SERIES A PREFERRED STOCK PURCHASE AGREEMENT

                                   Dated as of

                                December 16, 1999










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                                TABLE OF CONTENTS

1.       Purchase and Sale of Stock............................................1
         1.1.     Sale and Issuance of Series A Preferred Stock................1
         1.2.     Closing......................................................1
         1.3.     Delivery.....................................................1
2.       Representations and Warranties of the Company.........................2
         2.1.     Organization, Good Standing and Qualification................2
         2.2.     Capitalization...............................................2
         2.3.     Subsidiaries.................................................3
         2.4.     Liabilities..................................................3
         2.5.     Authorization................................................3
         2.6.     Valid Issuance of Preferred and Common Stock.................3
         2.7.     Governmental Consents........................................4
         2.8.     Litigation...................................................4
         2.9.     Compliance with Other Instruments............................4
         2.10.    Brokers or Finders...........................................5
3.       Representations and Warranties of the Investors.......................5
         3.1.     Experience...................................................5
         3.2.     Purchase Entirely for Own Account............................5
         3.3.     Rule 144.....................................................6
         3.4.     No Public Market.............................................6
         3.5.     Access to Data...............................................6
         3.6.     Authorization................................................6
         3.7.     Principal Address............................................7
4.       Conditions of the Investors' Obligations at Closing...................7
         4.1.     Representations and Warranties...............................7
         4.2.     Performance..................................................7
         4.3.     Compliance Certificate.......................................7
         4.4.     Absence of Litigation........................................7
         4.5.     Blue Sky.....................................................7
         4.6.     Opinion of Company Counsel...................................8
         4.7.     Supporting Documents.........................................8
         4.8.     Other Agreements.............................................8
         4.9.     Restated Certificate.........................................8
         4.10.    Stock Incentive Plan.........................................8
5.       Conditions of the Company's Obligations at the Closing................8
         5.1.     Representations and Warranties...............................8
         5.2.     Performance..................................................9
         5.3.     Compliance Certificate.......................................9
         5.4.     Blue Sky.....................................................9
         5.5.     Other Agreements.............................................9
         5.6.     Absence of Litigation........................................9
         5.7.     Restated Certificate.........................................9
         5.8.     Stock Incentive Plan.........................................9

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6.       Participation Rights.................................................10
7.       Miscellaneous........................................................10
         7.1.     Governing Law...............................................10
         7.2.     Survival....................................................11
         7.3.     Successors and Assigns......................................11
         7.4.     Entire Agreement; Amendment.................................11
         7.5.     Notices, Etc................................................11
         7.6.     Delays or Omissions.........................................11
         7.7.     California Corporate Securities Law.........................12
         7.8.     Expenses....................................................12
         7.9.     Counterparts................................................12
         7.10.    Severability................................................12
         7.11.    Dispute Resolution..........................................12


Exhibits:
--------

Exhibit A         List of Investors
Exhibit B         License Agreement
Exhibit C         Amended and Restated Certificate of Incorporation
Exhibit D         Form of Opinion of Company Counsel
Exhibit E         Stockholders Agreement
Exhibit F         Common Stock Purchase Agreement
Exhibit G         Warrants
Exhibit H         1999 Stock Incentive Plan
Exhibit I         Form of DTN Promissory Note
Exhibit J         Form of Opinion of DTN Counsel


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         This Series A Preferred Stock Purchase  Agreement (this "Agreement") is
made as of December  16, 1999 (the  "Effective  Date"),  by and among  EarthScan
Network Inc., a Delaware corporation (the "Company"), with its principal offices
located  at 6565  Americas  Parkway,  Albuquerque,  New  Mexico,  87110  and the
Investors  listed on Exhibit A attached  hereto,  each of which is  referred  to
herein as an "Investor" and all of which are collectively  referred to herein as
the "Investors."

         THE PARTIES HEREBY AGREE AS FOLLOWS:

         1. Purchase and Sale of Stock.

            1.1. Sale and Issuance of Series A Preferred  Stock.  Subject to the
terms and conditions of this Agreement, each Investor agrees to purchase and the
Company  agrees to sell and issue to each  Investor  on the Closing  Date,  that
number of shares of Series A Preferred  Stock set forth opposite such Investor's
name on Exhibit A hereto,  with a fair market  value as of the  Closing  Date of
$100.00 (One Hundred  Dollars) per share. The shares of Series A Preferred Stock
to be sold to the Investors pursuant to this Agreement are collectively referred
to herein as the "Shares." In exchange for its Shares, Data Transmission Network
Corporation  ("DTN")  will pay to the  Company in cash the  aggregate  amount of
$500,000  (Five Hundred  Thousand U.S.  Dollars) and will execute and deliver to
the Company the promissory  note with an initial  outstanding  principal  amount
equal to $2,500,000 (Two Million Five Hundred Thousand U.S. Dollars) in the form
attached  hereto as  Exhibit I (the  "Promissory  Note").  In  exchange  for its
Shares,  Photon Research Associates,  Inc. ("PRA") will grant to the Company the
exclusive  licenses  and  other  rights as set  forth in the  License  Agreement
attached hereto as Exhibit B (the "License Agreement"). The Shares will have the
powers,  rights,  preferences,  privileges  and  restrictions  set  forth in the
Amended and Restated  Certificate of Incorporation,  in the form attached hereto
as Exhibit C (the "Restated Certificate").

            1.2.  Closing.  The closing of the  purchase  and sale of the Shares
hereunder (the  "Closing")  shall take place at the offices of Latham & Watkins,
701 "B" Street, San Diego, California, at 10:00 a.m. on December 28, 1999, or at
such other time and place as the Company and the Investors  mutually  agree (the
"Closing Date").

            1.3. Delivery. On the Closing Date, the Company will deliver to each
Investor a  certificate  or  certificates  registered  in such  Investor's  name
representing  the Shares  purchased by the  Investor,  as set forth on Exhibit A
hereto, against (i) payment by DTN to the Company, by check or wire transfer, of
the cash  portion  of the  purchase  price  for its  Shares,  together  with the
execution and delivery of the Promissory Note,  representing  payment in full of
the purchase price for its Shares and (ii) execution and delivery of the License
Agreement by PRA,  representing  payment in full of the  purchase  price for its
Shares.  In addition to the  foregoing,  each party will  deliver at the Closing
such  other  agreements,  instruments,  documents  and  certificates  which  are
referred to in Sections 4 and 5 hereof.  Immediately  following the Closing, the
issuance of Shares will be recorded in the Company's share register.


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         2. Representations and Warranties of the Company. Except as affected by
the transactions contemplated hereby, the Company hereby represents and warrants
to the Investors as of the date hereof and as of the Closing as follows:

            2.1. Organization, Good Standing and Qualification. The Company is a
corporation duly organized, validly existing and in good standing under the laws
of the State of Delaware and has all requisite  corporate power and authority to
own its properties and carry on its business as currently conducted and as it is
currently planned to be conducted.  The Company is duly qualified to do business
as a  foreign  corporation  in each  state in which the  failure  to do so could
reasonably be expected to result in a material adverse effect on the Company.

            2.2. Capitalization.  As of the date hereof and immediately prior to
the  issuance  of the Shares (i) the  authorized  capital  stock of the  Company
consists of 200,000  shares of Common  Stock,  and 100,000  shares of  Preferred
Stock,  of which 60,000 are designated  Series A Preferred  Stock (the "Series A
Stock") and 40,000 remain undesignated; and (ii) the Company has reserved 60,000
shares of Common Stock for issuance upon conversion of the Shares,  9,000 shares
of Common Stock for issuance to key  employees  pursuant to the  Company's  1999
Stock Incentive  Plan,  4,000 shares of Common Stock for issuance to certain key
employees,  consultants and officers of the Company pursuant to the Common Stock
Purchase Agreement executed  concurrently  herewith,  and 1,500 shares of Common
Stock for issuance upon exercise of certain  Warrants  (defined below) issued to
the Company's financial advisor concurrently herewith. Except as contemplated by
this  Agreement,   the  Stockholders  Agreement  (defined  below),  the  License
Agreement  and the Warrants,  there are no other  outstanding  rights,  options,
warrants,  preemptive rights,  rights of first refusal or similar rights for the
purchase or  acquisition  from the Company (or any of its  subsidiaries)  of any
securities  of the  Company  (or  any of its  subsidiaries)  nor are  there  any
commitments to issue or execute any such rights, options,  warrants,  preemptive
rights or rights of first refusal. Neither the offer nor the issuance or sale of
the Shares  constitutes  an event,  under any  anti-dilution  provisions  of any
securities  issued or issuable by the Company or any agreements  with respect to
the issuance of securities by the Company, which will either increase the number
of shares issuable pursuant to such provisions or decrease the consideration per
share to be  received  by the Company  pursuant  to such  provisions.  Except as
provided in this Agreement, no holder of any security of the Company is entitled
to any  preemptive or similar  rights to purchase any  securities of the Company
from the Company.

            2.3. Subsidiaries.  The Company does not own or control, directly or
indirectly,  any interest in any other  corporation,  limited liability company,
trust, association or other business entity. The Company is not a participant in
any joint venture, partnership or similar arrangement.

            2.4.  Liabilities.  The  Company  has  no  material  liabilities  or
obligations,  absolute or contingent except liabilities and obligations that (i)
were  incurred  in the  ordinary  course  of  business  or (ii) are set forth on
Schedule 2.4 attached hereto.

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            2.5. Authorization. All corporate action on the part of the Company,
its  officers,  directors  and  stockholders  necessary  for the  authorization,
execution  and delivery of this  Agreement and each of such  documents  included
herein as Exhibits to this Agreement,  hereinafter referred to as the "Ancillary
Documents,"  the  performance of all  obligations  of the Company  hereunder and
thereunder, and the authorization,  issuance (or reservation for issuance), sale
and delivery of the Shares being sold  hereunder  and the Common Stock  issuable
upon  conversion  of the  Shares  has  been  taken  and this  Agreement  and the
Stockholders  Agreement  constitute valid and legally binding obligations of the
Company,  enforceable  against the Company in accordance  with their  respective
terms, subject to: (i) judicial principles limiting the availability of specific
performance,  injunctive relief, and other equitable remedies;  (ii) bankruptcy,
insolvency, reorganization, moratorium or other similar laws now or hereafter in
effect  generally  relating  to  or  affecting   creditors'  rights;  and  (iii)
limitations on the enforceability of any indemnification provisions.

            2.6. Valid Issuance of Preferred and Common Stock.  The Shares 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  Ancillary  Documents  and under  applicable  state and
federal securities laws. The Common Stock issuable upon conversion of the Shares
purchased  under this Agreement has been duly and validly  reserved for issuance
and,  upon  issuance  in  accordance  with the terms of this  Agreement  and the
Restated  Certificate,  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 Ancillary  Documents and
under applicable state and federal securities laws.

            2.7.  Governmental   Consents.  No  consent,   approval,   order  or
authorization of, or registration,  qualification,  designation,  declaration or
filing with, any federal, state or local governmental  authority, on the part of
the Company is required in  connection  with the offer,  sale or issuance of the
Shares (and the Common  Stock  issuable  upon  conversion  of the Shares) or the
consummation  of any  other  transaction  contemplated  hereby,  except  for the
following:  (i) the filing of a notice of exemption pursuant to Section 25102(f)
of the California  Corporate Securities Law of 1968, as amended (the "California
Securities  Law"),  which shall be filed by the Company  promptly  following the
Closing;  and (ii) the  compliance  with  other  applicable  state  and  federal
securities laws, which compliance will have occurred within the appropriate time
periods therefor.  Assuming that the  representations of the Investors set forth
in Section 3 below are true and  correct,  the offer,  sale and  issuance of the
Shares  in  conformity  with the terms of this  Agreement  are  exempt  from the
registration requirements of Section 5 of the Securities Act of 1933, as amended
(the "Securities Act"), and from the qualification requirements of Section 25110
of the California Securities Law.

            2.8.   Litigation.   There  is  no  action,   suit,   proceeding  or
investigation  pending  or, to the best of the  Company's  knowledge,  currently
threatened before any court,  administrative  agency or other  governmental body
(nor,  to best of the  Company's  knowledge,  is there  any  basis  for any such
action,  suit,  proceeding  or  investigation),  which (i) would  reasonably  be

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expected  to have a  material  adverse  effect on the  condition  (financial  or
otherwise), business, property, assets or liabilities of the Company, taken as a
whole,  or (ii) would  reasonably  be expected to have an adverse  effect on the
ability of the  Company to  consummate  the  transactions  contemplated  by this
Agreement or the Ancillary Documents,  or which otherwise challenges or seeks to
prevent, enjoin, alter or materially delay the transactions contemplated by this
Agreement or the Ancillary Documents.  The Company is not a party or subject to,
and none of the assets of the Company is bound by, the  provisions of any order,
writ,  injunction,  judgment  or  decree of any  court or  government  agency or
instrumentality.  To the best knowledge of the Company, the Company has not been
threatened with any action or proceeding under any business or zoning ordinance,
law or regulation.

            2.9. Compliance with Other Instruments.  The business and operations
of the Company have been and are being  conducted  in all  material  respects in
accordance with all applicable  laws,  rules and regulations of all governmental
authorities.  The Company is not in violation or default of any provision of its
Certificate of Incorporation or By-laws, each as amended and in effect as of the
Closing.  The Company is not in  violation  or default of any  provision  of any
instrument,  mortgage,  deed of trust,  loan,  contract,  commitment,  judgment,
decree,  order or obligation to which it is a party or by which it or any of its
properties  or assets are bound  which  would  materially  adversely  affect the
condition (financial or otherwise), business, property, assets or liabilities of
the Company or of any provision of any federal,  state or local statute, rule or
governmental  regulation which would  materially  adversely affect the condition
(financial or  otherwise),  business,  property,  assets or  liabilities  of the
Company,  taken as a whole.  The  execution,  delivery  and  performance  of and
compliance with this Agreement and the Ancillary  Documents and the issuance and
sale of the Shares will not result in any such violation, be in conflict with or
constitute,  with or without the passage of time or giving of notice,  a default
under any such provision, require any consent or waiver under any such provision
(other than any consents or waivers that have been  obtained),  or result in the
creation of any mortgage,  pledge,  lien,  encumbrance or charge upon any of the
properties or assets of the Company pursuant to any such provision.  The Company
is not subject to any legal or contractual  restriction  which would prohibit it
from entering into or performing  its  obligations  under this  Agreement or the
Ancillary Documents.

            2.10.  Brokers or Finders.  Except for the  issuance of the Warrants
and payment of $180,000 in fees to the Company's  financial  advisor,  Flemming,
Lessard & Shields,  the Company has not engaged any  brokers,  finders or agents
and the Investors have not incurred, and will not incur, directly or indirectly,
as a result of any action taken by the Company,  any  liability for brokerage or
finders' fees or agents'  commissions or any similar  charges in connection with
this  Agreement and the  transactions  it  contemplates.  The Company  agrees to
indemnify and hold harmless the Investors  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 Investors
or any of their respective officers,  partners,  employees or representatives is
responsible  as a result of any  action  taken by the  Company,  except for fees
disclosed in the preceding sentence.


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         3.  Representations  and  Warranties  of the  Investors.  Each Investor
severally and not jointly  hereby  represents and warrants as of the date hereof
and as of the Closing as follows:

            3.1. Experience. Such Investor is experienced in evaluating start-up
companies  such as the  Company,  and has either  individually  or  through  its
current officers such knowledge and experience in financial and business matters
that  such  Investor  is  capable  of  evaluating  the  merits  and risks of the
Investor's  prospective  investment in the Company,  and has the ability to bear
the  economic  risks of the  investment.  Investor is an  "accredited  investor"
within the meaning of Rule 501 promulgated under the Securities Act.

            3.2. Purchase  Entirely for Own Account.  Such Investor is acquiring
the Shares (and the Common Stock  issuable  upon  conversion  of the Shares) for
investment  for such  Investor's  own  account  and not with the view to, or for
resale in connection with, any distribution  thereof.  Such Investor understands
that the Shares (and the Common Stock  issuable  upon  conversion of the Shares)
have not been  registered  under the  Securities  Act by  reason  of a  specific
exemption from the  registration  provisions of the Securities Act which depends
upon,  among  other  things,  the bona fide nature of the  investment  intent as
expressed  herein.  Such Investor  further  represents that it does not have any
contract,  undertaking,  agreement  or  arrangement  with  any  person  to sell,
transfer or grant  participation  to any third person with respect to any of the
Shares (or any Common Stock  acquired upon  conversion  thereof).  Such Investor
understands  and  acknowledges  that the offering of the Shares pursuant to this
Agreement  will not, and any issuance of Common Stock on conversion  may not, be
registered  under the Securities Act on the ground that the sale provided for in
this  Agreement  and the  issuance of  securities  hereunder  is exempt from the
registration requirements of the Securities Act.

