Document:

<PAGE>   1

                                                                   EXHIBIT 10.56

              COST AND EXPENSE SHARING AND REIMBURSEMENT AGREEMENT

         THIS COST AND EXPENSE SHARING AND REIMBURSEMENT AGREEMENT (this
"AGREEMENT") is effective as of the 21st day of March, 2001, by and between
PINNACLE TOWERS INC., a Delaware corporation ("PTI") and Pinnacle Towers V Inc.,
a Florida corporation ("PT5").

         WHEREAS, PT5 on its own behalf and through its wholly owned
subsidiaries, Shaffer and Associates, Inc. and Sierra Towers, Inc. (each a
"Subsidiary" and collectively, the "Subsidiaries"), is engaged in the rental and
management of communications sites; and

         WHEREAS, PT5 considers it necessary or convenient to utilize certain of
PTI's personnel, facilities and general and administrative overhead in
connection with its business and that of its Subsidiaries, and PTI is willing to
make such available to PT5 and its Subsidiaries; and

         WHEREAS, PT5 has agreed to reimburse PTI for the allocable share of the
cost and expense of such shared personnel, facilities and general and
administrative overhead as determined in the manner hereinafter provided;

         NOW, THEREFORE, in consideration of the representations, warranties,
covenants and agreements herein contained, the parties agree as follows:

         1. PROVISION OF SHARED COSTS AND EXPENSES. During the term of this
Agreement, upon the reasonable request of PT5 or a Subsidiary, PTI will make
available to PT5 and such Subsidiary any of PTI's office and administrative
personnel and facilities, consultants and contractors, and general and
administrative office overhead and costs, including inter alia office space,
record retention, photocopy facilities, facsimile and telephone equipment, sales
and marketing support, office supplies, and computer services (collectively, the
"SHARED COSTS AND EXPENSES").

         2. REIMBURSEMENT. PT5 agrees to reimburse PTI for the costs and
expenses incurred by PTI on behalf of or for the benefit of PT5 and its
Subsidiaries, in an amount equal to the sum of the following amounts (the
"REIMBURSEMENT AMOUNT") determined annually as of the end of each calendar year:

                  (a) With respect to any Shared Costs and Expenses directly
         attributable solely to PT5 or a Subsidiary, an amount equal to the
         marginal or incremental cost or expense thereof incurred by PTI; and

                  (b) With respect to any Shared Costs and Expenses not
         described in (a) above, the pro rata share of such Shared Costs and
         Expenses based on the product obtained by multiplying the gross amount
         of such Shared Costs and Expenses by the quotient obtained by dividing
         the consolidated gross revenues of PT5 and its Subsidiaries for the
         year by the sum of the consolidated gross revenues for the year of all
         of PTI, PT5, and the Subsidiaries, or an amount determined on such
         other reasonable basis as the parties may mutually agree.

<PAGE>   2

The Reimbursement Amount for each calendar year shall be determined no later
than three months after the end of such calendar year and payment of the
Reimbursement Amount shall be due on or before the April 10th of the year
following the end of such calendar year.

         3. STANDARD OF CARE. PTI agrees that it and its personnel shall
exercise the same degree of diligence, care and prudence in connection with
matters conducted on behalf of, or provided for the benefit of, PT5 or its
Subsidiaries as it exercises matters conducted on its own behalf or provided for
its own benefit.

         4. LIMITATION OF LIABILITY.

                  (a) PTI and its affiliates, and the officers, directors,
         employees, shareholders, partners, representatives, consultants and
         agents of PTI and its affiliates (collectively, "PROVIDING PARTIES")
         shall not be liable to the party on whose behalf the Shared Costs and
         Expenses are incurred, its affiliates, or to any officer, director,
         employee, shareholder, partner, representative, consultant or agent of
         such party or its affiliates (collectively, "RECEIVING PARTIES"), for
         any liability, cost, damage, expense or loss, including, without
         limitation, any special, indirect, consequential or punitive damages
         (i) arising or allegedly arising out of any actions or failures to act
         by any of the Providing Parties with respect to the Shared Costs and
         Expenses to be provided hereunder, or (ii) as a result of the reliance
         by any of the Receiving Parties on any advice or data that any of the
         Providing Parties may provide pursuant to this Agreement; provided,
         however, that the foregoing shall not apply to limit liability of a
         party to the extent caused by such party's gross negligence or willful
         misconduct.

