THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
      REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT").
      THE SECURITIES MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED IN THE
      ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES
      UNDER SAID ACT, OR AN OPINION OF COUNSEL IN FORM, SUBSTANCE AND SCOPE
      CUSTOMARY FOR OPINIONS OF COUNSEL IN COMPARABLE TRANSACTIONS THAT
      REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR UNLESS SOLD PURSUANT
      TO RULE 144 OR REGULATION S UNDER SAID ACT.

                          SECURED CONVERTIBLE DEBENTURE

Palo Alto, California
November __, 2003                                                $______________

            FOR VALUE RECEIVED, AMNIS SYSTEMS INC., a Delaware corporation
(hereinafter called the "Borrower"), hereby promises to pay to the order of
_____________ or registered assigns (the "Holder") the sum of
___________________ ($___________), on November __, 2005 (the "Maturity Date"),
and to pay interest on the unpaid principal balance hereof at the rate of twelve
percent (12%) per annum from November __, 2003 (the "Issue Date") until the same
becomes due and payable, whether at maturity or upon acceleration or by
prepayment or otherwise. Any amount of principal or interest on this Debenture
which is not paid when due shall bear interest at the rate of fifteen percent
(15%) per annum from the due date thereof until the same is paid ("Default
Interest"). Interest shall commence accruing on the issue date, shall be
computed on the basis of a 365-day year and the actual number of days elapsed
and shall be payable, at the option of the Holder, either quarterly on March 31,
June 30, September 30 and December 31, of each year beginning on March 31, 2004,
or at the time of conversion of the principal to which such interest relates in
accordance with Article I below. All payments due hereunder (to the extent not
converted into common stock, $.0001 par value per share, of the Borrower (the
"Common Stock") in accordance with the terms hereof) shall be made in lawful
money of the United States of America or, at the option of the Borrower, in
whole or in part, in shares of Common Stock of the Borrower valued at the then
applicable Conversion Price (as defined herein). All payments shall be made at
such address as the Holder shall hereafter give to the Borrower by written
notice made in accordance with the provisions of this Debenture. Whenever any
amount expressed to be due by the terms of this Debenture is due on any day
which is not a business day, the same shall instead be due on the next
succeeding day which is a business day and, in the case of any interest payment
date which is not the date on which this Debenture is paid in full, the
extension of the due date thereof shall not be taken into account for purposes
of determining the amount of interest due on such date. As used in this
Debenture, the term "business day" shall mean any day other than a Saturday,
Sunday or a day

<PAGE>

on which commercial banks in the city of Palo Alto, California are authorized or
required by law or executive order to remain closed. Each capitalized term used
herein, and not otherwise defined, shall have the meaning ascribed thereto in
that certain Securities Purchase Agreement, dated November __, 2003, pursuant to
which this Debenture was originally issued (the "Purchase Agreement").

            This Debenture is free from all taxes, liens, claims and
encumbrances with respect to the issue thereof and shall not be subject to
preemptive rights or other similar rights of stockholders of the Borrower and
will not impose personal liability upon the holder thereof. The obligations of
the Borrower under this Debenture shall be secured by that certain Pledge and
Security Agreement dated by and between the Borrower and the Holder dated
November __, 2003.

            The following terms shall apply to this Debenture:

                          ARTICLE I. CONVERSION RIGHTS

            1.1 Conversion Right. The Holder shall have the right from time to
time, and at any time on or prior to the later of (i) the Maturity Date and (ii)
the date of payment in full of the outstanding principal amount of this
Debenture plus accrued and unpaid interest and any other amounts owed to the
Holder under the Debenture or Transaction Documents (as defined in Section 2(h)
of the Purchase Agreement) to convert all or any part of the outstanding and
unpaid principal amount of this Debenture into fully paid and non-assessable
shares of Common Stock, as such Common Stock exists on the Issue Date, or any
shares of capital stock or other securities of the Borrower into which such
Common Stock shall hereafter be changed or reclassified at the conversion price
(the "Conversion Price") determined as provided herein (a "Conversion");
provided, however, that in no event shall the Holder be entitled to convert any
portion of this Debenture in excess of that portion of this Debenture upon
conversion of which 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 the unexercised or unconverted portion
of any other security of the Borrower (including, without limitation, the
warrants issued by the Borrower pursuant to the Purchase Agreement) subject to a
limitation on conversion or exercise analogous to the limitations contained
herein) and (2) the number of shares of Common Stock issuable upon the
conversion of the portion of this Debenture 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 9.9% of the outstanding
shares of Common Stock. The Borrower shall have the authority and obligation to
determine whether the restriction contained in this Section 1.1 will limit any
conversion hereunder and to the extent that a Borrower determines that the
limitation contained in this Section applies, the determination of which portion
of this Debenture is convertible shall be the responsibility and obligation of
each such Borrower. A Borrower may allocate which of the equity of the Company
deemed beneficially owned by such Borrower shall be included in the 9.9% amount
described above and which shall be allocated to the excess above 9.9%. 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, and Regulations 13D-G thereunder, except as
otherwise


                                       2
<PAGE>

provided in clause (1) of such proviso. The Holder of this Debenture may waive
the limitations set forth herein by sixty-one (61) days written notice to the
Company. The number of shares of Common Stock to be issued upon each conversion
of this Debenture shall be determined by dividing the Conversion Amount (as
defined below) by the applicable Conversion Price then in effect on the date
specified in the notice of conversion, in the form attached hereto as Exhibit A
(the "Notice of Conversion"), delivered to the Borrower by the Holder in
accordance with Section 1.4 below; provided that the Notice of Conversion is
submitted by facsimile (or by other means resulting in, or reasonably expected
to result in, notice) to the Borrower before 6:00 p.m., Palo Alto, California
time on such conversion date (the "Conversion Date"). The term "Conversion
Amount" means, with respect to any conversion of this Debenture, the sum of (1)
the principal amount of this Debenture to be converted in such conversion plus
(2) accrued and unpaid interest, if any, on such principal amount at the
interest rates provided in this Debenture to the Conversion Date plus (3)
Default Interest, if any, on the amounts referred to in the immediately
preceding clauses (1) and/or (2) plus (4) at the Holder's option, any amounts
owed to the Holder pursuant to Sections 1.3 and 1.4(g) hereof or pursuant to
Section 2(c) of that certain Registration Rights Agreement, dated as of November
__, 2003, executed in connection with the initial issuance of this Debenture and
the other Debentures issued on the Issue Date (the "Registration Rights
Agreement").