            3.3. Rule 144. Such Investor  acknowledges  that the Shares (and the
Common Stock issuable upon  conversion of the Shares) must be held  indefinitely
unless  subsequently  registered  under the  Securities Act or an exemption from
such registration is available. Such Investor is aware of the provisions of Rule
144  promulgated  under the Securities Act which permit limited resale of shares
purchased  in a  private  placement  subject  to  the  satisfaction  of  certain
conditions.  Such  Investor  covenants  that,  in the  absence  of an  effective
registration statement covering the stock in question,  such Investor will sell,
transfer,  or  otherwise  dispose of the Shares (and any Common  Stock issued on
conversion  thereof)  only in a  manner  consistent  with  the  such  Investor's
representations  and  covenants  set  forth  in this  Section  3. In  connection
therewith,  such Investor  acknowledges that the Company will make a notation on
its stock  books  regarding  the  restrictions  on  transfers  set forth in this
Section 3 and will  transfer  securities on the books of the Company only to the
extent not inconsistent therewith.

            3.4. No Public  Market.  Such  Investor  understands  that no public
market now exists for any of the securities issued by the Company,  and there is
no assurance  that a public market will ever exist for the Shares (or the Common
Stock issuable upon conversion of the Shares).


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            3.5.  Access  to Data.  Such  Investor  has  received  and  reviewed
information  about  the  Company  and  has had an  opportunity  to  discuss  the
Company's business,  management and financial affairs with its management and to
review the Company's facilities. Such Investor understands and acknowledges that
such discussions,  as well as any written information issued by the Company, (i)
were  intended to describe the aspects of the  Company's  business and prospects
which  the  Company  believes  to be  material,  but  were  not  necessarily  an
exhaustive description,  and (ii) may have contained forward-looking  statements
involving  known  and  unknown  risks  and  uncertainties  which  may  cause the
Company's actual results in future periods or plans for future periods to differ
materially from what was anticipated and that no  representations  or warranties
were or are being made with respect to any such  forward-looking  statements  or
the  probability  of  achieving  any of the  results  projected  in any of  such
forward-looking  statements,  except that the Company  represents  that all such
written information was prepared in good faith with a reasonable basis.

            3.6.  Authorization.  Each of this  Agreement  and the  Stockholders
Agreement  when executed and delivered by such Investor will  constitute a valid
and legally binding obligation of such Investor,  enforceable in accordance with
its terms  subject to: (i)  judicial  principles  limiting the  availability  of
specific  performance,  injunctive relief, and other equitable remedies and (ii)
bankruptcy, insolvency, reorganization,  moratorium or other similar laws now or
hereafter in effect generally relating to or affecting creditors' rights.

         4. Conditions of the Investors'  Obligations at Closing. The obligation
of each Investor to purchase Shares at the Closing is subject to the fulfillment
on or  before  the  Closing  Date  of each of the  following  conditions  by the
Company,  the waiver of which shall not be  effective  against any  Investor who
does not consent in writing thereto:

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

            4.2.  Performance.  Each party  thereto  (other than such  Investor)
shall  have  performed  and  complied  with  all  agreements,   obligations  and
conditions  contained in this  Agreement  and the Ancillary  Documents  that are
required to be performed or complied with by it on or before the Closing Date.

            4.3.  Compliance  Certificate.  The  President  or  Chief  Executive
Officer of the Company  shall  deliver to each  Investor  on the Closing  Date a
certificate  stating that the conditions  specified in Sections 4.1 and 4.2 have
been fulfilled.

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            4.4. Absence of Litigation.  No action, suit, or proceeding shall be
threatened,  instituted or pending before any court or administrative  agency of
any federal, state or local jurisdiction seeking an injunction, judgment, order,
decree,  ruling,  or  charge  which  would  prevent  consummation  of any of the
transactions  contemplated  by this  Agreement or cause any of the  transactions
contemplated by this Agreement to be rescinded following consummation.

            4.5. Blue Sky. The Company shall have obtained all necessary permits
and qualifications,  if any, or secured an exemption therefrom,  required by any
state or country prior to the offer and sale of the Shares.

            4.6. Opinion of Company  Counsel.  Each Investor shall have received
from Latham & Watkins,  counsel for the Company,  an opinion with respect to the
Shares, dated as of the Closing Date, in the form attached hereto as Exhibit D.

                  (a) A copy of  resolutions  of the Board of  Directors  of the
         Company  certified  by the  secretary  of the Company  authorizing  and
         approving the execution, delivery and performance of this Agreement;

                  (b) A certificate  of incumbency  executed by the secretary of
         the Company certifying the names, titles and signatures of the officers
         authorized to execute this  Agreement and further  certifying  that the
         Restated  Certificate of the Company delivered to legal counsel for the
         Investors  at the time of the  execution  of this  Agreement  have been
         validly adopted and have not been amended or modified.

            4.8. Other Agreements. Each party thereto (other than such Investor)
shall have entered into: (i) the Stockholders  Agreement between the Company and
certain  named  investors  of even date  herewith  and  attached  in the form as
Exhibit E (the "Stockholders  Agreement");  and (ii) the License Agreement.  The
Company shall have entered into (a) the Common Stock  Purchase  Agreement in the
form  attached  hereto as Exhibit F (the "Common  Agreement");  and (b) the five
year  warrant to  purchase  1,500  shares of Common  Stock in the form  attached
hereto as Exhibit G (the "Warrants").

            4.9. Restated Certificate.  The Restated Certificate shall have been
filed with the Secretary of State of the State of Delaware.

            4.10.  Stock  Incentive Plan. The Company's Board of Directors shall
have  adopted and  approved  the 1999 Stock  Incentive  Plan of the Company (the
"Stock Option Plan") in the form attached hereto as Exhibit H.

         5.  Conditions  of  the  Company's  Obligations  at  the  Closing.  The
obligations  of the Company to each Investor under this Agreement are subject to
the  fulfillment  on or  before  the  Closing  Date  of  each  of the  following
conditions by that Investor:

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            5.1.   Representations  and  Warranties.   The  representations  and
warranties  of each  Investor  contained in Section 3 shall be true on and as of
the  Closing  Date  with the same  effect  as though  such  representations  and
warranties had been made on and as of the Closing Date.

            5.2.  Performance.  Each Investor  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 the Closing
Date.

            5.3. Compliance  Certificate.  An executive officer of each Investor
shall deliver to the Company at the Closing Date a certificate  stating that the
conditions specified in Sections 5.1 and 5.2 have been fulfilled.

            5.4. Blue Sky. The Company shall have obtained all necessary permits
and qualifications,  if any, or secured an exemption therefrom,  required by any
state for the offer and sale of the Shares.

            5.5.  Other  Agreements.  Each party  thereto other than the Company
shall have  entered  into the:  (i)  Stockholders  Agreement;  (ii) the  License
Agreement; (iii) the Common Agreement; and (iv) the Warrants.

            5.6. Absence of Litigation.  No action, suit, or proceeding shall be
threatened,  instituted or pending before any court or administrative  agency of
any federal, state or local jurisdiction seeking an injunction, judgment, order,
decree,  ruling,  or  charge  which  would  prevent  consummation  of any of the
transactions  contemplated  by this  Agreement or cause any of the  transactions
contemplated by this Agreement to be rescinded following consummation.

            5.7. Restated Certificate.  The Restated Certificate shall have been
filed with the Secretary of State of the State of Delaware.

            5.8. Stock  Incentive  Plan. The Company's  Board of Directors shall
have adopted and approved the Stock Incentive Plan.

            5.9  Promissory  Note.  DTN shall have  executed and  delivered  the
Promissory Note to the Company.

            5.10 Opinion of DTN Counsel.  The Company  shall have  received from
Abrahams  Kaslow & Cassman,  counsel  for DTN,  an opinion  with  respect to the
Promissory  Note,  dated as of the Closing Date, in the form attached  hereto as
Exhibit J.

         6. Participation Rights

            6.1.  The Company  agrees  that if it  proposes to issue  additional
equity securities or any instruments,  options, warrants, convertible securities
or  other  rights  for  or  convertible   into  additional   equity   securities
(collectively,  "New Equity  Securities"),  each holder of Shares (or any Common

                                       11
                                     -225-
<PAGE>

Stock issued upon conversion thereof) shall be entitled to purchase a percentage
of  such  New  Equity  Securities  to be  issued  by the  Company  equal  to the
percentage of the Company's  aggregate  outstanding Shares (and any Common Stock
issued upon conversion thereof) held by such stockholder. If a holder elects not
to purchase all of the New Equity Securities to which it is entitled,  then each
of the other such holders shall be entitled to purchase its proportionate  share
of such New Equity Securities.

            6.2. The rights set forth in Section 6.1 shall not apply to:

                  (a)  shares  issued in  connection  with  acquisitions  by the
         Company or any of its subsidiaries of businesses or assets;

                  (b) shares issued to strategic  partners of the Company or any
         of its subsidiaries  pursuant to transactions approved by the Company's
         Board of Directors;

                  (c) shares  reserved for issuance  upon exercise of options or
         warrants granted or to be granted to officers, directors, employees and
         consultants of the Company or any of its  subsidiaries  and approved by
         the Board of Directors of the Company;

                  (d) shares issued or issuable in connection  with credit lines
         and equipment financing and leasing;

                  (e) shares  issued  upon  exercise or  conversion  of options,
         warrants or convertible securities;

                  (f) shares issued  pursuant to a registered  public  offering;
         and

                  (g)  shares  issued in  connection  with stock  splits,  stock
         dividends and similar events.

            6.3. The rights set forth in this Section 6 shall terminate  without
further  action by the  Company or any  holder of Shares  upon  completion  of a
firmly underwritten public offering by the Company.

         7. Miscellaneous

            7.1. Governing Law. This Agreement shall be governed in all respects
by the  laws of the  State of  Delaware  without  regard  to  choice  of laws or
conflict of laws provisions thereof.

            7.2.  Survival.  The  representations,   warranties,  covenants  and
agreements   made  herein  shall   survive  the  closing  of  the   transactions
contemplated hereby.

            7.3.  Successors and Assigns.  Except as otherwise  provided herein,
the  provisions  hereof shall inure to the benefit of, and be binding upon,  the
successors,  assigns, heirs, executors and administrators of the parties hereto;

                                       12
                                     -226-
<PAGE>

provided, however, that the rights of each Investor to purchase Shares shall not
be assignable without the consent of the Company and the other Investor in their
sole discretion.

            7.4.  Entire  Agreement;  Amendment.  This  Agreement  and the other
documents delivered pursuant hereto constitute the full and entire understanding
and agreement  among the parties with regard to the subjects hereof and thereof.
Neither this Agreement nor any term hereof may be amended, waived, discharged or
terminated other than by a written  instrument  signed by the party against whom
enforcement of any such amendment,  waiver,  discharge or termination is sought.
Notwithstanding  the foregoing,  holders of a majority of the outstanding Shares
(whether or not  converted)  may waive or amend,  on behalf of each Investor and
other holders of Shares,  any provisions hereof benefiting the Investors so long
as the  effect  thereof  will be that all such  Investors  and other  holders of
Shares will be treated equally.

            7.5. Notices, Etc. All notices and other communications  required or
permitted  hereunder  shall be in writing and shall be mailed by  registered  or
certified  mail,  postage  prepaid,   return  receipt  requested,  or  otherwise
delivered  by hand or by  messenger,  addressed  (a) if to an  Investor  at such
Investor's  address  set forth on Exhibit A to this  Agreement  or at such other
address as such Investor shall have furnished to the Company in writing,  or (b)
if to any other holder of any Shares,  at such address as such holder shall have
furnished  the Company in writing,  or,  until any such holder so  furnishes  an
address to the  Company,  then to and at the  address of the last holder of such
Shares who has so furnished an address to the Company, or (c) if to the Company,
at its address set forth on the first page of this  Agreement  addressed  to the
attention of the  Corporate  Secretary,  or at such other address as the Company
shall have  furnished to the  Investors.  If notice is provided by mail,  notice
shall be deemed to be given upon proper deposit in a mailbox.

            7.6.  Delays or  Omissions.  No delay or omission  to  exercise  any
right,  power or remedy  accruing to any holder of any Shares upon any breach or
default of the Company under this Agreement  shall impair any such right,  power
or remedy of such  holder,  nor shall it be construed to be a waiver of any such
breach or default, or an acquiescence therein, or of or in any similar breach or
default  thereafter  occurring;  nor shall any  waiver of any  single  breach or
default  be deemed a waiver  of any  other  breach  or  default  theretofore  or
thereafter  occurring.  Any waiver,  permit,  consent or approval of any kind or
character  on the  part of any  holder  of any  breach  or  default  under  this
Agreement,  or any  waiver  on the  part  of any  holder  of any  provisions  or
conditions of this Agreement,  must be in writing and shall be effective only to
the  extent  specifically  set  forth in such  writing  or as  provided  in this
Agreement.  All  remedies,  either  under this  Agreement or by law or otherwise
afforded to any holder, shall be cumulative and not alternative.

            7.7. California Corporate Securities Law. THE SALE OF THE SECURITIES
WHICH  ARE THE  SUBJECT  OF THIS  AGREEMENT  HAS NOT  BEEN  QUALIFIED  WITH  THE
COMMISSIONER OF CORPORATIONS OF THE STATE OF CALIFORNIA AND THE ISSUANCE OF SUCH

                                       13
                                     -227-
<PAGE>

SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE  CONSIDERATION  THEREFOR
PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE OF SECURITIES IS EXEMPT
FROM THE  QUALIFICATION  BY SECTION  25100,  25102,  OR 25105 OF THE  CALIFORNIA
CORPORATIONS  CODE.  THE RIGHTS OF ALL PARTIES TO THIS  AGREEMENT  ARE EXPRESSLY
CONDITIONED  UPON  SUCH  QUALIFICATION  BEING  OBTAINED,  UNLESS  THE SALE IS SO
EXEMPT.

            7.8.  Expenses.  The Company and each Investor  shall bear their own
expenses and legal fees incurred on their behalf with respect to this  Agreement
and the transactions contemplated hereby.

            7.9.  Counterparts.  This Agreement may be executed in any number of
counterparts  and signatures may be delivered by facsimile,  each of which shall
be enforceable against the parties actually executing such counterparts, and all
of which together shall constitute one instrument.

            7.10. Severability. If any provision of this Agreement becomes or is
declared by a court of competent  jurisdiction to be illegal,  unenforceable  or
void,  portions of such  provision,  or such  provision in its entirety,  to the
extent  necessary,  shall be severed from this Agreement and the balance of this
Agreement shall be enforceable in accordance with its terms.

            7.11. Dispute Resolution.  Any dispute, claim or controversy arising
under  this  Agreement  or  in  any  way  related  to  this  Agreement,  or  its
interpretation,  enforceability  or  inapplicability  that cannot be resolved by
mutual agreement of the parties shall be submitted to binding  arbitration.  The
arbitration  shall be conducted by a single  arbitrator  mutually agreed upon by
the parties or, if no arbitrator is mutually selected within thirty (30) days of
a demand  therefor,  then by a retired judge from the Judicial  Arbitration  and
Mediation  Service/Endispute  ("JAMS") office located in San Diego,  California.
The arbitration  shall be conducted in San Diego,  California in accordance with
the Commercial  Arbitration Rules of the American Arbitration  Association.  The
arbitration  award shall be final and binding,  and judgment on the award may be
entered in any court having jurisdiction  thereof. The parties hereby consent to
the  consolidation of any arbitration  hereunder with any arbitration  commenced
under the  License  Agreement,  the  Stockholders  Agreement,  the Common  Stock
Purchase Agreement and/or the Warrants.

                            [SIGNATURE PAGE FOLLOWS]


                                       14
                                     -228-
<PAGE>



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

COMPANY:                            EARTHSCAN NETWORK INC.


                                    By:/s/ John Rasure
                                       ------------------------------
                                       John Rasure
                                    Title: President

                                    By:/s/ Sonya Kay Porth
                                       ------------------------------
                                       Sonya Kay Porth
                                    Title:Corporate Secretary


INVESTORS:                          DATA TRANSMISSION NETWORK CORPORATION

                                    By:/s/Greg T. Sloma
                                       ------------------------------
                                       Greg T. Sloma
                                    Title:President & COO

                                    By:/s/ Brian L. Larson
                                       ------------------------------
                                       Brian L. Larson
                                    Title:SVP & CFO


                                    PHOTON RESEARCH ASSOCIATES, INC.