                  (b) The Receiving Parties shall indemnify and hold harmless
         each and every of the Providing Parties from and against any liability,
         cost, damage, expense or loss (including court costs and reasonable
         attorneys' fees) which such Providing Parties may sustain or incur by
         reason of any claim, demand, suit or recovery by any person or entity,
         directly resulting from acts or omissions committed by the Receiving
         Party in connection with this Agreement; provided, however, that no
         person may benefit from the foregoing indemnity in the event of its
         gross negligence or willful misconduct.

         5. TERM. The term of this Agreement shall commence as of the date
hereof and end December 31, 2001, unless earlier terminated effective as of the
end of a calendar month by either party upon no less than two months' prior
written notice to the other party. The term of this Agreement shall
automatically renew for successive periods of one year each unless either party
provides to the other party notice in writing that this Agreement will not so
renew and such notice is given at least two months prior to the then termination
date of this Agreement. In the event this Agreement is terminated prior to the
end of a calendar year, the Reimbursement Amount shall be determined as of the
effective date of termination based on gross revenues of each party through the
date of termination.

         6. RELATIONSHIP OF THE PARTIES. In all matters relating to this
Agreement, each party hereto shall be solely responsible for the acts of its
employees, and employees of one party shall not be considered employees of the
other party. No party shall have any right, power or authority to create any
obligation, express or implied, on behalf of any other party. Nothing in

                                      -2-
<PAGE>   3

this Agreement is intended to create or constitute a joint venture or
partnership relationship between the parties hereto or persons referred to
herein.

         7. FORCE MAJEURE. PTI shall be excused from performance hereunder for
any period and to the extent that it is prevented from performance hereunder, in
whole or in part, as a result of delays caused by PT5 or its Subsidiaries or any
act of God, war, civil disturbance, court order, strike, labor dispute, law or
regulation of any governmental authority, or other cause beyond the reasonable
control of PTI. Such nonperformance shall not be a default hereunder. PTI shall
take all reasonable actions to resume performance of its obligations hereunder
as soon as feasible.

         8. AMENDMENTS AND WAIVER. No amendment, waiver or consent with respect
to any provision of this Agreement shall in any event be effective, unless the
same shall be in writing and signed by the parties hereto, and then such
amendment, waiver or consent shall be effective only in the specific instance
and for the specific purpose for which given.

         9. NOTICES. All notices, requests, demands and other communications
hereunder shall be in writing and shall be, personally delivered or sent by
facsimile transmission with confirming copy sent by overnight courier (such as
Express Mail, Federal Express, etc.) and a delivery receipt obtained and
addressed to the intended recipient as follows:

                  If to PTI:

                           Pinnacle Towers Inc.
                           301 North Cattlemen Road, Suite 300
                           Sarasota, FL 34232
                           Attention: Ben Gaboury
                           Telephone No.: (941) 364-8886
                           Facsimile No.: (941) 364-8761

                  If to PT5:

                           Pinnacle Towers V Inc.
                           301 North Cattlemen Road, Suite 300
                           Sarasota, FL 34232
                           Attention: Steve Day
                           Telephone No.: (941) 364-8886
                           Facsimile No.: (941) 364-8761

Any party may change its address or add or change parties for receiving notice
by written notice given to the others named above. Notices shall be deemed given
as of the date of receipt.

         10. COUNTERPARTS. This Agreement may be executed in counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         11. SUCCESSORS AND ASSIGNS; BENEFICIARIES. This Agreement shall bind
and inure to the benefit of the parties named herein and their respective
successors and assigns. No party may assign any rights, benefits, duties or
obligations under this Agreement without the prior written consent of the other
party. Except for the Subsidiaries each of which is an intended beneficiary

                                      -3-
<PAGE>   4

of this Agreement, and except as specifically provided in Section 4, no third
party shall be entitled to enforce any provision hereof or to benefit from this
Agreement.