            1.2 Conversion Price.

                  (a) Calculation of Conversion Price. The Conversion Price
shall be the lesser of (i) the Variable Conversion Price (as defined herein) and
(ii) the Fixed Conversion Price (as defined herein) (subject, in each case, to
equitable adjustments for stock splits, stock dividends or rights offerings by
the Borrower relating to the Borrower's securities or the securities of any
subsidiary of the Borrower, combinations, recapitalization, reclassifications,
extraordinary distributions and similar events). The "Variable Conversion Price"
shall mean the Applicable Percentage (as defined herein) multiplied by the
Market Price (as defined herein). "Market Price" means the average of the lowest
three (3) Trading Prices (as defined below) for the Common Stock during the
thirty (30) Trading Day period ending one Trading Day prior to the date the
Conversion Notice is sent by the Holder to the Borrower via facsimile (the
"Conversion Date"). "Trading Price" means, for any security as of any date, the
lowest intraday trading price on the Over-the-Counter Bulletin Board (the
"OTCBB") as reported by Bloomberg or, if the OTCBB is not the principal trading
market for such security, the intraday trading price of such security on the
principal securities exchange or trading market where such security is listed or
traded or, if no intraday trading price of such security is available in any of
the foregoing manners, the average of the intraday trading prices of any market
makers for such security that are listed in the "pink sheets" by the National
Quotation Bureau, Inc. If the Trading Price cannot be calculated for such
security on such date in the manner provided above, the Trading Price shall be
the fair market value as mutually determined by the Borrower and the holders of
a majority in interest of the Debentures being converted for which the
calculation of the Trading Price is required in order to determine the
Conversion Price of such Debentures. "Trading Day" shall mean any day on which
the Common Stock is actually traded for any period on the OTCBB, or on the
principal securities exchange or other securities market on which the Common
Stock is then being traded. "Applicable Percentage" shall mean 65.0%. The "Fixed
Conversion Price" shall mean $.03.


                                       3
<PAGE>

                  (b) Conversion Price During Major Announcements.
Notwithstanding anything contained in Section 1.2(a) to the contrary, in the
event the Borrower (i) makes a public announcement that it intends to
consolidate or merge with any other corporation (other than a merger in which
the Borrower is the surviving or continuing corporation and its capital stock is
unchanged) or sell or transfer all or substantially all of the assets of the
Borrower or (ii) any person, group or entity (including the Borrower) publicly
announces a tender offer to purchase 50% or more of the Borrower's Common Stock
(or any other takeover scheme) (the date of the announcement referred to in
clause (i) or (ii) is hereinafter referred to as the "Announcement Date"), then
the Conversion Price shall, effective upon the Announcement Date and continuing
through the Adjusted Conversion Price Termination Date (as defined below), be
equal to the lower of (x) the Conversion Price which would have been applicable
for a Conversion occurring on the Announcement Date and (y) the Conversion Price
that would otherwise be in effect. From and after the Adjusted Conversion Price
Termination Date, the Conversion Price shall be determined as set forth in this
Section 1.2(a). For purposes hereof, "Adjusted Conversion Price Termination
Date" shall mean, with respect to any proposed transaction or tender offer (or
takeover scheme) for which a public announcement as contemplated by this Section
1.2(b) has been made, the date upon which the Borrower (in the case of clause
(i) above) or the person, group or entity (in the case of clause (ii) above)
consummates or publicly announces the termination or abandonment of the proposed
transaction or tender offer (or takeover scheme) which caused this Section
1.2(b) to become operative.

                  (c) Injunction - Posting of Bond. In the event a Holder shall
elect to convert a Note or part thereof, the Company may not refuse conversion
based on any claim that such Holder or any one associated or affiliated with
such Holder has been engaged in any violation of law, or for any other reason,
unless, an injunction from a court, on notice, restraining and or enjoining
conversion of all or part of said Note shall have been sought and obtained and
the Company has posted a surety bond for the benefit of such Holder in the
amount of 130% of the amount of the Note, which is subject to the injunction,
which bond shall remain in effect until the completion of arbitration/litigation
of the dispute and the proceeds of which shall be payable to such Holder to the
extent Holder obtains judgment.

            1.3 Authorized Shares. The Borrower covenants that during the period
the conversion right exists, the Borrower will reserve from its authorized and
unissued Common Stock a sufficient number of shares, free from preemptive
rights, to provide for the issuance of Common Stock upon the full conversion of
this Debenture and the other Debentures issued pursuant to the Purchase
Agreement. The Borrower is required at all times to have authorized and reserved
two times the number of shares that is actually issuable upon full conversion of
the Debentures (based on the Conversion Price of the Debentures or the Exercise
Price of the Warrants in effect from time to time) (the "Reserved Amount"). The
Reserved Amount shall be increased from time to time in accordance with the
Borrower's obligations pursuant to Section 4(h) of the Purchase Agreement. The
Borrower represents that upon issuance, such shares will be duly and validly
issued, fully paid and non-assessable. In addition, if the Borrower shall issue
any securities or make any change to its capital structure which would change
the number of shares of Common Stock into which the Debentures shall be
convertible at the then current Conversion Price, the Borrower shall at the same
time make proper provision so that thereafter there shall be a sufficient number
of shares of Common Stock authorized and reserved, free from preemptive rights,
for conversion of the outstanding Debentures. The Borrower (i)


                                       4
<PAGE>

acknowledges that it has irrevocably instructed its transfer agent to issue
certificates for the Common Stock issuable upon conversion of this Debenture,
and (ii) agrees that its issuance of this Debenture shall constitute full
authority to its officers and agents who are charged with the duty of executing
stock certificates to execute and issue the necessary certificates for shares of
Common Stock in accordance with the terms and conditions of this Debenture.

