Document:

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                                                                  EXHIBIT 10.1

                            INTERFACE SYSTEMS, INC.

                         CONVERTIBLE SUBORDINATED NOTE
                               PURCHASE AGREEMENT

      THIS CONVERTIBLE SUBORDINATED NOTE PURCHASE AGREEMENT (this
"Agreement") is made as of the 28th day of June, 2000, by and between
Interface Systems, Inc., a Michigan corporation ("Interface" or the
"Company"), and Tumbleweed Communications Corp., a Delaware corporation
("Purchaser" or the "Parent").

                 RECITALS

      WHEREAS, the Board of Directors of the Company has approved the issuance
of Common Stock, no par value (the "Common Stock") in accordance with the Notes,
as defined below;

      WHEREAS, the Board of Directors of the Company has approved the sale and
issuance of an aggregate of up to $3,000,000 of Convertible Subordinated Notes
(individually, a "Note" and collectively, the "Notes") which can be converted
into Common Stock;

      WHEREAS, the Purchaser desires to purchase Notes on the terms and
conditions set forth herein; and

      WHEREAS, the Company desires to issue and sell Notes to the Purchaser on
the terms and conditions set forth herein;

      NOW, THEREFORE, in consideration of the foregoing recitals and the mutual
promises hereinafter set forth, the parties hereto agree as follows:

1.    PURCHASE AND SALE OF STOCK.

      1.1   SALE AND ISSUANCE OF NOTES.

      (a) Subject to the terms and conditions of this Agreement, the Purchaser
agrees, to purchase at the Closings and the Company agrees to sell and issue to
the Purchaser, a Note for $2,000,000 (the "$2,000,000 Note") and a Note for
$1,000,000 (the "$1,000,000 Note").

      1.2   THE CLOSINGS.

      (a) The purchase and sale of the $2,000,000 Note shall take place at the
offices of Skadden, Arps, Slate, Meagher & Flom LLP, Palo Alto, California, at
5:00 p.m., on July 3, 2000, or at such other time and place as the Company and
the Purchaser shall mutually agree, either orally or in writing (which time and
place are designated as the "$2,000,000 Closing").

      (b) The purchase and sale of the $1,000,000 Note shall take place at the
offices of Skadden, Arps, Slate, Meagher & Flom LLP, Palo Alto, California, at
5:00 p.m., on September 5, 2000, or at such other time and place as the Company
and the Purchaser shall mutually agree, either orally or in writing (which time
and place are designated as the "$1,000,000 Closing" and together with the
$2,000,000 Closing, the "Closings").

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      (c) At each of the Closings, the Company shall deliver to the Purchaser a
Note in exchange for payment of the purchase price therefor by check, wire
transfer, or such other form of payment as shall be mutually agreed upon by the
Purchaser and the Company.

2.    REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

      Reference is made to that certain Agreement and Plan of Merger by and
among Parent, Maize Acquisition Sub, Inc., a Delaware corporation, and the
Company dated June 28, 2000 (the "Merger Agreement"). The Company hereby
represents, warrants and covenants to the Purchaser each of the representations,
warranties and covenants set forth in Article III of the Merger Agreement
subject to the exceptions set forth in the Disclosure Schedule thereto, which is
incorporated by reference herein, and further represents, warrants, and
covenants, specifically identifying the relevant subparagraph(s) hereof and
attached hereto, as follows:

      2.1   REGISTRATION RIGHTS.

      Except as provided in the Merger Agreement, the Company is presently not
under any obligation and has not granted any rights to register under the
Securities Act any of its presently outstanding securities or any of its
securities that may subsequently be issued.

      2.2   AUTHORIZATION.

      All corporate action on the part of the Company, its officers, directors
and shareholders necessary for the authorization, execution and delivery of this
Agreement, that certain Registration Rights Agreement by and between the Company
and Parent (the "Registration Rights Agreement") and the Notes, the performance
of all obligations of the Company hereunder and thereunder at the Closings and
the authorization, issuance (or reservation for issuance), sale, and delivery of
the Notes being sold hereunder and the Common Stock issuable upon conversion
thereof has been taken or will be taken prior to the Closings, and this
Agreement, the Registration Rights Agreement, and the Notes, when executed and
delivered, will constitute valid and legally binding obligations of the Company,
enforceable in accordance with their respective terms except (i) as limited by
applicable bankruptcy, insolvency, reorganization, moratorium, and other laws of
general application affecting enforcement of creditors' rights generally, (ii)
as limited by laws relating to the availability of specific performance,
injunctive relief, or other equitable remedies, and (iii) to the extent that the
indemnification provisions contained in the Registration Rights Agreement may be
limited by applicable laws. The sale of the Notes is not and the subsequent
conversion of the Notes into Common Stock will not be subject to any preemptive
rights or rights of first refusal that have not been properly waived or complied
with.

      2.3   OFFERING.

      Subject in part to the truth and accuracy of the Purchaser's
representations set forth in this Agreement, the offer, sale and issuance of the
Notes as contemplated by this Agreement are exempt from the registration
requirements of the Securities Act, and neither the Company nor any authorized
agent acting on its behalf will take any action hereafter that would cause the
loss of such exemption.

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      2.4   VALID ISSUANCE OF NOTES AND COMMON STOCK.

      The Notes that are being purchased by the Investors hereunder, when
issued, sold, and delivered in accordance with the terms of this Agreement for
the consideration expressed herein, will be duly and validly issued, fully paid,
and nonassessable, and will be free of restrictions on transfer other than
restrictions on transfer under this Agreement and the Registration Rights
Agreement and under applicable state and federal securities laws. The Common
Stock issuable upon conversion of the Notes being purchased under this Agreement
has been duly and validly reserved for issuance and will be duly and validly
issued, fully paid, and nonassessable and will be free of restrictions on
transfer other than restrictions on transfer under this Agreement and the
Registration Rights Agreement and under applicable state and federal securities
laws.

      2.5   GOVERNMENTAL CONSENTS.

      No consent, approval, qualification, order or authorization of, or filing
with, any local, state, or federal governmental authority is required on the
part of the Company in connection with the Company's valid execution, delivery,
or performance of this Agreement, the offer, sale or issuance of the Notes by
the Company or the issuance of Common Stock upon conversion of the Notes, except
such filings as have been made prior to the Closings, except any notices of sale
required to be filed with the Securities and Exchange Commission under
Regulation D of the Securities Act of 1933, as amended (the "Securities Act"),
or such post- closing filings as may be required under applicable state
securities laws, which will be timely filed within the applicable periods
therefor.

      2.6   DISCLOSURE.

      The Company has provided the Purchaser with all the information reasonably
available to it without undue expense that such Purchaser has requested for
deciding whether to purchase the Notes and all information that the Company
believes is reasonably necessary to enable such Purchaser to make such decision.
To the best of the Company's knowledge after reasonable investigation, neither
this Agreement nor any other agreements, written statements or certificates made
or delivered in connection herewith contains any untrue statement of a material
fact or omits to state a material fact necessary to make the statements herein
or therein not misleading.

3.    REPRESENTATIONS AND WARRANTIES OF THE PURCHASER.

      The Purchaser hereby represents and warrants to the Company (severally and
not jointly) that:

      3.1   AUTHORIZATION.

      The Purchaser has full power and authority to enter into this Agreement
and the Registration Rights Agreement, and that this Agreement, when executed
and delivered, will constitute a valid and legally binding obligation of such
Purchaser.

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      3.2   LEGENDS.

      To the extent applicable, each certificate or other document evidencing
any of the Notes or any Common Stock issued upon conversion thereof shall be
endorsed with the legends substantially in the form set forth below:

      (a)   The following legend under the Securities Act:

      "THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
      AMENDED, OR ANY SECURITIES LAW OF ANY STATE OF THE UNITED STATES
      (COLLECTIVELY, THE "SECURITIES LAWS" AND MAY NOT BE TRANSFERRED OR RESOLD
      EXCEPT AS PERMITTED UNDER THE SECURITIES LAWS, PURSUANT TO REGISTRATION
      UNDER SUCH SECURITIES LAWS OR PURSUANT TO AN EXEMPTION FROM REGISTRATION,
      WHICH EXEMPTION FROM REGISTRATION SHALL BE DESCRIBED IN A WRITTEN OPINION
      OF COUNSEL REASONABLY SATISFACTORY TO THE PURCHASER AND DELIVERED TO THE
      PURCHASER."

      (b) Any legend imposed or required by the Company's Bylaws or applicable
state securities laws.

      3.3   ACCREDITED INVESTOR.

      (a) The Purchaser further represents to the Company that such Purchaser is
an Accredited Investor, as defined in Rule 501 of the Securities Act.

      3.4   PURCHASE ENTIRELY FOR OWN ACCOUNT.

      This Agreement is made with the Purchaser in reliance upon such
Purchaser's representation to the Company, which by such Purchaser's execution
of this Agreement such Purchaser hereby confirms, that the Note to be purchased
by such Purchaser and the Common Stock issuable upon conversion thereof
(collectively, the "Securities") will be acquired for investment for such
Purchaser's own account, not as a nominee or agent, and not with a view to the
resale or distribution of any part thereof, and that such Purchaser has no
present intention of selling, granting any participation in, or otherwise
distributing the same. By executing this Agreement, the Purchaser further
represents that it does not have any contract, undertaking, agreement or
arrangement with any person to sell, transfer or grant participations to such
person or to any third person, with respect to any of the Notes.