         12. ENTIRE AGREEMENT. This Agreement and the documents referred to
herein contain the entire agreement and understanding among the parties with
respect to the transactions contemplated hereby and supersede all other
agreements, understandings and undertakings among the parties on the subject
matter hereof.

         13. PARTIAL INVALIDITY. In the event that any provision of this
Agreement shall be held invalid or unenforceable by any court or competent
jurisdiction, such holding shall not invalidate or render unenforceable any
other provision hereof.

         14. GOVERNING LAW; JURISDICTION. This Agreement shall be interpreted in
accordance with the substantive laws of the State of Florida applicable to
contracts made and to be performed wholly within said State. All disputes, legal
actions, suits and proceedings arising out of or relating to this Agreement
shall be brought in a federal district or state court located in Tampa, Florida.
Each party hereby consents to the jurisdiction of the federal district or state
court in Tampa, Florida. Each party hereby irrevocably waives all claims of
immunity from jurisdiction and any right to object on the basis that any
dispute, action, suit or proceeding brought in the federal district or state
court of Tampa, Florida has been brought in an improper or inconvenient venue or
forum.

         15. DISPUTES.

                  (a) PTI and PT5 mutually desire that friendly collaboration
         will develop between themselves. Accordingly, they shall attempt to
         resolve in a friendly manner all disagreements and misunderstandings
         connected with their respective rights and obligations under this
         Agreement, including any amendments hereof.

                  (b)      (i) To the extent that any misunderstanding or
         dispute cannot be resolved agreeably in a friendly manner, the dispute
         will be mediated by a mutually acceptable mediator to be chosen by PTI
         and PT5 within forty-five (45) days after written notice by one of the
         parties demanding mediation. Neither party may unreasonably withhold
         consent to the selection of a mediator, however, by mutual agreement
         PTI and PT5 may postpone mediation until each has completed specified
         but limited discovery with respect to a dispute. The parties may also
         agree to attempt some other form of alternative dispute resolution
         ("ADR") in lieu of mediation, including by way of example and without
         limitation, neutral fact-finding or a mini-trial.

                           (ii) Any dispute which the parties cannot resolve
         through negotiation, mediation or other form of ADR within six months
         of the date of the initial demand for it by one of the parties may then
         be submitted to the courts for resolution. The use of any ADR
         procedures will not be construed under the doctrine of laches, waiver
         or estoppel to affect adversely the rights of either party. Nothing in
         this Section 15 will prevent any party from resorting to judicial
         proceedings if (A) good faith efforts to resolve the dispute under
         these procedures have been unsuccessful or (B) interim relief from a
         court is necessary to prevent serious and irreparable injury to one
         party or to others.

                                      -4-
<PAGE>   5

                  (c) Each of the parties shall bear its own costs of mediation
         or ADR, but the parties agree that the shared costs of mediation or ADR
         shall be shared 50% by PTI and 50% by PT5.

         16. AUTHORSHIP. The parties hereto agree that the terms and language of
this Agreement were the result of negotiations between the parties and, as a
result, there shall be no presumption that any ambiguities in this Agreement
shall be resolved against either party. Any controversy over construction of
this Agreement shall be decided without regard to events of authorship or
negotiation.

         17. DEFINED TERMS. All capitalized terms not defined herein shall have
the meanings ascribed to them in the Asset Purchase Agreement.

         18. RECITALS. The recitals hereto are true and correct and are by this
reference incorporated herein.

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

PINNACLE TOWERS INC.                         PINNACLE TOWERS V INC.

By:                                          By:
   --------------------------------             --------------------------------
   Name:                                        Name:
        ---------------------------                  ---------------------------
   Title:                                       Title:
         --------------------------                   --------------------------

                                      -5-<PAGE>   1
                                                                     EXHIBIT 4.3

         NEITHER THESE SECURITIES NOR THE SECURITIES ISSUABLE UPON
         CONVERSION HEREOF HAVE BEEN REGISTERED WITH THE UNITED STATES
         SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES
         COMMISSION OF ANY STATE OR UNDER THE SECURITIES ACT OF 1933,
         AS AMENDED. THE SECURITIES ARE RESTRICTED AND MAY NOT BE
         OFFERED, RESOLD, PLEDGED OR TRANSFERRED EXCEPT AS PERMITTED
         UNDER THE ACT PURSUANT TO REGISTRATION OR EXEMPTION OR SAFE
         HARBOR THEREFROM.