            If, at any time a Holder of this Debenture submits a Notice of
Conversion, and the Borrower does not have sufficient authorized but unissued
shares of Common Stock available to effect such conversion in accordance with
the provisions of this Article I (a "Conversion Default"), subject to Section
4.8, the Borrower shall issue to the Holder all of the shares of Common Stock
which are then available to effect such conversion. The portion of this
Debenture which the Holder included in its Conversion Notice and which exceeds
the amount which is then convertible into available shares of Common Stock (the
"Excess Amount") shall, notwithstanding anything to the contrary contained
herein, not be convertible into Common Stock in accordance with the terms hereof
until (and at the Holder's option at any time after) the date additional shares
of Common Stock are authorized by the Borrower to permit such conversion, at
which time the Conversion Price in respect thereof shall be the lesser of (i)
the Conversion Price on the Conversion Default Date (as defined below) and (ii)
the Conversion Price on the Conversion Date thereafter elected by the Holder in
respect thereof. In addition, the Borrower shall pay to the Holder payments
("Conversion Default Payments") for a Conversion Default in the amount of (x)
the sum of (1) the then outstanding principal amount of this Debenture plus (2)
accrued and unpaid interest on the unpaid principal amount of this Debenture
through the Authorization Date (as defined below) plus (3) Default Interest, if
any, on the amounts referred to in clauses (1) and/or (2), multiplied by (y)
..24, multiplied by (z) (N/365), where N = the number of days from the day the
holder submits a Notice of Conversion giving rise to a Conversion Default (the
"Conversion Default Date") to the date (the "Authorization Date") that the
Borrower authorizes a sufficient number of shares of Common Stock to effect
conversion of the full outstanding principal balance of this Debenture. The
Borrower shall use its best efforts to authorize a sufficient number of shares
of Common Stock as soon as practicable following the earlier of (i) such time
that the Holder notifies the Borrower or that the Borrower otherwise becomes
aware that there are or likely will be insufficient authorized and unissued
shares to allow full conversion thereof and (ii) a Conversion Default. The
Borrower shall send notice to the Holder of the authorization of additional
shares of Common Stock, the Authorization Date and the amount of Holder's
accrued Conversion Default Payments. The accrued Conversion Default Payments for
each calendar month shall be paid in cash or shall be convertible into Common
Stock (at such time as there are sufficient authorized shares of Common Stock)
at the applicable Conversion Price, at the Holder's option, as follows:

                  (a) In the event Holder elects to take such payment in cash,
cash payment shall be made to Holder by the fifth (5th) day of the month
following the month in which it has accrued; and

                  (b) In the event Holder elects to take such payment in Common
Stock, the Holder may convert such payment amount into Common Stock at the
Conversion Price (as in effect at the time of conversion) at any time after the
fifth day of the month following the month in which it has accrued in accordance
with the terms of this Article I (so long as there is then a sufficient number
of authorized shares of Common Stock).


                                       5
<PAGE>

            The Holder's election shall be made in writing to the Borrower at
any time prior to 6:00 p.m., Palo Alto, California time, on the third day of the
month following the month in which Conversion Default payments have accrued. If
no election is made, the Holder shall be deemed to have elected to receive cash.
Nothing herein shall limit the Holder's right to pursue actual damages (to the
extent in excess of the Conversion Default Payments) for the Borrower's failure
to maintain a sufficient number of authorized shares of Common Stock, and each
holder shall have the right to pursue all remedies available at law or in equity
(including degree of specific performance and/or injunctive relief).

            1.4 Method of Conversion.

                  (a) Mechanics of Conversion. Subject to Section 1.1, this
Debenture may be converted by the Holder in whole or in part at any time from
time to time after the Issue Date, by (A) submitting to the Borrower a Notice of
Conversion (by facsimile or other reasonable means of communication dispatched
on the Conversion Date prior to 6:00 p.m., Palo Alto, California time) and (B)
subject to Section 1.4(b), surrendering this Debenture at the principal office
of the Borrower.

                  (b) Surrender of Debenture Upon Conversion. Notwithstanding
anything to the contrary set forth herein, upon conversion of this Debenture in
accordance with the terms hereof, the Holder shall not be required to physically
surrender this Debenture to the Borrower unless the entire unpaid principal
amount of this Debenture is so converted. The Holder and the Borrower shall
maintain records showing the principal amount so converted and the dates of such
conversions or shall use such other method, reasonably satisfactory to the
Holder and the Borrower, so as not to require physical surrender of this
Debenture upon each such conversion. In the event of any dispute or discrepancy,
such records of the Borrower shall be controlling and determinative in the
absence of manifest error. Notwithstanding the foregoing, if any portion of this
Debenture is converted as aforesaid, the Holder may not transfer this Debenture
unless the Holder first physically surrenders this Debenture to the Borrower,
whereupon the Borrower will forthwith issue and deliver upon the order of the
Holder a new Debenture of like tenor, registered as the Holder (upon payment by
the Holder of any applicable transfer taxes) may request, representing in the
aggregate the remaining unpaid principal amount of this Debenture. The Holder
and any assignee, by acceptance of this Debenture, acknowledge and agree that,
by reason of the provisions of this paragraph, following conversion of a portion
of this Debenture, the unpaid and unconverted principal amount of this Debenture
represented by this Debenture may be less than the amount stated on the face
hereof.

                  (c) Payment of Taxes. The Borrower shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
issue and delivery of shares of Common Stock or other securities or property on
conversion of this Debenture in a name other than that of the Holder (or in
street name), and the Borrower shall not be required to issue or deliver any
such shares or other securities or property unless and until the person or
persons (other than the Holder or the custodian in whose street name such shares
are to be held for the Holder's account) requesting the issuance thereof shall
have paid to the Borrower the amount of any such tax or shall have established
to the satisfaction of the Borrower that such tax has been paid.


