<PAGE>
 
                                                                    Exhibit 10.3

                                  LEASE BETWEEN
                     TECHNOLOGY PARK VII LIMITED PARTNERSHIP
                                       AND
                              CARLETON CORPORATION
                                       FOR
                     BUILDING IX, 700 TECHNOLOGY PARK DRIVE
                            BILLERICA, MASSACHUSETTS

                                      INDEX
                                                                      Page No.
                                                                      --------

REFERENCE DATA                                                           1
--------------                                                           

         Paragraph 1.1   Subject Referred To                             1
         Paragraph 1.2   Exhibits                                        2

ARTICLE II - PREMISES AND TERM:                                          3
------------------------------

         Paragraph 2.1   Premises                                        3
         Paragraph 2.2   Term                                            3

ARTICLE III - CONSTRUCTION:                                              3
--------------------------

         Paragraph 3.1   Initial Construction                            3
         Paragraph 3.2   Preparation of Premises for Occupancy           4
         Paragraph 3.3   General Provisions Applicable to Construction   5
         Paragraph 3.4   Representatives                                 5

ARTICLE IV - RENT:                                                       5
-----------------

         Paragraph 4.1   Rent                                            5
         Paragraph 4.2   Operating Cost Escalation                       6
         Paragraph 4.3   Payments                                        8

ARTICLE V - LANDLORD'S COVENANTS:                                        8
--------------------------------

         Paragraph 5.1   Landlord's Covenants during the Term            8
         Paragraph 5.2   Interruptions                                   9

ARTICLE VI - TENANT'S COVENANTS:                                         9
-------------------------------

Paragraph 6.1            Tenant's Covenants during the Term              9
<PAGE>
 
ARTICLE VII - CASUALTY AND TAKING:                                       14
---------------------------------

         Paragraph 7.1   Casualty and Taking                             14
         Paragraph 7.2   Reservation of Award                            15

ARTICLE VIII - RIGHTS OF MORTGAGEE:                                      15
----------------------------------

         Paragraph 8.1   Priority of Lease                               15
         Paragraph 8.2   Limitation on Mortgagee's Liability             15
         Paragraph 8.3   Mortgagee's Election                            16
         Paragraph 8.4   No Prepayment or Modification, etc.             16
         Paragraph 8.5   No Release or Termination                       16
         Paragraph 8.6   Continuing Offer                                17
         Paragraph 8.7   Mortgagee's Approval                            17
         Paragraph 8.8   Submittal of Financial Statement                17

ARTICLE IX - DEFAULT:                                                    17
---------------------

         Paragraph 9.1   Events of Default                               17
         Paragraph 9.2   Tenant's Obligations After Termination          18

ARTICLE X - MISCELLANEOUS:                                               19
-------------------------

Paragraph 10.1           Titles                                          19
Paragraph 10.2           Notice of Lease                                 19
Paragraph 10.3           Relocation                                      19
Paragraph 10.4           Notices from One Party to the Other             19
Paragraph 10.5           Bind and Inure                                  19
Paragraph 10.6           No Surrender                                    19
Paragraph 10.7           No Waiver, etc.                                 20
Paragraph 10.8           No Accord and Satisfaction                      20
Paragraph 10.9           Cumulative Remedies                             20
Paragraph 10.10          Partial Invalidity                              20
Paragraph 10.11          Landlord's Right to Cure                        21
Paragraph 10.12          Estoppel Certificate                            21
Paragraph 10.13          Waiver of Subrogation                           21
Paragraph 10.14          Brokerage                                       21

ARTICLE XI - SECURITY DEPOSIT                                            22
-----------------------------
<PAGE>
 
                Date of Lease Execution: July 25, 1996

                                 REFERENCE DATA

1.1      SUBJECTS REFERRED TO:

         Each reference in this Lease to any of the following subjects shall
         incorporate the data stated for that subject in this Section 1.1.

LANDLORD: Technology Park VIII Limited Partnership

MANAGING AGENT: The Gutierrez Company

LANDLORD'S AND MANAGING AGENT'S ADDRESS: Burlington Office Park
                                         One Wall Street
                                         Burlington, Massachusetts 01803

LANDLORD'S REPRESENTATIVE: John A. Cataldo

TENANT: Carleton Corporation

TENANT'S ADDRESS (FOR NOTICE & BILLING): 700 Technology Park Drive - Building IX
                                         Billerica Massachusetts 01821

TENANT REPRESENTATIVE: Hem Desai

LANDLORD'S MORTGAGEE:  Teachers Insurance and Annuity Association of America
                       730 Third Avenue, New York, New York 10017

BUILDING: Building IX 700, Technology Park Drive        FLOOR: Second

RENTABLE FLOOR AREA OF TENANT'S SPACE: 11.881 SQUARE FEET

TOTAL RENTABLE FLOOR AREA OF THE BUILDING:  43.675  SQUARE FEET

TENANT'S DESIGN COMPLETION DATE:   JULY 29, 1996
                                   
CHECK ONE:        COMPLETE PLANS [ ]    INTERIOR SELECTION  [X]

SCHEDULED TERM COMMENCEMENT DATE: October 1, 1996
                                  
OUTSIDE DELIVERY DATE:  November 1, 1996
<PAGE>
 
TERM EXPIRATION DATE: September 30, 2001     APPROXIMATE TERM:  5 Years

FIXED RENT: $162,175.65/YEAR        MONTHLY FIXED RENT: $13,514.64

ANNUAL ESTIMATED OPERATING COSTS: $251,131.25 / $5.75/RSF

ESTIMATED COST OF ELECTRICAL SERVICE TO TENANTS SPACE
(Included in Fixed Rent):  $8,910.75  /  $0.75/RSF

FIRST FISCAL YEAR FOR TENANT'S PAYING OPERATING COSTS ESCALATION-
YEAR ENDING    December 31, 1997

SECURITY DEPOSIT: N/A                          GUARANTOR  N/A

TENANT IMPROVEMENT REIMBURSEMENT TO LANDLORD: N/A

PERMITTED USES:  General Office

REAL ESTATE BROKER(S):    The Leggat Company
                          Samuel E. Oddo, Inc.

PUBLIC LIABILITY INSURANCE:    BODILY INJURY AND PROPERTY DAMAGE
         EACH OCCURRENCE:      $1,000,000
         AGGREGATE:            $2,000,000

SPECIAL PROVISIONS: Landlord will build-out Premises at Landlord's sole cost
                    in accordance with Exhibits A & C.

1.2  EXHIBITS

         The Exhibits listed below in this Section are incorporated in this
         Lease by reference and are to be construed as part of this Lease:

         EXHIBIT A         Plan Showing Tenant's Space
         EXHIBIT B         Riders (not applicable)
         EXHIBIT C         Specifications of Leasehold Improvements and Tenant
                           Layout
                           (if applicable)
         EXHIBIT D         Landlord's Services
         EXHIBIT E         Rules and Regulations
         EXHIBIT F         Guaranty (not applicable)
         EXHIBIT G         Estoppel Certificate
         EXHIBIT H         Option to Extend


                                      2
<PAGE>
 
                                   ARTICLE II
                                PREMISES AND TERM


2.1      PREMISES

         Subject to and with the benefit of the provisions of this Lease and any
ground lease or land disposition agreement relating to the parcel on which the
Building is located (the "Lot"), Landlord hereby leases to Tenant and Tenant
leases from Landlord, Tenant's Space in the Building, excluding exterior faces
of exterior walls, the common facilities area and building service fixtures and
equipment serving exclusively or in common other parts of the Building. Tenant's
Space, with such exclusions, is hereinafter referred to as "the Premises."

         Tenant shall have, as appurtenant to the Premises, the right to use in
common with others entitled thereto, subject to reasonable rules of general
applicability to tenants of the Building from time to time made by Landlord of
which Tenant is given notice: (a) the common facilities included in the Building
or on the Lot, including the parking facility, if any, to the extent from time
to time designated by Landlord; and (b) the building service fixtures and
equipment serving the Premises.

         Landlord reserves the right from time to time, without unreasonable
interference with Tenant's use (a) to install repair, replace, use, maintain and
relocate for service to the Premises and to other parts of the Building or
either, building service fixtures and equipment wherever located in the
Building, and (b) to alter or relocate any other common facility provided that
substitutions are substantially equivalent or better.

2.2      TERM

         To have and to hold for a period (the "Term") commencing on the latter
of: a) when the Premises are deemed ready for occupancy as provided in Section
3.2, or b) if no work is to be performed by Landlord pursuant to Article m, on
the Scheduled Term Commencement Date (whichever of said dates is appropriate
being hereafter referred to as the "Commencement Date") and continuing until the
Expiration Date, unless sooner terminated as provided in Section 3.2 or 7.1 or
in Article IX.



                                   ARTICLE III
                                  CONSTRUCTION


3.1      INITIAL CONSTRUCTION

         Tenant shall on or before Tenant's Design Completion Date, provide to
Landlord for approval a plan of the Premises "marked" to show the appropriate
fit-up work to be performed by Landlord in accordance with the attached "Exhibit
C" hereto.