No. 00-1 US                                                           $ 250,000

                                   SATX, INC.

                8% CONVERTIBLE DEBENTURE DUE SEPTEMBER 14, 2001

         THIS DEBENTURE is one of a duly authorized issue of up to $1,000,000
in Debentures of SATX, INC., a corporation organized and existing under the
laws of the State of Nevada (the "Company") designated as its 8% Convertible
Debentures. Such Debentures may be issued in series, each of which may have a
different maturity date, but which otherwise have substantially similar terms.

         FOR VALUE RECEIVED, the Company promises to pay to, NASIMIA, LTD.,
the registered holder hereof (the "Holder"), the principal sum of Two Hundred
Fifty Thousand and 00/100 Dollars (US$250,000) on September 14, 2001 (the
"Maturity Date") and to pay interest on the principal sum outstanding in cash
or unrestricted shares of Common Stock, at the Holder's option from time to
time in arrears (i) prior to the Maturity Date, quarterly, on the last day of
December, March, June and September of each year, (ii) upon conversion as
provided herein or (iii) on the Maturity Date, at the rate of 8% per annum
accruing from September 14, 2000, the date of initial issuance of this
Debenture. Accrual of interest shall commence on the first such business day to
occur after the date hereof and shall continue to accrue on a daily basis until
payment in full of the principal sum has been made or duly provided for.

         This Debenture is subject to the following additional provisions:

                                       1
<PAGE>   2
         1.       The Debentures are issuable in denominations of Twenty-five
Thousand Dollars (US$25,000) and integral multiples thereof. The Debentures are
exchangeable for an equal aggregate principal amount of Debentures of different
authorized denominations, as requested by the Holder surrendering the same. No
service charge will be made for such registration or transfer or exchange.

         2.       The Company shall be entitled to withhold from all payments
of principal of, and interest on, this Debenture any amounts required to be
withheld under the applicable provisions of the United States income tax laws
or other applicable laws at the time of such payments, and Holder shall execute
and deliver all required documentation in connection therewith.

         3.       This Debenture has been issued subject to investment
representations of the original purchaser hereof and may be transferred or
exchanged only in compliance with the Securities Act of 1933, as amended (the
"Act"), and other applicable state and foreign securities laws. In the event of
any proposed transfer of this Debenture, the Company may require, prior to
issuance of a new Debenture in the name of such other person, that it receive
reasonable transfer documentation including legal opinions that the issuance of
tile Debenture in such other name does not and will not cause a violation of
the Act or any applicable state or foreign securities laws. Prior to due
presentment for transfer of this Debenture, the Company and any agent of the
Company may treat the person in whose name this Debenture is duly registered on
the Company's Debenture Register as the owner hereof for the purpose of
receiving payment as herein provided and for all other purposes, whether or not
this Debenture be overdue, and neither the Company nor any such agent shall be
affected by notice to the contrary.

         4.       A.       The Holder of this Debenture is entitled, at its
option, subject to the following provisions of this Section 4, to convert all
or a portion of this Debenture into shares of Common Stock of the Company,
$.001 par value per share ("Common Stock") at any time until the Maturity Date,
at a conversion price for each share of Common Stock equal to the lesser of
(x) seventy percent (70% ) of the Market Price of the Common Stock (as defined
below) on the Initial Closing Date or (y) seventy percent (70% ) of the Market
Price of the Common Stock on the Conversion Date, subject to a maximum
conversion price of $1.00.

                  B.       For purpose of this Debenture "Market Price of the
Common Stock" means (x) the closing bid price of the Common Stock for the
trading day immediately before the relevant date indicated in the relevant
provision hereof (unless a different relevant period is specified in the
relevant provision), as reported by Bloomberg, LP. If Bloomberg LP is
unavailable than as reported by Reuters Group PLC.