4.    CONDITIONS OF PURCHASER'S OBLIGATIONS AT THE CLOSINGS.

      The obligations of the Purchaser under subparagraph 1.2 of this Agreement
are subject to the fulfillment on or before each of the Closings of each of the
following conditions:

      4.1   REPRESENTATIONS AND WARRANTIES.

      The representations and warranties of the Company contained in Section 2
shall be true on and as of each Closing with the same effect as though such
representations and warranties had been made on and as of the date of each
Closing.

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      4.2   PERFORMANCE.

      The Company shall have performed and complied with all agreements,
obligations, and conditions contained in this Agreement that are required to be
performed or complied with by it on or before each Closing.

      4.3   COMPLIANCE CERTIFICATE.

      The President of the Company shall deliver to the Purchaser at each
Closing a certificate certifying that the conditions specified in paragraphs
4.1, 4.2, 4.4, 4.5 and 4.6 have been fulfilled.

      4.4   QUALIFICATIONS.

      All authorizations, approvals, or permits, if any, of any governmental
authority or regulatory body of the United States or of any state that are
required in connection with the lawful issuance and sale of the Notes pursuant
to this Agreement shall be duly obtained and effective as of each Closing.

      4.5   PROCEEDINGS AND DOCUMENTS.

      All corporate and other proceedings in connection with the transactions
contemplated at each Closing and all documents incident thereto shall be
reasonably satisfactory in form and substance to the Purchaser's special
counsel, which shall have received all such counterpart original and certified
or other copies of such documents as it may reasonably request.

      4.6   OPINION OF COMPANY COUNSEL.

      The Purchaser shall have received from Dykema Gossett PLLC, counsel for
the Company, an opinion, dated the date of each of the Closings, in the form
attached hereto as Exhibit A.

      4.7   NO MATERIAL ADVERSE CHANGE.

      Since the date of this Agreement, there shall not have occurred any event,
change or effect having, or which could be reasonably likely to have,
individually or in the aggregate, a material adverse effect on the Company and
its Subsidiaries.

      4.8   NO TERMINATION OF THE MERGER AGREEMENT.

      The Merger Agreement shall not have been terminated in accordance with its
terms.

      4.9   NO BREACH OF THE MERGER AGREEMENT.

      The Company shall not be in material breach of any representation,
warranty, covenant or other agreement contained in this Agreement, the Notes or
the Merger Agreement.

<PAGE>   6
5.   CONDITIONS OF THE COMPANY'S OBLIGATIONS AT CLOSING.

     The obligations of the Company to the Purchaser under this Agreement are
subject to the fulfillment on or before each Closings of each of the following
conditions by the Purchaser:

      5.1   REPRESENTATIONS AND WARRANTIES.

      The representations and warranties of the Purchaser contained in Section 3
shall be true on and as of each Closing with the same effect as though such
representations and warranties had been made on and as of the date of such
Closing.

      5.2   QUALIFICATIONS.

      All authorizations, approvals, or permits, if any, of any governmental
authority or regulatory body of the United States or of any state that are
required in connection with the lawful issuance and sale of the Notes pursuant
to this Agreement shall be duly obtained and effective as of each Closing.

6.    MISCELLANEOUS

      6.1   ENTIRE AGREEMENT.

      This Agreement and the documents referred to herein constitute the entire
agreement among the parties and no party shall be liable or bound to any other
party in any manner by any warranties, representations, or covenants except as
specifically set forth herein or therein.

      6.2   SURVIVAL OF WARRANTIES.

      The warranties, representations, and covenants of the Company and the
Purchaser contained in or made pursuant to this Agreement shall survive the
execution and delivery of this Agreement and both Closings.

      6.3   SUCCESSORS AND ASSIGNS.

      Except as otherwise provided herein, the terms and conditions of this
Agreement shall inure to the benefit of and be binding upon the respective
successors and assigns of the parties (including permitted transferees of any
Notes sold hereunder or any Common Stock issued upon conversion thereof).
Nothing in this Agreement, express or implied, is intended to confer upon any
party other than the parties hereto or their respective successors and assigns
any rights, remedies, obligations, or liabilities under or by reason of this
Agreement, except as expressly provided in this Agreement.

      6.4   GOVERNING LAW.

      This Agreement shall be governed and construed in accordance with the laws
of the State of Delaware without giving effect to the principles of conflicts of
law thereof.

      6.5   COUNTERPARTS.

      This Agreement may be executed in two or more counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.
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      6.6   TITLES AND SUBTITLES.

      The titles and subtitles used in this Agreement are used for convenience
only and are not to be considered in construing or interpreting this Agreement.

      6.7   NOTICES.

      Unless otherwise provided, all notices and other communications required
or permitted under this Agreement shall be in writing and shall be mailed by
United States first-class mail, postage prepaid, sent by facsimile or delivered
personally by hand or by a nationally recognized courier addressed to the party
to be notified at the address or facsimile number indicated for such person on
the signature page hereof, or at such other address or facsimile number as such
party may designate by ten (10) days' advance notice to the other parties
hereto. All such notices and other written communications shall be effective on
the date of mailing, confirmed facsimile transfer or delivery.

      6.8   FINDER'S FEES.

      Each party represents that it neither is nor will be obligated for any
finder's fee or commission in connection with this transaction.

      The Purchaser agrees to indemnify and to hold harmless the Company from
any liability for any commission or compensation in the nature of a finder's fee
(and the cost and expenses of defending against such liability or asserted
liability) for which it or any of its officers, partners, employees, or
representatives is responsible.

      The Company agrees to indemnify and hold harmless the Purchaser from any
liability for any commission or compensation in the nature of a finder's fee
(and the costs and expenses of defending against such liability or asserted
liability) for which the Company or any of its officers, employees, or
representatives is responsible.

      6.9   EXPENSES.

      Irrespective of whether either Closing is effected, the Company shall pay
all costs and expenses that it incurs with respect to the negotiation,
execution, delivery, and performance of this Agreement.

      6.10  ATTORNEYS' FEES.

      If any action at law or in equity is necessary to enforce or interpret the
terms of this Agreement, the prevailing party shall be entitled to reasonable
attorneys' fees, costs, and disbursements in addition to any other relief to
which such party may be entitled.

      6.11  AMENDMENTS AND WAIVERS.

      Any term of this Agreement may be amended and the observance of any term
of this Agreement may be waived (either generally or in a particular instance
and either retroactively or prospectively), only with the written consent of
both the Company and the Purchaser.

<PAGE>   8
      6.12  SEVERABILITY.

      If one or more provisions of this Agreement are held to be unenforceable
under applicable law, such provision shall be excluded from this Agreement and
the balance of the Agreement shall be interpreted as if such provision were so
excluded and shall be enforceable in accordance with its terms.

      IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first above written.

                               INTERFACE SYSTEMS, INC.

                               By:
                                  -------------------------------------------
                               Address:
                                       -------------------------------------
                               ----------------------------------------------
                               ----------------------------------------------

                               PURCHASER:

                               By:
                                  -------------------------------------------
                               Title:
                                     --------------------------------------
                               Address:
                                       -------------------------------------
                               ----------------------------------------------
                               ----------------------------------------------

<PAGE>   9
                                   Exhibit A

                     FORM OF OPINION OF DYKEMA GOSSETT PLLC

1. The Company has been duly incorporated and is validly existing in good
standing under the laws of the State of Michigan.

2. The Company has the requisite corporate power and authority to own and
operate its properties and assets and to conduct its business as currently
conducted.

3. The Transaction Agreements have been duly authorized, validly executed and
delivered by all requisite corporate action on the part of the Company and
constitute valid and binding obligations of the Company, enforceable against the
Company in accordance with their terms, except that (a) the enforceability
thereof may be limited by (i) bankruptcy, insolvency, reorganization, moratorium
or other similar laws now or hereafter in effect relating to creditors' rights
generally and (ii) general principles of equity (regardless of whether
enforceability is considered in a proceeding in equity or at law) and (b) the
enforceability of rights to indemnification and contribution thereunder may be
limited by federal or state securities laws, rules or regulations or the
policies underlying such laws, rules or regulations.

4. To our knowledge, the authorized capital stock of the Company is as set forth
in Section 3.2 of the Merger Agreement. To our knowledge, and except as set
forth in Section 3.2 of the Merger Agreement and the exhibits and schedules
thereto, there are no outstanding options, warrants, rights (including
conversion or preemptive rights and rights of first refusal) or agreements of
any kind for the purchase or acquisition from the Company of any of its
securities.

5. The Notes have been duly authorized for issuance by the Company. The shares
of Common Stock issuable upon conversion of the Notes have been reserved for
issuance by all requisite corporate action on the part of the Company and, when
issued upon conversion of the Notes in accordance with the terms of the Restated
Articles, will be validly issued, fully paid and nonassessable.

6. The execution and delivery by the Company of each of the Transaction
Agreements and the performance by the Company of its obligations thereunder will
not (i) violate any provision of the Restated Articles, the Bylaws or any
Material Agreement or (ii) contravene any Applicable Order against the Company.

7. No consent or approval of, or other action by or filing with, any
Governmental Authority under any Applicable Law is required to be obtained,
taken or made by the Company in connection with the execution, delivery and
performance by the Company of the transactions contemplated by the Purchase
Agreement, except where a failure to obtain such approval, make such filing or
take such action would not have a material adverse effect on the Company,
subject to the timely filing of a Form D pursuant to Regulation D promulgated
under the Securities Act of 1933, as amended (the "Securities Act").