                                       3
<PAGE>
 
         Tenant's interior furnishings, i.e., specification, coordination,
supply and installation of furniture, furnishings, computer equipment,
telephones and movable equipment will be the responsibility of Tenant. All of
Tenant's construction, installation of furnishings, and later changes or
additions shall be coordinated with any work being performed by Landlord in such
a manner as to maintain harmonious labor relations and not damage the Building
or Lot or interfere with Building operations. Except for installation of
furnishings, including carpets, the installation of telephone systems, and
computer network, which must be performed by Tenant's telephone contractor at
Tenant's direction and expense (all telephone equipment, including the telephone
interface, shall be installed within tenant's area), all such work shall be
performed by Landlord's general contractor and Tenant shall pay therefor an
amount equal to the cost of any changes requested by Tenant from the
specifications in Exhibit C, including the cost to Landlord of the general
contractor's overhead and profit, which amount shall be due and payable as
additional rent, on the Commencement Date. Tenant shall have the right to
install a wall in the lab area, as long as Landlord approves the plan, which
approval shall not be unreasonably withheld, and Tenant obtains all necessary
permits for such work. Landlord will not approve any construction, alterations,
or additions requiring unusual expense to readapt the Premises to normal offic
use on lease termination or increasing the cost of construction, insurance or
taxes on the Building or of Landlord's services called for by Section 5.1,
unless Tenant first gives assurances acceptable to landlord that such
readaptation will be made prior to such termination without expense to Landlord
and makes provisions acceptable to Landlord for payment of such increased cost.
Landlord will also disapprove any alterations or additions requested by Tenant
which will delay completion of the Premises or the Building. All changes and
additions shall be part of the Building, except such items as by writing at the
time of approval the parties agree either shall be removed by Tenant on
termination of this Lease, or shall be removed or left at Tenant's election.

3.2      PREPARATION OF PREMISES FOR OCCUPANCY

         If Landlord is obligated to perform construction work pursuant to
Exhibit C, Landlord agrees to use reasonable efforts to have the Premises ready
for occupancy on or before the Scheduled Term Commencement Date, which shall,
however, be extended for a period equal to that of any delays due to
governmental regulations, unusual scarcity of or inability to, obtain labor or
materials, labor difficulties, casualty or other causes reasonably beyond
Landlord's control. The Premises shall be deeme ready for occupancy on the
latter of:

         (a)      The Scheduled Term Commencement Date; or

         (b)      The date on which the Tenant's improvements, as specified in
                  Exhibit C, are substantially completed as certified by
                  Landlord's architect;

provided, however, that if Landlord is unable to complete construction due to
delay in Tenant's compliance with the provisions of Section 3.1 of this Lease,
then the Premises shall be deemed ready for occupancy no later than the
Scheduled Term Commencement Date.

         Landlord shall permit Tenant access for installing equipment and
furnishings in the Premises prior to the Term when it can be done without
material interference with Landlord's remaining work.


                                       4
<PAGE>
 
         In the event of Tenant's failure to comply with the provisions of
Section 3.1 of this Lease to submit information or to deliver construction
drawings and specifications which meet Landlord's approval, Landlord may, at
Landlord's option, exercisable by notice to Tenant, terminate this Lease on the
date specified in said notice to Tenant, and upon such termination Landlord
shall have all the rights provided in event of Tenant's default in Article IX of
this Lease. Notwithstanding the foregoing provisions, if the Premises are not
deemed ready for occupancy on or before the Outside Delivery Date for whatever
reason, other than Tenant's default, Tenant may elect to cancel this Lease at
any time thereafter while the Premises are not deemed ready for occupancy by
giving notice to Landlord of such cancellation which shall be effective when
given, it being understood that said election shall be Tenant's sole remedy at
law or in equity for Landlord's failure to have the Premises ready for
occupancy.

3.3      GENERAL PROVISIONS APPLICABLE TO CONSTRUCTION

         All construction work required or permitted by this Lease, whether by
Landlord or by Tenant, shall be done in a good and workmanlike manner and in
compliance with all applicable laws and all lawful ordinances, regulations and
orders of governmental authority and insurers of the Building. Either party may
inspect the work of the other at reasonable times and shall promptly give notice
of observed defects. Landlord's obligations under Section 3.1 shall be deemed to
have been performed when Tenant commences to occupy any portion of the Premises
for the Permitted Uses except for items which are incomplete or do not conform
with the requirements of Section 3.1 and as to which Tenant shall, in either
case, have given written notice to Landlord prior to such commencement. If
Tenant shall not have commenced to occupy the Premises for the Permitted Uses
within 30 days after they are deemed ready for occupancy as provided in Section
3.2, a certificate of completion by a licensed architect or registered engineer
shall be conclusive evidence that Landlord has performed all such obligations
except for items stated in such certificate to be incomplete or not in
conformity with such requirements.

3.4      REPRESENTATIVES

         Each party authorizes the other to rely in connection with their
respective rights and obligations under this Article m upon approval and other
actions on the party's behalf by Landlord's Representative in the case of
Landlord or Tenant's Representative in the case of Tenant or by any person
designated in substitution or addition by notice to the party relying.


                                   ARTICLE IV
                                      RENT


4.1      RENT

         Tenant agrees to pay, without any offset or reduction whatever, fixed
rent equal to 1/12th of the Fixed Rent in equal installments in advance on the
first day of each calendar month included in the Term; and for any portion of a
calendar month at the beginning or end of the Term, at the rate payable for such
portion in advance. Notwithstanding the foregoing, the Fixed Rent shall be
abated for the first seven (7) days of the Lease Term.


                                       5
<PAGE>
 
4.2      OPERATING COST ESCALATION

         With respect to the First Fiscal Year for Tenant's Paying Operating
Cost Escalation, or fraction thereof, and any Fiscal Year or fraction
thereafter, Tenant shall pay to Landlord, as additional rent, Operating Cost
Escalation (as defined below), if any, on or before the thirtieth (30th) day
following receipt by Tenant of Landlord's Statement (as defined below). As soon
as practicable after the end of each Fiscal Year ending during the Term and
after Lease termination, Landlord shall rende a statement ("Landlord's
Statement") in reasonable detail and according to usual accounting practices
certified by Landlord and showing for the preceding Fiscal Year or fraction
thereof, as the case may be, Landlord's Operating Costs,

         EXCLUDING the interest and amortization on mortgages for the Building
and Lot or leasehold interests therein and the cost of special services rendered
to tenants (including Tenant) for which a special charge is made,

         BUT INCLUDING, without limitation: real estate taxes on the Building
and Lot; installments and interest on assessments for public betterments or
public improvements; expenses of any proceedings for abatement of taxes and
assessments with respect to any Fiscal Year or fraction of a Fiscal Year;
premiums for insurance; compensation and all fringe benefits, workmen's
compensation, insurance premiums and payroll taxes paid by Landlord to, for or
with respect to all persons engaged in the operating, maintaining, or cleaning
of the Building and Lot; steam, water, sewer, electric, gas, telephone, and
other utility charges not billed directly to tenants by Landlord or the utility,
but not including the cost to Landlord of electricity furnished for lighting,
electrical facilities, equipment, machinery, fixtures and appliances used by
Tenant in Tenant's Space (other than Building heating, ventilating and air
conditioning equipment) as set forth in Paragraph VII of Exhibit D; costs of
building and cleaning supplies and equipment (including rental); cost of
maintenance, cleaning and repairs; cost of snow plowing or removal, or both, and
care of landscaping; payments to independent contractors under service contracts
for cleaning, operating, managing, maintaining and repairing the Building and
Lot (which payments may be to affiliates of Landlord provided the same are at
reasonable rates consistent with the type of occupancy and the services
rendered); imputed cost equal to the loss of rent by Landlord for making
available to the managing agent space for a Building office on the ground floor
or above (limited to 200 square feet); if the building is located in an office
park, the Building's pro rata share (as reasonably determined by landlord) of
the cost of operating, maintaining and repairing the common areas and facilities
within such park (such as, but not limited to, snow plowing, landscaping, common
area and street lighting, security and management); and all other reasonable and
necessary expenses paid in connection with the operation, cleaning, maintenance,
and repair of the Building and Lot, or either, and properly chargeable against
income, it being agreed that if Landlord installs a new or replacement capital
item for the purpose of reducing Landlord's Operating Costs, the costs thereof
as reasonably amortized by Landlord, with legal interests on the unamortized
amount, shall be included in Landlord's Operating Costs. If the Building is not
fully occupied, Landlord's Statement shall also show the average number of
square feet of the Building which were occupied for the preceding Fiscal Year or
fraction thereof.

         If the management fee is reduced by reason of a tenant's default in the
payment of fixed or additional rent, Landlord shall reduce the Annual Estimated
Operating Costs by the amount of such reduction in the management fee. In case
of services which are not rendered to all areas on a comparable basis, the
proportion allocable to the Premises shall be the same proportion which the
Rentable Floor Area of Tenant's


                                       6
<PAGE>
 
Space bears to the total rentable floor area to which such service is so
rendered (such latter area to be determined in the same manner as the Total
Rentable Floor Area of the Building).

         "Operating Cost Escalation" shall be equal to the difference, if any,
between:

         (a)      the product of Landlord's Operating Costs per rentable square
                  foot as indicated in Landlord's Statement times the Rentable
                  Floor Area of Tenant's Space; and

         (b)      the product of the Annual Estimated Operating Costs (as
                  reduced pursuant to this Section 4.2) per rentable square foot
                  times the Rentable Floor Area of Tenant's Space.