                                       6
<PAGE>

                  (d) Delivery of Common Stock Upon Conversion. Upon receipt by
the Borrower from the Holder of a facsimile transmission (or other reasonable
means of communication) of a Notice of Conversion meeting the requirements for
conversion as provided in this Section 1.4, the Borrower shall issue and deliver
or cause to be issued and delivered to or upon the order of the Holder
certificates for the Common Stock issuable upon such conversion within two (2)
business days after such receipt (and, solely in the case of conversion of the
entire unpaid principal amount hereof, surrender of this Debenture) (such second
business day being hereinafter referred to as the "Deadline") in accordance with
the terms hereof and the Purchase Agreement (including, without limitation, in
accordance with the requirements of Section 2(g) of the Purchase Agreement that
certificates for shares of Common Stock issued on or after the effective date of
the Registration Statement upon conversion of this Debenture shall not bear any
restrictive legend).

                  (e) Obligation of Borrower to Deliver Common Stock. Upon
receipt by the Borrower of a Notice of Conversion, the Holder shall be deemed to
be the holder of record of the Common Stock issuable upon such conversion, the
outstanding principal amount and the amount of accrued and unpaid interest on
this Debenture shall be reduced to reflect such conversion, and, unless the
Borrower defaults on its obligations under this Article I, all rights with
respect to the portion of this Debenture being so converted shall forthwith
terminate except the right to receive the Common Stock or other securities, cash
or other assets, as herein provided, on such conversion. If the Holder shall
have given a Notice of Conversion as provided herein, the Borrower's obligation
to issue and deliver the certificates for Common Stock shall be absolute and
unconditional, irrespective of the absence of any action by the Holder to
enforce the same, any waiver or consent with respect to any provision thereof,
the recovery of any judgment against any person or any action to enforce the
same, any failure or delay in the enforcement of any other obligation of the
Borrower to the holder of record, or any setoff, counterclaim, recoupment,
limitation or termination, or any breach or alleged breach by the Holder of any
obligation to the Borrower, and irrespective of any other circumstance which
might otherwise limit such obligation of the Borrower to the Holder in
connection with such conversion. The Conversion Date specified in the Notice of
Conversion shall be the Conversion Date so long as the Notice of Conversion is
received by the Borrower before 6:00 p.m., Palo Alto, California time, on such
date.

                  (f) Delivery of Common Stock by Electronic Transfer. In lieu
of delivering physical certificates representing the Common Stock issuable upon
conversion, provided the Borrower's transfer agent is participating in the
Depository Trust Company ("DTC") Fast Automated Securities Transfer ("FAST")
program, upon request of the Holder and its compliance with the provisions
contained in Section 1.1 and in this Section 1.4, the Borrower shall use its
best efforts to cause its transfer agent to electronically transmit the Common
Stock issuable upon conversion to the Holder by crediting the account of
Holder's Prime Broker with DTC through its Deposit Withdrawal Agent Commission
("DWAC") system.

                  (g) Failure to Deliver Common Stock Prior to Deadline. Without
in any way limiting the Holder's right to pursue other remedies, including
actual damages and/or equitable relief, the parties agree that if delivery of
the Common Stock issuable upon conversion of this Debenture is more than two (2)
days after the Deadline (other than a failure due to the circumstances described
in Section 1.3 above, which failure shall be governed by such Section)


                                       7
<PAGE>

the Borrower shall pay to the Holder in cash, as liquidated damages and not as a
penalty, for each $5,000 of principal amount being converted, $50 per Trading
Day (increasing to $100 per Trading Day on the third Trading Day following the
Deadline and increasing to $200 per Trading Day on the sixth Trading Day after
the Deadline) for each Trading Day after the Deadline until the shares of Common
Stock are delivered. Such cash amount shall be paid to Holder by the fifth day
of the month following the month in which it has accrued or, at the option of
the Holder (by written notice to the Borrower by the first day of the month
following the month in which it has accrued), shall be added to the principal
amount of this Debenture, in which event interest shall accrue thereon in
accordance with the terms of this Debenture and such additional principal amount
shall be convertible into Common Stock in accordance with the terms of this
Debenture.

                  (h) Buy-In. In addition to any other rights available to the
Holder, if the Company fails to deliver to the Holder such shares issuable upon
conversion of a Note by the Deadline and if ten (10) days after the Deadline the
Holder purchases (in an open market transaction or otherwise) shares of Common
Stock to deliver in satisfaction of a sale by such Holder of the Common Stock
which the Subscriber anticipated receiving upon such conversion (a "Buy-In"),
then the Company shall pay in cash to the Holder (in addition to any remedies
available to or elected by the Subscriber) the amount by which (A) the Holder's
total purchase price (including brokerage commissions, if any) for the shares of
Common Stock so purchased exceeds (B) the aggregate principal and/or interest
amount of the Note for which such conversion was not timely honored, together
with interest thereon at a rate of 15% per annum, accruing until such amount and
any accrued interest thereon is paid in full (which amount shall be paid as
liquidated damages and not as a penalty). For example, if the Holder purchases
shares of Common Stock having a total purchase price of $11,000 to cover a
Buy-In with respect to an attempted conversion of $10,000 of note principal
and/or interest, the Company shall be required to pay the Holder $1,000, plus
interest. The Holder shall provide the Company written notice indicating the
amounts payable to the Holder in respect of the Buy-In. The delivery date by
which Common Stock must be delivered pursuant to this Section shall be tolled
for the amount of days that the Holder does not deliver information reasonably
requested by the Company's transfer agent.

            1.5 Concerning the Shares. The shares of Common Stock issuable upon
conversion of this Debenture may not be sold or transferred unless (i) such
shares are sold pursuant to an effective registration statement under the Act or
(ii) the Borrower or its transfer agent shall have been furnished with an
opinion of counsel (which opinion shall be in form, substance and scope
customary for opinions of counsel in comparable transactions) to the effect that
the shares to be sold or transferred may be sold or transferred pursuant to an
exemption from such registration or (iii) such shares are sold or transferred
pursuant to Rule 144 under the Act (or a successor rule) ("Rule 144") or (iv)
such shares are transferred to an "affiliate" (as defined in Rule 144) of the
Borrower who agrees to sell or otherwise transfer the shares only in accordance
with this Section 1.5 and who is an Accredited Investor (as defined in the
Purchase Agreement). Except as otherwise provided in the Purchase Agreement (and
subject to the removal provisions set forth below), until such time as the
shares of Common Stock issuable upon conversion of this Debenture have been
registered under the Act as contemplated by the Registration Rights Agreement or
otherwise may be sold pursuant to Rule 144 without any restriction as to the
number of securities as of a particular date that can then be immediately sold,


                                       8
<PAGE>

each certificate for shares of Common Stock issuable upon conversion of this
Debenture that has not been so included in an effective registration statement
or that has not been sold pursuant to an effective registration statement or an
exemption that permits removal of the legend, shall bear a legend substantially
in the following form, as appropriate:

      "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
      REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THE
      SECURITIES MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF
      AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER SAID
      ACT, OR AN OPINION OF COUNSEL IN FORM, SUBSTANCE AND SCOPE CUSTOMARY
      FOR OPINIONS OF COUNSEL IN COMPARABLE TRANSACTIONS, THAT REGISTRATION
      IS NOT REQUIRED UNDER SAID ACT UNLESS SOLD PURSUANT TO RULE 144 OR
      REGULATION S UNDER SAID ACT."