8. No registration is required under the Securities Act in connection with the
offer and sale of the Notes, subject to the timely filing of a Form D pursuant
to Regulation D promulgated under the Securities Act.

9. Except as may be set forth in the Schedule of Exceptions to the Purchase
Agreement, to the best of our knowledge, there is no action, proceeding or
investigation pending or overtly threatened against the Company before any court
or administrative agency that questions the validity of any of the Transaction
Agreements or might result, either individually or in the aggregate, in any
material adverse change in the assets, financial condition or operations of the
Company.

<PAGE>   10

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
OR ANY SECURITIES LAW OF ANY STATE OF THE UNITED STATES (COLLECTIVELY, THE
"SECURITIES LAWS" AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER
THE SECURITIES LAWS, PURSUANT TO REGISTRATION UNDER SUCH SECURITIES LAWS OR
PURSUANT TO AN EXEMPTION FROM REGISTRATION, WHICH EXEMPTION FROM REGISTRATION
SHALL BE DESCRIBED IN A WRITTEN OPINION OF COUNSEL REASONABLY SATISFACTORY TO
THE PURCHASER AND DELIVERED TO THE PURCHASER.

                                    FORM OF
                            INTERFACE SYSTEMS, INC.
                    CONVERTIBLE SUBORDINATED PROMISSORY NOTE

$                                                          Palo Alto, California
----------------
                                                                   June 28, 2000

     Interface Systems, Inc., a Michigan corporation (the "Company"), the
principal office of which is located at 5855 Interface Drive, Ann Arbor, MI, for
value received hereby promises to pay to Tumbleweed Communications Corp., a
Delaware corporation ("Parent" or the "Purchaser"), or its registered assigns,
the sum             ($         ), or such lesser amount as shall then equal the
outstanding principal amount hereof and any unpaid accrued interest hereon, as
set forth below, shall be due and payable on the earlier to occur of (i) June
28, 2001, or (ii) when declared due and payable by the Holder upon the
occurrence of an Event of Default (as defined below). Payment for all amounts
due hereunder shall be made by mail to the registered address of the Holder.
This Note is issued in connection with that certain Convertible Subordinated
Note Purchase Agreement between the Company and the Purchasers described
therein, dated as of June 28, 2000, as the same may from time to time be
amended, modified or supplemented (the "Purchase Agreement"). The holder of this
Note is subject to certain restrictions set forth in the Purchase Agreement and
shall be entitled to certain rights and privileges set forth in the Purchase
Agreement. This Note is one of the Notes referred to as the "Notes" in the
Purchase Agreement.

     The following is a statement of the rights of the Holder of this Note and
the conditions to which this Note is subject, and to which the Holder hereof, by
the acceptance of this Note, agrees:

1.   DEFINITIONS.

     As used in this Note, the following terms, unless the context otherwise
requires, have the following meanings:

          (i)   "Company" includes any corporation which shall succeed to or
     assume the obligations of the Company under this Note.

          (ii)  "Holder," when the context refers to a holder of this Note,
     shall mean any person who shall at the time be the registered holder of
     this Note.

<PAGE>   11
          (iii) "Merger Agreement" shall refer to that certain Agreement and
     Plan of Merger by and among the Company, Parent, and Maize Acquisition Sub,
     Inc., dated June 28, 2000.

2.   INTEREST.

     Commencing on December 31, 2000, and on each June 30 and December 31
thereafter until all outstanding principal and interest on this Note shall have
been paid in full, the Company shall pay interest at the rate of ten percent
(10%) per annum (the "Initial Interest Rate") on the principal of this Note
outstanding during the period beginning on the date of issuance of this Note and
ending on the date that the principal amount of this Note becomes due and
payable. In the event that the principal amount of this Note is not paid in full
when such amount becomes due and payable, interest at the same rate as the
Initial Interest Rate plus three percent (3%) shall continue to accrue on the
balance of any unpaid principal until such balance is paid.

3.   EVENTS OF DEFAULT.

     If any of the events specified in this Section 3 shall occur (herein
individually referred to as an "Event of Default"), the Holder of the Note may,
so long as such condition exists, declare the entire principal and unpaid
accrued interest hereon immediately due and payable, by notice in writing to the
Company:

     (i)  Default in the payment of the principal and unpaid accrued interest of
this Note when due and payable if such default is not cured by the Company
within ten (10) days after the Holder has given the Company written notice of
such default; or

     (ii)  The institution by the Company of proceedings to be adjudicated as
bankrupt or insolvent, or the consent by it to institution of bankruptcy or
insolvency proceedings against it or the filing by it of a petition or answer or
consent seeking reorganization or release under the federal Bankruptcy Act, or
any other applicable federal or state law, or the consent by it to the filing of
any such petition or the appointment of a receiver, liquidator, assignee,
trustee or other similar official of the Company, or of any substantial part of
its property, or the making by it of an assignment for the benefit of creditors,
or the taking of corporate action by the Company in furtherance of any such
action; or

     (iii) If, within sixty (60) days after the commencement of an action
against the Company (and service of process in connection therewith on the
Company) seeking any bankruptcy, insolvency, reorganization, liquidation,
dissolution or similar relief under any present or future statute, law or
regulation, such action shall not have been resolved in favor of the Company or
all orders or proceedings thereunder affecting the operations or the business of
the Company stayed, or if the stay of any such order or proceeding shall
thereafter be set aside, or if, within sixty (60) days after the appointment
without the consent or acquiescence of the Company of any trustee, receiver or
liquidator of the Company or of all or any substantial part of the properties of
the Company, such appointment shall not have been vacated; or

<PAGE>   12
      (iv)  Any declared default of the Company under any Senior Indebtedness
(as defined below) that gives the holder thereof the right to accelerate such
Senior Indebtedness, and such Senior Indebtedness is in fact accelerated by the
holder; or

     (v) If the Company or the Purchaser terminates the Merger Agreement under
any section other than section 7.1(c) of the Merger Agreement, sixty (60) days
following such termination..

4.   SUBORDINATION.

     The indebtedness evidenced by this Note is hereby expressly subordinated,
to the extent and in the manner hereinafter set forth, in right of payment to
the prior payment in full of all the Company's Senior Indebtedness, as
hereinafter defined.

     4.1 SENIOR INDEBTEDNESS. As used in this Note, the term "Senior
Indebtedness" shall mean the principal of and unpaid accrued interest on: (i)
all indebtedness of the Company to banks, commercial finance lenders, insurance
companies or other financial institutions regularly engaged in the business of
lending money, which is for money borrowed by the Company (whether or not
secured), and (ii) any such indebtedness or any debentures, notes or other
evidence of indebtedness issued in exchange for or to refinance such Senior
Indebtedness, or any indebtedness arising from the satisfaction of such Senior
Indebtedness by a guarantor.

     4.2 DEFAULT ON SENIOR INDEBTEDNESS. If there should occur any receivership,
insolvency, assignment for the benefit of creditors, bankruptcy, reorganization
or arrangements with creditors (whether or not pursuant to bankruptcy or other
insolvency laws), sale of all or substantially all of the assets, dissolution,
liquidation or any other marshalling of the assets and liabilities of the
Company, or if this Note shall be declared due and payable upon the occurrence
of an Event of Default with respect to any Senior Indebtedness, then (i) no
amount shall be paid by the Company in respect of the principal of or interest
on this Note at the time outstanding, unless and until the principal of and
interest on the Senior Indebtedness then outstanding shall be paid in full, and
(ii) no claim or proof of claim shall be filed with the Company by or on behalf
of the Holder of this Note that shall assert any right to receive any payments
in respect of the principal of and interest on this Note, except subject to the
payment in full of the principal of and interest on all of the Senior
Indebtedness then outstanding. If there occurs an event of default that has been
declared in writing with respect to any Senior Indebtedness, or in the
instrument under which any Senior Indebtedness is outstanding, permitting the
holder of such Senior Indebtedness to accelerate the maturity thereof, then,
unless and until such event of default shall have been cured or waived or shall
have ceased to exist, or all Senior Indebtedness shall have been paid in full,
no payment shall be made in respect of the principal of or interest on this
Note, unless within three (3) months after the happening of such event of
default, the maturity of such Senior Indebtedness shall not have been
accelerated.

     4.3 EFFECT OF SUBORDINATION. Subject to the rights, if any, of the holders
of Senior Indebtedness under this Section 4 to receive cash, securities or other
properties otherwise payable or deliverable to the Holder of this Note, nothing
contained in this Section 4 shall impair, as between the Company and the Holder,
the obligation of the Company, subject to the terms and conditions hereof, to
pay to the Holder the principal

<PAGE>   13

hereof and interest hereon as and when the same become due and payable, or shall
prevent the Holder of this Note, upon default hereunder, from exercising all
rights, powers and remedies otherwise provided herein or by applicable law.

     4.4 SUBROGATION. Subject to the payment in full of all Senior Indebtedness
and until this Note shall be paid in full, the Holder shall be subrogated to the
rights of the holders of Senior Indebtedness (to the extent of payments or
distributions previously made to such holders of Senior Indebtedness pursuant to
the provisions of Section 4.2 above) to receive payments or distributions of
assets of the Company applicable to the Senior Indebtedness. No such payments or
distributions applicable to the Senior Indebtedness shall, as between the
Company and its creditors, other than the holders of Senior Indebtedness and the
Holder, be deemed to be a payment by the Company to or on account of this Note;
and for the purposes of such subrogation, no payments or distributions to the
holders of Senior Indebtedness to which the Holder would be entitled except for
the provisions of this Section 4 shall, as between the Company and its
creditors, other than the holders of Senior Indebtedness and the Holder, be
deemed to be a payment by the Company to or on account of the Senior
Indebtedness.