                  C.       The Company will permit Buyer to exercise its right
to convert this Debenture upon the Holder's telecopying or delivering an
executed and completed Notice of Conversion to the Company and delivering,
within five (5) business days thereafter, this original Debenture to the
Company by express courier, with a copy to the Company's transfer agent. The
Notice Conversion shall be in the form attached hereto as Exhibit A, and shall
be, executed by the Holder of the

                                       2
<PAGE>   3

Debenture evidencing such Holder's intention to convert this Debenture or a
specified portion hereof, and accompanied, if required by the Company, by
proper assignment hereof in blank. Subject to the provisions of Section 4(D)
hereof, interest accrued or accruing from the date of issuance to the date of
conversion shall, at the option of the Company, be paid in cash or Common Stock
upon conversion at the Fixed Conversion Rate applicable to such conversion. No
fractional shares of Common Stock or scrip representing fractions of shares will
be issued on conversion, but the number of shares issuable shall be rounded to
the nearest whole share. The term "Conversion Date" means with respect to any
conversion elected by the holder of this Debenture, the date specified in the
Notice of Conversion, provided the copy of the Notice of Conversion is
telecopied to or otherwise delivered to the Company in accordance with the
provisions hereof so that it is received by the Company on or before such
specified date. Facsimile delivery of the Notice of Conversion shall be
accepted by the Company at facsimile number 813-290-0616; ATTN: Merrit Jesson.
Certificates representing Common Stock upon conversion will be delivered within
five (5) business days if the address for delivery is in the United States (and
within seven (7) business days if the address for delivery is outside the
United States) after the business day on which the Company has received both of
the Notice of Conversion (by facsimile or other delivery) and this original
Debenture (and if the same are not delivered to the Company on the same date,
the date of delivery of the second of such items).

                  D.       Notwithstanding any other provision hereof, of the
Warrants or of any of the other Transaction Agreements (as those terms are
defined in the Securities Purchase Agreement), in no event (except (i) with
respect to an automatic conversion, if any, of a Debenture as provided in the
Debentures or upon the occurrence of an Event of Default (as defined below),
(ii) as specifically provided in this Debenture as an exception to this
provision, or (iii) while there is outstanding a tender offer for any or all of
the shares of the Company's Common Stock) shall the Holder be entitled to
convert any Debenture, or shall the Company have the obligation to convert all
or any portion of this Debenture (and the Company shall not have the right to
pay interest in Company unrestricted Common Stock on this Debenture), to the
extent that, after such conversion, the sum of (1) the number of shares of
Common Stock beneficially owned by the Holder and its affiliates (other than
shares of Common Stock which may be deemed beneficially owned through the
ownership of the unconverted portion of the Debentures or unexercised portion
of the Warrants), and (2) the number of shares of Common Stock issuable upon
the conversion of the Debentures with respect to which the determination of
this proviso is being made, would result in beneficial ownership by the Holder
and its affiliates of more than 9.99% of the outstanding shares of Common Stock
(after taking into account the shares to be issued to the Holder upon such
conversion). For purposes of the proviso to the immediately preceding sentence,
beneficial ownership shall be determined in accordance with Section 13(d) of the
Securities Exchange Act of 1934, as amended (the "1934 Act"), except as
otherwise provided in clause (1) of such sentence. The Holder, by its
acceptance of this Debenture, further agrees that if the Holder transfers or
assigns any of the Debentures to a party who or which would not be considered
such an affiliate, such assignment shall be made subject to the transferee's or
assignee's specific agreement to be bound by the provisions of this Section
4(D) as if such transferee or assignee were the original Holder hereof.

                                       3
<PAGE>   4

         5.       Subject to the terms of the Securities Purchase Agreement,
dated September 14, 2000 (the "Securities Purchase Agreement"), between the
Company and the Holder (or the Holder's predecessor in interest), no provision
of this Debenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of, and interest on, this
Debenture at the time, place, and rate, and in the coin or currency, herein
prescribed. This Debenture and all other Debentures now or hereafter issued of
similar terms are direct obligations of the Company.