                                    By:/s/ James A. Myer
                                       -------------------------------
                                       James A. Myer
                                    Title: CO-COB

                                    By:/s/ Sonya Kay Porth
                                       ------------------------------
                                       Sonya Kay Porth
                                    Title:Corporate Secretary/Treasurer



                                       15
                                     -229-
<PAGE>



                                   Exhibit A

                               List of Investors

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       16
                                     -230-
<PAGE>


                                   Exhibit B

                               License Agreement

                                LICENSE AGREEMENT

         THIS LICENSE  AGREEMENT  ("Agreement")  is made as of December 16, 1999
(the  "Effective  Date") by and between  Photon  Research  Associates,  Inc.,  a
California  corporation  ("Licensor")  and  EarthScan  Network  Inc., a Delaware
corporation ("Licensee"), with reference to the following facts:

         A. Licensor has developed and owns certain Technology.

         B. Licensee is desirous of licensing and exploiting the Technology,  on
the terms and conditions set forth within this Agreement.

         NOW  THEREFORE,  in  consideration  of the  foregoing and of the mutual
promises   hereinafter   set  forth,   as  well  as  other  good  and   valuable
consideration,  the  sufficiency  of which is hereby  acknowledged,  the parties
agree as set forth below.

1.  Definitions.


            a. "Affiliate"  shall mean any corporation or other business entity,
in whatever  country  organized,  which,  directly or indirectly,  controls,  is
controlled  by or is under common  control with  Licensee.  "Control" as used in
this  definition  shall mean the  ownership of more than 50% of the issued share
capital  or the legal  power to direct or cause  the  direction  of the  general
management and policies of the party in question, by contract or otherwise.

            b.  "Documentation"  means (i) the internal source code  (including,
without limitation,  all comments and procedural code, flow charts,  schematics,
statements  of  principles of operations  and  architecture  standards)  for the
software  included in the Licensed  Products (other than Third Party  Software);
(ii) development  process  documents  (including  schematics,  diagrams and flow
charts)  prepared in connection  with the  development of the Licensed  Products
(other  than  Third  Party  Software);  and  (iii) the end user  manual  for the
Licensed Products.

            c. "Improvements" means and comprises any correction,  modification,
alteration,  enhancement,  improvement,  update  or  revision  to  the  Licensed
Products or the Documentation.

            d. "Intellectual  Property" means and comprises any patents,  patent
applications,  copyrights  and  copyright  applications  and  trade  secrets  of
Licensor claiming or embodied in the Licensed Products, the Documentation or the
Improvements thereto.

            e. "Know How" means and comprises  technical data and information in
Licensor's  possession  necessary or helpful for Licensee to make, have made and
use the  Licensed  Products,  the  Documentation  or any  Improvements  thereto,
including,  but  not  limited  to,  techniques,  methods,  formulations,  plans,
specifications, programs, schematics, designs and other similar information.

                                       17
                                     -231-
<PAGE>

            f.  "Licensed  Products"  means and comprises  the "Tierra  Station"
system and related  software which  incorporates  or is derived in part from the
Technology  and is described in Exhibit "A" attached  hereto,  but excluding any
Third Party Software.

            g.  "Technology"  means and comprises the Know-How and  Intellectual
Property.

            h.  "Third  Party  Software"  means  and  comprises  those  software
programs  owned by  third  parties  which  are  used in  connection  with or are
integrated  with the  Licensed  Products,  as set forth on Exhibit "B"  attached
hereto.

2. Grant of Licenses.


            a. Technology  License.  Subject to the terms and conditions of this
Agreement,  Licensor  hereby  grants to Licensee an  exclusive  (even as against
Licensor), worldwide,  fully-paid, perpetual license, with rights to sublicense,
to (i) use, test, update, upgrade,  enhance, modify, lease and sell the tangible
elements of the  Technology,  Licensed  Products and Licensor's  Improvements to
Licensed  Products and Documentation to ingest,  process,  store and disseminate
information to customers within the Field of Exploitation (as defined in Section
2(b) below) and (ii)  reproduce,  make derivative  works of,  publicly  perform,
publicly  display in any form or medium,  whether now known or later  developed,
distribute,  make and have  made,  use and  sell any of the  Technology  and all
intangible  elements of the Licensed  Products and  Documentation and Licensor's
Improvements  to  Licensed  Products  and  Documentation  for  the  purposes  of
developing and marketing  products and services of Licensee  within the Field of
Exploitation.  Notwithstanding  the  foregoing,  Licensee  will not  sublicense,
distribute,  lease  or sell  all or any  portions  of the  Technology,  Licensed
Products or  Documentation or Licensor's  Improvements  thereto to third parties
without the prior approval of Licensee's Board of Directors.

            b.  Field  of  Exploitation.   "Field  of  Exploitation"  means  all
commercial  applications  or markets for  information  disseminated  through the
Licensed Products and any Improvements  thereto,  but excluding the exploitation
in any manner of Licensed  Products and any Improvements  thereto in military or
government intelligence  applications or markets worldwide.  Notwithstanding the
foregoing,  if  Licensor  desires  to  exploit  the  Licensed  Products  or  any
Improvements  thereto in a  commercial  application  or market that is otherwise
included in the Field of  Exploitation,  Licensor  may so indicate its desire by
written notice to Licensee and Data Transmission  Network  Corporation  ("DTN").
Within thirty (30) days following receipt of such notice, Licensee shall convene
a  meeting  of its  Board of  Directors,  who  shall  consider  such  commercial
application or market described in Licensor's  notice,  and the Licensee's Board
of Directors shall determine  whether Licensee shall (i) pursue such application
or market (in which case Licensee shall then use commercially reasonable efforts
to pursue  such  application  or  market,  in light of  Licensee's  then-current
business  plan and  product  development  plan) or (ii) elect not to pursue such
application or market. However, if Licensee's Board of Directors is evenly split
on  whether  or not to pursue  any such  application  or  market  and all of the
directors appointed by DTN (pursuant to Section ___ of that certain Stockholders
Agreement  between  Licensor,  Licensee,  DTN and  other  persons  of even  date
herewith)  have  voted  to  pursue  such  appplication  or  market,   then  such
application  or  market  shall  remain  included  in the  Field of  Exploitation

                                       18
                                     -232-
<PAGE>

regardless of whether Licensee pursues such application or market. If Licensee's
Board of Directors  elects not to pursue any such  application  or market or the
Board is at an  impasse  other  than under the  circumstances  described  in the
preceding  sentence,  then such application or market shall thereafter be deemed
excluded from the Field of Exploitation and Licensor may pursue the exploitation
of such application or market independently.

            c. Third  Party  Software.  Notwithstanding  any  provision  of this
Agreement  to the  contrary,  Licensee  acknowledges  and agrees that the use of
Third Party  Software is required to achieve the intended  functionality  of the
Licensed Products,  that Licensee must independently  obtain its own licenses to
use the Third Party  Software,  and that  Licensor is not licensing or otherwise
providing  to  Licensee   any  rights  to  the  Third  Party   Software  or  the
documentation  related  thereto.  Licensor makes no  representation  or warranty
whatsoever concerning the Third Party Software or related documentation,  or the
ability  of  Licensee  to obtain  the  rights to use such  software  or  related
documentation.

            d.  Ownership.  The entire  rights,  title and  interest in and full
ownership  of the  Licensed  Products,  Documentation  and  Technology,  and all
Improvements and copies thereof,  together with all Intellectual Property rights
claiming or embodied in the  foregoing,  shall remain  exclusively  with and the
exclusive property of Licensor,  subject only to the right and license expressly
granted to Licensee herein.  This Agreement does not provide Licensee with title
or ownership of the  Licensed  Products,  Documentation  or  Technology,  or any
Improvements thereto, but only a right of limited use.

3.  Improvements.


            a.  Licensee  Improvements.  To the extent  developed,  written,  or
conceived by Licensee or its agents or  contractors  after the  Effective  Date,
Licensee  shall  own  all   Improvements   and  all  technology,   know-how  and
intellectual property claiming or embodied in such Improvements or the documents
related  thereto  (to the extent not already  licensed  to Licensee  hereunder).
Licensee  agrees  to  promptly   disclose  and  deliver  to  Licensor  all  such
Improvements  during  the Term of this  Agreement.  Licensee  hereby  grants  to
Licensor a non-exclusive,  worldwide, fully-paid, perpetual license, with rights
to sublicense,  to (i) use, test, update,  upgrade,  enhance,  modify, lease and
sell the tangible elements of the technology, know-how and intellectual property
claiming  or embodied  in  Licensor's  Improvements  to  Licensed  Products  and
Documentation to ingest, process, store and disseminate information to customers
outside the Field of Exploitation and (ii) reproduce,  make derivative works of,
publicly perform,  publicly display in any form or medium,  whether now known or
later  developed,  distribute,  make and have made,  use and sell all intangible
elements of Licensee's  Improvements to Licensed  Products and Documentation for
the  purposes of  developing  and  marketing  products  and services of Licensor
outside of the Field of Exploitation.

            b.  Licensor  Improvements.  To the extent  developed,  written,  or
conceived  by  Licensor  or its agents or  contractors,  Licensor  shall own all
Improvements and all Technology claiming or embodied in such Improvements or the
documents  related thereto.  Licensor agrees to promptly disclose and deliver to
Licensee  all  such  Improvements  during  the  Term  of  this  Agreement.   All
Improvements  by Licensor  during the Term of this Agreement shall become a part

                                       19
                                     -233-
<PAGE>

of the  Technology  upon  creation  and subject to the  licenses  granted  under
Section 2 and the other terms and conditions of this Agreement.

4. Non-Disclosure of Information.

            a. Confidentiality  Obligation. Each party shall keep in confidence,
use only for the purposes and as expressly  authorized  herein,  and prevent the
disclosure  to  any  person  or  persons  (outside  its  organization  or to any
unauthorized person or persons) of all of the ideas,  processes,  trade secrets,
inventions, discoveries, know-how, other technical research and development, and
commercial  and  proprietary  information  disclosed  to such party by the other
party (collectively, "Proprietary Information"). Each party's obligation to keep
Proprietary  Information  of the other in  confidence  will  include  disclosing
Proprietary  Information  to employees or agents of such party only as necessary
for the performance of such party's obligations under this Agreement,  requiring
third parties to whom such party discloses Proprietary Information to enter into
confidentiality obligations similar to those included in this Paragraph, marking
written copies of Proprietary  Information  as  "Confidential/Proprietary  Trade
Secret   Information"  and  maintaining  similar  markings  on  files  in  which
Proprietary Information is stored. Either party shall have the right to disclose
Proprietary  Information of the other to any  sublicensee,  subject to its first
obtaining the written  agreement of such  sublicensee to abide by the provisions
of this Section 4.

            b. Information Not Included.  Proprietary Information, as defined in
Paragraph 4(a), does not include any information which:

                  (i) was in the public domain at the time it was disclosed;

                  (ii)  was  independently  known  to a  party  at the  time  of
disclosure as shown by  documentation  sufficient to establish  such  knowledge,
from a source not subject to confidentiality obligations to the other party; or

                  (iii) was disclosed to a party by third parties not subject to
confidentiality obligations to the other party.

            c. Documents.  All documents,  books, notebooks,  papers,  drawings,
sketches,  formulas (or copies of extracts thereof),  and other data of any kind
and  description  pertaining  to  the  Proprietary  Information   (collectively,
"Proprietary Documents") that have been or will be disclosed by one party to the
other party have been or will be  disclosed  with a clear  understanding  by the
receiving party that they contained or will contain information  valuable to the
disclosing  party.  The  receiving  party  shall  make  only  one  copy  of  the
Proprietary  Documents  and  Documentation  (other than the end user  manual) to
create an archive copy for use as a backup.  Upon termination of this Agreement,
each party will promptly  deliver to the other party all  Proprietary  Documents
and  Documentation  of the other party,  including all copies of the Proprietary
Documents and Documentation in its possession.

            d. Compelled Disclosure. In the event that a party or anyone to whom
such party transmits any Proprietary Information or Proprietary Documents of the
other party in  accordance  with this  Agreement is legally  requested  (by oral
questions,  interrogatories,  request for  information  or documents,  subpoena,

                                       20
                                     -234-
<PAGE>

civil investigative demand or similar process) or otherwise required to disclose
any Proprietary  Information or Proprietary  Documents of the other party,  such
party  will  provide  the other  party with  notice,  prior to  disclosing  such
Proprietary  Information or Proprietary  Documents,  so that the other party may
seek  an  appropriate   protective  order  and/or  waive  compliance  with  this
Agreement.  If, in the absence of a protective  order or the receipt of a waiver
hereunder,  such  party  is  nonetheless  legally  compelled  to  disclose  such
information,  it may, without liability hereunder,  furnish that portion of such
Proprietary Information or Proprietary Documents.

5. [Intentionally Omitted.]

6. Marking  Products.  Licensee shall  appropriately  mark all Licensed Products
(and components thereof) as reasonably required by Licensor from time to time.

7. Representations and Warranties.  Licensor represents and warrants to Licensee
and DTN as of the  Effective  Date that:  (a) Licensor has the right,  power and
authority to grant the  licenses  granted in this  Agreement  and to perform its
obligations hereunder;  (b) the Technology does not infringe any U.S. or foreign
patent,  trademark or copyright of any third party, nor is Licensor aware of any
threatened  claim of any such  infringement;  (c)  Licensor  is not aware of any
third-party products which infringe on its proprietary rights in the Technology;
(d)  this  Agreement  constitutes  valid  and  legally  binding  obligations  of
Licensor, enforceable against Licensor in accordance with its terms, subject to:
(i) judicial  principles  limiting  the  availability  of specific  performance,
injunctive relief, and other equitable  remedies;  (ii) bankruptcy,  insolvency,
reorganization,  moratorium  or other  similar  laws now or  hereafter in effect
generally  relating to or affecting  creditors' rights; and (iii) limitations on
the  enforceability of  indemnification  provisions;  (e) except with respect to
Third Party Software and hardware  manufactured by third parties included in the
Licensed  Products,  for which no  representation or warranty is made hereunder,
Licensor is the owner of all right,  title and  interest in and to the  Licensed
Products and  Technology  and has not granted  licenses  thereunder to any other
entity in the Field of  Exploitation;  (f) except  with  respect to Third  Party
Software and hardware  manufactured  by third  parties  included in the Licensed
Products,  for  which no  representation  or  warranty  is made  hereunder,  the
Licensed  Products are free from defects in  manufacture,  materials and design;
(g) the Licensed  Products  function on the machines and with operating  systems
for which  they are  designed;  and (h) the  Licensed  Products  conform  to the
specifications  and functions set forth in the  Documentation.  Licensor further
represents and warrants to Licensee and DTN that neither the performance nor the
functionality  of the Licensed  Products  will be affected by any changes to the
date format or date calculations within any part of the Licensed Products either
before,  during or after the year 2000.  Without  limiting the generality of the
foregoing,  Licensor represents and warrants that the Licensed Products are year
2000  compliant.  Year  2000  compliant  means  fault-free  performance  in  the
processing  of date  and  date-related  data  (including,  but not  limited  to,
calculating,  comparing and sequencing) by the Licensed  Products,  individually
and in combination,  as a system. Fault-free performance means (i) no invalid or
incorrect results or abnormal  termination will occur prior to, during and after
January  1, 2000 as a result of date or  date-related  data or data  processing;
(ii) proper  calculation and handling of leap years; and (iii) except for normal
user interfaces  (e.g. four digit date entry)  identified in the  Documentation,
such date data processing shall be transparent to a user.  Except as provided in
this Section 7, Licensor  makes no  representations  or  warranties,  express or
implied,  concerning this Agreement,  the Technology,  the  Documentation or the

                                       21
                                     -235-
<PAGE>

Licensed  Products.  The  representations  and warranties of Licensor under this
Section 7 shall  survive for a period of five years from and after the Effective
Date.  Any  claim  for a  breach  of  such  representations  and  warranties  or
indemnification   in  respect   thereof   must  be  asserted  in  writing   with
particularity against Licensor prior to the expiration of such five-year period.
EXCEPT  FOR THE  EXPRESS  WARRANTIES  SET  FORTH  IN THIS  SECTION  7,  LICENSOR
DISCLAIMS ALL OTHER  WARRANTIES,  EITHER  EXPRESS OR IMPLIED,  INCLUDING BUT NOT
LIMITED TO  WARRANTIES  OF  MERCHANTABILITY,  FITNESS FOR A PARTICULAR  PURPOSE,
NON-INFRINGEMENT OR ARISING FROM A COURSE OF DEALING OR USAGE IN TRADE.