         If, with respect to any Fiscal Year or fraction thereof during the
Term, Tenant is obligated to pay Operating Cost Escalation, then Tenant shall
pay, as additional rent, on the first day of each month of each ensuing Fiscal
Year thereafter, until Landlord's Statement for an ensuing Fiscal Year reflects
that Tenant is not obligated to pay Operating Cost Escalation, Estimated Monthly
Escalation Payments equal to 1/12th of the annualized Operating Cost Escalation
for the immediately preceding Fiscal Year. Estimated Monthly Escalation Payments
for each ensuing Fiscal Year shall be made retroactively from the first day of
such Fiscal Year and on account of the payment to be made pursuant to the first
sentence of this Section 4.2 for such Fiscal Year, with an appropriate
additional payment or refund to be made within thirty (30) days after Landlord's
Statement is delivered.

         The term "real estate taxes" as used above shall mean all taxes of
every laud and nature assessed by any governmental authority on the Lot, the
Building and improvements, or both, which the Landlord shall become obligated to
pay because of or in connection with the ownership, leasing and operation of the
Lot, the Building and improvements, or both, subject to the following: There
shall be excluded for such taxes all income taxes, excess profits taxes, excise
taxes, franchise taxes, estate, succession, inheritance and transfer taxes,
provided, however, that if at any time during the Term the present system of ad
valorem taxation of real property shall be changed so that in lieu of the whole
or any part of the ad valorem tax on real property, there shall be assessed on
Landlord a capital levy or other tax on the gross rents received with respect to
the Lot, Building and improvements, or both, a federal, state, county,
municipal, or other local income, franchise, excise or similar tax, assessment,
levy or charge (distinct from any now in effect) measured by or based, in whole
or in part, upon any such gross rents, then any and all of such taxes,
assessments, levies or charges, to the extent so measured or based, shall be
deemed to be included within the term "real estate taxes."

         Landlord shall have the right from time to time to change the periods
of accounting under this Section 4.2 to any annual period other than the Fiscal
Year and upon any such change all items referred to in this Section shall be
appropriately apportioned. In all Landlord's Statements, rendered under this
Section, amounts for periods partially within and partially without the
accounting periods shall be appropriately apportioned, and any items which are
not determinable at the time of a Landlord's Statement shall be included therein
on the basis of Landlord's estimate, and with respect thereto Landlord shall
render promptly after determination a supplemental Landlord's Statement, and
appropriate adjustment shall be made according thereto. All Landlord's
Statements shall be prepared on an accrual basis of accounting.


                                       7
<PAGE>
 
         Notwithstanding any other provision of this Section 4.2, if the Term
expires or is terminated as of a date other than the last day of a Fiscal Year
at the end of the Term, Tenant's last payment to Landlord under this Section 4.2
shall be made on the basis of Landlord's best estimate of the items otherwise
includable in Landlord's Statement and shall be made on or before the later of
(a) 10 days after Landlord delivers such estimate to Tenant, or (b) the last day
of the Term, with an appropriate payment or refund to be made upon submission of
Landlord's Statement.

4.3      PAYMENTS

         All payments of fixed and additional rent shall be made to Managing
Agent, or to such other person as Landlord may from time to time designate by
notice to Tenant. If any installment of rent, fixed or additional or on account
of leasehold improvements is paid more than 5 days after the due date thereof,
at Landlord's election, it shall bear interest at a rate equal to the average
prime commercial rate from time to time established by the three largest bars in
Boston, Massachusetts, plus two percent (2%) per annum from such due date, which
interest shall be immediately due and payable as further additional rent.



                                    ARTICLE V
                              LANDLORD'S COVENANTS


5.1      LANDLORD'S COVENANTS DURING THE TERM

         Landlord covenants during the Term:

         5.1.1    Building Services - To furnish, through Landlord's employees
                  or independent contractors, the services listed in Exhibit D;

         5.1.2    Additional Building Services - To furnish, through Landlord's
                  employees or independent contractors, reasonable additional
                  Building operation services upon reasonable advance request of
                  Tenant at equitable rates from time to time established by
                  Landlord to be paid by Tenant;

         5.1.3    Repairs - Except as otherwise provided in Article VII, to make
                  such repairs to the roof, exterior walls, floor slabs and
                  common facilities of the Building as may be necessary to keep
                  them in serviceable condition; and

         5.1.4    Quiet Enjoyment - That Landlord has the right to make this
                  Lease and that Tenant, on paying the rent and performing its
                  obligations hereunder, shall peacefully and quietly have, hold
                  and enjoy the Premises throughout the Term without any manner
                  of hindrance or molestation from Landlord or anyone claiming
                  under Landlord, subject, however, to all the terms and
                  provisions hereof.


                                       8
<PAGE>
 
         5.1.5    Landlord represents that the description of the Premises, the
                  Building and the Lot in the Lease Proposal is true, accurate
                  and complete in all materials respects, and that the heating,
                  ventilation and air conditioning systems and all utilities
                  serving the Premises will be in good working order on the
                  Commencement Date.

         5.1.6    Indemnity - To defend, with counsel reasonably acceptable to
                  Tenant, save harmless, and indemnify Tenant from any liability
                  for injury, loss, accident or damage to any person or property
                  and from any claims, actions, proceedings and expenses and
                  costs in connection therewith (including, without implied
                  limitation, reasonable counsel fees): (i) arising from the
                  omission fault, willful act, negligence or other misconduct of
                  Landlord or its agents and representatives; or (ii) resulting
                  from the failure of Landlord to perform and discharge its
                  covenants and obligations under this Lease.

         5.1.7    Insurance - Landlord shall insure the Building with full
                  replacement cost coverage.

5.2      INTERRUPTIONS

         Landlord shall not be liable to Tenant for any compensation or
reduction of rent by reason of inconvenience or annoyance or for loss of
business arising from power losses or shortages or from the necessity of
Landlord's entering the Premises for any of the purposes in this Lease
authorized, or for repairing the Premises or any portion of the Building or Lot.
In case Landlord is prevented or delayed from making any repairs, alterations or
improvements, or furnishing any service or performing any other covenant or duty
to be performed on Landlord's part, by reason of any cause reasonably beyond
Landlord's control, Landlord shall not be liable to Tenant therefore, nor,
except as expressly otherwise provided in Article VII, shall Tenant be entitled
to any abatement or reduction of rent by reason thereof, nor shall the same give
rise to a claim in Tenant's favor that such failure constitutes, actual or
constructive, total or partial, eviction from the Premises.

         Landlord reserves the right to stop any service or utility system when
necessary by reason of accident or emergency or until necessary repairs have
been completed. Except in case of emergency repairs, Landlord will give Tenant
reasonable advance notice of any contemplated stoppage and will use reasonable
efforts to avoid unnecessary inconvenience to Tenant by reason thereof.



                                   ARTICLE VI
                               TENANT'S COVENANTS


6.1      TENANTS COVENANTS DURING THE TERM

         Tenant covenants during the Term and such further time as Tenant
occupies any part of the Premises:


                                       9
<PAGE>
 
         6.1.1    Tenant's Payments - To pay when due (a) all Fixed Rent and
                  additional rent, (b) all taxes which may be imposed on
                  Tenant's personal property in the Premises (including, without
                  limitation, Tenant's fixtures and equipment) regardless to
                  whomever assessed, (c) all charges by public utility for
                  telephone and other utility services (including service
                  inspections therefor) rendered to the Premises not otherwise
                  required hereunder to be furnished by Landlord without charge
                  and not consumed in connectio with any services required to be
                  furnished by Landlord without charge, and (d) as additional
                  rent, all charges of Landlord for services rendered pursuant
                  to Section 5.1.2 hereof;

         6.1.2    Repairs and Yielding Up - Except as otherwise provided in
                  Article VII and Section 5.1.3, to keep the Premises in good
                  order, repair and condition, reasonable wear only excepted,
                  and at the expiration or termination of this Lease peaceably
                  to yield up the Premises and all changes and additions therein
                  in such order, repair and condition, first removing all goods
                  and effects of Tenant and any items, the removal of which is
                  required by agreement or specified therein to be removed at
                  Tenant's electio and which Tenant elects to remove, and
                  repairing all damage caused by such removal and restoring the
                  Premises and leaving them clean and neat; any property not so
                  removed shall be deemed abandoned and may be removed and
                  disposed of by Landlord, in such manner as Landlord shall
                  determine, and Tenant shall pay Landlord the entire cost and
                  expense incurred by it by effecting such removal and
                  disposition and in making any incidental repairs and
                  replacements to the Premises for use and occupancy durin the
                  period after the expiration of the term; it being agreed that
                  the acceptance of reasonable use and wear shall not apply so
                  as to permit Tenant to keep the Premises in anything less than
                  suitable, tenantable and usable condition, considering the
                  nature of the Premises and the use reasonably made thereof, or
                  in less than good and tenantable repair;

         6.1.3    Occupancy and Use - Continuously from the Commencement Date,
                  to use and occupy the Premises only for the Permitted Uses;
                  and not to injure or deface the Premises, Building or Lot; and
                  not to permit in the Premises any auction sale, nuisance, or
                  the emission from the Premises of any objectionable noise or
                  odor; nor any use thereof which is improper, offensive,
                  contrary to law or ordinances, or liable to invalidate or
                  increase the premiums for any insurance on the Building or its
                  contents or liable to render necessary any alteration or
                  addition to the Building;