         6.       No recourse shall be had for the payment of the principal of,
or the interest on, this Debenture, or for any claim based hereon, or otherwise
in respect hereof, against any incorporator, shareholder, officer or director,
as such, past, present or future, of the Company or any successor corporation,
whether by virtue of any constitution, statute or rule of law, or by the
enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

         7.       If the Company merges or consolidates with another
corporation or sells or transfers all or substantially all of its assets to
another person and the holders of the Common Stock are entitled to receive
stock, securities or property in respect of or in exchange for Common Stock,
then as a condition of such merger, consolidation, sale or transfer, the
Company and any such successor, purchaser or transferee agree that the
Debenture may thereafter be converted on the terms and subject to the
conditions set forth above into the kind and amount of stock, securities or
property receivable upon such merger, consolidation, sale or transfer by a
holder of the number of shares of Common Stock into which this Debenture might
have been converted immediately before such merger, consolidation, sale or
transfer, subject to adjustments which shall be as nearly equivalent as may be
practicable. In the event of any proposed merger, consolidation or sale or
transfer of all or substantially all of the assets of the Company (a "Sale"),
the Holder hereof shall have the right to convert this Debenture by delivering
a Notice of Conversion to the Company within fifteen (15) days of receipt of
notice of such Sale from the Company.

         8.       If, for any reason, prior to the Conversion Date, the Company
spins off or otherwise divests itself of a part of its business or operations
or disposes of all or of a part of its assets in a transaction (the "Spin Off")
in which the Company does not receive compensation (other than nominal
non-material compensation) for such business, operations or assets, but causes
securities of another entity (the "Spin Off Securities") to be issued to
security holders of the Company, then the Company shall cause (i) to be
reserved Spin Off Securities equal to the number thereof which would have been
issued to the Holder had all of the Holder's Debentures outstanding on the
record date (the "Record Date") for determining the amount and number of Spin
Off Securities to be issued to security holders of the Company (the
"Outstanding Debentures") been converted as of the close of business on the
trading day immediately before the Record Date (the "Reserved Spin Off
Shares"), and (ii) to be issued to the Holder on the conversion of all or any
of the Outstanding Debentures, such amount of the Reserved Spin Off Shares
equal to (x) the Reserved Spin Off Shares multiplied by (y) a fraction, of
which (I) the numerator is the principal amount of the Outstanding Debentures

                                       4
<PAGE>   5

then being converted, and (II) the denominator is the principal amount of the
Outstanding Debentures.

         9.       If, at any time while any portion of this Debenture remains
outstanding, the Company effectuates a stock split or reverse stock split of
its Common Stock or issues a dividend on its Common Stock consisting of shares
of Common Stock, the Conversion Rate shall be equitably adjusted to reflect
such action. By way of illustration, and not in limitation, of the foregoing
(i) if the Company effectuates a 2:1 split of its Common Stock, thereafter,
with respect to any conversion for which the Company issues the shares after
the record date of such split, the Conversion Rate shall be deemed to be
one-half of what it had been calculated to be immediately prior to such split;
(ii) if the Company effectuates a 1:10 reverse split of its Common Stock,
thereafter, with respect to any conversion for which the Company issues the
shares after the record date of such reverse split, the Conversion Rate shall
be deemed to be ten times what it had been calculated to be immediately prior
to such split; and (iii) if the Company declares a stock dividend of one share
of Common Stock for every 10 shares outstanding, thereafter, with respect to
any conversion for which the Company issues the shares after the record date of
such dividend, the Conversion Rate shall be deemed to be the amount of such
Conversion Rate calculated immediately prior to such record date multiplied by
a fraction, of which the numerator is the number of shares (10) for which a
dividend share will be issued and the denominator is such number of shares plus
the dividend shares) issuable or issued thereon (11).

         10.      All payments contemplated hereby to be made "in cash" shall
be made in immediately available good funds in such coin or currency of the
United States of America as at the time of payment is legal tender for payment
of public and private debts. All payments of cash and each delivery of shares
of Common Stock issuable to the Holder as contemplated hereby shall be made to
the Holder at the address last appearing on the Debenture Register of the
Company as designated in writing by the Holder from time to time; except that
the Holder can designate, by notice to the Company, a different delivery
address for any one or more specific payments or deliveries.