     4.5 UNDERTAKING. By its acceptance of this Note, the Holder agrees to
execute and deliver such documents as may be reasonably requested from time to
time by the Company or the lender of any Senior Indebtedness in order to
implement the foregoing provisions of this Section 4.

5.   PREPAYMENT.

     The principal amount of this note plus accrued and unpaid interest may be
prepaid upon thirty (30) days' prior written notice to the Holder.

6.   CONVERSION.

     6.1 VOLUNTARY CONVERSION. Any Holder of this Note has the right, at the
Holder's option, at any time prior to payment in full of the principal balance
of this Note, to convert this Note, in accordance with the provisions of Section
6.3 hereof, in whole or in part, into fully paid and nonassessable shares of
Common Stock of the Company (the "Company Common Stock"). The number of shares
of Company Common Stock into which this Note may be converted ("Conversion
Shares") shall be determined by dividing the aggregate principal amount together
with all accrued interest to the date of conversion by the Conversion Price (as
defined below) in effect at the time of such conversion. The initial Conversion
Price shall be equal to $9.50.

     6.2 AUTOMATIC CONVERSION. If at any time the Merger Agreement is terminated
pursuant to Section 7.1(c) by the Company, the entire principal amount of this
Note shall be automatically converted into shares of Company Common Stock at the
Conversion Price in effect at that time.

     6.3 CONVERSION PROCEDURE.

     6.3.1 Notice of Conversion Pursuant to Section 6.1. Before the Holder shall
be entitled to convert this Note into shares of Company Common Stock, it shall
surrender this Note at the office of the Company and shall give

<PAGE>   14

written notice by mail, postage prepaid, to the Company at its principal
corporate office, of the election to convert the same pursuant to this Section
6.1, and shall state therein the name or names in which the certificate or
certificates for shares of Company Common Stock are to be issued. The Company
shall, as soon as practicable thereafter, issue and deliver at such office to
the Holder of this Note a certificate or certificates for the number of shares
of Company Common Stock to which the Holder of this Note shall be entitled as
aforesaid. Such conversion shall be deemed to have been made immediately prior
to the close of business on the date of such surrender of this Note, and the
person or persons entitled to receive the shares of Company Common Stock
issuable upon such conversion shall be treated for all purposes as the record
holder or holders of such shares of Company Common Stock as of such date.

          6.3.2 Notice of Conversion Pursuant to Section 6.2. If this Note is
automatically converted, written notice shall be delivered to the Holder of this
Note at the address last shown on the records of the Company for the Holder or
given by the Holder to the Company for the purpose of notice or, if no such
address appears or is given, at the place where the principal executive office
of the Holder is located, notifying the Holder of the conversion to be effected,
specifying the Conversion Price, the principal amount of the Note to be
converted, the amount of accrued interest to be converted, the date on which
such conversion will occur and calling upon such Holder to surrender to the
Company, in the manner and at the place designated, the Note.

     6.4 DELIVERY OF STOCK CERTIFICATES. As promptly as practicable after the
conversion of this Note, the Company at its expense will issue and deliver to
the Holder of this Note a certificate or certificates for the number of full
shares of Company Common Stock issuable upon such conversion.

     6.5 MECHANICS AND EFFECT OF CONVERSION. No fractional shares of Company
Common Stock shall be issued upon conversion of this Note. In lieu of the
Company issuing any fractional shares to the Holder upon the conversion of this
Note, the Company shall pay to the Holder the amount of outstanding principal
that is not so converted, such payment to be in the form as provided below. Upon
the conversion of this Note pursuant to Section 6.1 above, the Holder shall
surrender this Note, duly endorsed, at the principal office of the Company. At
its expense, the Company shall, as soon as practicable thereafter, issue and
deliver to such Holder at such principal office a certificate or certificates
for the number of shares of such Common Stock to which the Holder shall be
entitled upon such conversion (bearing such legends as are required by the
Purchase Agreement and applicable state and federal securities laws in the
opinion of counsel to the Company), together with any other securities and
property to which the Holder is entitled upon such conversion under the terms of
this Note, including a check payable to the Holder for any cash amounts payable
as described above. In the event of any conversion of this Note pursuant to
Section 6.1 above, such conversion shall be deemed to have been made immediately
prior to the closing of the issuance and sale of such Company Common Stock and
on and after such date the Holder of this Note entitled to receive the shares of
such Company Common Stock issuable upon such conversion shall be treated for all
purpose as the record Holder of such shares and a purchaser of such shares under
the Purchase Agreement and shall be bound by the terms of the Purchase
Agreement. Upon conversion of

<PAGE>   15

this Note, the Company shall be forever released from all its obligations and
liabilities under this Note, except that the Company shall be obligated to pay
the Holder, within ten (l0) days after the date of such conversion, any interest
accrued and unpaid or unconverted to and including the date of such conversion,
and no more.

7.   CONVERSION PRICE ADJUSTMENTS.

     7.1 ADJUSTMENTS FOR STOCK SPLITS AND SUBDIVISIONS. In the event the Company
should at any time or from time to time after the date of issuance hereof fix a
record date for the effectuation of a split or subdivision of the outstanding
shares of Company Common Stock or the determination of holders of Company Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Company Common Stock or other securities or rights convertible into,
or entitling the holder thereof to receive directly or indirectly, additional
shares of Company Common Stock (hereinafter referred to as "Company Common Stock
Equivalents") without payment of any consideration by such holder for the
additional shares of Company Common Stock or the Company Common Stock
Equivalents (including the additional shares of Company Common Stock issuable
upon conversion or exercise thereof), then, as of such record date (or the date
of such dividend distribution, split or subdivision if no record date is fixed),
the Conversion Price of this Note shall be appropriately decreased so that the
number of shares of Company Common Stock issuable upon conversion of this Note
shall be increased in proportion to such increase of outstanding shares.

     7.2 ADJUSTMENTS FOR REVERSE STOCK SPLITS. If the number of shares of
Company Common Stock outstanding at any time after the date hereof is decreased
by a combination of the outstanding shares of Company Common Stock, then,
following the record date of such combination, the Conversion Price for this
Note shall be appropriately increased so that the number of shares of Company
Common Stock issuable on conversion hereof shall be decreased in proportion to
such decrease in outstanding shares.

     7.3 RESTRICTIONS AND LIMITATIONS. So long as any Notes are outstanding, the
Company shall not, without the prior written consent by the Purchaser, authorize
or issue or obligate itself to issue, any other security (including any security
convertible into or exercisable for any equity security) senior to or on a
parity with the Note, or borrow any funds, or incur any indebtedness.

     7.4 NOTICES OF RECORD DATE, ETC. In the event of:

          7.4.1 Any taking by the Company of a record of the holders of any
class of securities of the Company for the purpose of determining the holders
thereof who are entitled to receive any dividend (other than a cash dividend
payable out of earned surplus at the same rate as that of the last such cash
dividend theretofore paid) or other distribution, or any right to subscribe for,
purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

          7.4.2 Any capital reorganization of the Company, any reclassification
or recapitalization of the capital stock of the Company or any transfer of all
or substantially all of the assets of the Company to any other person or any
consolidation or merger involving the Company; or

<PAGE>   16

     7.4.3 Any voluntary or involuntary dissolution, liquidation or winding up
of the Company, the Company will mail to the holder of this Note at least ten
(10) days prior to the earliest date specified therein, a notice specifying:

          7.4.3.1 The date on which any such record is to be taken for the
purpose of such dividend, distribution or right, and the amount and character of
such dividend, distribution or right; and

          7.4.3.2 The date on which any such reorganization, reclassification,
transfer, consolidation, merger, dissolution, liquidation or winding up is
expected to become effective and the record date for determining stockholders
entitled to vote thereon.

     7.5 RESERVATION OF STOCK ISSUABLE UPON CONVERSION. The Company shall at all
times reserve and keep available out of its authorized but unissued shares of
Company Common Stock solely for the purpose of effecting the conversion of the
Note such number of its shares of Company Common Stock as shall from time to
time be sufficient to effect the conversion of the Note; and if at any time the
number of authorized but unissued shares of Company Common Stock shall not be
sufficient to effect the conversion of the entire outstanding principal amount
of this Note, in addition to such other remedies as shall be available to the
holder of this Note, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Company Common Stock to such number of
shares as shall be sufficient for such purposes.

8.   WAIVER AND AMENDMENT.

     Any provision of this Note may be amended, waived or modified upon the
written consent of the Company and holders of at least two-thirds of the face
amount of all then outstanding Notes issued pursuant to the Purchase Agreement.

9.   TREATMENT OF NOTE.

     To the extent permitted by generally accepted accounting principles, the
Company will treat, account and report the Note as debt and not equity for
accounting purposes and with respect to any returns filed with federal, state or
local tax authorities.

10.  NOTICES.

     Any notice, request or other communication required or permitted hereunder
shall be in writing and shall be deemed to have been duly given if personally
delivered or if telegraphed or mailed by registered or certified mail, postage
prepaid, at the respective addresses of the parties as set forth herein. Any
party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given when
personally delivered or when deposited in the mail or telegraphed in the manner
set forth above and shall be deemed to have been received when delivered.