         6.1.4    Rules and Regulations - To comply with the Rules and
                  Regulations set forth in Exhibit E and all other reasonable
                  Rules and Regulations hereafter made by Landlord, of which
                  Tenant has been given notice, for the care and use of the
                  Building and Lot and their facilities and approaches, it being
                  understood that Landlord shall not be liable to Tenant for the
                  failure of other tenants of the Building to conform to such
                  Rules and Regulations;


                                       10
<PAGE>
 
         6.1.5    Safety Appliances - To keep the Premises equipped with all
                  safety appliances required by law or ordinance or any other
                  regulation of any public authority because of any use made by
                  Tenant and to procure all licenses and permits so required
                  because of such use and, if requested by Landlord, to do any
                  work so required because of such use, it being understood that
                  the foregoing provisions shall not be construed to broaden in
                  any way Tenant's Permitted Uses;

         6.1.6    Assignment and Subletting - Not without prior written consent
                  of Landlord (which consent shall not be unreasonably withheld)
                  to assign this Lease, to make any sublease, or to permit
                  occupancy of the Premises or any part thereof by anyone other
                  than Tenant, voluntarily or by operation of law, and as
                  additional rent, to reimburse Landlord promptly for reasonable
                  legal and other expenses incurred by Landlord in connection
                  with any request by Tenant for consent to assignment or
                  subletting; no assignment or subletting shall affect the
                  continuing primary liability of Tenant (which, following
                  assignment, shall be joint and several with the assignee); no
                  consent to any of the foregoing in a specific instance shall
                  operate as waiver in any subsequent instance. Any rental
                  received by Tenant from sub-tenant must be remitted to
                  Landlord. Anything contained in the foregoing provisions of
                  this section to the contrary notwithstanding, neither Tenant
                  nor any other person having interest in the possession, use,
                  occupancy or utilization of the Premises shall enter into any
                  lease, sublease, license, concession or other agreement for
                  use, occupancy or utilization of space in the Premises which
                  provides for rental or other payment for such use, occupancy
                  or utilization based, in whole or in part, on the net income
                  or profits derived by any person from the Premises leased,
                  used, occupied or utilized (other than an amount based on a
                  fixed percentage or percentages of receipts or sales), and any
                  such purported lease, sublease, license, concession or other
                  agreement shall be absolutely void and ineffective as a
                  conveyance of any right or interest in the possession use,
                  occupancy or utilization of any part of the Premises. Tenant
                  shall have the right, without the consent of Landlord, to
                  assign its interest under the Lease I to any natural person,
                  partnership, corporation or other form of business or legal
                  association or entity which (i) acquires all or substantially
                  all of Tenant's assets, either by merger or consolidation; and
                  (ii) has a net worth, determined in accordance with generally
                  accepted accounting principles consistently applied,
                  immediately after the assignment which is at least as great as
                  the net worth of Tenant (determined in the same manner)
                  immediately before the assignment;

         6.1.7    Indemnity - To defend, with counsel reasonably acceptable to
                  Landlord, save harmless, and indemnify Landlord from any
                  liability for injury, loss, accident or damage to any person
                  or property and from any claims, actions, proceedings and
                  expenses and costs in connection therewith (including, without
                  implied limitation, reasonable counsel fees): (i) arising from
                  the omission, fault, willful act, negligence or other
                  misconduct of Tenant or from any use made or thing done or
                  occurring on


                                       11
<PAGE>
 
                  the Premises not due to the omission, fault, willful act,
                  negligence or other misconduct of Landlord, or (ii) resulting
                  from the failure of Tenant to perform and discharge its
                  covenants and obligations under this Lease;

         6.1.8    Tenant's Liability Insurance - To maintain public liability
                  insurance in the Premises in amounts which shall, at the
                  beginning of the Term, be at least equal to the limits set
                  forth in Section 1.1 and from time to time during the Term,
                  shall be for such higher limits, if any, as are customarily
                  carried in the area in which the Premises are located on
                  property similar to the Premises and used for similar purposes
                  and to furnish Landlord with the certificates thereof;

         6.1.9    Tenant's Workmen's Compensation Insurance - To keep all
                  Tenant's employees working in the Premises covered by
                  workmen's compensation insurance in statutory amounts and to
                  furnish Landlord with certificates thereof;

         6.1.10   Landlord's Right of Entry - To permit Landlord and Landlord's
                  agents entry; to examine the Premises at reasonable times and,
                  if Landlord shall so elect, to make repairs or replacements;
                  to remove, at Tenant's expense, any changes, additions, signs,
                  curtains, blinds, shades, awnings, aerials, flagpoles, or the
                  like not consented to in writing; and to show the Premises to
                  prospective tenants during the 12 months preceding expiration
                  of the Term and to prospective purchasers and mortgagees at
                  all reasonable times, provided that Landlord and Landlord's
                  agents use reasonable efforts to minimize interference with
                  the operation of Tenant's business caused by any entry
                  described above;

         6.1.11   Loading - Not to place a load upon the Premises exceeding an
                  average rate of 60 pounds of live load per square foot of
                  floor area; and not to move any safe, vault or other heavy
                  equipment in, about or out of the Premises except in such a
                  manner and at such times as Landlord shall in each instance
                  approve; Tenant's business machines and mechanical equipment
                  which cause vibration or noise that may be transmitted to the
                  Building structure or to any other leased space in the
                  Building shall be placed and maintained by Tenant in settings
                  of cork, rubber, spring, or other types of vibration
                  eliminators sufficient to eliminate such vibration or noise;

         6.1.12   Landlord's Costs - In case Landlord shall, without any fault
                  on its part, be made party to any litigation commenced by or
                  against Tenant or by or against any parties in possession of
                  the Premises or any part thereof claiming under Tenant, to
                  pay, as additional rent, all costs including, without implied
                  limitation, reasonable counsel fees incurred by or imposed
                  upon Landlord in connection with such litigation and as
                  additional rent, also to pay all such costs and fees incurred
                  by Landlord in connection with the successful enforcement by
                  Landlord of any obligations of Tenant under this Lease;


                                       12
<PAGE>
 
         6.1.13   Tenant's Property - All the furnishings, fixtures, equipment,
                  effects and property of every kind, nature and description of
                  Tenant and of all persons claiming by, through or under Tenant
                  which, during the continuance of this Lease or any occupancy
                  of the Premises by Tenant or anyone claiming under Tenant, may
                  be on the Premises or elsewhere in the Building or on the Lot
                  shall be at the sole risk and hazard of Tenant, except for
                  Landlord's negligence or willful act of omission, and if the
                  whole or any part thereof shall be destroyed or damaged by
                  fire, water or otherwise, or by the leakage or bursting of
                  water pipes, steam pipes, or other pipes, by theft, or from
                  any other cause, no part of said loss or damage is to be
                  charged to or to be borne by Landlord;

         6.1.14   Labor or Materialmen's Liens - To pay promptly when due the
                  entire cost of any work done on the premises by Tenant, its
                  agents, employees, or independent contractors; not to cause or
                  permit any liens for labor or material performed or furnished
                  in connection therewith to attach to the Premises; and
                  immediately to discharge any such liens which may so attach;

         6.1.15   Changes or Additions - Not to make any material changes or
                  additions to the Premises without Landlord's prior written
                  consent; and

         6.1.16   Holdover - To pay to Landlord 1.75 times the total of the
                  Fixed and additional rent then applicable for each month or
                  portion thereof Tenant shall retain possession of the Premises
                  or any part thereof after the termination of this Lease,
                  whether by lapse of time or otherwise, and also to pay all
                  damages sustained by Landlord on account thereof; the
                  provisions of this subsection shall not operate as a waiver by
                  Landlord of any right of re-entry provided in this Lease; at
                  the option of the Landlor exercised by a written notice given
                  to Tenant while such holding over continues, such holding over
                  shall constitute an extension of this Lease for a period of a
                  month to month tenancy at 1.75 times the Fixed and additional
                  rent.

         6.1.17   Hazardous Materials - Tenant shall not (either with or without
                  negligence) cause or permit the escape, disposal or release of
                  any biologically or chemically active or other hazardous
                  substances, or materials onto or in the vicinity of the
                  Premises. Tenant shall not allow the storage or use of such
                  substances or materials in any manner not sanctioned by law or
                  by the highest standards prevailing in the industry for the
                  storage and use of such substances or materials, nor allow to
                  be brought into the Premises any such materials or substances
                  except to use in the ordinary course of Tenant's business, and
                  then only after written notice is given to Landlord of the
                  identity of such substances or materials. Without limitation,
                  hazardous substances and materials shall include those
                  described in the Comprehensive Environmental Response,
                  Compensation and Liability Act of 1980, as amended, 42 U.S.C.
                  Section 9601 et seq., the Resource Conservation and Recovery
                  Act, as amended, 42 U.S.C. Section 6901 et seq., the
                  Massachusetts Hazardous Waste Management Act, as amended,
                  M.G.L. c.21C, the Massachusetts Oil and Hazardous Material
                  Release Prevention and


                                       13
<PAGE>
 
                  Response Act, as amended, M.G.L. c.21E, any applicable local
                  ordinance or bylaw, and the regulations adopted under these
                  acts, (collectively, the "Hazardous Waste Laws"). If any
                  lender or governmental agency shall ever require testing to
                  ascertain whether or not there has been any release of
                  hazardous materials, then the reasonable costs thereof shall
                  be reimbursed by Tenant to Landlord upon demand as additional
                  charges if such requirement applies to the Premises, and onl
                  if such release of hazardous materials was caused by Tenant.
                  If Tenant receives from any federal, state or local
                  governmental agency any notice of violation or alleged
                  violation of any Hazardous Waste Law, or if Tenant is
                  obligated to give any notice under any Hazardous Waste Law,
                  Tenant agrees to forward to Landlord a copy of any such notice
                  within three (3) days of Tenant's receipt or transmittal
                  thereof. In addition, Tenant shall execute affidavits,
                  representations and the like from time to time at Landlord's
                  request concerning Tenant's best knowledge of belief regarding
                  the presence of hazardous substances or materials on the
                  Premises. In all events, Tenant shall indemnify Landlord in
                  the manner elsewhere provided in this lease from any release
                  of hazardous materials on the Premises occurring while Tenant
                  is in possession, or elsewhere on the Lot if caused by Tenant
                  or persons acting under Tenant. Landlord retains the right to
                  inspect the Premises at all reasonable times, upon reasonable
                  notice t Tenant, to ensure compliance with this paragraph. The
                  within covenants shall survive the expiration or earlier
                  termination of the lease term.