            The legend set forth above shall be removed and the Borrower shall
issue to the Holder a new certificate therefor free of any transfer legend if
(i) the Borrower or its transfer agent shall have received an opinion of
counsel, in form, substance and scope customary for opinions of counsel in
comparable transactions, to the effect that a public sale or transfer of such
Common Stock may be made without registration under the Act and the shares are
so sold or transferred, (ii) such Holder provides the Borrower or its transfer
agent with reasonable assurances that the Common Stock issuable upon conversion
of this Debenture (to the extent such securities are deemed to have been
acquired on the same date) can be sold pursuant to Rule 144 or (iii) in the case
of the Common Stock issuable upon conversion of this Debenture, such security is
registered for sale by the Holder under an effective registration statement
filed under the Act or otherwise may be sold pursuant to Rule 144 without any
restriction as to the number of securities as of a particular date that can then
be immediately sold. Nothing in this Debenture shall (i) limit the Borrower's
obligation under the Registration Rights Agreement or (ii) affect in any way the
Holder's obligations to comply with applicable prospectus delivery requirements
upon the resale of the securities referred to herein.

            1.6 Effect of Certain Events.

                  (a) Effect of Merger, Consolidation, Etc. At the option of the
Holder, the sale, conveyance or disposition of all or substantially all of the
assets of the Borrower, the effectuation by the Borrower of a transaction or
series of related transactions in which more than 50% of the voting power of the
Borrower is disposed of, or the consolidation, merger or other business
combination of the Borrower with or into any other Person (as defined below) or
Persons when the Borrower is not the survivor shall either: (i) be deemed to be
an Event of Default (as defined in Article III) pursuant to which the Borrower
shall be required to pay to the Holder upon the consummation of and as a
condition to such transaction an amount equal to the Default Amount (as defined
in Article III) or (ii) be treated pursuant to Section 1.6(b) hereof. "Person"
shall mean any individual, corporation, limited liability company, partnership,
association, trust or other entity or organization.

                  (b) Adjustment Due to Merger, Consolidation, Etc. If, at any
time when this Debenture is issued and outstanding and prior to conversion of
all of the Debentures,


                                       9
<PAGE>

there shall be any merger, consolidation, exchange of shares, recapitalization,
reorganization, or other similar event, as a result of which shares of Common
Stock of the Borrower shall be changed into the same or a different number of
shares of another class or classes of stock or securities of the Borrower or
another entity, or in case of any sale or conveyance of all or substantially all
of the assets of the Borrower other than in connection with a plan of complete
liquidation of the Borrower, then the Holder of this Debenture shall thereafter
have the right to receive upon conversion of this Debenture, upon the basis and
upon the terms and conditions specified herein and in lieu of the shares of
Common Stock immediately theretofore issuable upon conversion, such stock,
securities or assets which the Holder would have been entitled to receive in
such transaction had this Debenture been converted in full immediately prior to
such transaction (without regard to any limitations on conversion set forth
herein), and in any such case appropriate provisions shall be made with respect
to the rights and interests of the Holder of this Debenture to the end that the
provisions hereof (including, without limitation, provisions for adjustment of
the Conversion Price and of the number of shares issuable upon conversion of the
Debenture) shall thereafter be applicable, as nearly as may be practicable in
relation to any securities or assets thereafter deliverable upon the conversion
hereof. The Borrower shall not effect any transaction described in this Section
1.6(b) unless (a) it first gives, to the extent practicable, thirty (30) days
prior written notice (but in any event at least fifteen (15) days prior written
notice) of the record date of the special meeting of stockholders to approve, or
if there is no such record date, the consummation of, such merger,
consolidation, exchange of shares, recapitalization, reorganization or other
similar event or sale of assets (during which time the Holder shall be entitled
to convert this Debenture) and (b) the resulting successor or acquiring entity
(if not the Borrower) assumes by written instrument the obligations of this
Section 1.6(b). The above provisions shall similarly apply to successive
consolidations, mergers, sales, transfers or share exchanges.

                  (c) Adjustment Due to Distribution. If the Borrower shall
declare or make any distribution of its assets (or rights to acquire its assets)
to holders of Common Stock as a dividend, stock repurchase, by way of return of
capital or otherwise (including any dividend or distribution to the Borrower's
stockholders in cash or shares (or rights to acquire shares) of capital stock of
a subsidiary (i.e., a spin-off)) (a "Distribution"), then the Holder of this
Debenture shall be entitled, upon any conversion of this Debenture after the
date of record for determining stockholders entitled to such Distribution, to
receive the amount of such assets which would have been payable to the Holder
with respect to the shares of Common Stock issuable upon such conversion had
such Holder been the holder of such shares of Common Stock on the record date
for the determination of stockholders entitled to such Distribution.