<PAGE>   17

11.  NO STOCKHOLDER RIGHTS.

     Nothing contained in this Note shall be construed as conferring upon the
Holder or any other person the right to vote or to consent or to receive notice
as a stockholder in respect of meetings of stockholders for the election of
directors of the Company or any other matters or any rights whatsoever as a
stockholder of the Company; and no dividends or interest shall be payable or
accrued in respect of this Note or the interest represented hereby or the
Conversion Shares obtainable hereunder until, and only to the extent that, this
Note shall have been converted.

12.  GOVERNING LAW.

     This Agreement shall be governed by and construed in accordance with the
laws of the State of Delaware, excluding that body of law relating to conflict
of laws.

13.  HEADING; REFERENCES.

     All headings used herein are used for convenience only and shall not be
used to construe or interpret this Note. Except where otherwise indicated, all
references herein to Sections refer to Sections hereof.

     IN WITNESS WHEREOF, the Company has caused this Note to be issued this
        day of            , 2000.

                              INTERFACE SYSTEMS, INC.

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

                              ----------------------------------------------

Holder:  TUMBLEWEED COMMUNICATIONS CORP.

Address:  700 Saginaw Drive, Redwood City, CA

<PAGE>   18
                       NOTICE OF CONVERSION

TO INTERFACE SYSTEMS, INC.

     The undersigned, the holder of the foregoing Note, hereby surrenders such
Note for conversion into shares of Company Common Stock of Interface Systems,
Inc., to the extent of $             unpaid principal amount of such Note, and
requests that the certificates for such shares be issued in the name of, and
delivered to,                                          , whose address is      .

Dated:
      -------------------

                                 ---------------------------------------------
                                 Signature

                                 ---------------------------------------------
                                 Address<PAGE>   1
                             CONFIDENTIAL TREATMENT

*****[Omitted pursuant to a request for confidential treatment and filed
separately with the Securities and Exchange Commission]

                                                                    Exhibit 10.7

                            MASTER LICENSE AGREEMENT

          THIS AGREEMENT is dated 16 January 1996, between EATON CORPORATION, a
corporation organized and existing under the laws of the State of Ohio, United
States of America, and having its principal place of business at Eaton Center,
1111 Superior Avenue, Cleveland, Ohio 44114, United States of America
(hereinafter called "EATON") and SUMITOMO EATON NOVA KABUSHIKI KAISHA (SUMITOMO
EATON NOVA CORPORATION), a corporation organized and existing under the laws of
Japan and having its principal place of business at 13-16, Mita 3 Chome,
Minato-ku, Tokyo 108, Japan, (hereinafter called "SEN").

                                  WITNESSETH:

          WHEREAS, EATON manufactures certain Products (as hereinafter defined)
in the United States of America under various patents and patent applications
and sells such Products throughout the world;

          WHEREAS, EATON has developed, through substantial research and
development and many years of successful manufacture of such Products, valuable
and confidential technical information, know-how and data relating to the
design, manufacture and assembly of the Products;

          WHEREAS, SEN is a joint venture company organized by EATON and
SUMITOMO HEAVY INDUSTRIES, LTD., a company organized and existing under the laws
of Japan and having its principal place of business at 9-11, 5 Chome,
Kitashinagawa, Shinagawa-ku, Tokyo 141, Japan (hereinafter called "SUMITOMO"),
for the purpose of manufacturing, using and selling the Products in the
Territory (as hereinafter defined); and

          WHEREAS, SEN has manufactured and sold certain of the Products under
License Agreements dated April 1, 1983 and February 24, 1989 including
applicable amendments, which agreements shall terminate as of the effective date
of this Agreement; and

          WHEREAS, SEN desires to acquire from EATON, and EATON is willing to
grant to SEN, a license to manufacture, use and sell the Products in the
Territory under EATON's applicable patents and patent applications and through
the use of EATON's Technical Information (as hereinafter defined);

          NOW, THEREFORE, in consideration of the premises and mutual covenants
herein contained, the parties agree as follows:

                                      -1-

<PAGE>   2

I.        DEFINITIONS:

          1.01 "Affiliated Company" as used herein shall mean any corporation or
          other legal entity in which EATON, SUMITOMO or a Related Company (as
          defined later in this Article I) of either owns less than the majority
          of the outstanding voting stock.

          1.02 "Related Company" as used herein shall mean any corporation or
          other legal entity (a) which owns, directly or indirectly, the
          majority of the outstanding voting stock of a party hereto, (b) the
          majority of the outstanding voting stock of which is owned by a party
          hereto, or (c) the majority of the outstanding voting stock of which
          is owned, directly or indirectly, by any corporation or other legal
          entity described in clauses (a) and (b) of this sentence.

          1.03 "Effective Date" as used herein shall mean 1 October 1995.

          1.04 "Territory" as used herein shall mean Japan.

          1.05 "Net Sales" as used herein shall mean the aggregate sums invoiced
          by SEN for any and all sales of Products, less:

                (a) actual returns, applicable discounts, sales commissions,
                freight allowances, packing and crating costs, insurance
                costs, and local sales or turnover taxes, if any, relating
                to individual Product sales and separately stated in
                SEN's invoices to its customers or otherwise documented to
                EATON's satisfaction: and

                (b) the FOB factory invoiced amounts charged to SEN for the
                Products purchased by SEN from the Semiconductor Equipment
                Operations of Eaton Corporation.

          1.06 "Patents" as used herein shall mean (a) patent applications which
          EATON has filed or will hereafter file in the Territory relating to
          the Products, and (b) patents in the Territory which hereafter issue
          on such patent applications, and (c) patents relating to the Products
          to which EATON acquires the right to grant licenses during the term of
          this Agreement.

          1.07 "Products" as used herein shall mean the ion implantation systems
          defined in Appendix A attached hereto as part of this Agreement,
          including software, components and parts therefor. Other Products may
          be added to Appendix A upon agreement of the parties as to their
          inclusion and applicable royalty schedule.

          1.08 "Technical Information" as used herein shall mean confidential
          and secret technical information, know-how, engineering drawings,
          data, processes, bills of materials, detailed drawings and
          specifications, descriptions of assembly and manufacturing procedures,
          computerized production control systems, software and related source
          code, quality and inspection standards, drawings of jigs and fixtures,
          sales

                                       -2-

<PAGE>   3
                             CONFIDENTIAL TREATMENT

*****[Omitted pursuant to a request for confidential treatment and filed
separately with the Securities and Exchange Commission]

          literature and reports relating to the design, assembly and
          manufacture of the Products owned or to be owned by EATON and which
          EATON has the right to furnish to SEN during the term of this
          Agreement.

          1.09 "Existing Technical Information" as used herein shall mean the
          Technical Information which EATON has developed or acquired (whether
          pursuant to a license agreement or otherwise) and has owned for at
          least twelve (12) months prior to the effective date of this
          Agreement.

          1.10 "Future Technical Information" as used herein shall mean the
          Technical Information which EATON (a) has developed or acquired
          (whether pursuant to a license agreement or otherwise) during the
          twelve (12) month period immediately preceding the effective date of
          this Agreement or (b) develops, or acquires (whether pursuant to a
          license agreement or otherwise), and under which EATON is entitled to
          grant licenses during the term of this Agreement.

II.       GRANT

          EATON hereby grants to SEN the following license, subject to the
          terms and conditions set forth hereinafter:

                (a) An exclusive license to utilize the Existing and Future
                Technical Information, and an exclusive license under the
                Patents to manufacture, use and sell the Products in the
                Territory; and

                (b) A non-exclusive license to sell the Products outside the
                Territory, provided such sales are made pursuant to the terms
                of the Export Sales Agreement as entered into between SEN and
                EATON on 16 January 1996.

III.      PAYMENTS:

          In consideration of the license rights granted under Section II above,
          SEN shall pay to EATON the following percentage royalties based on Net
          Sales:

                (a) For Products designated as High Current Products in Appendix
                A, [*] from the Effective Date of this Agreement until March 31,
                1998 and [*] thereafter;

                (b) For Products designated as Medium Current Products in
                Appendix A, [*] from the Effective Date of this Agreement until
                February 28, 1999 and [*] thereafter; and

                (c) For Products designated as High Energy Products in Appendix
                A, [*] from the Effective Date of this Agreement until March 31,
                1998 and [*] thereafter.

                                       -3-

<PAGE>   4

IV.       TIME AND METHOD OF PAYMENT:

          4.01 The royalty payments to be paid to EATON pursuant to Section III
          above shall be paid within thirty (30) days after the close of each
          calendar semi-annual period ending on the last day of September and
          March, respectively, of each year during the term of this Agreement,
          including any extensions thereof.

          4.02 All amounts to be paid to EATON under Section III above, unless
          EATON shall have previously otherwise notified SEN in writing, shall
          be payable in U.S. Dollars converted from Japanese Yen at the lawful
          exchange rate of an authorized foreign exchange bank in Japan
          favorable to EATON, prevailing on the date when payment of such
          amounts is made. Payments shall be made by telegraphic transfer to
          EATON's account at Chase Manhattan Bank, One Chase Manhattan Plaza,
          New York, New York 10081, U.S.A., Account Number 910-1-419894. Upon
          termination of this Agreement for any reason whatsoever, any unpaid
          royalty payments shall become immediately due and payable to EATON.

V.        RECORD KEEPING AND REPORTS:

          5.01 SEN shall keep complete and accurate records and books relating
          to the manufacture, use and sale of the Products. EATON, through its
          representatives and employees, shall have the right to inspect and
          audit such records and books for the purpose of determining the
          sufficiency and accuracy thereof and the correctness of any payments
          made hereunder.

