longer, any period
                  during which such optionee's reemployment is guaranteed by
                  statute. A bona fide 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
                  Corporations to continue the employment of the optionee after
                  the expiration of the approved period of absence. ISOs granted
                  under the Plan shall not be affected by any change in
                  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 guarantee of any Stock
                  Fight the fight 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 / her death, any ISO
                  of his / hers may be exercised, to the extent of the number of
                  shares with respect to which he / she could have exercised it
                  on the date of his / her death, by his 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 the specified expiration date of the
                  ISO, or 180 days from the date of the optionee's death.

                  B.       DISABILITY.

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                  If an ISO optionee ceases to be employed by the Company and
                  all Related Corporations by reason of his / her disability
                  he/she shall have the right to exercise any ISO held by him
                  her on the date of termination of employment, to the extent
                  of the number of shares with respect to which he / she could
                  have exercised it on that date, at any time prior the earlier
                  of the specified expiration date of the ISO, or 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 Stock Right shall be assignable or transferable by the grantee except by
will, or by the laws of descent and distribution. During the lifetime of the
grantee each Stock Right shall be exercisable only by him / her.

12.      TERMS AND CONDITIONS OF OPTIONS.

Options shall be evidenced by instruments (which need not be identical) in such
form 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 NQ 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 actions 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 him / her 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 lesser 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.

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                  If the Company is to be consolidated with, or acquired by
                  another entity in a merger, sale of all, or substantially all
                  of the Company's assets, or otherwise (an "Acquisition"), the
                  Committee, or the board of directors of such entity assuming
                  the obligations of the Company hereunder (the "Successor
                  Board"), shall, as to outstanding Options, either (i) make
                  appropriate provisions for the continuation of such Options,
                  by substituting, on an equitable basis, for the shares then
                  subject to such Options the consideration payable with respect
                  to the outstanding shares of Common Stock in connection with
                  the Acquisition; or (ii) upon written notice to the optionees,
                  provide that all Options must be exercised, to the extent then
                  exercisable, within the specified number of days from the date
                  of such notice; at the end of which period the Options shall
                  terminate; or (iii) terminate all Options in exchange for a
                  cash payment equal to the excess of the fair market value of
                  the shares subject to such Options (to the extent then
                  exercisable) over the exercise price thereof.

                  C.       RECAPITALIZATION OR REORGANIZATION.

                  In the event of a recapitalization 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/she would have received, if he / she had exercised his/her
                  Option prior to such recapitalization, or reorganization.

                  D.       MODIFICATION OF ISOS.

                  Notwithstanding the foregoing, any adjustments made with
                  respect to ISOs, pursuant to subparagraph A, B or C above,
                  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.       DISSOLUTION OR LIQUIDATION.

                  In the event of the proposed dissolution or liquidation of the
                  Company, each Option will terminate immediately prior to the
                  consummation of such proposed action, or at such other time
                  and subject to such other conditions as shall be determined by
                  the Committee.

                  F.       ISSUANCE OF SECURITIES.

                  Except as expressly provided herein, no issuance by the
                  Company of the shares of stock of any class, or securities
                  convertible into shares of stock of any class of stock, shall
                  effect, and no adjustments by reason thereof shall affect or
                  result in an adjustment to the number, or price of shares
                  subject to Options. No adjustments

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                  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 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 subparagraph 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, or the Successor Board, 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.

A Stock Right (or any part or installment thereof) shall be exercised by giving
written notice to the Company at its principal office address. Such notice shall
identify the Stock Right being exercised and specify the number of shares as to
which such Stock Right 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 exercise, to
the cash exercise price of the Stock Rights, (c) at the discretion of the
Committee, by delivery of the grantee's personal recourse note, bearing interest
payable, not less than annually, at no less than one hundred percent (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
Stock Right, 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 the exercise, or (e) at the discretion of the Committee, by any
combination of (a), (b), (c) or (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 (a), (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 a Stock Right shall not have the fights of
a shareholder with respect to the shares covered by this Stock Right, until the
date of issuance of a stock certificate to him/ her 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 fights 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 and shareholder on March 8, 1996 and shall
expire at the end of the day on December 31, 2005 (except as to Options
outstanding on that date). The Board may terminate or amend the Plan at any
time, except that, without the approval of the stockholders obtained within
twelve (12) months before or after the Board adopts the resolution

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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 benefits accruing to participants under the Plan may
not be materially increased, (c) the requirement as to eligibility for
participation in the Plan may not be materially modified; (d) the provisions of
paragraph 3 regarding eligibility for grants of ISOs may not be modified; (e)
the provision 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); (f) the expiration date of the Plan may not be extended; and
(g) the Board may not take any action which would cause the Plan to fail to
comply with Rule 16b-3. Except as otherwise provided in this paragraph 15, in no
event may action of the Board or the stockholders alter or impair the fights of
the grantee, without his consent, under any Stock Right previously granted to
him.

16. CONVERSION OF ISOS INTO NON-QUALIFIED OPTIONS.

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 ISO's (or any installment or portions of installments thereof)
that have not been exercised on the date of conversion, into NQs, at any time
prior to the expiration of such ISOs, regardless of whether such optionee is an
employee of the Company or a Related Corporation at the time of such conversion.
Such actions may include, but not be limited to, extending the exercise period,
or reducing the exercise price of the appropriate installment 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 NQs 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 the
optionee the right to have such optionee's ISO's converted into NQs and no such
conversion shall occur until and unless the Committee takes appropriate action.

17.      APPLICATION OF FUNDS.

The proceeds received by the Company from the sale of shares pursuant to Options
granted 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 he makes a Disqualifying Disposition (as
described in Sections 421, 422 and 424 of the Code and the regulations
thereunder) of any stock acquired pursuant to the exercise of ISOs granted under
the Plan. A Disqualifying Disposition is generally any disposition occurring
within two years of the date the ISO was granted, or within one year of the date
the ISO was exercised, whichever period ends later.

19.      WITHHOLDING OF ADDITIONAL INCOME TAXES.

Upon the exercise of an NQ or the grant of an Award 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 a Stock Right hereunder, or the making of a distribution or other
payment with respect to such stock or securities, the Company may withhold taxes
for amounts that constitute compensation includable in gross income. The
Committee in its discretion may condition (i) the exercise of an Option, (ii)
the grant of an Award, or (iii) the vesting or transferability of restricted
stock or securities acquired by

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exercising a Stock Right, 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 an agreement for the withholding or offset against any compensation
due to grantee by the Company, or, by the grantee's delivery of previously held
shares of Common Stock otherwise deliverable upon exercise of a Stock Right
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 Stock Rights in connection with the
Plan.

21.      GOVERNING LAW: CONSTRUCTION.

The validity and construction of the Plan and the instrument evidencing Stock
Rights shall be governed by the laws of the State of New Hampshire, or the laws
of any jurisdiction in which the Company, or its successors in interest, may be
organized. In construing this Plan, the singular shall include the plural,
unless the context otherwise requires.