                  (d) Adjustment Due to Dilutive Issuance. If the Company or any
subsidiary thereof, as applicable, at any time while Debentures are outstanding,
shall offer, sell, grant any option to purchase or offer, sell or grant any
right to reprice its securities, or otherwise dispose of or issue (or announce
any offer, sale, grant or any option to purchase or other disposition) any
Common Stock or any equity or equity equivalent securities (including any
equity, debt or other instrument that is at any time over the life thereof
convertible into or exchangeable for Common Stock) (collectively, "Common Stock
Equivalents") entitling any person to acquire shares of Common Stock, at a price
per share less than the Conversion Price (if the holder of the Common Stock or
Common Stock Equivalent so issued shall at any time, whether by operation of
purchase price adjustments, reset provisions, floating conversion,


                                       10
<PAGE>

exercise or exchange prices or otherwise, or due to warrants, options or rights
per share which is issued in connection with such issuance, be entitled to
receive shares of Common Stock at a price per share which is less than the
Conversion Price, such issuance shall be deemed to have occurred for less than
the Conversion Price), then, the Conversion Price shall be adjusted for such
conversions as Holders shall indicate in its Conversion Notices to equal the
conversion, exchange or purchase price for such Common Stock or Common Stock
Equivalents (including any reset provisions thereof) at issue. Such adjustment
shall be made whenever such Common Stock or Common Stock Equivalents are issued.
The Company shall notify the Holder in writing, no later than the business day
following the issuance of any Common Stock or Common Stock Equivalent subject to
this section, indicating therein the applicable issuance price, or of applicable
reset price, exchange price, conversion price and other pricing terms.

                  (e) Purchase Rights. If, at any time when any Debentures are
issued and outstanding, the Borrower issues any convertible securities or rights
to purchase stock, warrants, securities or other property (the "Purchase
Rights") pro rata to the record holders of any class of Common Stock, then the
Holder of this Debenture will be entitled to acquire, upon the terms applicable
to such Purchase Rights, the aggregate Purchase Rights which such Holder could
have acquired if such Holder had held the number of shares of Common Stock
acquirable upon complete conversion of this Debenture (without regard to any
limitations on conversion contained herein) immediately before the date on which
a record is taken for the grant, issuance or sale of such Purchase Rights or, if
no such record is taken, the date as of which the record holders of Common Stock
are to be determined for the grant, issue or sale of such Purchase Rights.

                  (f) Notice of Adjustments. Upon the occurrence of each
adjustment or readjustment of the Conversion Price as a result of the events
described in this Section 1.6, the Borrower, at its expense, shall promptly
compute such adjustment or readjustment and prepare and furnish to the Holder of
a certificate setting forth such adjustment or readjustment and showing in
detail the facts upon which such adjustment or readjustment is based. The
Borrower shall, upon the written request at any time of the Holder, furnish to
such Holder a like certificate setting forth (i) such adjustment or
readjustment, (ii) the Conversion Price at the time in effect and (iii) the
number of shares of Common Stock and the amount, if any, of other securities or
property which at the time would be received upon conversion of the Debenture.

            1.7 Status as Stockholder. Upon submission of a Notice of Conversion
by a Holder, (i) the shares covered thereby (other than the shares, if any,
which cannot be issued because their issuance would exceed such Holder's
allocated portion of the Reserved Amount or Maximum Share Amount) shall be
deemed converted into shares of Common Stock and (ii) the Holder's rights as a
Holder of such converted portion of this Debenture shall cease and terminate,
excepting only the right to receive certificates for such shares of Common Stock
and to any remedies provided herein or otherwise available at law or in equity
to such Holder because of a failure by the Borrower to comply with the terms of
this Debenture. Notwithstanding the foregoing, if a Holder has not received
certificates for all shares of Common Stock prior to the tenth (10th) business
day after the expiration of the Deadline with respect to a conversion of any
portion of this Debenture for any reason, then (unless the Holder otherwise
elects to retain its status as a holder of Common Stock by so notifying the
Borrower) the Holder shall regain the rights of a Holder of this Debenture with
respect to such unconverted portions of


                                       11
<PAGE>

this Debenture and the Borrower shall, as soon as practicable, return such
unconverted Debenture to the Holder or, if the Debenture has not been
surrendered, adjust its records to reflect that such portion of this Debenture
has not been converted. In all cases, the Holder shall retain all of its rights
and remedies (including, without limitation, (i) the right to receive Conversion
Default Payments pursuant to Section 1.3 to the extent required thereby for such
Conversion Default and any subsequent Conversion Default and (ii) the right to
have the Conversion Price with respect to subsequent conversions determined in
accordance with Section 1.3) for the Borrower's failure to convert this
Debenture.

                         ARTICLE II. CERTAIN COVENANTS

            2.1 Distributions on Capital Stock. So long as the Borrower shall
have any obligation under this Debenture, the Borrower shall not without the
Holder's written consent (a) pay, declare or set apart for such payment, any
dividend or other distribution (whether in cash, property or other securities)
on shares of capital stock other than dividends on shares of Common Stock solely
in the form of additional shares of Common Stock or (b) directly or indirectly
or through any subsidiary make any other payment or distribution in respect of
its capital stock except for distributions pursuant to any shareholders' rights
plan which is approved by a majority of the Borrower's disinterested directors.

            2.2 Restriction on Stock Repurchases. So long as the Borrower shall
have any obligation under this Debenture, the Borrower shall not without the
Holder's written consent redeem, repurchase or otherwise acquire (whether for
cash or in exchange for property or other securities or otherwise) in any one
transaction or series of related transactions any shares of capital stock of the
Borrower or any warrants, rights or options to purchase or acquire any such
shares.

            2.3 Borrowings. So long as the Borrower shall have any obligation
under this Debenture, the Borrower shall not, without the Holder's written
consent, create, incur, assume or suffer to exist any liability for borrowed
money, except (a) borrowings in existence or committed on the date hereof and of
which the Borrower has informed Holder in writing prior to the date hereof, (b)
indebtedness to trade creditors or financial institutions incurred in the
ordinary course of business or (c) borrowings, the proceeds of which shall be
used to repay this Debenture.

            2.4 Sale of Assets. So long as the Borrower shall have any
obligation under this Debenture, the Borrower shall not, without the Holder's
written consent, sell, lease or otherwise dispose of any significant portion of
its assets outside the ordinary course of business. Any consent to the
disposition of any assets may be conditioned on a specified use of the proceeds
of disposition.