8. Indemnification.

            a. Except for claims which are subject to Licensor's indemnification
as set forth in Section 8(b) below,  Licensee  hereby  indemnifies and agrees to
hold harmless  Licensor and its officers,  directors and  shareholders  from and
against any and all claims, demands, and actions, and any liabilities,  damages,
or expenses resulting therefrom, including court costs and reasonable attorneys'
fees,  resulting from the  manufacture or use (or misuse) of Licensed  Products,
Documentation  or Technology (or any  Improvements  thereto made by Licensee) by
Licensee or its  Affiliates or any breach of Licensee's  obligations  under this
Agreement.  Licensee's  obligations  under this Section  8(a) shall  survive the
termination of this Agreement for any reason.  Licensor  agrees to give Licensee
prompt  notice of any such  claim,  demand,  or action and to  cooperate  in the
defense and settlement of said claim,  demand, or action as reasonably requested
by Licensee; provided, that Licensee shall reimburse Licensor for all reasonable
expenses incurred by such cooperation. Licensee shall not settle any such claim,
demand or action  without  the prior  written  consent  of  Licensor,  not to be
unreasonably withheld or delayed.

            b. Licensor hereby  indemnifies and agrees to hold harmless Licensee
and DTN and their respective officers and directors from and against any and all
claims,  demands,  and  actions,  and  any  liabilities,  damages,  or  expenses
resulting  therefrom,  including  court costs and  reasonable  attorneys'  fees,
resulting  from  a  breach  of  Licensor's  representations  and  warranties  or
covenants set forth herein.  Subject to Section 7, Licensor's  obligations under
this  Section  8(b) shall  survive the  termination  of this  Agreement  for any
reason. Licensee and DTN agree to give Licensor prompt notice of any such claim,
demand,  or action and to cooperate in the defense and settlement of said claim,
demand, or action as reasonably requested by Licensor;  provided,  that Licensor
shall reimburse  Licensee and DTN for all reasonable  expenses  incurred by such
cooperation.  If Licensee's use of the Licensed Products or Improvements thereto
made by Licensor is enjoined,  Licensee  agrees to allow  Licensor at Licensor's
option and  expense,  to either  secure the right for  Licensee  to  continue to
exercise its rights in such Licensed Products or Improvements,  or to replace or
modify  them in an  equivalent  manner so they  become  noninfringing.  Licensee
hereby  agrees that  Licensor  shall have no  liability  for or with  respect to
infringement actions or claims to the extent that they arise by reason or result
from:  (a)  modification  of  Licensed  Products or  Improvements  other than by
Licensor;  or (b) Licensee's  failure to utilize an updated or modified  version
provided by Licensor;  or (c) Licensor's  compliance  with  Licensee's  designs,
plans or  specifications;  or (d) the combination of  non-infringing  items with
items  not  supplied  or  specified  by  Licensor;  provided,  the  infringement
described in (a) through (d) would have been avoided but for such  modification,
use, compliance or combination;  or (e) any infringement claim in which Licensee

                                       22
                                     -236-
<PAGE>

has an interest. Licensee shall indemnify Licensor from all claims and expenses,
including  reasonable  attorneys'  fees,  which are occasioned by the exceptions
stated in the preceding sentence of this paragraph.

9. Enforcement of Intellectual Property.

            a. Enforcement.  Licensee, at its sole expense, shall have the first
right,  but not  the  obligation,  to  enforce  all  proprietary  rights  in the
Technology with respect to any suspected infringement of such proprietary rights
in the  Field of  Exploitation  which  occurs  in whole or in part  prior to the
termination  of this  Agreement  and,  subject  to Section  9(c),  to retain any
recovery arising out of the prosecution of such actions. Licensee shall promptly
notify  Licensor  if it becomes  aware of any  suspected  infringement  by third
parties of any  proprietary  rights in the  Technology.  Licensor shall have the
non-exclusive  right to enforce the  proprietary  rights in the Technology  with
respect to any suspected infringement in the Field of Exploitation which occurs,
if after thirty (30) days after  Licensee's  receipt of  Licensor's  request for
Licensee to initiate an action,  Licensee has not initiated an action to enforce
such  proprietary  rights  with  respect to such  infringement.  Licensee  shall
cooperate  with Licensor in any such action at  Licensor's  request and expense,
but Licensee  shall not be  obligated  to become a party to any such  proceeding
unless the laws of the  jurisdiction in which the action is to be filed preclude
Licensor from enforcing the proprietary rights in the Technology without joining
Licensee  as a  party.  Licensor  shall be  entitled  to any  recovery  from any
proceeding it pursues at its sole expense  under this Section 9. Licensor  shall
have the exclusive  right to enforce all  proprietary  rights in the  Technology
with respect to any suspected infringement outside the Field of Exploitation.

            b. Right to Intervene.  Each party shall have the right to intervene
in any action  relating to an  infringement  of the  Technology  in the Field of
Exploitation  brought  by the  other  party,  at the  intervening  party's  sole
expense.

            c. Joint  Action.  If any action  relates to  infringing  activities
described  above under Section 9(a) and the parties  jointly  participate in the
proceeding (in more than name only),  each bearing their own expenses,  then the
parties shall equitably share the recovery.

10.  Termination.


            a.  Termination.  This  Agreement  shall  be  effective  as  of  the
Effective  Date and shall  continue in effect  until  terminated  as provided in
Section 10(b) below (the "Term").

            b.  Termination  Rights.  This Agreement may be terminated,  without
liability to the party terminating:

                  (i) By Licensee, upon 90 days' notice to Licensor.


                  (ii) By a party,  immediately  upon notice to the other party,
if:
                                       23
                                     -237-
<PAGE>

                       (1) that other party makes a general assignment of all or
substantially all of its assets for the benefit of its creditors;

                       (2)  that  other  party  applies  for,  consents  to,  or
acquiesces in the appointment of a receiver,  trustee,  custodian, or liquidator
for its business or all or substantially all of its assets;

                       (3) that other party files,  or consents to or acquiesces
in, a  petition  seeking  relief  or  reorganization  under  any  bankruptcy  or
insolvency laws; or

                       (4) a petition seeking relief or reorganization under any
bankruptcy  or  insolvency  laws is filed  against  that other  party and is not
dismissed within 90 days after it was filed.

                  (iii) By a party,  immediately upon notice to the other party,
if the other party's  material  breach of this  Agreement  continues  uncured or
uncorrected for 30 days after notice; provided,  however, if the breaching party
(i)  reasonably  requires  longer  than 30 days to cure or correct  such  breach
within such 30-day  period,  and (ii)  notifies the  non-breaching  party of the
circumstances  requiring  such longer  period to cure or correct such breach and
the breaching party's plans to cure or correct such breach, then the cure period
shall be extended for such  reasonable time as may be so required to effect such
cure or  correction,  subject to a maximum of 180 days,  so long as during  that
time the breaching party  diligently acts in accordance with such plan to effect
that cure or correction.

            c. Effect of Termination. Upon the termination of this Agreement:

                  (i) The rights and licenses  granted  hereby to Licensee shall
immediately  terminate,  notwithstanding  the  designation  of such  licenses as
perpetual hereunder; and

                  (ii) The rights and licenses  granted hereby to Licensor under
Section 3(a) shall  immediately  terminate,  notwithstanding  the designation of
such licenses as perpetual hereunder;

                  (iii) each  party  shall  immediately  return to the other all
physical  embodiments of all technology and Proprietary  Information,  including
all  Proprietary  Documents and  documentation,  owned by the other party.  Each
party  shall  thereafter  cease  to  use  the  technology  and  any  Proprietary
Information, including all Proprietary Documents and documentation, of the other
party; and

                  (iv) notwithstanding the termination of license rights granted
to a party,  said license  rights shall  survive  such  termination  solely with
respect to those products (including improvements thereto) which have been sold,
leased or distributed to third parties during the Term of this Agreement.

                                       24
                                     -238-
<PAGE>

11.  Limitation  of Liability.  In no event shall  Licensor's  total  cumulative
liability to Licensee and/or DTN (considered in the aggregate),  if any, for all
claims of any kind resulting from Licensor's breach of its  representations  and
warranties  hereunder or indemnification in respect thereof or otherwise arising
from or  relating to a breach of such  representations  and  warranties,  exceed
$3,000,000 in the aggregate.  IN THE EVENT OF ANY CONFLICT  BETWEEN THIS SECTION
11 AND ANY OTHER  PROVISION OF THIS  AGREEMENT,  THIS SECTION 11 SHALL  CONTROL.
THIS SECTION 11 SHALL APPLY NOTWITHSTANDING ANY FAILURE OF REMEDY HEREUNDER.

12.  Miscellaneous.

            a. Entire  Agreement;  Modifications.  This  Agreement  contains the
entire  agreement  between the parties  hereto with respect to the  transactions
contemplated  hereby,  and contains all of the terms and conditions  thereof and
supersedes  all prior  agreements  and  understandings  relating  to the subject
matter  hereof.  No changes or  modifications  of or additions to this Agreement
shall be valid  unless  the same  shall be in  writing  and signed by each party
hereto.

            b.  Severability.  The provisions of this Agreement  shall be deemed
severable  and  the  invalidity  or  unenforceability  of any one or more of the
provisions hereof shall not affect the validity and  enforceability of the other
provisions hereof.

            c. Successors and Assigns.  This Agreement shall be binding upon and
inure to the benefit of the parties, their successors and assigns.

            d. Waivers.  No waiver of any of the  provisions  of this  Agreement
shall be deemed to be or shall  constitute  a waiver of any other  provision  of
this  Agreement,  whether  or not  similar,  nor shall any waiver  constitute  a
continuing waiver. No waiver of any provision of this Agreement shall be binding
on the parties  hereto  unless it is executed in writing by the party making the
waiver.

            e. Notices. All notices,  requests, demands and other communications
under this Agreement shall be in writing and by overnight  courier with next-day
delivery, and shall be effective as of the delivery date shown by such overnight
courier's  documentation if sent postage prepaid,  and properly addressed to the
following addresses:

         If to Licensor:

                  Photon Research Associates, Inc.
                  5720 Oberlin Drive
                  San Diego, CA  92121
                  Attention: Sonya Porth, Corporate Secretary

                                       25
                                     -239-
<PAGE>

         If to Licensee:

                  EarthScan Network Inc.
                  6565 Americas Parkway
                  Albuquerque, New Mexico  87110
                  Attention: John Rasure, President

         If to DTN:

                  Data Transmission Network Corp.
                  9110 W Dodge Road., Suite 200
                  Omaha, Nebraska  68114-3316
                  Attention:  Greg Sloma, President

Either  party may  change the  address to which  notices to such party are to be
addressed by giving the other party hereto  written notice of such change in the
manner herein set forth.

            f.  Governing  Law. This Agreement is made and shall be governed by,
and construed and enforced in accordance  with (i) the laws of the United States
of America and (ii) the internal laws of the State of California, without regard
to the  conflict of laws  principles  thereof,  as the same apply to  agreements
executed  solely by residents of  California  and wholly to be performed  within
California.

            g. Dispute  Resolution.  Any dispute,  claim or controversy  arising
under  this  Agreement  or  in  any  way  related  to  this  Agreement,  or  its
interpretation,  enforceability  or  inapplicability  that cannot be resolved by
mutual agreement of the parties shall be submitted to binding  arbitration.  The
arbitration  shall be conducted by a single  arbitrator  mutually agreed upon by
the parties or, if no arbitrator is mutually selected within thirty (30) days of
a demand  therefor,  then by a retired judge from the Judicial  Arbitration  and
Mediation  Service/Endispute  ("JAMS") office located in San Diego,  California.
The arbitration  shall be conducted in San Diego,  California in accordance with
the Commercial  Arbitration Rules of the American Arbitration  Association.  The
arbitration  award shall be final and binding,  and judgment on the award may be
entered in any court having jurisdiction  thereof. The parties hereby consent to
the  consolidation of any arbitration  hereunder with any arbitration  commenced
under  the  Series  A  Preferred  Stock  Purchase  Agreement,  the  Stockholders
Agreement, the Common Stock Purchase Agreement and/or the Warrants.

            h. Independent Contractors.  Each party is engaged in an independent
business  and  shall  perform  its  obligations   under  this  Agreement  as  an
independent contractor and not as an agent or representative of any other party.
Neither party shall have any right or authority to create any obligation or make
any representation or warranty in the name or on behalf of the other party. This
Agreement shall not be interpreted or construed to create an association,  joint
venture  or  partnership  between  the  parties  or to  impose  any  partnership
obligation or liability upon any party.

            i.  Attorneys'  Fees.  In any  arbitration  or  other  legal  action
hereunder,  the  prevailing  party shall be  entitled,  in addition to any other

                                       26
                                      -240-
<PAGE>

relief granted, to all actual  out-of-pocket costs and expenses incurred by such
prevailing  party  in  connection  with  such  arbitration  or  action  and  the
enforcement and collection of any judgment rendered therein, including,  without
limitation,  all reasonable  attorneys' fees, consultant fees and expert witness
fees,  and a right to such costs and  expenses  shall be deemed to have  accrued
upon the  commencement  of such action and shall be  enforceable  whether or not
such action is prosecuted to judgment.

            j.  Survival.  The parties  hereto agree that,  upon  termination or
expiration of this Agreement for any reason,  Sections 1, 2(d), 4, 8, 10(c),  11
and 12 shall survive.

            k. No Third-Party Benefits. None of the provisions of this Agreement
shall be for the benefit of, or  enforceable  by, any  third-party  beneficiary;
provided,  however, that DTN shall be an express third-party  beneficiary of the
representations  and warranties  set forth in Section 7 and the  indemnification
provisions in Section 8(b) but in connection  therewith  shall be subject to the
provisions of Sections 4, 11 and 12 hereof.

            l.   Counterparts.   This  Agreement  may  be  executed  in  several
counterparts  all of which together shall constitute one and the same instrument
with the same force and effect as though each of the parties  had  executed  the
same document.

            m. Headings. The Section and Subsection headings used herein are for
convenience  of reference  only, are not a part of this Agreement and are not to
affect the construction of, or be taken into consideration in interpreting,  any
provision of this Agreement.

            n.  Bankruptcy.  THE  PARTIES  INTEND  FOR  THIS  AGREEMENT  AND THE
LICENSES  GRANTED  HEREUNDER  PRIOR TO THE DATE OF  TERMINATION  PURSUANT TO THE
TERMS  HEREOF TO COME WITHIN  SECTION  365(n) OF THE U.S.  BANKRUPTCY  CODE AND,
NOTWITHSTANDING  THE  BANKRUPTCY  OR  INSOLVENCY  OF  LICENSOR OR  LICENSEE,  AS
APPLICABLE,  THIS AGREEMENT AND THE LICENSES GRANTED HEREIN SHALL REMAIN IN FULL
FORCE AND EFFECT SO LONG AS LICENSEE OR LICENSOR, AS APPLICABLE,  IS IN MATERIAL
COMPLIANCE WITH THE TERMS AND CONDITIONS HEREOF.

            o. Compliance with Export  Regulations.  Licensee shall at all times
comply with all export control statutes and regulations of the United States and
foreign  governments  in  effect  from  time  to  time,   including  the  Export
Administration  Regulations of the U.S.  Department of Commerce.  Licensee shall
not:  (i)  ship,   transfer  or  export  the  Licensed  Products  or  underlying
information or Technology or any Improvements  thereto into any country to which
the U.S.  has  embargoed  goods;  or (ii) let it be used by  anyone  on the U.S.
Treasury  Department's  list  of  Specially  Designated  Nationals  or the  U.S.
Commerce  Department's Table of Denial Orders. By using the Licensed Products or
any Improvements thereto, Licensee acknowledges the foregoing and represents and
warrants  that it is not under the control of a national or resident of any such
country or on any such list.

                            [SIGNATURE PAGE FOLLOWS]


                                       27
                                     -241-
<PAGE>



         IN WITNESS  HEREOF,  the parties hereto have executed this Agreement as
of the Effective Date.

                                         Photon Research Associates, Inc.


                                         By:/s/ James A. Myer
                                            ----------------------------
                                            James A. Myer
                                         Title: COB


                                         By:/s/ Sonya Kay Porth
                                            ----------------------------
                                            Sonya Kay Porth
                                         Title: Corporate Secretary/Treasurer


                                         EarthScan Network Inc.


                                         By:/s/ John Rasure
                                            ------------------------
                                            John Rasure
                                         Title: President


                                         By:/s/ Sonya Kay Porth
                                            -----------------------------
                                            Sonya Kay Porth
                                         Title: Corporate Secretary/Treasurer



                                       28
                                     -242-
<PAGE>

                                    EXHIBIT A

                        Description of Licensed Products

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
exhibit to the Securities and Exchange Commission upon request."