                                  ARTICLE VII
                              CASUALTY AND TAKING

7.1      CASUALTY AND TAKING

         In case during the Term all or any substantial part of the Premises,
the Building, or Lot or any one or more of them (i.e. requiring greater than ten
months to rebuild in Landlord's judgment) are damaged materially by fire or any
other cause or by action of public or other authority in consequence thereof or
are taken by eminent domain or Landlord receives compensable damage by reason of
anything lawfully done in pursuance of public or other authority, this Lease
shall terminate at Landlor or Tenant's election, which may be made,
notwithstanding Landlord's entire interest may have been divested, by notice
given to each other within 30 days after (i) the occurrence of the event giving
rise to the election to terminate and (ii) notice from Landlord to Tenant of
Landlord's estimate of the approximate construction period to repair the
casualty, which notice will be given to Tenant within 60 days after the
occurrence, which notice shall specify the effective date of termination which
shall be no less than 30 nor more than 60 days after the date of notice of such
termination. If in any such case the Premises are rendered unfit for use and
occupation and the Lease is not so terminated, Landlord shall use due diligence
to put the Premises, or in case of taking, what may remain thereof (excluding
any items installed or paid for by Tenant which Tenant may be required or
permitted to remove) into proper condition for use and occupation to the extent
permitted by the net award of insurance or damages, and a just proportion of the
Fixed Rent and additional rent according to the nature and extent of the injury
shall be abated until the Premises or such remainder shall have been put by
Landlord


                                       14
<PAGE>
 
in such condition; and in case of a taking which permanently reduces the area of
the Premises, a just proportion of the Fixed Rent and additional rent shall be
abated for the remainder of the Term and an appropriate adjustment shall be made
to the Annual Estimated Operating Expenses.

7.2      RESERVATION OF AWARD

         Landlord reserves to itself any and all rights to receive awards made
for damages to the Premises, Building or Lot and the leasehold hereby created,
or any one or more of them, accruing by reason of exercise of eminent domain or
by reason of anything lawfully done in pursuance of public or other authority.
Tenant hereby releases and assigns to Landlord all Tenant's rights to such
awards, and covenants to deliver such further assignments and assurances thereof
as Landlord may from time to time request, hereby irrevocably designating and
appointing Landlord as its attorney-in-fact to execute and deliver in Tenant's
name and behalf all such further assignments thereof. It is agreed and
understood, however, that Landlord does not reserve to itself and Tenant does
not assign to Landlord, any damages payable for (i) movable trade fixtures
installed by Tenant or anybody claiming under Tenant, at its own expense, or
(ii) relocation expenses recoverable by Tenant from such authority in a separate
action.


                                  ARTICLE VIII
                               RIGHTS OF MORTGAGEE


8.1      PRIORITY OF LEASE

         Landlord shall have the option to subordinate this Lease to any
mortgagee or deed of trust of the Lot or Building, or both ("the mortgaged
premises"), provided that the holder thereof enters into an agreement with
Tenant by the terms of which the holder will agree to recognize the rights of
Tenant under this Lease and to accept Tenant as tenant of the Premises under the
terms and conditions of this Lease in the event of acquisition of title by such
holder through foreclosure proceedings or otherwise and Tenant will agree to
recognize the holder of such mortgage as Landlord in such event, which agreement
shall be made to expressly bind and inure to the benefit of the successors and
assigns of Tenant and of the holder and upon anyone purchasing the mortgaged
premises at any foreclosure sale. Any such mortgage to which this Lease shall be
subordinated may contain such terms, provisions and conditions as the holder
deems usual or customary. Unless Landlord exercises such option, this Lease
shall be superior to and shall not be subordinated to any mortgage or other
voluntary lien or other encumbrance on the mortgaged premises.

8.2      LIMITATION ON MORTGAGEE'S LIABILITY

         Upon entry and taking possession of the mortgaged premises for any
purpose other than foreclosure, the holder of a mortgage shall have all rights
of Landlord, and during the period of such possession, the duty to perform all
Landlord's obligations hereunder. Except during such period of possession, no
such holder shall be liable, either as mortgagee or as holder of a collateral
assignment of this Lease, to perform, or be liable in damages for failure to
perform any of the obligations of Landlord unless


                                       15
<PAGE>
 
and until such holder shall enter and take possession of the mortgaged premises
for the purpose of foreclosing a mortgage. Upon entry for the purpose of
foreclosing a mortgage, such holder shall be liable to perform all of the
obligations of Landlord, subject to the provisions of Section 8.3 provided that
a discontinuance of any foreclosure proceeding shall be deemed a conveyance
under the provisions of Section 10.5 to the owner of the equity of the mortgaged
premises.

8.3      MORTGAGEE'S ELECTION

         Notwithstanding any other provision to the contrary contained in this
Lease, if prior to the substantial completion of Landlord's obligations under
Article III, any holder of a first mortgage on the mortgaged premises enters and
takes possession thereof for the purpose of foreclosing the mortgage, such
holder may elect by written notice given to Tenant and Landlord at any time
within 90 days after such entry and taking of possession, not to perform
Landlord's obligations under Article III, and in such event such holder and all
persons claiming under it shall be relieved of all obligations to perform, and
all liability for failure to perform, said Landlord's obligations under Article
III, and Tenant may terminate this Lease and all its obligations hereunder by
written notice to Landlord and such holder given within 30 days after the day on
which such holder shall have given its notice as aforesaid.

8.4      NO PREPAYMENT OR MODIFICATION,  ETC.

         No Fixed Rent, additional rent, or any other charge shall be paid more
than ten days prior to the due dates thereof, and payments made in violation of
this provision shall (except to the extent that such payments are actually
received by a mortgagee in possession or in the process of foreclosing its
mortgage) be a nullity as against such mortgagee, and Tenant shall be liable for
the amount of such payments to such mortgagee. No assignment of this Lease and
no agreement to make or accept any surrender, termination or cancellation of
this Lease and no agreement to modify so as to reduce the rent, change the Term,
or otherwise materially change the rights of Landlord under this Lease, or to
relieve Tenant of any obligations or liability under this Lease, shall be valid
unless consented to in writing by Landlord's mortgagees of record, if any.

8.5      NO RELEASE OR TERMINATION

         No act or failure to act on the part of Landlord which would entitle
Tenant under the terms of this Lease, or by law, to be relieved of Tenant's
obligations hereunder or to terminate this Lease, shall result in a release or
termination of such obligations or a termination of this Lease unless (i) Tenant
shall have first given written notice of Landlord's act or failure to act to
Landlord's mortgagees of record, if any, specifying the act or failure to act on
the part of Landlord which coul or would give basis to Tenant's rights, and (ii)
such mortgagees, after receipt of such notice, have failed or refused to correct
or cure the condition complained of within a reasonable time thereafter, but
nothing contained in this Section 8.5 shall be deemed to impose any obligation
on any such mortgagee to correct or cure any such condition. "Reasonable time"
as used above means and includes a reasonable time to obtain possession of the
mortgaged premises, if the mortgagee elects to do so, and a reasonable time to
correct or cure the condition if such condition is determined to exist.


                                       16
<PAGE>
 
8.6      CONTINUING OFFER

         The covenants and agreements contained in this Lease with respect to
the rights, powers and benefits of a mortgagee (particularly, without limitation
thereby, the covenants and agreements contained in this Article VIII) constitute
a continuing offer to any person, corporation or other entity, which by
accepting or requiring an assignment of this Lease or by entry or foreclosure
assumes the obligations herein set forth with respect to such mortgagee, and
such mortgagee shall be entitled to enforce such provisions in its own name.
Tenant agrees on request of Landlord to execute and deliver from time to time
any reasonable agreement which may reasonably be deemed necessary to implement
the provisions of this Article VIII.

8.7      MORTGAGEE'S APPROVAL

         Landlord's obligation to perform its covenants and agreements hereunder
is subject to the condition precedent that this Lease be approved by the holder
of any mortgage of which the Premises are a part. Unless Landlord gives Tenant
written notice within thirty (30) days after the date hereof that such holder or
issuer, or both, disapprove this Lease, then this condition shall be deemed to
have been satisfied or waived and the provisions of this Section 8.7 shall be of
no further force or effect.

8.8      SUBMITTAL OF FINANCIAL STATEMENT

         At any time and from time to time during the term of this Lease, within
fifteen (15) days after request therefor by Landlord, Tenant shall supply to
Landlord and/or any Mortgagee a current financial statement or such other
financial information as may be reasonably required by any such party.