            2.5 Advances and Loans. So long as the Borrower shall have any
obligation under this Debenture, the Borrower shall not, without the Holder's
written consent, lend money, give credit or make advances to any person, firm,
joint venture or corporation, including, without limitation, officers,
directors, employees, subsidiaries and affiliates of the Borrower, except loans,
credits or advances (a) in existence or committed on the date hereof and which
the


                                       12
<PAGE>

Borrower has informed Holder in writing prior to the date hereof, (b) made in
the ordinary course of business or (c) not in excess of $25,000.

            2.6 Contingent Liabilities. So long as the Borrower shall have any
obligation under this Debenture, the Borrower shall not, without the Holder's
written consent, assume, guarantee, endorse, contingently agree to purchase or
otherwise become liable upon the obligation of any person, firm, partnership,
joint venture or corporation, except by the endorsement of negotiable
instruments for deposit or collection and except assumptions, guarantees,
endorsements and contingencies (a) in existence or committed on the date hereof
and which the Borrower has informed Holder in writing prior to the date hereof,
and (b) similar transactions in the ordinary course of business.

                         ARTICLE III. EVENTS OF DEFAULT

            If any of the following events of default (each, an "Event of
Default") shall occur:

            3.1 Failure to Pay Principal or Interest. The Borrower fails to pay
the principal hereof or interest thereon when due on this Debenture, whether at
maturity, upon acceleration or otherwise.

            3.2 Conversion and the Shares. The Borrower fails to issue shares of
Common Stock to the Holder (or announces or threatens that it will not honor its
obligation to do so) upon exercise by the Holder of the conversion rights of the
Holder in accordance with the terms of this Debenture (for a period of at least
seven (7) days, if such failure is solely as a result of the circumstances
governed by Section 1.3 and the Borrower is using its best efforts to authorize
a sufficient number of shares of Common Stock as soon as practicable), fails to
transfer or cause its transfer agent to transfer (electronically or in
certificated form) any certificate for shares of Common Stock issued to the
Holder upon conversion of or otherwise pursuant to this Debenture as and when
required by this Debenture or the Registration Rights Agreement, or fails to
remove any restrictive legend (or to withdraw any stop transfer instructions in
respect thereof) on any certificate for any shares of Common Stock issued to the
Holder upon conversion of or otherwise pursuant to this Debenture as and when
required by this Debenture or the Registration Rights Agreement (or makes any
announcement, statement or threat that it does not intend to honor the
obligations described in this paragraph) and any such failure shall continue
uncured (or any announcement, statement or threat not to honor its obligations
shall not be rescinded in writing) for five (5) days after the Borrower shall
have been notified thereof in writing by the Holder.

            3.3 Failure to Timely File Registration or Effect Registration. The
Borrower fails to file the Registration Statement within 30 days of the Closing
(as defined in the Purchase Agreement), or obtain effectiveness with the
Securities and Exchange Commission of the Registration Statement within ninety
(90) days following the Filing Date (as defined in the Registration Rights
Agreement), or such Registration Statement lapses in effect (or sales cannot
otherwise be made thereunder effective, whether by reason of the Borrower's
failure to amend or supplement the prospectus included therein in accordance
with the Registration Rights


                                       13
<PAGE>

Agreement or otherwise) for more than twenty (20) consecutive days or forty (40)
days in any twelve month period after the Registration Statement becomes
effective;

            3.4 Breach of Covenants. The Borrower breaches any material covenant
or other material term or condition contained in Sections 1.3 or 1.6 of this
Debenture, Sections 4(c), 4(e), 4(h), 4(i), 4(j), 4(l), 4(m) or 5 of the
Purchase Agreement or Section 2 of the Registration Rights Agreement and such
breach continues for a period of five (5) days after written notice thereof to
the Borrower from the Holder;

            3.5 Failure to Pay Standard Liquidated Damages and/or other amounts
due under Transaction Documents. The Borrower fails to pay any Standard
Liquidated Damages due under the Securities Purchase Agreement or any other
amounts due under the Transaction Documents within five (5) days after written
notice thereof to the Borrower from the Holder.

            3.6 Failure to remove legend from shares upon valid 144 sale. The
Borrower fails to instruct its transfer agent to remove any legends from shares
of Common Stock eligible to be sold under Rule 144 of the Securities Act and
issue such unlegended certificates to the Holder within three (3) business days
of the Holder's request so long as the Holder has provided the standard
representations regarding the Rule 144 sale.

            3.7 Breach of Representations and Warranties. Any representation or
warranty of the Borrower made herein or in any agreement, statement or
certificate given in writing pursuant hereto or in connection herewith
(including, without limitation, the Purchase Agreement and the Registration
Rights Agreement), shall be false or misleading in any material respect when
made and the breach of which has (or with the passage of time will have) a
material adverse effect on the rights of the Holder with respect to this
Debenture, the Purchase Agreement or the Registration Rights Agreement;

            3.8 Receiver or Trustee. The Borrower or any subsidiary of the
Borrower shall make an assignment for the benefit of creditors, or apply for or
consent to the appointment of a receiver or trustee for it or for a substantial
part of its property or business, or such a receiver or trustee shall otherwise
be appointed;

            3.9 Judgments. Any money judgment, writ or similar process shall be
entered or filed against the Borrower or any subsidiary of the Borrower or any
of its property or other assets for more than $50,000, and shall remain
unvacated, unbonded or unstayed for a period of twenty (20) days unless
otherwise consented to by the Holder, which consent will not be unreasonably
withheld;

            3.10 Bankruptcy. Bankruptcy, insolvency, reorganization 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
Borrower or any subsidiary of the Borrower;

            3.11 Delisting of Common Stock. The Borrower shall fail to maintain
the listing of the Common Stock on at least one of the OTCBB, the Nasdaq
National Market, the Nasdaq SmallCap Market, the New York Stock Exchange, or the
American Stock Exchange;