                                       29
                                     -243-
<PAGE>



                                    EXHIBIT B

                       Description of Third Party Software

Microsoft Windows NT Server 4.0 (Includes Internet Information Server 4.0)
Microsoft Windows SQL Server 7.0 with Internet Extension
Microsoft Windows Visual Studio 6.0
ESRI MapObjects 2.0 and Internet Map Server 2.0
Research Systems, Inc.'s Interactive Data Language (IDL) 5.2


                                       30
                                     -244-
<PAGE>


                                   Exhibit C

                Amended and Restated Certificate of Incorporation

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       31
                                     -245-
<PAGE>


                                   Exhibit D

                       Form of Opinion of Company Counsel

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       32
                                     -246-
<PAGE>


                                   Exhibit E

                             Stockholders Agreement

         THIS  STOCKHOLDERS  AGREEMENT (the  "Agreement")  is entered into as of
December 16, 1999 (the "Effective Date"), by and among EarthScan Network Inc., a
Delaware  corporation (the "Company"),  the persons set forth on the Schedule of
Preferred   Stockholders   attached   hereto  as   Exhibit  A  (the   "Preferred
Stockholders"),  the  persons set forth on the  Schedule of Common  Stockholders
attached hereto as Exhibit B (the "Founders"),  and Flemming, Lessard & Shields,
LLC ("Warrant Holder"). The Preferred Stockholders, the Founders and the Warrant
Holder are referred to herein as the "Investors."

                                    RECITALS

         WHEREAS,   concurrently   herewith   the  Company  and  the   Preferred
Stockholders are entering into a Series A Preferred Stock Purchase  Agreement of
even date herewith (the  "Preferred  Agreement"),  pursuant to which the Company
shall  sell,  and  the  Preferred  Stockholders  shall  acquire,  shares  of the
Company's Series A Preferred Stock.

         WHEREAS,  concurrently  herewith  the  Company  and  the  Founders  are
entering  into a Common  Stock  Purchase  Agreement of even date  herewith  (the
"Common Agreement"),  pursuant to which the Company shall sell, and the Founders
shall acquire,  shares of the Company's Common Stock. The shares of Common Stock
sold  pursuant  to the Common  Agreement  are  collectively  referred  to as the
"Founder Shares."

         WHEREAS,  concurrently  herewith the Company is granting to the Warrant
Holder  certain  five-year  warrants to purchase  1,500 shares of the  Company's
Common Stock ("the Warrants").

         WHEREAS, the Company, the Preferred Stockholders,  the Founders and the
Warrant  Holder  desire  certain  rights and are  willing to  undertake  certain
obligations with respect to the outstanding securities of the Company which they
own or may acquire, as set forth in this Agreement.

         NOW,  THEREFORE,  in consideration of the mutual promises and covenants
set forth herein, the parties hereto agree as follows:

                                   SECTION 1.

                        Restrictions on Transferability;

                               Registration Rights

         1.1 Certain Definitions. As used in this Agreement, the following terms
shall have the following respective meanings:

         "Affiliates"  shall  have  the  meaning  set  forth  in Rule 405 of the
Securities Act.

                                       33
                                     -247-
<PAGE>

         "Commission"  shall mean the Securities and Exchange  Commission or any
other federal agency at the time administering the Securities Act.

         "Common Stock" shall mean the Company's Common Stock, par value $0.0001
per share.

         "Common Stock Equivalents" shall mean all options ("Options") and stock
purchase rights ("Stock  Purchase  Rights")  received by participants  under the
Company's 1999 Stock Incentive Plan.

         "Conversion Shares" shall mean the Common Stock issued or issuable upon
conversion of the Series A Preferred Stock or upon exercise of the Warrants.

         "Exchange  Act"  shall mean the  Securities  Exchange  Act of 1934,  as
amended, or any similar successor federal statute, and the rules and regulations
thereunder, all as the same shall be in effect from time to time.

         "Holder" shall mean (i) any Investor holding Registrable Securities and
(ii) any person  holding  Registrable  Securities  to whom the rights under this
Agreement  have been  transferred  in accordance  with Section 1.14 hereof,  and
(iii) any holder of Common Stock Equivalents.

         "Initiating Holders" shall mean any holder of Registrable Securities or
transferees of holders of Registrable  Securities  under Section 1.14 hereof who
in the  aggregate  are  Holders  of not less  than  fifty  percent  (50%) of the
Registrable  Securities  of  Common  Stock  (including,   without  limiting  the
definition  of  Conversion  Shares,  shares which will be issued upon the future
conversion  of the  Series A  Preferred  Stock or upon  future  exercise  of the
Warrants).

         "Permitted  Transferee" means an Affiliate of any Investor or a Related
Party of any Investor.

         "Qualified  Public  Offering" shall mean a firmly  underwritten  public
offering of Common  Stock  registered  under the  Securities  Act,  other than a
registration  relating  solely  to  a  transaction  under  Rule  145  under  the
Securities Act (or any successor  thereto) or to an employee benefit plan of the
Company.

         The  terms  "register",  "registered"  and  "registration"  refer  to a
registration  effected  by  preparing  and filing a  registration  statement  in
compliance  with the  Securities  Act,  and the  declaration  or ordering of the
effectiveness of such registration statement.

         "Registrable  Common Stock" shall mean (i) the Common  Stock;  (ii) any
Common Stock or other  securities  issued or issuable with respect to the Common
Stock upon any stock split, stock dividend, recapitalization,  or similar event;
provided,   however,   (x)  the  Registrable  Common  Stock  shall  not  include
Registrable Securities, and (y) shares of Common Stock or other securities shall
only be treated as Registrable Common Stock if and so long as they have not been
(A)  sold  to  or  through  a  broker  or  dealer  or  underwriter  in a  public

                                       34
                                     -248-
<PAGE>

distribution  or a public  securities  transaction,  (B)  sold in a  transaction
exempt  from  the  registration  and  prospectus  delivery  requirements  of the
Securities Act under Section 4(1) thereof so that all transfer  restrictions and
restrictive  legends with respect  thereto are removed upon the  consummation of
such sale, (C) transferred in a transaction  pursuant to which the  registration
rights are not also  assigned in  accordance  with Section  1.14 hereof,  or (D)
become eligible for sale under Rule 144 of the Securities Act (or any similar or
successor rule).

         "Registrable Securities" shall mean (i) the Conversion Shares; (ii) the
Founder Shares; (iii) Common Stock issued pursuant to the exercise of Options or
Stock Purchase  Rights under the Company's 1999 Stock  Incentive  Plan; and (iv)
any Common  Stock of the  Company  issued or  issuable  in respect to the Common
Stock  referred to in clauses  (i),  (ii) and (iii) above by way of stock split,
stock dividend,  recapitalization,  or similar event;  provided,  however,  that
shares of Common Stock or other  securities shall only be treated as Registrable
Securities  if and so long as they have not been (A) sold to or through a broker
or  dealer  or  underwriter  in a public  distribution  or a  public  securities
transaction,  (B)  sold  in a  transaction  exempt  from  the  registration  and
prospectus  delivery  requirements  of the  Securities  Act under  Section  4(1)
thereof so that all transfer  restrictions and restrictive  legends with respect
thereto are removed upon the  consummation  of such sale,  (C)  transferred in a
transaction  pursuant to which the registration  rights are not also assigned in
accordance with Section 1.14 hereof,  or (D) become eligible for sale under Rule
144 of the Securities Act (or any similar or successor rule).

         "Registration Expenses" shall mean all expenses incurred by the Company
in  complying  with  Sections  1.5,  1.6  and  1.7  hereof,  including,  without
limitation, all registration,  qualification,  listing and filing fees, printing
expenses, escrow fees, fees and disbursements of counsel for the Company and one
special  counsel for the selling  Holders,  blue sky fees and expenses,  and the
expense of any special audits  incident to or required by any such  registration
(but excluding the compensation of regular  employees of the Company which shall
be paid in any event by the Company).

         "Related Party" means an individual's spouse, issue, sibling, parent or
other  member  of his or her  immediate  family or a trust  established  for the
benefit of such person(s) for estate planning purposes.

         "Restricted  Securities"  shall  mean  the  securities  of the  Company
required to bear the legend set forth in Section 1.3 hereof.

         "Securities Act" shall mean the Securities Act of 1933, as amended, and
the rules and regulations  promulgated thereunder or any similar federal statute
and the rules and  regulations  of the  Commission  thereunder,  all as the same
shall be in effect at the time.

         "Selling  Expenses"  shall  mean all  underwriting  discounts,  selling
commissions and stock transfer taxes applicable to the securities  registered by
the Holders, and all fees and disbursements of counsel for the Holders except as
provided under Registration Expenses.

                                       35
                                     -249-
<PAGE>

         "Series A Preferred Stock" shall mean Series A Preferred Stock, $0.0001
par value per share, issued to certain Investors pursuant to that certain Series
A Preferred Stock Purchase Agreement of even date herewith.

         "Shares" shall mean the Series A Preferred  Stock sold to the Preferred
Stockholders  pursuant  to the  Preferred  Agreement,  the Common  Stock sold to
Founders pursuant to the Founders Agreements and the Warrants.

         "Transfer" shall have the meaning set forth in Section 3.1 herein.

     1.2 Restrictions. Subject to the provisions of Sections 2.1 and 2.2 of this
Agreement,  neither the Shares nor the Conversion Shares may be sold,  assigned,
transferred  or pledged to any third party other than to a Permitted  Transferee
of such  Investor.  Each Investor will cause any proposed  purchaser,  assignee,
transferee  or  pledgee  of the  Shares or the  Conversion  Shares  held by such
Investor to assume the transferor's obligations under and agree to take and hold
such  securities  subject  to the  rights  and upon  the  conditions  and  other
provisions  specified  in this  Agreement,  and,  as  applicable,  the  Series A
Preferred Stock Purchase Agreement and the Common Stock Purchase Agreement.  The
provisions set forth in this Section 1.2 shall  terminate  immediately  prior to
the consummation of a Qualified Public Offering.

     1.3 Restrictive Legend. Each certificate representing (i) the Shares (other
than the Warrants),  (ii) the Conversion  Shares, and (iii) any other securities
issued in respect of the securities  referenced in clauses (i) and (ii) upon any
stock split, stock dividend, recapitalization,  merger, consolidation or similar
event, shall (unless otherwise permitted by the provisions of Section 1.4 below)
be  stamped  or  otherwise  imprinted  with a legend in the  following  form (in
addition to any legend required under applicable state securities laws):

     "THE  SHARES  REPRESENTED  BY  THIS  CERTIFICATE  HAVE  BEEN  ACQUIRED  FOR
     INVESTMENT AND HAVE NOT BEEN  REGISTERED  UNDER THE SECURITIES ACT OF 1933,
     AS  AMENDED.  SUCH  SHARES MAY NOT BE SOLD,  TRANSFERRED  OR PLEDGED IN THE
     ABSENCE OF SUCH  REGISTRATION  OR, IF THE COMPANY SO  REQUESTS,  UNLESS THE
     COMPANY  RECEIVES  AN  OPINION OF  COUNSEL  (WHICH  MAY BE COUNSEL  FOR THE
     COMPANY) STATING THAT SUCH SALE OR TRANSFER IS EXEMPT FROM THE REGISTRATION
     AND PROSPECTUS DELIVERY REQUIREMENTS OF SAID ACT."

     "THE SHARES  REPRESENTED BY THIS  CERTIFICATE  MAY BE  TRANSFERRED  ONLY IN
     ACCORDANCE  WITH THE TERMS OF AN  AGREEMENT  BETWEEN  THE  COMPANY  AND THE
     SHAREHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY."

     Each  Warrant  shall bear the legends set forth  above,  but  modified,  as
appropriate,  to  replace  the word  "SHARES"  with the  word  "WARRANTS".  Each
Investor  consents to the Company's  making a notation on its records and giving
instructions  to any transfer  agent of the  Restricted  Securities  in order to

                                       36
                                     -250-
<PAGE>

implement the restrictions on transfer established in this Section 1.

     1.4  Notice  of  Proposed   Transfers.   The  holder  of  each  certificate
representing  Restricted Securities,  by acceptance thereof, agrees to comply in
all respects with the  provisions of this Section 1. Prior to any proposed sale,
assignment,  transfer or pledge of any Restricted Securities, unless there is in
effect a registration  statement  under the Securities Act covering the proposed
transfer,  the holder  thereof shall give written  notice to the Company of such
holder's  intention to effect such transfer,  sale,  assignment or pledge.  Each
such  notice  shall  describe  the  manner  and  circumstances  of the  proposed
transfer,  sale, assignment or pledge in sufficient detail to permit the Company
to  ascertain  transferor's  compliance  with  this  Section  1,  and  shall  be
accompanied  at such holder's  expense by either (i) a written  opinion of legal
counsel who shall, and whose legal opinion shall, be reasonably  satisfactory to
the Company,  addressed to the Company, to the effect that the proposed transfer
of the Restricted  Securities  may be effected  without  registration  under the
Securities  Act, or (ii) a "no action"  letter from the Commission to the effect
that the transfer of such securities  without  registration will not result in a
recommendation  by the staff of the Commission that action be taken with respect
thereto, or (iii) any other evidence  reasonably  satisfactory to counsel to the
Company, whereupon the holder of such Restricted Securities shall be entitled to
transfer such  Restricted  Securities in accordance with the terms of the notice
delivered  by the holder to the  Company and the terms of this  Agreement.  Each
certificate  evidencing the Restricted Securities  transferred as above provided
shall  bear,  except if such  transfer is made  pursuant to Rule 144,  the first
paragraph of the restrictive legend set forth in Section 1.3 above,  except that
such certificate  shall not bear such first paragraph of the restrictive  legend
if, in the opinion of counsel for such  holder and the  Company,  such legend is
not  required  in order to  establish  compliance  with  any  provisions  of the
Securities Act. Until the  consummation  of a Qualified  Public  Offering,  each
certificate evidencing Restricted Securities transferred as above provided shall
bear the second  paragraph  of the  restrictive  legend set forth in Section 1.3
above.

     1.5 Requested Registration.

         (a)  Request  for  Registration.  If the  Company  shall  receive  from
Initiating  Holders a written request that the Company effect any  registration,
qualification or compliance, the Company will:

            (i)  promptly  give  written  notice of the  proposed  registration,
qualification or compliance to all other Holders; and

            (ii) as soon as  practicable,  and in any event within 120 days, use
its best  efforts  to effect  such  registration,  qualification  or  compliance
(including,  without  limitation,  the  execution  of  an  undertaking  to  file
post-effective  amendments,  appropriate qualification under applicable blue sky
or other  state  securities  laws and  appropriate  compliance  with  applicable
regulations   issued  under  the  Securities  Act  and  any  other  governmental
requirements  or  regulations)  as may be so  requested  and as would  permit or
facilitate the sale and  distribution of all or such portion of such Registrable
Securities as are  specified in such request,  together with all or such portion

                                       37
                                     -251-
<PAGE>

of the  Registrable  Securities of any Holder or Holders joining in such request
as are specified in a written request received by the Company within thirty (30)
days after receipt of such written notice from the Company;  provided,  however,
that the Company  shall not be  obligated  to take any action to effect any such
registration, qualification or compliance pursuant to this Section 1.5:

                  (1) In any particular  jurisdiction in which the Company would
be required to execute a general consent to service of process in effecting such
registration,  qualification or compliance unless the Company is already subject
to service in such  jurisdiction and except as may be required by the Securities
Act;

                  (2) Prior to six  months  following  the  effective  date of a
Qualified Public Offering;

                  (3) During the period  starting  with the date sixty (60) days
prior to the Company's  estimated date of filing of, and ending the date six (6)
months immediately  following the effective date of, any registration  statement
pertaining to securities of the Company (other than a registration of securities
in a Rule 145 transaction or with respect to an employee benefit plan), provided
that the Company is actively  employing in good faith all reasonable  efforts to
cause such  registration  statement to become  effective  and that the Company's
estimate  of the date of  filing  such  registration  statement  is made in good
faith;

                  (4) After the Company has effected two (2) such  registrations
pursuant to this subparagraph  1.5(a),  and each of such  registrations has been
declared or ordered  effective and the  securities  offered  pursuant to each of
such registrations have been sold; or

                  (5)  If  the  Company   shall   furnish  to  such   Holders  a
certificate,  signed by the President or Chief Executive Officer of the Company,
stating  that in the good  faith  judgment  of the Board of  Directors  it would
adversely  affect or would  require the premature  disclosure of any  financing,
acquisition,  disposition,  or other corporate transaction, or would require the
Company to make public  disclosure  of  information  which would have a material
adverse  effect on the Company,  then the  Company's  obligation to use its best
efforts to register,  qualify or comply under this Section 1.5 shall be deferred
for a period not to exceed  one-hundred  and twenty  (120) days from the date of
receipt of written request from the Initiating Holders; provided,  however, that
the Company may not utilize  this right more than twice in any twelve (12) month
period.

         Subject to the  foregoing  clauses (1) through (5),  the Company  shall
file a registration  statement covering the Registrable  Securities so requested
to be registered as soon as practicable after receipt of the request or requests
of the Initiating Holders.