          5.02 Each sale of Products shall be deemed made when invoiced to the
          customer. Accompanying each semi-annual royalty payment due under
          Section III hereof, SEN shall furnish to EATON a statement in writing
          showing in reasonable detail the following information:

                (a) Net Sales, including quantity, description and price of
                all Products invoiced to customers during the preceding
                semi-annual period;

                (b) A computation of the gross amount of the semi-annual
                royalty payment due EATON;

                (c) Taxes levied in the Territory with respect to each such
                payment;

                (d) A computation of the net amount to be paid to EATON; and

                (e) Every schedule of any prices established by SEN for the
                sale of the Products, including any and all amendments,
                changes or supplements to such schedules.

VI.       TAXES:

          SEN shall be entitled to withhold any taxes required by Japanese law
to be withheld from payments made to EATON hereunder and shall promptly remit
such taxes to the Japanese Government on behalf of EATON. SEN shall promptly
furnish to EATON a tax withholding

                                       -4-
<PAGE>   5

receipt acknowledging the payment of any such withholding tax when such receipt
is received by SEN from the Japanese Government.

VII.      DISCLOSURE OF EXISTING TECHNICAL INFORMATION:

          7.01 Within thirty (30) days after the signing of this Agreement,
          EATON shall begin to disclose and supply to SEN all Existing Technical
          Information which is not already in SEN's possession. However,
          notwithstanding anything in the preceding sentence to the contrary,
          in no event shall EATON furnish any Existing Technical Information to
          SEN on or after the date of any notice of termination of this
          Agreement. All Existing Technical Information to be supplied under the
          terms of this Agreement shall be in the language and the system of
          measures commonly used by EATON or its Affiliated or Related Company
          supplying the Existing Technical Information.

          7.02 The Existing and Future Technical Information to be furnished by
          EATON hereunder is confidential and secret, and title to all such
          Technical Information shall remain vested in EATON. SEN shall preserve
          and protect the confidential nature of the Technical Information and
          shall not disclose the Technical Information to any parties outside
          SEN's organization without the written consent of EATON except
          suppliers, subcontractors and customers to the extent necessary to
          enable SEN to manufacture, use and sell the Products in accordance
          with the licenses granted to SEN hereunder. Any and all drawings,
          blueprints, specifications and other written materials produced by or
          at the request or direction of SEN disclosing Technical Information to
          any such party shall be marked with the following language in the
          English and/or Japanese languages:

          Notice to persons receiving this information:

          The technical information disclosed herein is the confidential
          property of Eaton Corporation, Cleveland, Ohio, U.S.A., and is issued
          in confidence for engineering information only. It may not be
          reproduced or used in any way without an express written license from
          Eaton Corporation.

          7.03 The disclosures permitted under Paragraph 7.02 above shall not
          relieve SEN of its obligation to maintain the confidentiality of the
          Technical Information, and SEN shall be liable for any unauthorized
          disclosure by it or by those to whom SEN has made any disclosure.

          7.04 During the term of this Agreement, EATON shall not convey any of
          the Technical Information to any party in the Territory other than SEN
          and shall not use the Technical Information in the manufacture of the
          Products in the Territory.

                                       -5-

<PAGE>   6

VIII.     TECHNICAL ASSISTANCE:

          8.01 During an initial period after the Effective Date of this
          Agreement and from time to time thereafter, EATON shall furnish, upon
          the written request of SEN, the services of qualified engineers or
          technicians of EATON, its Affiliated or Related Companies to assist
          SEN for reasonable periods of time in acquiring knowledge and training
          relating to the Technical Information and the design, manufacture,
          assembly and marketing of the Products. The final decision as to the
          availability of such EATON personnel shall be made exclusively by
          EATON, and EATON shall exercise every reasonable effort to furnish
          such personnel for the period requested by SEN insofar as such request
          does not interfere with the activities of EATON, its Affiliated or
          Related Companies.

          8.02 EATON shall permit SEN's employees to make a reasonable number of
          routine visits to certain facilities of EATON, its Affiliated or
          Related Companies that manufacture the Products to enable SEN to gain
          knowledge with respect to the manufacture of the Products. EATON and
          SEN shall agree upon the number of SEN's employees to make such visits
          prior to any such visit. Any and all expenses, including salaries, of
          SEN's personnel making such visits shall be paid solely by SEN.

IX.       PARTS AND COMPONENTS:

          It is the intention of the parties that the Products, parts and
components to be sold by SEN under the licenses granted herein will be
manufactured and/or purchased by SEN using the most economical sources available
to SEN, and the parties understand that due to economies of scale and/or
currency relationships EATON may be such most economical source at any given
time during the term of this Agreement. Accordingly, Eaton shall, to the best of
its ability and capacity, sell and supply to SEN Products, parts and components
when requested by SEN. The price to SEN for such Products, parts and components
shall be mutually agreed upon by the parties.

X.        PURCHASE OF PRODUCTS BY EATON FROM SEN:

          SEN shall, to the best of its ability and capacity, sell and supply
Products, parts and components to EATON and its Affiliated or Related Company
when requested by Eaton. The price to Eaton or any such Affiliated or Related
Company for such Products, parts and components shall be mutually agreed upon by
the parties. Purchases from SEN under this section shall be paid for in the
currency specified by SEN.

XI.       MODIFICATIONS OF PRODUCTS:

          11.01 It is the intention of the parties that the Products to be
          manufactured by SEN under this Agreement shall meet the needs of the
          worldwide markets addressed by EATON and SEN, thus such products shall
          conform to EATON's basic designs and specifications for the Products
          and shall be of substantially the same quality and serviceability as
          the Products manufactured by EATON.

                                       -6-
<PAGE>   7

          11.02 Any modifications to the Products which SEN deems to be required
          to further conform them to the Japanese market and/or to satisfy
          special customer needs may be made by SEN without prior approval by
          EATON, provided however, that such modifications are consistent with
          and conform to Eaton's specifications. SEN shall within two (2) weeks
          after releasing such modifications to production provide EATON with
          details of such modifications in the English language sufficient for
          EATON to verify their consistency with and conformity to Eaton's
          specifications.

          11.03 Any modifications to the Products which SEN deems to be required
          and which are not consistent with and in conformity with the
          specifications shall be reviewed by appropriate representatives of
          EATON and SEN to determine if they are to be made. If the parties
          agree that such modifications are to be made, EATON shall at its sole
          discretion either carry out such modifications itself, or shall
          subcontract such modifications to SEN under terms and conditions to be
          agreed upon by the parties.

XII.      DISCLOSURE OF FUTURE TECHNICAL INFORMATION:

          12.01 During the term of this Agreement, EATON shall, at its sole
          expense, fully disclose to SEN any Future Technical Information and
          Patents in the Territory resulting from such Future Technical
          Information which are developed by EATON or any of its Affiliated and
          Related Companies if EATON then owns and has the right to furnish SEN
          such Future Technical Information. Effective as of a date twelve (12)
          months after EATON's acquisition of such Future Technical Information,
          the exclusive license granted under Section II hereof shall be deemed
          to apply to such Future Technical Information.

          12.02 During the term of this Agreement, SEN shall, at its sole
          expense, fully disclose in the English language to EATON all Technical
          Information improvements and modifications, and patents in the
          Territory resulting from such improvements and modifications, which
          are developed by SEN relating to the Products, SEN hereby grants to
          EATON and its Affiliated and Related Companies during the term of this
          Agreement, a non-exclusive, royalty-free license to manufacture, have
          manufactured, use and sell the Products in any country of the world
          outside the Territory utilizing such Technical Information
          improvements and modifications developed by SEN, subject to SEN's
          exclusive right to use such improvements and modifications in the
          Territory. If any such Technical Information improvements and
          modifications developed by SEN during the term of this Agreement
          constitute patentable subject matter, SEN shall have the right, at its
          sole expense, to file patent applications and obtain patents therefor
          in its own name in any country of its choice; provided, however, that
          SEN, at its sole expense, shall furnish to EATON a copy of each such
          patent application immediately after filing such application. All such
          applications and patents resulting therefrom on Technical Information
          modifications and improvements of SEN shall be the property of SEN.
          SEN hereby grants to EATON, during the term of this Agreement, a
          non-exclusive, royalty-free license with the right to grant
          sublicenses to manufacture, have manufactured, use

                                       -7-
<PAGE>   8

          and sell the Products under such applications and patents resulting
          therefrom in all countries of the world outside the Territory.

          12.03 During the term of this Agreement, EATON shall have the right at
          its sole expense, to file patent applications in its own name in any
          country of the world in which SEN does not file such applications with
          respect to any and all Technical Information improvements and
          modifications developed by SEN relating to the Products. SEN shall,
          upon the request of EATON, and without any cost to EATON, promptly
          execute and procure the execution of any and all documents necessary
          or desirable to enable EATON to file such applications in countries in
          which SEN does not file such applications. EATON hereby grants to SEN
          (a) an exclusive, royalty-free license in the Territory during the
          effective period of said patents and (b) a non-exclusive, royalty-free
          license in any other country of the world during the effective period
          of said patents to manufacture, use and sell the Products under such
          applications and patents resulting therefrom with respect to Technical
          Information improvements and modifications developed by SEN.