         11.      The Holder of the Debenture, by acceptance hereof, agrees
that this Debenture is being acquired for investment and that such Holder will
not offer, sell or otherwise dispose of this Debenture or the Shares of Common
Stock issuable upon conversion thereof except under circumstances which will
not result in a violation of the Act or any applicable state Blue Sky or
foreign laws or similar laws relating to the sale of securities and except in
the case of the Debenture upon prior written consent of the Company.

         12.      This Debenture shall be governed by and construed in
accordance with the laws of the State of New York. Each of the parties consents
to the exclusive jurisdiction of the federal courts whose districts encompass
any part of the City of New York or the state courts of the State of New York
sitting in the City of New York in connection with any dispute arising under
this Agreement and hereby waives, to the maximum extent permitted by law, any
objection, including any objection based on forum non coveniens, to the
bringing of any such proceeding in such jurisdictions. To the extent determined
by such court, the Company shall reimburse the Holder for any reasonable legal

                                       5
<PAGE>   6

fees and disbursements incurred by the Holder in enforcement of or protection
of any of its rights under any of this Debenture.

         13.      The following shall constitute an "Event of Default":

                  a.       The Company shall default in the payment of
                           principal or interest on this Debenture and same
                           shall continue for a period of five (5) consecutive
                           days; or

                  b.       Any of the representations or warranties made by the
                           Company herein, in the Securities Purchase
                           Agreement, the Registration Rights Agreement or in
                           any certificate or financial or other written
                           statements heretofore or hereafter furnished by the
                           Company in connection with the execution and
                           delivery of this Debenture or the Securities
                           Purchase Agreement shall be false or misleading in
                           any material respect at the time made and such
                           falsity shall continue uncured for a period of ten
                           (10) days after written notice from the Holder of
                           such falsity; or

                  c.       The Company fails to issue shares of Common Stock to
                           the Holder or to cause its Transfer Agent to issue
                           shares of Common Stock upon exercise by the Holder
                           of the conversion rights of the Holder in accordance
                           with the terms of this Debenture, fails to transfer
                           or to cause its Transfer Agent to transfer any
                           certificate for shares of Common Stock issued to the
                           Holder upon conversion of this Debenture and when
                           required by this Debenture or the Registration
                           Rights Agreement, and such transfer is otherwise
                           lawful, or fails to remove any restrictive legend or
                           to cause its Transfer Agent to transfer on any
                           certificate or any shares of Common Stock issued to
                           the Holder upon conversion of thus Debenture as and
                           when required by this Debenture, the Agreement or
                           the Registration Rights Agreement and such legend
                           removal is otherwise lawful, and any such failure
                           shall continue uncured for ten (10) business days.

                  d.       The Company shall fail to perform or observe, in any
                           material respect, any other covenant, term,
                           provision, condition, agreement or obligation of any
                           Debenture in this series and such failure shall
                           continue uncured for a period of thirty (30) days
                           after written notice from the Holder of such
                           failure; or

                  e.       The Company shall fail to perform or observe, in any
                           material respect, any covenant, term, provision,
                           condition, agreement or obligation of the Company
                           under the Securities Purchase Agreement or the
                           Registration Rights Agreement and such failure shall
                           continue uncured for a period of thirty (30) days
                           after written notice from the Holder of such failure
                           (other than a failure

                                       6
<PAGE>   7
                           to cause the Registration Statement to become
                           effective no later than the Required Effective Date,
                           as defined and provided in the Registration Rights
                           Agreement, as to which no such cure period shall
                           apply); or

                  f.       The Company shall (1) admit in writing its inability
                           to pay its debts generally as they mature; (2) make
                           an assignment for the benefit of creditors or
                           commence proceedings for its dissolution; or (3)
                           apply for or consent to the appointment of a
                           trustee, liquidator or receiver for its or for a
                           substantial part of its property or business; or

                  g.       A trustee, liquidator or receiver shall be appointed
                           for the Company or for a substantial part of its
                           property or business without its consent and shall
                           not be discharged within sixty (60) days after such
                           appointment; or