                                   ARTICLE IX
                                     DEFAULT



9.1      EVENTS OF DEFAULT

         If any default by Tenant continues after certified notice, in case of
Fixed Rent or additional rent for more than ten days, or in any other case for
more than 30 days and such additional time, if any, as is reasonably necessary
to cure the default if the default is of such a nature that it cannot reasonably
be cured in 30 days; or if Tenant or Guarantor makes any assignment for the
benefit of creditors, or files a petition under any bankruptcy or insolvency
law; or if such a petition is filed against Tenant or any Guarantor and is not
dismissed within 30 days; or if a receiver or similar officer becomes entitled
to Tenant's leasehold hereunder and it is not returned to Tenant within 90 days;
or if such leasehold is taken on execution or other process of law in any action
against Tenant; then, and in any such cases, Landlord and the agents and
servants of Landlord may, in addition to and not in derogation of any remedies
for any preceding breach of covenant,


                                       17
<PAGE>
 
immediately or at any time thereafter while such default continues and without
further notice and with or without process of law enter into and upon the
Premises or any part thereof in the name of the whole or mail a notice of
termination addressed to Tenant at the Premises and repossess the same as of
Landlord's former estate and expel Tenant and those claiming through or under
Tenant and remove its and their effects (forcibly, if necessary) without being
deemed guilty of any manner of trespass and without prejudice to any remedies
which might otherwise be used for arrears of rent or prior breach of covenant,
and upon such entry or mailing as aforesaid, this Lease shall terminate, but
Tenant shall remain liable as hereinafter provided. Tenant hereby waives all
statutory rights including, without limitation, rights of redemption, if any) to
the extent such rights may be lawfully waived, and Landlord, without notice to
Tenant, may store Tenant's effects and those of any person claiming through or
under Tenant at the expense and risk of Tenant and, if Landlord so elects, may
sell such effects at public auction or private sale and apply the net proceeds
to the payment of all sums due to Landlord from Tenant, if any, and pay over the
balance, if any, to Tenant.

9.2      TENANTS OBLIGATIONS AFTER TERMINATION

         In the event that this Lease is terminated under any of the provisions
contained in Section 9.1 or shall be otherwise terminated for breach of any
obligation of Tenant, Tenant covenants to pay forthwith to Landlord, as
compensation, the excess of the total rent reserved for the residue of the Term
over the rental value of the Premises for said residue of the Term. In
calculating the rent reserved, there shall be included, in addition to the Fixed
Rent and all additional rent, the value of all other consideration agreed to be
paid or performed by Tenant for said residue. Tenant further covenants as an
additional and cumulative obligation after any such ending to pay punctually to
Landlord all the sums and perform all the obligations which Tenant covenants in
this Lease to pay and to perform in the same manner and to the same extent and
at the same time as if this Lease had not been terminated. In calculating the
amounts to be paid by Tenant under the next foregoing covenant, Tenant shall be
credited with any amount paid to Landlord as compensation as provided in the
first sentence of this Section 9.2 and also with the net proceeds of any rents
obtained by Landlord by reletting the Premises, after deducting all Landlord's
reasonable expenses in connection with such reletting, including, without
implied limitation, all repossession costs, brokerage commissions, fees for
legal services and expense of preparing the Premises for such reletting, it
being agreed by Tenant that Landlord may (i) relet the Premises or any part or
parts thereof for a term or terms which may, at Landlord's option, be equal to
or less than or exceed the period which would otherwise have constituted the
balance of the Term and may grant such concessions and free rent as Landlord in
its reasonable judgment considers advisable or necessary to relet the same, and
(ii) make such alterations, repairs and decorations in the Premises as Landlord
in its reasonable judgment considers advisable or necessary to relet the same,
and no action of Landlord in accordance with the foregoing or failure to relet
or to collect rent under reletting shall operate or be construed to release or
reduce Tenant's liability as aforesaid.

         Nothing contained in this Lease shall, however, limit or prejudice the
right of Landlord to prove and obtain in proceedings for bankruptcy or
insolvency by reason of the termination of this Lease, an amount equal to the
maximum allowed by any statute or rule of law in effect at the time when, and
governing the proceedings in which, the damages are to be proved, whether or not
the amount be greater, equal to, or less than the amount of the loss or damages
referred to above.


                                       18
<PAGE>
 
                                    ARTICLE X
                                  MISCELLANEOUS


10.1     TITLES

         The titles of the Articles are for convenience and are not to be
considered in construing this Lease.

10.2     NOTICE OF LEASE

         Upon request of either party, both parties shall execute and deliver,
after the Term begins, a short form of this Lease in a form appropriate for
recording or registration, and if this Lease is terminated before the Term
expires, an instrument in such form acknowledging the date of termination.

10.3     RELOCATION

         (Not Applicable)

10.4     NOTICES FROM ONE PARTY TO THE OTHER

         No notice, approval, consent requested or election required or
permitted to be given or made pursuant to this Lease shall be effective unless
the same is in writing. Communications shall be addressed, if to Landlord, at
Landlord's Address, or at such other address as may have been specified by prior
notice to Tenant and, if to Tenant, at Tenant's Address or at such other place
as may have been specified by prior notice to Landlord. Any communication so
addressed shall be deemed duly served if mailed by registered or certified mail,
return receipt requested, delivered by hand, or by overnight express service by
a carrier providing a receipt of delivery. Notices shall be deemed received on
the earlier of (a) actual receipt, or (b) five business days after being mailed
as provided above.

10.5     BIND AND INURE

         The obligations of this Lease shall run with the land, and this Lease
shall be binding upon and inure to the benefit of the parties hereto and their
respective successors and assigns, except that the Landlord named herein and
each successive owner of the Premises shall be liable only for the obligations
accruing during the period of its ownership. Neither the Landlord named herein
nor any successive owner of the Premises whether an individual trust, a
corporation or otherwise shall have any personal liability beyond their equity
interest in the Premises.

10.6     NO SURRENDER

         The delivery of keys to any employees of Landlord or to Landlord's
agent or any employee thereof shall not operate as a termination of this Lease
or a surrender of the Premises.


                                       19
<PAGE>
 
10.7     NO WAIVER, ETC.

         The failure of Landlord or of Tenant to seek redress for violation of,
or to insist upon the strict performance of any covenant or condition of this
Lease or, with respect to such failure of Landlord, any of the Rules and
Regulations referred to in Section 6.1.4, whether heretofore or hereafter
adopted by Landlord, shall not be deemed a waiver of such violation nor prevent
a subsequent act, which would have originally constituted a violation, from
having all the force and effect of an original violation, nor shall the failure
of Landlord to enforce any of said Rules and Regulations against any other
tenant in the Building be deemed a waiver of any such Rules or Regulations. The
receipt by Landlord of Fixed Rent or additional rent with knowledge of the
breach of any covenant of this Lease shall not be deemed a waiver of such breach
by Landlord, unless such waiver be in writing signed by Landlord. No consent or
waiver, express or implied, by Landlord or Tenant to or of any breach of an
agreement or duty shall be construed as a waiver or consent to or of any other
breach of the same or any other agreement or duty.

10.8     NO ACCORD AND SATISFACTION

         No acceptance by Landlord of a lesser sum than the Fixed Rent and
additional rent then due shall be deemed to be other than on account of the
earliest installment of such rent due, nor shall any endorsement or statement on
any check or any letter accompanying any check or payment as rent be deemed as
accord and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance of such installment or
pursue any other remedy in this Lease provided.

10.9     CUMULATIVE REMEDIES

         The specific remedies to which Landlord may resort under the terms of
this Lease are cumulative and are not intended to be exclusive of any other
remedies or means of redress to which it may be lawfully entitled in case of any
breach or threatened breach by Tenant of any provisions of this Lease. In
addition to the other remedies provided in this Lease, Landlord shall be
entitled to the restraint by injunction of the violation or attempted or
threatened violation of any of the covenants, conditions or provisions of this
Lease or to a decree compelling specific performance of any such covenants,
conditions or provisions.

10.10    PARTIAL INVALIDITY

         If any term of this Lease, or the application thereof to any person or
circumstances shall to any extent be invalid or unenforceable, the remainder of
this Lease, or the application of such term to persons or circumstances other
than those as to which it is invalid or unenforceable, shall not be affected
thereby, and each term of this Lease shall be valid and enforceable to the
fullest extent permitted by law.


                                       20
<PAGE>
 
10.11    LANDLORD'S RIGHT TO CURE

         If Tenant shall at any time default in the performance of any
obligation under this Lease, Landlord shall have the right, but shall not be
obligated, to enter upon the Premises and to perform such obligation,
notwithstanding the fact that no specific provision for such substituted
performance by Landlord is made in this Lease with respect to such default. In
performing such obligation, Landlord may make any payment of money or perform
any other act. All sums so paid by Landlord (together with interest at the rate
of two percent (2%) per annum in excess of the then prime rate of interest being
charged by a majority of the banks in Boston), and all necessary incidental
costs and expenses in connection with the performance of any such acts by
Landlord, shall be deemed to be additional rent under this Lease and shall be
payable to Landlord immediately on demand. Landlord may exercise the foregoing
rights without waiving any other of its rights or releasing Tenant from any of
its obligations under this Lease.