XIII.     RIGHT TO SUBLICENSE AND SUBCONTRACT:

          Notwithstanding anything to the contrary contained in this Agreement,
SEN shall not have the right to sublicense the rights granted or to be granted
under this Agreement without the prior written consent of EATON. SEN shall have
the right to subcontract the manufacture of parts and components for the
Products from time to time.

XIV.      SIMILAR TRADEMARKS:

          The parties have entered into a separate Trademark Agreement governing
the use of EATON trademarks on the Products. If such Trademark Agreement is
terminated for any reason, the following provisions of this Section XIV shall
apply: SEN shall not use any of the Trademarks (as defined in the Trademark
Agreement) or any trademark which is confusingly similar to any of the
Trademarks. If SEN during the term of this Agreement asserts ownership in any
trademark which, in the opinion of EATON, is the same as or confusingly similar
to any of the Trademarks, SEN will, upon the written request of EATON,
immediately (1) transfer and assign all right, title and interest which it
asserts in such trademark to EATON or EATON's designee, and (2) discontinue the
use of such trademark. SEN shall not file or cause to be filed any trademark
application in any country of the world covering any trademark which, in the
opinion of EATON, is confusingly similar to any of the Trademarks.

XV.       QUALITY CONTROL:

          All rights and privileges granted or to be granted under this
Agreement to SEN are expressly conditioned upon the maintenance by SEN of the
standards of quality and reliability for the Products established worldwide by
EATON and its Affiliated and Related Companies. SEN shall manufacture the
Products in accordance with the Technical Information supplied or to be supplied
hereafter by EATON. SEN shall permit EATON, through its representatives, at all

                                       -8-
<PAGE>   9

reasonable times to inspect the plant, equipment, manufacturing and assembly
techniques of SEN which relate to the Products, and EATON shall have the right
to test, at its sole expense, regular production specimens of the Products on
the premises of SEN at any time so as to determine whether SEN is manufacturing
the Products in conformity with the established quality standards and
specifications of EATON and its Affiliated and Related Companies. EATON shall
promptly advise SEN of any features of the quality standards and specifications
of the Products manufactured by SEN which are not substantially the same as
EATON's quality standards and specifications for the Products, and SEN, upon
receipt of such advice, shall correct any such sub-quality features to the
satisfaction of EATON within a reasonable period of time, not to exceed one
hundred twenty (120) days after the receipt of such advice.

XVI.      PRODUCT IDENTIFICATION:

          Unless otherwise directed by EATON, SEN shall see that the following
statement, in the English and/or Japanese language, is contained in all of SEN's
advertising and promotional materials and on a name plate prominently displayed
on each of the Products manufactured hereunder:

          Manufactured under license from Eaton Corporation, U.S.A.

          SEN's use of the foregoing statement or any subsequently authorized
statement shall apply only to the Products manufactured by SEN which are under
complete quality control and which meet the standards of quality specified by
EATON, its Affiliated and Related Companies, as provided for in Section XV
hereof.

XVII.     RECORDING OF DOCUMENTS:

          The parties shall execute or have executed all papers and documents
which may be necessary or desirable to record SEN as a licensee or sub-licensee
user of said Patents, Technical Information, improvements and modifications of
Technical Information and related patents in the different jurisdictions of the
world where such recording is necessary in order to protect the rights of either
party in and to said Patents, Technical Information, improvements and
modifications and related patents.

XVIII.    INFRINGEMENT OF THIRD PARTY RIGHTS:

          18.01 If SEN is charged with infringement of third parties' patents in
          the Territory or any other jurisdiction of the world and/or is made a
          defendant in a lawsuit as a result of the manufacture, use or sale of
          the Products under the provisions of this Agreement, SEN shall (a)
          assume all cost, expenses, damages and other obligations for payments
          incurred as a consequence of such charge of infringement and/or
          lawsuit and (b) indemnify and hold EATON harmless from any and all
          liability resulting from such charge of infringement and/or lawsuit or
          any such charge and/or lawsuit against SEN's customers.

                                       -9-
<PAGE>   10

          18.02 At the request of SEN, EATON shall lend SEN the assistance of
          EATON, its Affiliated and Related Companies in the defense of any such
          infringement charge and/or lawsuit, but any expense incurred by such
          parties in such undertaking shall be borne solely by SEN and shall be
          paid by SEN to EATON within thirty (30) days after receipt of an
          itemization of such expenses from EATON.

XIX.      INFRINGEMENT OF PATENTS BY THIRD PARTIES:

          19.01 If SEN becomes aware of any infringement or alleged infringement
          in the Territory of any of the Patents, it shall immediately notify
          EATON in writing of the name and address of each infringer or alleged
          infringer and the acts or alleged acts of infringement of the Patents.
          EATON shall have the first right, consistent with the law of the place
          of infringement, to bring an infringement action against any or all
          such infringers or alleged infringers of the Patents. In the event
          that EATON elects to bring any such infringement action in its own
          name, EATON shall bear any and all expenses incurred in maintaining
          such infringement action and shall retain for itself any and all
          moneys or other benefits derived from such infringement action. If
          EATON shall deem it necessary or desirable to join SEN as a party
          plaintiff in any infringement action against an infringer or alleged
          infringer of the Patents, EATON shall consult with and obtain the
          approval of SEN prior to institution of such infringement action. In
          the event that EATON and SEN so agree jointly to bring such an
          infringement action, the parties shall (a) bear equally any and all
          expenses incurred in maintaining such infringement action, and (b)
          share equally any and all moneys or other benefits derived from such
          infringement action.

          19.02 If EATON does not bring an infringement action within six (6)
          months after notification from SEN of infringement or alleged
          infringement of the Patents, SEN shall have the first right,
          consistent with the law of the place of infringement, to bring an
          infringement action in its own name after the expiration of said six
          (6) month period. The total cost of any such infringement action
          brought by SEN shall be borne solely by SEN, and SEN shall retain for
          itself any and all moneys or other benefits derived from such
          infringement action. Each party shall indemnify and hold the other
          harmless from any and all damages, costs or expenditures arising
          directly or indirectly as a result of any infringement action
          undertaken solely in the name of such party hereunder.

          19.03 If at any time during the term of this Agreement EATON or SEN
          shall be unable to enforce the Patents against any alleged infringer,
          EATON shall not be responsible for the validity or for the
          enforceability of the Patents.

          19.04 The parties shall keep each other fully informed as to the
          progress of any infringement action under this Section brought in the
          names of either or both parties. The parties shall cooperate with each
          other in the prosecution of any infringement action undertaken under
          this Section, and each shall provide the other with all data in its
          possession which may be helpful in the prosecution of such action.

                                      -10-

<PAGE>   11

          19.05 Any party bringing any infringement action under this Section in
          its own name and without joining the other party shall have the right
          to dispose of such action in whatever reasonable manner it determines
          to be in the best interest of the parties. In any infringement action
          brought under this Section by either party without the other, the
          party not bringing such action shall have the right to be represented
          at its own expense by its own counsel in such action.

          19.06 The parties shall cooperate and confer from time to time as may
          be necessary and shall agree upon a method or procedure for defending
          any proceedings for the revocation of any of the Patents.

XX.       EFFECTIVE DATE:

          The effective date of this Agreement shall be 1 October 1995.

XXI.      TERM:

          21.01 The term of this Agreement, unless sooner terminated as provided
          for in Section XXII, shall commence upon the Effective Date of this
          Agreement and shall continue for an initial term extending to December
          31, 2004, and shall be automatically renewed thereafter for additional
          five (5) year periods unless either of the parties provides written
          notice to the other of its intention to terminate the Agreement at
          least one (1) year prior to the end of the then current term.

          21.02 Both parties shall have the additional right, which must be
          exercised at least one (1) year prior to the end of the then current
          term, to provide a written notification to the other of an intention
          to renew with modifications. In the event a written notification of an
          intention to renew with modifications is properly provided, both
          parties will undertake to renegotiate, in good faith, the terms and
          conditions of this Agreement.

          21.03 In the event a written notification of an intention to renew
          with modifications pursuant to Section 21.02 above is properly
          provided and no agreement has been reached at the end of the then
          current term, the Agreement will be continuously extended until
          agreement as to modifications is reached or either of the parties
          provides written notice to the other of its intention to terminate.
          Such termination shall take effect at the end of one (1) year
          following the written notice. In the event agreement as to
          modifications is reached, then the appropriately modified Agreement
          will continue to the end of a five (5) year period as if renewed
          pursuant to 21.01.

XXII.     TERMINATION:

          22.01 Either party may have the right to terminate this Agreement by
          sending written notice of termination to the other if the other shall
          fail to observe the terms, covenants

                                      -11-

<PAGE>   12

          and conditions hereof and shall fail to cure or substantially cure
          such default within ninety (90) days after written notice thereof,
          such termination will take effect immediately upon written notice to
          the defaulting party after the expiration of said ninety (90) day
          period.

          22.02 In the event of bankruptcy, insolvency, or dissolution of either
          party, the other may terminate this Agreement in its entirety,
          effective immediately, by sending written notice to the bankrupt,
          insolvent or dissolved party.

          22.03 EATON shall be entitled to terminate this Agreement, upon ninety
          (90) days' written notice to SEN, in the event of either of the
          following events:

                (a) Exercise of authority by a supervening power resulting in
                the appropriation or confiscation of SEN's plants, facilities,
                other assets, Technical Information or Patents; or

                (b) Denial at any time by any governmental authority of the
                right of SEN to make the remittances provided for in this
                Agreement.