         (b) Underwriting.  In the event that a registration pursuant to Section
1.5 is for a registered public offering  involving an underwriting,  the Company
shall so advise  the  Holders as part of the notice  given  pursuant  to Section
1.5(a)(i). The right of any Holder to registration pursuant to Section 1.5 shall
be conditioned upon such Holder's participation in the underwriting arrangements
required by this  Section 1.5 and the  inclusion  of such  Holder's  Registrable
Securities in the underwriting,  to the extent requested, to the extent provided
herein.

                                       38
                                     -252-
<PAGE>

         The Company shall  (together  with all Holders  proposing to distribute
their  securities  through  such  underwriting)   enter  into  and  perform  its
obligations under an underwriting  agreement in customary form with the managing
underwriter  selected  for such  underwriting  by a majority  in interest of the
Initiating Holders (which managing underwriter shall be reasonably acceptable to
the Company).  Notwithstanding  any other  provision of this Section 1.5, if the
managing  underwriter  advises the Initiating  Holders in writing that marketing
factors  require a limitation of the number of shares to be  underwritten,  then
the Company shall so advise all Holders of Registrable Securities and the number
of shares of Registrable Securities that may be included in the registration and
underwriting  shall be allocated  among all Holders  thereof in  proportion,  as
nearly as practicable,  to the respective amounts of Registrable Securities held
by such Holders at the time of filing the registration statement. No Registrable
Securities  excluded  from  the  underwriting  by  reason  of the  underwriter's
marketing  limitation shall be included in such registration.  To facilitate the
allocation of shares in accordance with the above provisions, the Company or the
underwriters  may round the  number of  shares  allocated  to any  Holder to the
nearest 100 shares.

         If any Holder of Registrable Securities disapproves of the terms of the
underwriting,  such person may elect to withdraw  therefrom by written notice to
the  Company,   the  managing   underwriter  and  the  Initiating  Holders.  The
Registrable  Securities  and/or  other  securities  so  withdrawn  shall also be
withdrawn  from  registration,  and such  Registrable  Securities  shall  not be
transferred  in a public  distribution  during the period  specified  in Section
1.15.

     1.6 Company Registration

         (a) Notice of Registration.  If at any time the Company shall determine
to register any of its securities,  either for its own account or the account of
a security  holder or holders other than (i) a registration  relating  solely to
employee  benefit  plans,  (ii) a  registration  relating  solely  to a Rule 145
transaction,  or (iii) a  registration  on any  registration  form that does not
permit secondary sales, the Company will:

            (i) promptly give to each Holder written notice thereof; and

            (ii)  include in such  registration  (and any related  qualification
under  blue sky  laws or other  compliance),  and in any  underwriting  involved
therein,  all the  Registrable  Securities  specified  in a written  request  or
requests made within fifteen (15) days after receipt of such written notice from
the Company by any Holder,  but only to the extent that such  inclusion will not
diminish the number of  securities  included by the Company or by holders of the
Company's securities who have demanded such registration.

         (b) Underwriting. If the registration of which the Company gives notice
is for a registered public offering involving an underwriting, the Company shall
so advise the Holders as a part of the written  notice given pursuant to Section
1.6(a)(i).  In such event,  the right of any Holder to registration  pursuant to
Section  1.6 shall be  conditioned  upon  such  Holder's  participation  in such

                                       39
                                     -253-
<PAGE>

underwriting and the inclusion of Registrable  Securities in the underwriting to
the extent provided herein. All Holders proposing to distribute their securities
through such underwriting shall (together with the Company and the other holders
distributing their securities through such underwriting)  enter into and perform
its  obligations  under an  underwriting  agreement in  customary  form with the
managing  underwriter  selected for such  underwriting by the Company (or by the
holders  who  have  demanded  such  registration).   Notwithstanding  any  other
provision  of this  Section 1.6, if the  managing  underwriter  determines  that
marketing   factors  require  a  limitation  of  the  number  of  shares  to  be
underwritten,  the managing  underwriter may exclude all Registrable  Securities
from,  or limit the  number of  Registrable  Securities  to be  included  in the
registration  and  underwriting on a pro rata basis based on the total number of
securities (including,  without limitation,  Registrable Securities) entitled to
registration  pursuant  to  registration  rights  granted  to the  participating
Holders by the Company.  To  facilitate  the  allocation of shares in accordance
with the above provisions,  the Company or the underwriters may round the number
of shares allocated to any Holder or other holder to the nearest 100 shares.  If
any Holder or other holder disapproves of the terms of any such underwriting, he
or she may elect to withdraw  therefrom by written notice to the Company and the
managing   underwriter.   Any   securities   excluded  or  withdrawn  from  such
underwriting  shall be  withdrawn  from  such  registration,  and  shall  not be
transferred  in a public  distribution  during the period  specified  in Section
1.15.

         (c) Right to Terminate  Registration.  The Company shall have the right
to terminate or withdraw any registration initiated by it under this Section 1.6
prior to the effectiveness of such  registration,  whether or not any Holder has
elected to include securities in such registration.

     1.7 Registration on Form S-3

         (a) The Company  shall  register  (whether or not required by law to do
so) its Common Stock under the Exchange Act in accordance with the provisions of
the Exchange Act following the effective date of the first  registration  of any
securities  of the Company on Form S-1 or any  comparable  or successor  form or
forms, and the Company shall use its best efforts to qualify for registration on
Form S-3 or any comparable or successor form at such time.

         (b) If any Holder or Holders of not less than twenty  percent  (20%) of
the  Registrable  Securities then  outstanding  requests that the Company file a
registration  statement  on Form S-3 (or any  successor  form to Form S-3) for a
public  offering  of  shares  of  the  Registrable  Securities,  the  reasonably
anticipated  aggregate  price  to the  public  of  which,  net  of  underwriting
discounts  and  commissions,  would  exceed  $1,000,000,  and the  Company  is a
registrant  entitled to use Form S-3 to register the Registrable  Securities for
such an  offering,  the  Company  shall  use its  best  efforts  to  cause  such
Registrable  Securities  to be  registered  for the  offering on such form.  The
Company will (i) promptly give written  notice of the proposed  registration  to
all other  Holders,  and (ii) as soon as  practicable,  use its best  efforts to

                                       40
                                     -254-
<PAGE>

effect such registration  (including,  without  limitation,  the execution of an
undertaking to file post-effective  amendments,  appropriate qualification under
applicable blue sky or other state  securities  laws and appropriate  compliance
with  applicable  regulations  issued  under  the  Securities  Act and any other
governmental  requirements  or  regulations) as may be so requested and as would
permit or facilitate  the sale and  distribution  of all or such portion of such
Registrable  Securities as are  specified in such request,  together with all or
such portion of the  Registrable  Securities of any Holder or Holders joining in
such  request as are  specified  in a written  request  received  by the Company
within  thirty (30) days after  receipt of the  written  notice from the Company
referred to in the preceding  clause (i). The substantive  provisions of Section
1.5(b) shall be applicable  to each  registration  initiated  under this Section
1.7.

         (c) Notwithstanding  the foregoing,  the Company shall not be obligated
to  take  any  action  pursuant  to  this  Section  1.7:  (i) in any  particular
jurisdiction in which the Company would be required to execute a general consent
to  service  of  process  in  effecting  such  registration,   qualification  or
compliance unless the Company is already subject to service in such jurisdiction
and except as may be  required  by the  Securities  Act;  (ii) during the period
starting with the date sixty (60) days prior to the filing of, and ending on the
date six (6) months following the effective date of, any registration  statement
(other  than with  respect to a  registration  statement  relating to a Rule 145
transaction,  an offering solely to employees or any other registration which is
not appropriate for the registration of Registrable  Securities),  provided that
the Company is actively  employing in good faith all reasonable efforts to cause
such registration  statement to become effective;  or (iii) if the Company shall
furnish to such Holder a certificate  signed by the President or Chief Executive
Officer of the Company  stating that, in the good faith judgment of the Board of
Directors,  it would adversely affect or would require the premature  disclosure
of any financing,  acquisition,  disposition or other corporate transaction,  or
would require the Company to make public  disclosure of information  which would
have a material adverse effect on the Company,  then the Company's obligation to
use its best efforts to file a  registration  statement  shall be deferred for a
period  not to exceed one  hundred  twenty  (120)  days from the  receipt of the
request to file such registration by such Holder or Holders; provided,  however,
that the Company  may not utilize  this right more than twice in any twelve (12)
month period.

     1.8 Limitations on Subsequent  Registration Rights. From and after the date
hereof,  the Company shall not enter into any  agreement  granting any holder or
prospective  holder of any  securities of the Company  registration  rights with
respect to such securities  unless (i) such new registration  rights,  including
standoff obligations, are on a pari passu basis with those rights of the Holders
hereunder; or (ii) such new registration rights, including standoff obligations,
are subordinate to the registration rights granted Holders hereunder.

     1.9  Expenses  of  Registration.  All  Registration  Expenses  incurred  in
connection with any registration pursuant to Sections 1.5 and 1.6 shall be borne
by the  Company,  provided  that the  Company  shall not be  required to pay the
Registration  Expenses of any registration  proceeding begun pursuant to Section
1.5,  the request of which has been  subsequently  withdrawn  by the  Initiating
Holders.  In such case, (i) the Holders of  Registrable  Securities to have been
registered  shall bear all such  Registration  Expenses pro rata on the basis of
the  number of shares to have been  registered,  and (ii) the  Company  shall be
deemed not to have effected a registration  pursuant to  subparagraph  1.5(a) of
this Agreement.  Notwithstanding  the foregoing,  however, if at the time of the
withdrawal,  the  Holders  have  learned  of a  material  adverse  change in the
condition,  business or  prospects of the Company from that known to the Holders
at the time of their request,  of which the Company had knowledge at the time of
the  request,  then  the  Holders  shall  not be  required  to pay  any of  said
Registration  Expenses.  In such case,  the Company  shall be deemed not to have
effected a  registration  pursuant  to  subparagraph  1.5(a) of this  Agreement.

                                       41
                                     -255-
<PAGE>

Unless otherwise stated, all Selling Expenses relating to securities  registered
on behalf of the Holders and all  Registration  Expenses  incurred in connection
with any  registration  pursuant to Section 1.7 shall be borne by the Holders of
the registered securities included in such registration pro rata on the basis of
the number of shares so registered.

     1.10   Registration   Procedures.   In  the  case  of  each   registration,
qualification or compliance  effected by the Company pursuant to this Section 1,
the Company  will keep each Holder  advised in writing as to the  initiation  of
each registration, qualification and compliance and as to the completion thereof
and, at its expense, the Company will:

         (a) Prepare and file with the Commission a registration  statement with
respect to such  securities and use its best efforts to cause such  registration
statement to become and remain  effective for at least ninety (90) days or until
the  distribution  described in the  registration  statement has been completed;
provided,  however,  that  in  the  case  of  any  registration  of  Registrable
Securities  on Form S-3 which are  intended  to be  offered on a  continuous  or
delayed  basis,  such  period  shall  be  extended,  if  necessary,  to keep the
registration statement effective until all such Registrable Securities are sold,
provided  that if Rule 415,  or any  successor  rule under the  Securities  Act,
permits an offering on a continuous or delayed basis,  and provided further that
if applicable  rules under the Securities Act governing the obligation to file a
post-effective  amendment permit,  in lieu of filing a post-effective  amendment
which (y) includes any prospectus required by Section 10(a)(3) of the Securities
Act or (z)  reflects  facts or events  representing  a material  or  fundamental
change  in  the  information  set  forth  in  the  registration  statement,  the
incorporation by reference of information required to be included in (y) and (z)
above shall be contained  in periodic  reports  filed  pursuant to Section 13 or
15(d) of the Exchange Act in the registration statement;

         (b) Furnish to the Holders  participating  in such  registration and to
the underwriters of the securities  being  registered such reasonable  number of
copies of the registration statement,  preliminary prospectus,  final prospectus
and such other documents as such underwriters may reasonably request in order to
facilitate the public offering of such securities;

         (c)  Prepare  and  file  with  the  Commission   such   amendments  and
supplements to such registration statement and the prospectus used in connection
with  such  registration  statement  as may be  necessary  to  comply  with  the
provisions  of  the  Securities  Act  with  respect  to the  disposition  of all
securities covered by such registration statement;

         (d)  Notify  each  seller of  Registrable  Securities  covered  by such
registration  statement  at any  time  when a  prospectus  relating  thereto  is
required to be delivered  under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration  statement, as
then in effect,  includes  an untrue  statement  of a material  fact or omits to

                                       42
                                     -256-
<PAGE>

state a material  fact  required to be stated  therein or  necessary to make the
statements   therein  not   misleading   or  incomplete  in  the  light  of  the
circumstances then existing,  and at the request of any such seller, prepare and
furnish to such seller a reasonable  number of copies of a  supplement  to or an
amendment  of  such  prospectus  as may be  necessary  so  that,  as  thereafter
delivered to the purchaser of such shares,  such prospectus shall not include an
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary to make the statements  therein not misleading or
incomplete in the light of the circumstances then existing;

         (e) Use its best efforts to register and qualify the securities covered
by such  registration  statement under such other securities or Blue Sky laws of
such  jurisdictions  as shall be reasonably  requested by the Holders,  provided
that the Company shall not be required in connection therewith or as a condition
thereto  to qualify to do  business  or to file a general  consent to service of
process in any such states or jurisdictions;

         (f)  Cause  all  such  Registrable  Securities  to be  listed  on  each
securities  exchange on which similar  securities issued by the Company are then
listed;

         (g)  Provide  a  transfer  agent  and  registrar  for  all  Registrable
Securities and a CUSIP number for all such Registrable Securities,  in each case
not later than the effective date of such registration;

         (h) Otherwise use its best efforts to comply with the applicable  rules
and regulations promulgated by the Securities and Exchange Commission;

         (i) If and  to the  extent  obtained  from  the  Company's  independent
accountants,  provide to each Holder a copy of any  "comfort  letter"  regarding
such registration statement and prospectus; and

         (j) Make available for inspection by any Holder  participating  in such
registration,  any underwriter participating in any disposition pursuant to such
registration,  and any  attorney  or  accountant  retained by any such Holder or
underwriter,  all financial and other records, pertinent corporate documents and
properties  of the Company,  and cause the  Company's  officers and directors to
supply all  information  reasonably  requested by any such Holder,  underwriter,
attorney or accountant in connection with such registration statement; provided,
however,  that such Holder,  underwriter,  attorney or accountant shall agree to
hold in confidence and trust all information so provided.

     1.11 Indemnification

         (a) The Company will  indemnify  each Holder,  each of its officers and
directors  and  partners,  and each person  controlling  such Holder  within the
meaning of Section 15 of the Securities Act, with respect to which registration,
qualification  or compliance  has been effected  pursuant to this Section 1, and
each  underwriter,  if any, and each person who controls any underwriter  within
the meaning of Section 15 of the Securities Act,  against all expenses,  claims,
losses, damages or liabilities (or actions in respect thereof) arising out of or
based on any untrue  statement (or alleged untrue  statement) of a material fact

                                       43
                                     -257-
<PAGE>

contained in any registration statement,  prospectus, offering circular or other
document,  or  any  amendment  or  supplement  thereto,  incident  to  any  such
registration,  qualification or compliance, or based on any omission (or alleged
omission)  to state  therein a material  fact  required to be stated  therein or
necessary to make the statements therein, in light of the circumstances in which
they were made, not  misleading,  or any violation by the Company of any rule or
regulation  promulgated  under the  Securities  Act applicable to the Company in
connection  with any such  registration,  qualification  or compliance,  and the
Company will reimburse each such Holder, each of its officers and directors, and
each person  controlling such Holder,  each such underwriter and each person who
controls any such underwriter,  for any legal and any other expenses  reasonably
incurred in  connection  with  investigating,  preparing or  defending  any such
claim,  loss,  damage,  liability  or action,  as such  expenses  are  incurred,
provided that the Company will not be liable in any such case to the extent that
any such claim, loss, damage,  liability or expense arises out of or is based on
any untrue statement or omission or alleged untrue  statement or omission,  made
in reliance upon and in  conformity  with written  information  furnished to the
Company by an  instrument  duly executed by such Holder,  controlling  person or
underwriter and stated to be specifically for use therein.