10.12    ESTOPPEL CERTIFICATE

         Tenant agrees on the Commencement Date, and from time to time
thereafter, upon not less than 15 days' prior written request by Landlord, to
execute, acknowledge and deliver to Landlord a statement in writing in the form
attached hereto as Exhibit G, certifying that this Lease is unmodified and in
full force and effect; that Tenant has no defenses, offsets or counterclaims
against its obligations to pay the Fixed Rent and additional rent and to perform
its other covenants under this Lease; that there are no uncured defaults of
Landlord or Tenant under this Lease (or, if there are any defenses, offsets,
counterclaims, or defaults, setting them forth in reasonable detail); and the
dates to which the Fixed Rent, additional rent and other charges have been paid.
Any such statements delivered pursuant to this Section 10.12 may be relied upon
by any prospective purchaser or mortgage of premises which include the Premises
or any prospective assignee of any such mortgagee. Landlord agrees to execute,
acknowledge and deliver a similar estoppel certificate to Tenant as soon as
reasonably possible after receipt of such request from Tenant.

10.13    WAIVER OF SUBROGATION

         Any insurance carried by either party with respect to the Premises and
property therein or occurrences thereon, shall if the other party so requests
and it can be so written without additional premium or with any additional
premium which the other party agrees to pay, include a clause or endorsement
denying to the insurer rights of subrogation against the other party to the
extent rights have been waived by the insured prior to occurrence of injury or
loss. Each party, notwithstanding any provisions of this Lease to the contrary,
hereby waives any rights of recovery against the other for injury or loss due to
hazards covered by insurance containing such clause or endorsement to the extent
of the indemnification received thereunder.

10.14    BROKERAGE

         Tenant and Landlord represent and warrant to the other that they have
dealt with no broker, other than those listed in Section 1.1, in connection with
this transaction and agree to defend, indemnify and save each other harmless
from and against any and all claims for a commission arising out of this Lease
made by anyone, other than those listed in Section 1.1.


                                       21
<PAGE>
 
                                   ARTICLE XI
                                SECURITY DEPOSIT

                                (Not Applicable)


EXECUTED as a sealed instrument in two or more counterparts on the day and year
first above written.

TENANT:                        LANDLORD:

CARLETON CORPORATION           TECHNOLOGY PARK VIII
                               LIMITED PARTNERSHIP

                               By: The Gutierrez Company
                                   Managing Agent



By: /s/ Hem Desai              By: /s/ Arturo J. Gutierrez
    -------------------------      --------------------------------
    Hem Desai                      Arturo J. Gutierrez
    Chief Financial Officer        President
      and Treasurer                        


                                       22
<PAGE>
 
                                   EXHIBIT "C"

                   (SPECIFICATIONS OF LANDLORD'S CONSTRUCTION)

                        CARLETON CORPORATION - 11,881 RSF
                            700 Technology Park Drive
                                   Building IX
                            Billerica, Massachusetts


Description of "Landlord's Work":

1.       Repaint only (no wall covering) damaged walls with one coat of latex
         paint as shown on attached Exhibit "A".

2.       Patch and repair damaged walls as shown on attached Exhibit "A".

3.       Repair and/or replace damaged doors, frames and hardware as shown on
         attached Exhibit "A".

4.       Furnish and install new door frames and hardware only in the area where
         the door frames are missing as shown on attached Exhibit "A".

5.       Replace damaged acoustical ceiling tiles.

6.       Construct a hallway opening connecting the former RJO Enterprises and
         HFS suite(s) as shown on attached Exhibit "A".

7.       Remove electrical outlets in the computer room and install normal 120
         volt outlets necessary for normal office use at locations as determined
         by Landlord.

8.       Remove wall in office adjacent to UniKix space, and patch carpet, etc.

9.       Change lock on emergency exit door to normal egress hardware.

10.      Provide Tenant with keys to all offices.


<PAGE>
 
                                   EXHIBIT "D"
                               LANDLORD'S SERVICES

I.       CLEANING

A.       General

         1.       All cleaning work will be performed between 8:00 AM and
                  midnight, Monday through Friday, unless otherwise necessary
                  for stripping, waxing, etc.

         2.       Abnormal waste removal (e.g., computer installation paper,
                  bulk packaging, wood or cardboard crates, refuse from
                  cafeteria operation, etc.) shall be Tenant's responsibility.

B.       Daily Operations (5 times per week)

         1.       Tenant Areas

                  a.       Empty and clean all waste receptacles. Wash
                           receptacles as necessary.
                  b.       Vacuum all rugs and carpeted areas.
                  c.       Empty, damp-wipe and dry all ashtrays.

         2.       Lavatories

                  a.       Sweep and wash floors with disinfectant.
                  b.       Wash both sides of toilet seats with disinfectant.
                  c.       Wash all mirrors, basins, bowls, urinals.
                  d.       Spot-clean toilet partitions.
                  e.       Empty and disinfect sanitary napkin disposal
                           receptacles.
                  f.       Refill toilet tissue, towel, soap and sanitary napkin
                           dispensers.

         3.       Public Areas

                  a.       Wipe down entrance doors and clean glass (interior
                           and exterior). 
                  b.       Vacuum elevator carpets and wipe down doors and
                           walls.

C.       Operations as Needed (but not less than every other day)

         1.       Tenant and Public Areas

                  a.       Buff all resilient floor areas every other day.
                  b.       Clean water coolers.


                                  Page 1 of 3
<PAGE>
 
D.       Weekly Operations

         1.       Tenant Areas, Lavatories, Public Areas

                  a.       Hand dust and wipe clean all horizontal surfaces with
                           treated cloths to include furniture, office
                           equipment, window sills, door ledges, chair rails,
                           baseboards, convector tops, etc. within normal reach.
                  b.       Remove finger marks from private entrance doors,
                           light switches, and doorways.
                  c.       Sweep all stairways.

E.       Monthly Operations

         1.       Tenant and Public Areas

                  a.       Thoroughly vacuum seat cushions on chairs, sofas,
                           etc. b. Vacuum and dust grillwork.

                  2.       Lavatories

                  a.       Wash down interior walls and toilet partitions.

F.       As Required and Weather Permitting (but not less than three times per 
         year)

         1.       Entire Building

                  a.       Clean inside of all windows.
                  b.       Clean outside of all windows.

G.       Yearly

         1.       Tenant and Public Areas

                  a.       Strip and wax all resilient tile floor areas.

II.      HEATING,  VENTILATING AND AIR CONDITIONING

         1.       Heating, ventilation and air conditioning as required to
                  provide reasonably comfortable temperatures for normal
                  business day occupancy (except holidays), Monday through
                  Friday, from 8:00 AM to 6:00 PM and Saturday from 8:00 AM to
                  1:00 PM.

         2.       Maintenance on any additional or special air conditioning
                  equipment and the associated operating cost will be at
                  Tenant's expense.



                                   Page 2 of 3
<PAGE>
 
III.     WATER

         Hot water for lavatory purposes and cold water for drinking, lavatory
         and toilet purposes.

IV.      ELEVATORS (If building is elevated)

         Elevators for the use of all tenants and the general public for access
         to and from all Doors of the Building, programming of elevators
         (including, but not limited to, service elevators), shall be as
         Landlord from time to time determines best for the Building as a whole.

V.       RELAMPING OF LIGHT FIXTURES

         Tenant will reimburse Landlord for relamping, ballasts and starters
         within the Premises.

VI.      CAFETERIA,  VENDING AND PLUMBING INSTALLATIONS

         1.       Any space to be used primarily for lunchroom or cafeteria
                  operation shall be Tenant's responsibility to keep clean and
                  sanitary. Cafeteria, vending machines or refreshment service
                  installations by Tenant must be approved by Landlord in
                  writing. All maintenance, repairs and additional cleaning
                  necessitated by such installations shall be at Tenant's
                  expense.

         2.       Tenant is responsible for the maintenance and repair of
                  plumbing fixtures and related equipment installed in the
                  leased premises for its exclusive use (such as in coffee room,
                  cafeteria or employee exercise area).

VII.     ELECTRICITY

         Tenant shall pay for all electricity consumed in Tenant's space. If not
         metered separately, Landlord shall reasonably estimate the cost of such
         electrical usage for Tenant's lights and plugs, and Tenant shall
         reimburse Landlord for such costs on a monthly basis. If Tenant's use
         of electrical energy in Tenant's Space is disproportionate to other
         tenants' use of electrical energy, Tenant shall also pay for all excess
         electricity consumed in Tenant's space as estimated by Landlord.
         Tenant's use of electrical energy in Tenant's space shall not at any
         time exceed the capacity of any of the electrical conductors or
         equipment in or otherwise serving Tenant's space. To ensure that such
         capacity is not exceeded and to avert possible adverse effects upon the
         Building's electrical system, Tenant shall not, without prior written
         notice to Landlord in each instance, connect to the Building electric
         distribution system any fixtures, appliances or equipment which
         operates on a voltage in excess of 120 volts nominal, or which requires
         a single (dedicated) circuit without so providing, or make any
         alteration or addition to the electric system of the Tenant's space.
         Unless Landlord shall reasonably object to the connection of any such
         fixtures, appliances or equipment, all additional risers or other
         equipment required therefore shall be provided by Landlord and the cost
         thereto shall be paid by Tenant upon Landlord's demand.