                  h.       Any governmental agency or any court of competent
                           jurisdiction at the instance of any governmental
                           agency shall assume custody or control of the whole
                           or any substantial portion of the properties or
                           assets of the Company and shall not be dismissed
                           within sixty (60) days thereafter; or

                  i:       Any money judgment, writ or warrant of attachment,
                           or similar process in excess of Two Hundred Thousand
                           ($200,000) Dollars in the aggregate shall be entered
                           or filed against the Company or any of its
                           properties or other assets and shall remain unpaid,
                           unvacated, unbonded or unstayed for a period of
                           sixty (60) days or in any event later than five (5)
                           days prior to the date of any proposed sale
                           thereunder; or

                  j.       Bankruptcy, reorganization, insolvency or
                           liquidation proceedings or other proceedings for
                           relief under any bankruptcy law or any law for the
                           relief of debtors shall be instituted by or against
                           the Company and, if instituted against the Company,
                           shall not be dismissed within sixty (60) days after
                           such institution or the Company shall by any action
                           or answer approve of, consent to, or acquiesce in
                           any such proceedings or admit the material
                           allegations of, or default in answering a petition
                           filed in any such proceeding; or

                  k.       The Company shall have its Common Stock suspended or
                           delisted from an exchange or over-the-counter
                           market from trading for in excess of eleven (11)
                           consecutive trading days.

Then, or at any time thereafter continue uncured for a period of ten (10) days
after written notice from the Holder of such Event of Default, and in each and
every such case, unless such Event of Default shall have been waived in writing
by the Holder (which waiver shall not be deemed to be a waiver of any
subsequent default) at the option of the Holder and in the Holder's sole
discretion, the Holder may consider this Debenture immediately due and payable,
without presentment, demand,

                                       7
<PAGE>   8

protest or notice of any kinds, all of which are hereby expressly waived,
anything herein or in any note or other instruments contained to the contrary
notwithstanding, and the Holder may immediately enforce any and all of the
Holder's rights and remedies provided herein or any other rights or remedies
afforded by law.

         14.      Nothing contained in this Debenture shall be construed as
conferring upon the Holder the right to vote or to receive dividends or to
consent or receive notice as a shareholder in respect of any meeting of
shareholders or any rights whatsoever as a shareholder of the Company, unless
and to the extent converted in accordance with the terms hereof.

         15.      In the event for any reason, any payment by or act of the
Company or the Holder shall result in payment of interest which would exceed
the limit authorized by or be in violation of the law of the jurisdiction
applicable to this Debenture, then ipso facto the obligation of the Company to
pay interest or perform such act or requirement shall be reduced to the limit
authorized under such law, so that in no event shall the Company be obligated
to pay any such interest, perform any such act or be bound by any requirement
which would result in the payment of interest in excess of the limit so
authorized. In the event any payment by or act of the Company shall result in
the extraction of a rate of interest in excess of a sum which is lawfully
collectible as interest, then such amount (to the extent of such excess not
returned to the Company) shall, without further agreement or notice between or
by the Company or the Holder, be deemed applied to the payment of principal, if
any, hereunder immediately upon receipt of such excess funds by the Holder,
with the same force and effect as though the Company had specifically
designated such sums to be so applied to principal and the Holder had agreed to
accept such sums as an interest-free prepayment of this Debenture. If any part
of such excess remains after the principal has been paid in full, whether by
the provisions of the preceding sentences of this Section 15 or otherwise, such
excess shall be deemed to be an interest-free loan from the Company to the
Holder, which loan shall be payable immediately upon demand by (the Company.
The provisions of this Section 15 shall control every other provision of this
Debenture.

                  [BALANCE OF PAGE INTENTIONALLY LEFT BLANK]

                                       8
<PAGE>   9

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed by an officer thereunto duly authorized.

Dated: September 14, 2000

                                          SATX, INC.

                                          By: /s/ Merritt Jesson
                                             ----------------------------------

                                                  MERRITT JESSON
                                          -------------------------------------
                                          (Print name)

                                                  President & CEO
                                          -------------------------------------
                                          (Title)

                                       9

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00024-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00024-of-00352.parquet"}]]