         (b) Each Holder will, if Registrable Securities held by such Holder are
included  in the  securities  as to which such  registration,  qualification  or
compliance is being effected,  indemnify the Company,  each of its directors and
officers, each underwriter,  if any, of the Company's securities covered by such
a  registration  statement,  each  person  who  controls  the  Company  or  such
underwriter  within the meaning of Section 15 of the  Securities  Act,  and each
other  such  Holder,  each  of  its  officers  and  directors  and  each  person
controlling  such Holder within the meaning of Section 15 of the Securities Act,
against  all claims,  losses,  damages  and  liabilities  (or actions in respect
thereof)  arising out of or based on any untrue  statement  (or  alleged  untrue
statement)  of a material  fact  contained in any such  registration  statement,
prospectus,  offering  circular or other  document,  or any omission (or alleged
omission)  to state  therein a material  fact  required to be stated  therein or
necessary to make the statements therein not misleading,  and will reimburse the
Company,  such Holders,  such  directors,  officers,  persons,  underwriters  or
control  persons  for any legal or any other  expenses  reasonably  incurred  in
connection  with  investigating  or  defending  any such  claim,  loss,  damage,
liability or action, as such expenses are incurred,  in each case to the extent,
but only to the extent, that such untrue statement (or alleged untrue statement)
or  omission  (or  alleged  omission)  is made in such  registration  statement,
prospectus,  offering  circular  or  other  document  in  reliance  upon  and in
conformity  with written  information  furnished to the Company by an instrument
duly  executed by such  Holder and stated to be  specifically  for use  therein;
provided that in no event shall any indemnity  under this  subparagraph  1.11(b)
exceed the net  proceeds  received  by such  Holder in such  registration.  Each
Holder under this subparagraph 1.11(b) shall be severally, not jointly, liable.

         (c) Each party entitled to indemnification under this Section 1.11 (the
"Indemnified  Party")  shall  give  notice  to the  party  required  to  provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall

                                       44
                                     -258-
<PAGE>

permit the  Indemnifying  Party to assume  the  defense of any such claim or any
litigation  resulting  therefrom,  provided  that  counsel for the  Indemnifying
Party,  who shall  conduct  the  defense of such claim or  litigation,  shall be
approved by the  Indemnified  Party (whose  approval shall not  unreasonably  be
withheld),  and the  Indemnified  Party may  participate in such defense at such
party's expense; provided, however, that an Indemnified Party (together with all
other  Indemnified  Parties  which may be  represented  without  conflict by one
counsel) shall have the right to retain one separate counsel,  with the fees and
expenses  to be  paid  by the  Indemnifying  Party,  if  representation  of such
Indemnified  Party by the counsel  retained by the  Indemnifying  Party would be
inappropriate  due to actual  or  potential  differing  interests  between  such
Indemnified  Party and any  other  party  represented  by such  counsel  in such
proceeding.  The  failure of any  Indemnified  Party to give  notice as provided
herein shall not relieve the  Indemnifying  Party of its obligations  under this
Section 1 unless the failure to give such notice is materially prejudicial to an
Indemnifying  Party's ability to defend such action.  No Indemnifying  Party, in
the defense of any such claim or litigation,  shall,  except with the consent of
each  Indemnified  Party,  consent  to entry of any  judgment  or enter into any
settlement which does not include as an unconditional term thereof the giving by
the  claimant  or  plaintiff  to such  Indemnified  Party of a release  from all
liability in respect to such claim or litigation.

         (d) If the indemnification provided for in this Section 1.11 is held by
a court of competent jurisdiction to be unavailable to an Indemnified Party with
respect to any claim,  loss,  damage,  liability or action  referred to therein,
then the  Indemnifying  Party, in lieu of indemnifying  such  Indemnified  Party
hereunder,  shall  contribute to the amount paid or payable by such  Indemnified
Party as a result  of such  claim,  loss,  damage,  liability  or action in such
proportion as is appropriate  to reflect the relative fault of the  Indemnifying
Party on the one hand and the Indemnified  party on the other in connection with
the actions that resulted in such claims, loss, damage,  liability or action, as
well as any other relevant equitable  considerations.  The relative fault of the
Indemnifying Party and of the Indemnified Party shall be determined by reference
to,  among other  things,  whether the untrue or alleged  untrue  statement of a
material  fact or the omission to state a material  fact related to  information
supplied by the Indemnifying  Party or by the Indemnified Party and the parties'
relative intent, knowledge,  access to information and opportunity to correct or
prevent such  statement or omission.  The Company and the Holders  agree that it
would not be just and equitable if contribution pursuant to this Section 1.11(d)
were  based  solely  upon the  number of  entities  from whom  contribution  was
requested  or by any other method of  allocation  which does not take account of
the equitable considerations referred to above in this Section 1.11(d).

         (e) The amount paid or payable by an  Indemnified  Party as a result of
the losses,  claims,  damages and liabilities  referred to above in this Section
1.11 shall be deemed to include any legal or other expenses  reasonably incurred
by such Indemnified Party in connection with investigating or defending any such
action  or  claim,   subject  to  the   provisions   of  Section   1.11  hereof.
Notwithstanding the provisions of this Section 1.11, no Holder shall be required
to contribute any amount or make any other  payments under this Agreement  which
in the aggregate  exceed the net proceeds (after selling  expenses)  received by
such  Holder.  No person  guilty of  fraudulent  misrepresentation  (within  the
meaning of the Securities Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation.

                                       45
                                     -259-
<PAGE>

     1.12 Information by Holder. The Holder or Holders of Registrable Securities
included  in any  registration  shall  furnish to the Company  such  information
regarding such Holder or Holders,  the  Registrable  Securities held by them and
the  distribution  proposed by such Holder or Holders as the Company may request
in  writing  and as shall  be  required  in  connection  with any  registration,
qualification or compliance referred to in this Section 1.

     1.13 Rule 144  Reporting.  With a view to making  available the benefits of
certain rules and regulations of the Commission which may at any time permit the
sale of the Restricted Securities to the public without registration, after such
time as a public market exists for the Common Stock of the Company,  the Company
agrees to use its best efforts to:

         (a) Make and keep  public  information  available,  as those  terms are
understood and defined in Rule 144 under the Securities  Act, at all times after
the  effective  date  that  the  Company   becomes   subject  to  the  reporting
requirements of the Securities Act or the Exchange Act;

         (b) File with the  Commission  in a timely manner all reports and other
documents  required of the Company under the Securities Act and the Exchange Act
(at any time after it has become subject to such reporting requirements); and

         (c) So long as a Holder owns any Restricted  Securities,  to furnish to
the Holder  forthwith upon request a written  statement by the Company as to its
compliance  with the reporting  requirements of said Rule 144 (at any time after
ninety (90) days after the effective  date of the first  registration  statement
filed by the Company for an offering of its  securities to the general  public),
and of the  Securities Act and the Exchange Act (at any time after it has become
subject to such  reporting  requirements),  a copy of the most recent  annual or
quarterly  report of the Company,  and such other  reports and  documents of the
Company and other  information in the possession of or reasonably  obtainable by
the Company as a Holder may reasonably request in availing itself of any rule or
regulation  of the  Commission  allowing  a Holder  to sell any such  securities
without registration.

     1.14 Transfer of  Registration  Rights.  The rights to cause the Company to
register  securities granted to any party hereto under Sections 1.5, 1.6 and 1.7
may be assigned to a transferee or assignee reasonably acceptable to the Company
in connection with any transfer or assignment of Registrable  Securities by such
party  (together  with any  Affiliate);  provided  that (a)  such  transfer  may
otherwise be effected in accordance with applicable  securities laws, (b) notice
of such assignment is given to the Company and the Company has given its consent
in writing to such transfer as provided above in this Section 1.14, and (c) such
transferee or assignee is a Permitted Transferee.

     1.15  Standoff  Agreement.  Each  Holder  agrees  in  connection  with  any
registration  of  the  Company's   securities  (other  than  a  registration  of
securities  in a Rule 145  transaction  or with  respect to an employee  benefit
plan) that, upon request of the underwriters  managing any underwritten offering
of the Company's  securities,  not to sell, make any short sale of, loan, pledge
or otherwise  hypothecate or encumber,  grant any option for the purchase of, or
otherwise  dispose of any  Registrable  Securities or  Registrable  Common Stock
(other  than those  included  in the  registration)  without  the prior  written

                                       46
                                     -260-
<PAGE>

consent of such  underwriters,  as the case may be, for such period of time (not
to  exceed  one  hundred  eighty  (180)  days  from the  effective  date of such
registration  in the case of a  registration  for the Company's  initial  public
offering and ninety (90) days from the effective  date of such  registration  in
the  case  of  other  registrations)  as  may  be  requested  by  such  managing
underwriters.

     1.16  Termination of Rights.  The rights of any particular  Holder to cause
the Company to register  Registrable  Securities under Sections 1.5, 1.6 and 1.7
shall terminate with respect to such Registrable Securities owned by such Holder
on the date such  securities  become  eligible  for sale  under  Rule 144 of the
Securities Act (or any similar or successor rule).

     1.17 Additional Equity Securities.  If the Company issues additional equity
securities  in the future,  the Company and the parties  hereto  shall cause any
person or entity who acquires such  securities  to become an Investor  hereunder
and such holder and the Company shall execute a  counterpart  of this  Agreement
and an amendment  adding such  holder's  name hereto shall be a condition of any
issuance of such additional securities.  The covenants set forth in this Section
1.17 shall terminate  immediately  prior to the consummation by the Company of a
qualified Public Offering.

                                   SECTION 2.

                     TAG ALONG RIGHT; RIGHTS TO COMPEL SALE

     2.1 Tag Along.


         (a) At  least  20 days  prior  to any  proposed  transfer  (other  than
pursuant to a public sale) of an  aggregate  of at least 20% of the  outstanding
Common  Stock  (assuming  the  exercise  of all  options  and  warrants  and the
conversion of all  convertible  securities)  or more of the  outstanding  Common
Stock in a transaction or series of  transactions to one or more bona fide third
parties  and,  for so long as they  continue to own shares of Series A Preferred
Stock (or Common Stock issued upon conversion  thereof),  with the prior written
consent  of each of DTN and  PRA,  in  their  sole and  absolute  discretion  (a
"Transfer"), by one or more Investors making such a Transfer (the "Transferor"),
the Transferor  shall give or cause to be given a written notice (the "Tag Along
Notice") to the Company  and the other  Investors  (which may be included in the
Notice of Proposed Transfer delivered pursuant to section 1.4);

         (b) Each Tag Along Notice shall  specify:  (i) the name of the proposed
transferee,  (ii) the number of shares of Preferred  Stock or Common Stock to be
transferred  and (iii) the  price  per  share and all other  material  terms and
conditions  of the offer.  Each  Investor may  participate  in the  contemplated
transfer described in the Tag Along Notice on a pro rata basis at the same price
per Share and on the same terms by delivering  written to the Transferor  within
15 days after  delivery of the Tag Along  Notice.  The failure of an Investor to
provide the selling  Investor  with notice  within such 15-day  period  shall be
deemed for all purposes of this Agreement to be an irrevocable  election by such
Investor  not to  participate  in the  Transfer.  If any Investor has elected to
participate  in such  Transfer,  he or she may sell in the Transfer (at the same
price and on the same terms), a number of Shares equal to the product of (i) the

                                       47
                                     -261-
<PAGE>

quotient  determined  by dividing  the  percentage  of the  Corporation's  total
outstanding  shares  which  are  owned  by such  participating  Investor  by the
percentage of the Corporation's  total outstanding shares which are owned by the
Transferor  and the  participating  Investors  participating  in such sale (as a
group) and (ii) the number of Shares to be sold in the contemplated Transfer.

         (c) The Transferor  shall use its reasonable best efforts to obtain the
agreement of the prospective transferee(s) to the participation by the Investors
in any contemplated  Transfer,  and the Transferor shall not transfer any of its
Shares to any prospective transferee if such prospective  transferee(s) declines
to allow the participation by the Investors.  Each Investor  transferring Shares
pursuant  to this  section  2.1 shall be  obligated  to join on a pro rata basis
(based  on  the  number  of  Shares  to  sold  to  the   transferee(s))  in  any
indemnification  or other  obligations that the Transferor  reasonably agrees to
provide in connection with such Transfer (other than any such  obligations  that
relate  specifically  to a  particular  Investor  such as  indemnification  with
respect to  representations  and warranties given by an Investor  regarding such
Investor's title to and ownership of shares,  provided that no Investor shall be
obligated  in  connection  with  such  Transfer  to agree to  indemnify  or hold
harmless  the  transferees  with  respect to an amount in excess of the net cash
proceeds paid to such Investor in connection with such Transfer).

         (d) All reasonable  costs and expenses  incurred in connection with any
Transfer  made pursuant to Section 2.1,  including  all cost and  disbursements,
finders'  fees or  brokerage  commissions  and the fees and  disbursements  of a
single  counsel   representing  all  shares  to  be  transferred  in  connection
therewith,   shall  be  allocated  pro  rata  between  the  Transferor  and  the
participating  Investors  based  on  the  aggregate  proceeds  received  by  the
Transferor and the participating Investors in the Transfer.

         (e) The rights and obligations of the parties set forth in this Section
2.1 shall terminate  immediately  prior to the  consummation by the Company of a
Qualified Public Offering.

     2.2 Rights to Compel Sale.

         (a) If one or more  Investors  propose  to sell all or any  portion  of
their Shares in any transaction or any series of transactions in which Shares in
an  aggregate  amount  of at least  51% of the  outstanding  Common  Stock (on a
fully-diluted  basis assuming  exercise of outstanding  options and warrants and
conversion of convertible securities) will be sold to a third party, and, for so
long as they  continue to own shares of Series A  Preferred  Stock (or shares of
Common Stock issued upon conversion thereof),  with the prior written consent of
each of DTN and  PRA,  in  their  sole  and  absolute  discretion,  the  selling
Investor(s)  may  compel  all other  Investors  to sell their Pro Rata Share (as
defined  below) of the  aggregate  number of Shares owned by such  Investor (the
"Seller  Shares") to such third party for the same per Share  consideration  and
otherwise on the terms and conditions provided in this Section 2.2.

         (b) The selling  Investor(s)  shall send written notice of the exercise
of their rights pursuant to this Section 2.2 to each of the remaining  Investors
(the "Drag Along  Notice"),  setting  forth the  percentage  of the  outstanding

                                       48
                                     -262-
<PAGE>

Common Stock to be transferred  (the "Pro Rata Share"),  the  consideration  per
Share to be paid by a third party  purchaser and the other terms and  conditions
of the transaction.  Within 15 days following the date of the Drag Along Notice,
each Investor shall deliver  certificates  representing the Seller Shares,  duly
endorsed,  together  with  all  other  documents  required  to  be  executed  in
connection with such  transactions.  If any Investor should fail to deliver such
certificates,  the  Company  shall cause the books and records of the Company to
show that such Shares are bound by the  provisions  of this Section 2.2 and that
such Shares have been transferred to the third party purchaser and each Investor
consents to such action by the Company.

         (c)  Simultaneously  with the  consummation  of the sale of the  Shares
pursuant to this Section 2.2, the selling Investor(s) shall promptly, but in any
event not later than three (3)  business  days  thereafter,  remit to each other
Investor  the  total  sale  price of the  Seller  Shares  sold by such  Investor
pursuant  thereto;  and shall furnish such other  evidence of the completion and
time of  completion of such sale or other  disposition  and the terms thereof as
may be reasonably requested by such other Investor.

         (d) The purchase  from the Investor  pursuant to this Section 2.2 shall
be on the same date of transfer and on the same terms and  conditions  as are to
be received by the selling  Investor(s),  which date, terms and conditions shall
be stated in the Drag Along Notice  (provided,  however,  that if any securities
are to be received by the Investors in connection  with such sale, each Investor
will have the right to receive  non-voting  securities).  No  Investor  shall be
required to make any  representations or warranties in connection with such sale
other  than  customary  limited  representations  solely  with  respect  to such
Investor's  ownership  of its Shares and  authorization  to  participate  in the
transaction.

         (e) The rights and obligations of the parties set forth in this Section
2.2 shall terminate  immediately prior to the consummation of a Qualified Public
Offering.

                                   SECTION 3.

                      AFFIRMATIVE COVENANTS OF THE COMPANY

     The Company hereby covenants and agrees as follows:

     3.1 Financial  Information.  So long as an Investor is a holder of at least
10% of the issued and outstanding  Series A Preferred Stock (including shares of
Common Stock issued upon conversion  thereof),  the Company will furnish to such
Investor the following reports:

         (a) As soon as  practicable  after the end of each fiscal year,  and in
any event  within one hundred  and twenty  (120) days  thereafter,  consolidated
balance  sheets of the  Company and its  subsidiaries,  if any, as of the end of
such fiscal year,  and  consolidated  statements of income and cash flows of the
Company and its subsidiaries, if any, for such year, prepared in accordance with
generally  accepted  accounting  principles  and  setting  forth in each case in
comparative  form the figures for the previous  fiscal year,  all in  reasonable
detail and certified by  independent  public  accountants  of national  standing
selected by the Company; and

                                       49
                                     -263-
<PAGE>

         (b) As soon as practicable after the end of each calendar quarter,  and
in any  event  within 30 days  thereafter,  consolidated  balance  sheets of the
Company and its  subsidiaries,  if any, as of the end of each calendar  quarter,
and consolidated  statements of income and cash flow for such period and for the
current  fiscal year to date,  together with a comparison of such  statements to
the Company's operating plan then in effect.