XXIII.    RIGHTS AFTER TERMINATION:

          23.01 Within thirty (30) days after the termination of this Agreement
          for any reason whatsoever, SEN shall furnish EATON the following
          information and shall permit EATON access to the records and
          facilities of SEN during regular working hours to verify such
          information:

                (a) Full details of all orders for the Products in the
                Territory, accepted by SEN and not yet completed, including a
                description of work to be done regarding such orders; and

                (b) A statement showing the amounts due EATON from SEN up to the
                date of termination. SEN shall have the right, after
                termination of this Agreement, to complete sales of all orders
                for Products in the Territory, accepted but not completed
                prior to the date of termination; provided, however, that
                royalty payments shall be due and payable on such uncompleted
                sales of Products when completed in accordance with the terms
                and conditions hereof.

          23.02 Any and all proprietary rights in the Patents shall remain
          exclusively with EATON, its Affiliated or Related Companies, and
          nothing in this Agreement shall be construed to confer any proprietary
          interest other than the license rights granted hereunder in the
          Patents to SEN or to any other party. All rights granted hereunder in
          the Patents shall revert immediately and automatically to EATON upon
          termination of this Agreement. If EATON shall terminate this Agreement
          as a result of a default of any provision hereof by SEN or the other
          contingencies set forth in Section XXII, (a) SEN shall not after such
          termination, either directly or indirectly, make use of any Technical
          Information furnished or disclosed to it by EATON hereunder, excluding
          the Technical Information already generally known to the public
          through no fault of SEN or its Affiliated or Related Companies during
          the term of this Agreement provided, however,

                                      -12-

<PAGE>   13

          that SEN shall be obliged to establish in reasonable detail to EATON's
          satisfaction that such Technical Information is in fact generally
          known to the public, (b) SEN's rights in the Technical Information
          shall automatically terminate and (c) SEN shall immediately return any
          and all Technical Information to EATON. If SEN shall terminate this
          Agreement as a result of a default of any provision hereof by EATON or
          the other contingencies set forth in Section XXII, SEN shall be
          entitled to continue to utilize the Technical Information in the
          manufacture of the Products; provided, however, that if a dispute
          arises as to said default of EATON and arbitration pursuant to Section
          XXXII hereof results from such dispute, EATON shall have ninety (90)
          days from the date of the arbitration decision, if against EATON, to
          rectify said default consistent with the arbitration decision and
          remove the grounds for termination. Likewise, if a dispute arises as
          to default of SEN and arbitration pursuant to Section XXXII hereof
          results from such dispute, SEN shall also have ninety (90) days from
          the date of the arbitration decision, if against SEN, to rectify said
          default consistent with the arbitration decision and remove the
          grounds for termination.

XXIV.     GOVERNMENT APPROVAL:

          SEN shall, at its sole expense, apply for and obtain any approvals,
authorizations or validations relative to this Agreement that shall be required
by law, either under the Foreign Exchange and Foreign Trade Control Law of Japan
or otherwise, including authorization of all payments to be made hereunder. SEN
shall, at its sole expense, obtain translations of this Agreement and prepare
any documents necessary for such approvals and authorizations of the Japanese
Government.

XXV.      DISCLAIMER OF WARRANTY AND PRODUCT LIABILITY:

          25.01 SEN shall assume all warranty obligations for the Products
          manufactured, used or sold by it hereunder.

          25.02 SEN shall indemnify and save EATON harmless from and against any
          and all loss, cost, claim, liability, obligation and damage arising
          from (a) any negligence, representation, promise, agreement or
          warranty by SEN or its agents, employees, distributors, dealers,
          representatives, subcontractors, or suppliers relating to the Products
          or (b) any Product defect or deficiency in production, manufacture,
          use, design, operation or otherwise of the Products.

XXVI.     ASSIGNMENT:

          Neither of the parties shall be entitled to assign its rights or
delegate its obligations under this Agreement without the prior written approval
of the other party hereto, except that either party hereto may, without the
written consent of the other party, assign its interest in this Agreement or any
portion thereof to a Related Company or a successor of the whole of the

                                      -13-
<PAGE>   14

business relating to the Products which is capable of performing and assuming
the obligations hereunder.

XXVII.    TRANSLATION OF AGREEMENT:

          This Agreement has been written in the English language, but in the
event it is also written in the Japanese or another language and there are
differences from the English text, the English text will govern.

XXVIII.   ENTIRE AGREEMENT:

          The terms and provisions of this Agreement constitute the entire
agreement between the parties as to the granting of license rights by EATON to
SEN under the Patents and Technical Information. This Agreement shall supersede
all previous communications, either oral or written, between the parties with
respect to the subject matter hereof, and no agreement or understanding varying
or extending them shall be binding upon either party unless in writing signed by
a duly authorized officer or representative thereof.

XXIX.     NON-WAIVER OF RIGHTS AND DISCLAIMER OF LIABILITY:

          Failure of either party to enforce any of the provisions of this
Agreement or any rights with respect thereto or failure to exercise any election
provided for herein (except as expressly otherwise provided herein) shall in no
way be considered a waiver of such provisions, rights or elections or in any way
to affect the validity of this Agreement. The failure of either party to enforce
any of said provisions, rights or elections shall not preclude or prejudice such
party from later enforcing or exercising the same or any other provisions,
rights, or elections which it may have under this Agreement.

XXX.      COUNTERPARTS:

          This Agreement may be executed in any number of counterparts, each of
which shall be deemed to be an original, all of which shall constitute one and
the same agreement.

XXXI.     DISCLAIMER OF AGENCY:

          This Agreement shall not constitute SEN the legal agent of EATON, nor
shall SEN have the right or authority to assume, create, or incur any liability
or any obligation of any kind, express or implied, against or on behalf of
EATON.

XXXII.    ARBITRATION:

          Any and all disputes or differences between the parties pertaining to
or arising out of this Agreement, or the breach thereof, shall be settled by
arbitration to be held in Tokyo, Japan, if EATON shall demand the arbitration,
or in Cleveland, Ohio, United States of America, if SEN shall demand the
arbitration, in accordance with the provisions of the Japan-America Trade

                                      -14-
<PAGE>   15

Arbitration Agreement of 1952 under the rules specified in said agreement in
effect upon the date that either party serves notice upon the other party of a
demand for arbitration. The dispute shall be arbitrated by one arbitrator (who
shall not be a national of Japan or the United States of America) selected by
agreement of both parties; provided, however, in the event the parties cannot
agree upon an arbitrator, the arbitrator shall be appointed by the chairman of
the Japan Commercial Arbitration Association, if arbitration is to be in Japan,
or of the American Arbitration Association, if arbitration is to be in the
United States of America. The award rendered by the arbitrator shall be final,
binding upon the parties, and enforceable by any court of competent
jurisdiction.

XXXIII.   LIABILITIES TO SURVIVE TERMINATION:

          Termination of this Agreement or any rights conveyed hereunder for any
cause shall not relieve either party from its obligation to pay to the other all
compensation which shall have accrued prior to such termination pursuant to the
provisions of this Agreement or release either party from any obligations which
may have been incurred prior to such termination as a result of operations
conducted under this Agreement. This clause shall not be construed to prevent or
limit any award for damages consequent upon a breach of this Agreement.

XXXIV.    NOTICES:

          All notices for all purposes under this Agreement shall be deemed to
have been sufficiently addressed when, if given to EATON, addressed to:

                        Office of The Secretary
                        Eaton Corporation
                        1111 Superior Avenue
                        Cleveland, Ohio 44114 U.S.A.

or when, if given to SEN, addressed to:

                        President
                        Sumitomo Eaton Nova Kabushiki Kaisha
                        13-16, Mita 3 Chome,
                        Minato-ku, Tokyo 108, Japan

and if sent by registered airmail with return receipt requested. The date of
posting shall be deemed to be the date on which such notice or request has been
given or served. The parties may give written notice of change of address by
mail or by facsimile and, after notice of such change has been received, any
notice or request shall thereafter be given to such party as above provided at
such changed address.

                                      -15-
<PAGE>   16

          IN WITNESS THEREOF, each of the parties has duly executed this
Agreement as of the Effective Date.

                                      EATON CORPORATION

                                      By: /s/ [signature illegible]
                                         ----------------------------------
ATTEST:                                  Vice President

/s/ [signature illegible]
--------------------------------
Director of Business Development

                                      SUMITOMO EATON NOVA
                                      KABUSHIKI KAISHA

                                      By: /s/ [signature illegible]
                                         ----------------------------------
ATTEST:                                  President

/s/ N. Takahashi
--------------------------------
     Managing Director

          SUMITOMO HEAVY INDUSTRIES, LTD., hereby approves the terms and
conditions of this Agreement, by the below execution of its Representative
Director:

                                      SUMITOMO HEAVY INDUSTRIES, LTD.

                                      By: /s/ Mitoshi Ozawa
                                         ----------------------------------
ATTEST:                                  President

/s/ H. Taniguchi
--------------------------------
     Managing, Director

                                      -16-
<PAGE>   17
                                   APPENDIX A

                                    PRODUCTS

HIGH CURRENT PRODUCTS
---------------------

NV-10                    GSDIII
NV-20                    GSD100
NV-20A                   GSD200
NV-10SD                  GSD200E
GSD                      GSDULE
GSDA

MEDIUM CURRENT PRODUCTS
-----------------------

6200
6200A
6200AV
8200GD
8200P

HIGH ENERGY PRODUCTS
--------------------

NV1002
GSD-HE
GSD-VHE
GSD-UHE

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