                                   Page 3 of 3
<PAGE>
 
                                   EXHIBIT "E"
                              RULES AND REGULATIONS

1.       The entrance, lobbies, passages, corridors, elevators and stairways
         shall not be encumbered or obstructed by Tenant, Tenant's agents,
         servants, employees, licensees, and visitors be used by them for any
         purpose other than for ingress and egress to and from the Premises. The
         moving in or out of all safes, freight, furniture, or bulky matter of
         any description must take place during the hours which Landlord may
         determine from time to time. Landlord reserves the right to inspect all
         freight and bulky matter to be brought into the Building and to exclude
         from the Building all freight and bulky matter which violates any of
         these Rules and Regulations or the Lease of which these Rules and
         Regulations are a part.

2.       No curtains, blinds, shades, screens, or signs other than those
         furnished by Landlord shall be attached to, hung in, or used in
         connection with any window or door of the Premises without the prior
         written consent of the Landlord. Interior signs on doors shall be
         painted or affixed for Tenant by Landlord or by sign painters first
         approved by Landlord, at the expense of Tenant, and shall be of a size,
         color and style acceptable to Landlord.

3.       No additional locks or bolts of any kind shall be placed upon any of
         the doors or windows by Tenant, nor shall any changes be made in
         existing locks or the mechanism thereof without the prior written
         consent of Landlord. Tenant must, upon the termination of its tenancy,
         restore to Landlord all keys of stores, shops, booths, stands, offices
         and toilet rooms, either furnished to or otherwise procured by Tenant;
         and in the event of the loss of any keys so furnished, Tenant shall pay
         to Landlord the cost thereof.

4.       Canvassing, soliciting and peddling in the Building are prohibited, and
         Tenant shall cooperate to prevent the same.

5.       Tenant may request heating and/or air conditioning during other periods
         in addition to normal working hours by submitting their request in
         writing to the Building Manager's office no later than 2:00 PM the
         preceding workday (Monday through Friday) on forms available from the
         Building Manager. The request shall clearly state the start and stop
         hours of the "off-hour" service. Tenant shall submit to the Building
         Manager a list of personnel who are authorized to make such requests.
         Charges are t be determined by the Building Manager on the additional
         hours of operations and shall be fair and reasonable and reflect the
         additional operating costs involved.

6.       Tenant shall comply with all security measures from time to time
         established by Landlord for the Building.

7.       Should Tenant's organization have a non-smoking policy presently in
         effect for their visitors and/or employees or institute such a policy
         during the term of this lease, Tenant shall set aside a smoking area
         within the leased premises, properly ventilated and/or with smoke
         filtration units, so as not to interfere with any fire protection
         devices, such as smoke detectors, or the quality of air recirculated in
         the building's HVAC system.
<PAGE>
 
                                  EXHIBIT "G"
                              ESTOPPEL CERTIFICATE

         THIS CERTIFICATE is made to _________________ with respect to a Lease
between _________________ as Landlord and the undersigned, covering a building
located in ________________ , such lease being dated, _____________________ as
amended by (list all amendments):

         The undersigned has been advised that Teachers Insurance and Annuity
Association of America, as Trustee as aforesaid, with an address at 730 Third
Avenue, New York, NY 10017 (the "Bank"), is about to enter into a transaction
whereby the Bank is making a loan secured by the aforesaid real estate and the
Lease to the undersigned, and under which the Bank may acquire an ownership
interest in such real estate. In connection with this transaction, the entire
interest of the Landlord under the Lease to the undersigned will be assigned to
the Bank. The undersigned acknowledges that the Bank is and will be relying upon
the truth, accuracy and completeness of this letter in proceeding with the
transaction described above.

         The undersigned, for the benefit of the bank, their successors and
assigns, hereby certifies, represents, warrants, agrees and acknowledges that:

1.       The Lease is in full force and effect in accordance with its terms
         without modification or amendment except as noted above and the
         undersigned is the holder of the Tenant's interest under the Lease.

2.       The undersigned is in possession of all of the Premises described in
         the Lease under and pursuant to the Lease and is doing business
         thereon; and the premises are completed as required by the Lease.

3.       To the knowledge of the undersigned, the undersigned has no claims or
         offsets with respect to any of its obligations as Tenant under the
         Lease, and neither the undersigned nor the Landlord is claimed to be in
         default under the Lease.

4.       The undersigned has not paid any rental or installments thereof in
         advance of the due date as set forth in the Lease.

5.       The undersigned has no notice of prior assignment, hypothecation or
         pledge of rents of the Lease or the Landlord's interest thereunder or
         of the Tenant's interest thereunder.

6.       The term of the Lease has commenced and is presently scheduled to
         expire on ___________. If there are any rights of extension or renewal
         under the terms of the Lease, the same have not, as of the date of this
         letter, been exercised.



                                   Page 1 of 2
<PAGE>
 
7.       Until such time as the Bank shall become the Landlord, if the
         undersigned should assert a claim that the Landlord has failed to
         perform an obligation to the undersigned under the terms of the Lease
         or otherwise, notice thereof shall promptly be furnished to the Bank at
         the address set forth above; and the undersigned agrees that the
         undersigned will not exercise any rights which the undersigned might
         otherwise have on account of any such failure until notice thereof has
         been give to the Bank, and the Bank has had the same opportunity to
         cure any such failure as the Landlord may have under the terms of the
         Lease.

8.       Each of the statements set forth in Paragraphs 1 through 7 are true,
         accurate and complete except as follows (state specifically any
         exception):



DATED:

ATTEST:


                                              By:
                                                 ----------------------------


                                              By:
                                                 ----------------------------


                                   Page 2 of 2
<PAGE>
 
                                   EXHIBIT "H"
                                OPTION TO EXTEND

         Provided Tenant is not in default under this Lease at the time of the
exercise thereof, Tenant shall have one option to extend the term of this Lease
for a period of three years, commencing at the expiration of the initial Lease
Term, and such option to extend to be exercised by Tenant notifying Landlord in
writing thereof, at least nine (9) months prior to the end of the initial Lease
Term. The exercise of such option shall without the necessity of additional
documentation, automatically extend the term of this Lease, except that: (i)
there shall be no additional options to extend after the termination of this
option; and (ii) the applicable Annual Base Rent shall be the "Market Rent" as
set forth herein:

The Market Rent for the Premises shall be determined as follows:

(a)      The Market Rent shall be proposed by Landlord within 45 days of receipt
         of Tenant's notice that it intends to exercise its option to extend the
         term (the "Landlord's Proposed Market Rent"). The Landlord's Proposed
         Market Rent shall be the Market Rent unless Tenant notifies Landlord,
         within 30 days of Tenant's receipt of Landlord's Proposed Market Rent,
         that Landlord's Proposed Market Rent is not satisfactory to Tenant
         ("Tenant's Rejection Notice").

(b)      If the Market Rent is not otherwise agreed upon by Landlord and Tenant
         within 30 days after Landlord's receipt of Tenant's Rejection Notice,
         then the Market Rent shall be determined by the following appraisal
         procedure. Tenant shall provide Landlord with notice specifying the
         name and address of the appraiser designated by Tenant (the "Tenant's
         Appraisal Notice").

         Landlord shall within five days after receipt of Tenant's Appraisal
Notice, notify Tenant of the name and address of the appraiser designated by
Landlord. Such two appraisers shall, within 20 days after the designation of the
second appraiser, make their determinations of the Market Rent in writing and
give notice thereof to each other and to Landlord and Tenant. Such two
appraisers shall have 20 days after the receipt of notice of each other's
determination to confer with each other and to attempt to reach agreement as to
the determination of the Market Rent. If such appraisers shall concur in such
determination, they shall give notice thereof to Landlord and Tenant and such
concurrence shall be final and binding upon Landlord and Tenant. If such
appraisers shall fail to concur as to such determination within said 20 day
period, they shall give notice thereof to Landlord and Tenant and shall
immediately designate a third appraiser. If the two appraisers shall fail to
agree upon the designation of such third appraiser within five days after said
20 day period, then they or either of them shall give notice of such failure to
agree to Landlord and Tenant, and if Landlord and Tenant fail to agree upon the
selection of such third appraiser within five days after the appraiser(s)
appointed by the parties give notice as aforesaid, then either party on behalf
of both may apply to the American Arbitration Association, or any successor
thereto, or on his or her failure, refusal, or inability to act, to a court of
competent jurisdiction, for the designation of such third appraiser.



                                   Page 1 of 2
<PAGE>
 
         All appraisers shall be real estate appraisers or consultants who shall
have had at least seven years continuous experience in the business of
appraising real estate in the suburban Boston area.

         The third appraiser shall conduct such hearings and investigations as
he or she may deem appropriate and shall within ten days after the date of his
or her designation, make an independent determination of the Market Rent.

         If none of the determinations of the appraisers varies from the mean of
the determinations of the other appraisers by more than ten percent (10%), the
mean of the determinations of the three appraisers shall be the Market Rent for
the Premises. If, on the other hand, the determination of any single appraiser
varies from the mean of the determinations of the other two appraisers whose
determinations are closest in number by more than 10%, then the average of the
determinations of the two closest appraisers shall be the Market Rent.

         The determination of the appraisers, as provided above, shall be
conclusive upon the parties and shall have the same force and effect as a
judgment made in a court of competent jurisdiction.

         Each party shall pay fees, costs and expenses of the appraiser selected
by it and its own counsel fees and one-half of all other expenses and fees of
any such appraisal.

         Notwithstanding the foregoing, the Annual Fixed Rent for the Extension
Term shall not be less than the Annual Fixed Rent for the initial Lease Term.

                                   Page 2 of 2