     3.2  Assignment  of Rights to  Financial  Information.  The rights  granted
pursuant  to  Section  3.1  may  be  assigned  by  an  Investor  to a  Permitted
Transferee,  provided that the Company receives notice thirty (30) days prior to
such assignment.

     3.3  Termination  of Covenants.  The covenants set forth in Section 3 shall
terminate on, and be of no further force or effect after,  the date on which the
Company is required to file reports with the  Commission  pursuant to Section 13
or 15(d) of the Exchange Act.

     3.4  Definition  of  Investor.  For purposes of  determining  the amount of
Shares held by an Investor,  all Investors affiliated with any Investor shall be
treated as a single Investor.

                                   SECTION 4.

                        Election of Directors; DEADLOCKS

     4.1 Voting Agreement.  Until the termination of the covenants  contained in
this  Section 4.1 in  accordance  with  Section 4.2 below,  and  notwithstanding
anything in the Company's  Amended and Restated  Certificate of Incorporation or
Bylaws to the contrary,  (i) the Company's  Board of Directors  shall consist of
six members,  and (ii) at any annual or special  meeting of the  stockholders of
the  Company at which one or more Board  members  are to be  elected,  or in any
action by written consent of the  stockholders of the Company  pursuant to which
one or more Board members are to be elected (whether such Board member(s) are to
be elected due to  expiration of term,  or a vacancy,  removal or  resignation),
each  Investor  agrees that he, she or it shall vote the Common  Stock and other
voting  securities of the Company held by such  Investor in a manner  consistent
with the following  appointments:  (i) three  representatives  appointed by Data
Transmission  Network  Corporation ("DTN") without  limitations;  and (ii) three
representatives  appointed by Photon Research  Associates,  Inc. ("PRA") without
limitations.  A Director  appointed by DTN and a Director appointed by PRA shall
each serve as Co-Chairmen of the Board, with the initial  Co-Chairmen being Greg
Sloma and Jim Myer.

     4.2 Termination of Voting Agreement. The covenants set forth in Section 4.1
shall terminate  immediately  prior to the  consummation  of a Qualified  Public
Offering.

     4.3 Impasses.

         (a)  Negotiation.  In the event the  Company's  Board of  Directors  is
evenly split with respect to any proposed  action by the Company which  requires
the  approval  of its Board of  Directors  (an  "Impasse"),  the matter  will be
immediately  referred to the Co-Chairmen of the Board,  who will attempt in good
faith to negotiate a mutually  acceptable  resolution  for  presentation  to the
Board of Directors.

                                       50
                                     -264-
<PAGE>

         (b) Mediation. If the Co-Chairmen of the Board are unable to agree on a
resolution  which  breaks the Impasse  within ten (10) days,  the  parties  will
attempt  in good  faith to reach a  mutually  acceptable  resolution  through  a
non-binding mediation to be conducted in accordance with procedures to be agreed
upon by the parties at that time.  The  mediation  process shall be concluded as
expeditiously  as  possible  but not more than  forty-five  (45) days  after the
expiration of the initial ten-day  negotiation  period. Any such mediation shall
be held in Albuquerque, New Mexico unless the parties otherwise agree to another
location.

         (c) Impasse Sale.

            (i) If the Impasse  still exists  following  the  conclusion  of the
mediation  referred to in Section  4.3(b) above,  then either DTN or PRA, as the
case may be (the "First  Party") may deliver  written  notice to the other party
(the  "Second  Party") of its  election to  commence an Impasse  sale under this
Section  4.3(c) (an "Impasse  Sale  Notice").  The Impasse Sale Notice shall set
forth the purchase  price (the  "Purchase  Price") for the First Party's  entire
ownership interest in the Company  determined in its sole discretion,  and shall
constitute a binding  offer by the First Party to (A) sell its entire  ownership
interest in the Company to the Second  Party for the Purchase  Price,  or (B) to
purchase the Second  Party's  entire  ownership  interest in the Company for the
Purchase Price.

            (ii) Within  thirty  (30) days of its  receipt of the  Impasse  Sale
Notice,  the Second Party shall elect by written  notice to the First Party (the
"Response")  either to sell its entire ownership  interest in the Company to the
First Party for the  Purchase  Price,  or to purchase the First  Party's  entire
ownership  interest  in the  Company for the  Purchase  Price.  In the event the
Second Party fails to respond  within the requisite  30-day  period,  the Second
Party shall be  compelled to sell its entire  ownership  interest in the Company
for the Purchase Price.

            (iii)  Within one hundred  twenty  (120) days of the delivery of the
Response or, if no Response is  delivered,  the  expiration of the 30-day period
described in clause (ii) above,  the parties shall  consummate  the purchase and
sale of the selling  party's  entire  ownership  interest  in the  Company  (the
"Impasse Sale Closing") in accordance with the Response and this Section 4.3(c).
The party acquiring the other party's ownership  interest shall provide ten (10)
days'  prior  written  notice  to the  other  party  of the date and time of the
Impasse Sale Closing.

            (iv) The purchase and sale pursuant to this Section  4.3(c) shall be
accomplished  through  an  escrow  established  at a title  insurance  or escrow
company mutually approved by the parties. The parties shall execute such further
instructions  as the  escrow  holder and the  purchasing  party  reasonably  may
require  to  consummate  such  escrow,   provided  such   instructions  are  not
inconsistent  with the terms of this  Agreement.  Closing  costs shall be shared
equally by the parties. The selling party shall transfer to the purchasing party
its  entire  ownership  interest  in the  Company  free and clear of all  liens,
security  interests and competing  claims,  and shall deliver to the  purchasing
party such  instruments  of transfer  and such  evidence  of due  authorization,
execution and delivery and of the absence of such liens,  security  interests or
competing claims as the purchasing party shall reasonably  request.  The selling
party  shall also  deliver  letters of  resignation  from the  directors  it has

                                       51
                                     -265-
<PAGE>

appointed  pursuant  to Section  4.1 above.  At the Impasse  Sale  Closing,  the
purchasing  party shall pay the  Purchase  Price to the selling  party by a wire
transfer of  immediately  available  funds to a bank account  designated  by the
selling party.

            (v) If the selling party or any of its  affiliates is a guarantor of
any obligations of the Company or otherwise liable thereon, prior to the Impasse
Sale Closing the purchasing  party shall use reasonable best efforts to obtain a
release  of each such  guaranty  or  liability  in form and  content  reasonably
acceptable to the selling party and its  guarantor  affiliates.  If such release
cannot be obtained prior to the Impasse Sale Closing, the purchasing party shall
hold the selling  party and its  guarantor  affiliates  harmless with respect to
such guarantees and liabilities in form and content reasonably acceptable to the
selling party and its guarantor affiliates.

            (vi) If the purchasing  party fails to close the transaction  within
the 120-day  period  referred to in clause  (iii)  above,  and such  failure was
caused by or within the  reasonable  control of the purchasing  party,  then the
selling  party may elect to acquire the  defaulting  purchasing  party's  entire
ownership  interest  in the  Company for ninety  percent  (90%) of the  Purchase
Price,  by  delivering  written  notice  of  such  election  to  the  defaulting
purchasing  party within ten (10) days of the expiration of the 120-day  period.
If the other  party so elects,  then the  transaction  shall be  consummated  in
accordance with clauses (iii)-(v) above. If the selling party does not deliver a
notice to the defaulting  purchasing  party within such 10-day period,  then the
Company's  business shall continue as before and the First Party may not deliver
another  Impasse Sale Notice for a period of eighteen (18) months  following the
date of such party's original Impasse Sale Notice.

            (vii) Either party shall have the right to seek specific performance
of this Section 4.3(c) in a court of competent jurisdiction or arbitration,  and
the other  party  shall not plead as a defense  that an  adequate  remedy at law
exists.

         (d) The covenants set forth in Section 4.3 shall terminate  immediately
prior to the consummation of a Qualified Public Offering.

                                   SECTION 5.

                                  Miscellaneous

     5.1  Assignment.  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 hereto.

     5.2 Third  Parties.  Nothing  in this  Agreement,  express or  implied,  is
intended to confer  upon any party,  other than the  parties  hereto,  and their
respective  successors  and  assigns,  any  rights,  remedies,   obligations  or
liabilities under or by reason of this Agreement,  except as expressly  provided
herein.

                                       52
                                     -266-
<PAGE>

     5.3 Governing Law. This Agreement  shall be governed by and construed under
the laws of the State of Delaware  without  regard to choice of laws or conflict
of laws' provisions thereof.

     5.4   Counterparts.   This  Agreement  may  be  executed  in  two  or  more
counterparts  and signature  pages may be delivered by facsimile,  each of which
shall be deemed an original,  but all of which together shall constitute one and
the same instrument.

     5.5 Notices. Any notice required or permitted by this Agreement shall be in
writing  and shall be sent by  prepaid  registered  or  certified  mail,  return
receipt requested, addressed to the other party at the address shown below or at
such other  address for which such party  gives  notice  hereunder.  Such notice
shall be deemed to have been given three (3) days after deposit in the mail.

     5.6  Severability.  If one or more provisions of this Agreement are held to
be  unenforceable  under applicable law,  portions of such  provisions,  or such
provisions in their  entirety,  to the extent  necessary,  shall be severed from
this  Agreement,  and the  balance of this  Agreement  shall be  enforceable  in
accordance with its terms.

     5.7 Amendment and Waiver. Any provision of this Agreement may be amended or
waived  with the  written  consent of the  Company  and the  Holders of at least
sixty-six and  two-thirds  percent  (66-2/3%) of the  outstanding  shares of the
Registrable  Securities;  provided  that (i) no such  amendment  or waiver shall
impose or increase any liability or  obligation on a Holder  without the consent
of such Holder; and (ii) no such amendment or waiver having a disproportionately
adverse  effect on any  Holder in  relation  to the  other  Holders  may be made
without  consent of such Holder.  Any amendment or waiver effected in accordance
with this paragraph shall be binding upon each Holder of Registrable  Securities
and  the  Company.  In  addition,  the  Company  may  waive  performance  of any
obligation  owing  to it,  as to  some  or all of  the  Holders  of  Registrable
Securities,  or  agree  to  accept  alternatives  to such  performance,  without
obtaining the consent of any Holder of Registrable Securities. In the event that
an  underwriting  agreement  is entered into between the Company and any Holder,
and such underwriting agreement contains terms differing from this Agreement, as
to any such Holder the terms of such underwriting agreement shall govern.

     5.8 Effect of Amendment or Waiver.  The Investors and their  successors and
assigns  acknowledge that by the operation of Section 5.7 hereof (but subject to
the  limitations  therein)  the  Holders  of  the  requisite  percentage  of the
outstanding Registrable Securities, acting in conjunction with the Company, will
have the right and power to diminish or eliminate any or all rights  pursuant to
this Agreement.

     5.9 Rights of Holders. Each party to this Agreement shall have the absolute
right to exercise or refrain from exercising any right or rights that such party
may have by reason of this Agreement,  including,  without limitation, the right
to consent to the waiver or modification of any obligation under this Agreement,
and such party shall not incur any  liability to any other party or other Holder
of any  securities of the Company as a result of  exercising or refraining  from
exercising any such right or rights.

                                       53
                                     -267-
<PAGE>

     5.10 Delays or Omissions. No delay or omission to exercise any right, power
or remedy accruing to any party to this Agreement, upon any breach or default of
the  other  party,  shall  impair  any  such  right,  power  or  remedy  of such
non-breaching  party nor shall it be construed to be a waiver of any such breach
or  default,  or an  acquiescence  therein,  or of or in any  similar  breach or
default  thereafter  occurring;  nor shall any  waiver of any  single  breach or
default  be deemed a waiver  of any  other  breach  or  default  theretofore  or
thereafter  occurring.  Any waiver,  permit,  consent or approval of any kind or
character  on the  part  of any  party  of any  breach  or  default  under  this
Agreement,  or any  waiver  on  the  part  of any  party  of any  provisions  or
conditions  of this  Agreement,  must be made in writing and shall be  effective
only to the extent specifically set forth in such writing. All remedies,  either
under this Agreement,  or by law or otherwise  afforded to any holder,  shall be
cumulative and not alternative.

     5.11 Entire Agreement.  This Agreement  constitutes the entire agreement of
the parties  hereto  related to the subject  matter  hereof,  and supersedes all
prior agreements  between the parties,  whether written or oral, related to such
subject matter.

     5.12  Aggregation of Stock.  All securities  held or acquired by Affiliated
entities or persons shall be aggregated  together for the purpose of determining
the availability of any rights under this Agreement.

     5.13 Dispute  Resolution.  Any dispute,  claim or controversy arising under
this Agreement or in any way related to this Agreement,  or its  interpretation,
enforceability or inapplicability that cannot be resolved by mutual agreement of
the parties shall be submitted to binding arbitration.  The arbitration shall be
conducted by a single  arbitrator  mutually agreed upon by the parties or, if no
arbitrator is mutually  selected  within thirty (30) days of a demand  therefor,
then  by  a  retired   judge  from  the  Judicial   Arbitration   and  Mediation
Service/Endispute   ("JAMS")  office  located  in  San  Diego,  California.  The
arbitration shall be conducted in San Diego, California,  in accordance with the
Commercial  Arbitration  Rules  of the  American  Arbitration  Association.  The
arbitration  award shall be final and binding,  and judgment on the award may be
entered in any court having jurisdiction  thereof. The parties hereby consent to
the  consolidation  of any arbitration  hereunder with any and all  arbitrations
commenced  under the License  Agreement,  the Series A Preferred  Stock Purchase
Agreement, the Common Stock Purchase Agreement and/or the Warrants.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       54
                                     -268-
<PAGE>


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

FOUNDERS:

                                          /s/ John Rasure
                                          -----------------------------
                                          John Rasure

                                          /s/ Mark Servilla
                                          -----------------------------

                                          /s/ Dan Long
                                          -----------------------------
                                          Dan Long

COMPANY:                                             EARTHSCAN NETWORK INC.


                                          By:/s/ John Rasure
                                             ----------------------
                                             John Rasure
                                          Title: President

                                          By:/s/ Sonya Kay Porth
                                             ----------------------
                                             Sonya Kay Porth
                                          Title:Corporate Secretary/Treasurer
                                       55
                                     -269-
<PAGE>

INVESTORS:                                DATA TRANSMISSION NETWORK CORPORATION


                                          By:/s/ Greg T. Sloma
                                             -------------------------
                                             Greg T. Sloma
                                          Title: President & COO

                                          By: /s/ Brian L. Larson
                                              ------------------------
                                              Brian L. Larson
                                          Title: SVP & CFO

                                          PHOTON RESEARCH ASSOCIATES, INC.


                                          By:/s/ James A. Myer
                                             -------------------------
                                             James A. Myer
                                          Title:CO-COB

                                          By:/s/ Sonya Kay Porth
                                             -------------------------
                                             Sonya Kay Porth
                                          Title:Corporate Secretary

                                          FLEMMING, LESSARD & SHIELDS, LLC


                                          By:/s/ B. Mason Flemming, Jr.
                                             ----------------------------
                                             B. Mason Flemming, Jr.
                                          Title: Managing Director

                                          By:
                                          Title:
                                       56
                                     -270-
<PAGE>

                                       A-1


                                    EXHIBIT A

                              Schedule of Investors

                             Investor Name & Address


Photon Research Associates, Inc.
5720 Oberlin Drive
San Diego, California 92121


Data Transmission Network Corporation
9110 W. Dodge Road, #200
Omaha, NE  68114-3316

John Rasure
6565 Americas Parkway, Suite 660
Albuquerque, New Mexico  87110

Mark Servilla
6565 Americas Parkway, Suite 660
Albuquerque, New Mexico  87110

Dan Long
6565 Americas Parkway, Suite 660
Albuquerque, New Mexico  87110

                                       57
                                     -271-
<PAGE>


                                   Exhibit F

                         Common Stock Purchase Agreement

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       58
                                     -272-
<PAGE>


                                   Exhibit G

                                    Warrants

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       59
                                     -273-
<PAGE>


                                   Exhibit H

                            1999 Stock Incentive Plan

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       60
                                     -274-
<PAGE>


                                   Exhibit I

                           Form of DTN Promissory Note

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       61
                                     -275-
<PAGE>

                                   Exhibit J

                         Form of Opinion of DTN Counsel

"The reporting  person agrees to furnish  supplementally  a copy of this omitted
Exhibit to the Securities and Exchange Commission upon request."

                                       62
                                     -276-
<PAGE>