                                       14
<PAGE>

            3.12 Default Under Other Debentures. An Event of Default has
occurred and is continuing under any of the other Debentures issued pursuant to
the Purchase Agreement,

then, upon the occurrence and during the continuation of any Event of Default
specified in Section 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.9, 3.11 or 3.12, at
the option of the Holders of a majority of the aggregate principal amount of the
outstanding Debentures issued pursuant to the Purchase Agreement exercisable
through the delivery of written notice to the Borrower by such Holders (the
"Default Notice"), and upon the occurrence of an Event of Default specified in
Section 3.6 or 3.8, the Debentures shall become immediately due and payable and
the Borrower shall pay to the Holder, in full satisfaction of its obligations
hereunder, an amount equal to the greater of (i) 135% times the sum of (w) the
then outstanding principal amount of this Debenture plus (x) accrued and unpaid
interest on the unpaid principal amount of this Debenture to the date of payment
(the "Mandatory Prepayment Date") plus (y) Default Interest, if any, on the
amounts referred to in clauses (w) and/or (x) plus (z) any amounts owed to the
Holder pursuant to Sections 1.3 and 1.4(g) hereof or pursuant to Section 2(c) of
the Registration Rights Agreement (the then outstanding principal amount of this
Debenture to the date of payment plus the amounts referred to in clauses (x),
(y) and (z) shall collectively be known as the "Default Sum") or (ii) the
"parity value" of the Default Sum to be prepaid, where parity value means (a)
the highest number of shares of Common Stock issuable upon conversion of or
otherwise pursuant to such Default Sum in accordance with Article I, treating
the Trading Day immediately preceding the Mandatory Prepayment Date as the
"Conversion Date" for purposes of determining the lowest applicable Conversion
Price, unless the Default Event arises as a result of a breach in respect of a
specific Conversion Date in which case such Conversion Date shall be the
Conversion Date), multiplied by (b) the highest Closing Price for the Common
Stock during the period beginning on the date of first occurrence of the Event
of Default and ending one day prior to the Mandatory Prepayment Date (the
"Default Amount") and all other amounts payable hereunder shall immediately
become due and payable, all without demand, presentment or notice, all of which
hereby are expressly waived, together with all costs, including, without
limitation, legal fees and expenses, of collection, and the Holder shall be
entitled to exercise all other rights and remedies available at law or in
equity. If the Borrower fails to pay the Default Amount within five (5) business
days of written notice that such amount is due and payable, then the Holder
shall have the right at any time, so long as the Borrower remains in default
(and so long and to the extent that there are sufficient authorized shares), to
require the Borrower, upon written notice, to immediately issue, in lieu of the
Default Amount, the number of shares of Common Stock of the Borrower equal to
the Default Amount divided by the Conversion Price then in effect.

                           ARTICLE IV. MISCELLANEOUS

            4.1 Failure or Indulgence Not Waiver. No failure or delay on the
part of the Holder in the exercise of any power, right or privilege hereunder
shall operate as a waiver thereof, nor shall any single or partial exercise of
any such power, right or privilege preclude other or further exercise thereof or
of any other right, power or privileges. All rights and remedies existing
hereunder are cumulative to, and not exclusive of, any rights or remedies
otherwise available.


                                       15
<PAGE>

            4.2 Notices. Any notice herein required or permitted to be given
shall be in writing and may be personally served or delivered by courier or sent
by United States mail and shall be deemed to have been given upon receipt if
personally served (which shall include telephone line facsimile transmission) or
sent by courier or three (3) days after being deposited in the United States
mail, certified, with postage pre-paid and properly addressed, if sent by mail.
For the purposes hereof, the address of the Holder shall be as shown on the
records of the Borrower; and the address of the Borrower shall be 3450 Hillview
Avenue, Palo Alto, California 94304, facsimile number: 650-855-0222. Both the
Holder and the Borrower may change the address for service by service of written
notice to the other as herein provided.

            4.3 Amendments. This Debenture and any provision hereof may only be
amended by an instrument in writing signed by the Borrower and the Holder. The
term "Debenture" and all reference thereto, as used throughout this instrument,
shall mean this instrument (and the other Debentures issued pursuant to the
Purchase Agreement) as originally executed, or if later amended or supplemented,
then as so amended or supplemented.

            4.4 Assignability. This Debenture shall be binding upon the Borrower
and its successors and assigns, and shall inure to be the benefit of the Holder
and its successors and assigns. Each transferee of this Debenture must be an
"accredited investor" (as defined in Rule 501(a) of the 1933 Act).
Notwithstanding anything in this Debenture to the contrary, this Debenture may
be pledged as collateral in connection with a bona fide margin account or other
lending arrangement.

            4.5 Cost of Collection. If default is made in the payment of this
Debenture, the Borrower shall pay the Holder hereof costs of collection,
including reasonable attorneys' fees.

            4.6 Governing Law. THIS AGREEMENT SHALL BE ENFORCED, GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD
TO THE PRINCIPLES OF CONFLICT OF LAWS. THE PARTIES HERETO HEREBY SUBMIT TO THE
EXCLUSIVE JURISDICTION OF THE STATE COURTS OR THE UNITED STATES FEDERAL COURTS
LOCATED IN NEW YORK WITH RESPECT TO ANY DISPUTE ARISING UNDER THIS AGREEMENT,
THE AGREEMENTS ENTERED INTO IN CONNECTION HEREWITH OR THE TRANSACTIONS
CONTEMPLATED HEREBY OR THEREBY. BOTH PARTIES IRREVOCABLY WAIVE THE DEFENSE OF AN
INCONVENIENT FORUM TO THE MAINTENANCE OF SUCH SUIT OR PROCEEDING. BOTH PARTIES
FURTHER AGREE THAT SERVICE OF PROCESS UPON A PARTY MAILED BY FIRST CLASS MAIL
SHALL BE DEEMED IN EVERY RESPECT EFFECTIVE SERVICE OF PROCESS UPON THE PARTY IN
ANY SUCH SUIT OR PROCEEDING. NOTHING HEREIN SHALL AFFECT EITHER PARTY'S RIGHT TO
SERVE PROCESS IN ANY OTHER MANNER PERMITTED BY LAW. BOTH PARTIES AGREE THAT A
FINAL NON-APPEALABLE JUDGMENT IN ANY SUCH SUIT OR PROCEEDING SHALL BE CONCLUSIVE
AND MAY BE ENFORCED IN OTHER JURISDICTIONS BY SUIT ON SUCH JUDGMENT OR IN ANY
OTHER LAWFUL MANNER. THE PARTY WHICH DOES NOT PREVAIL IN ANY DISPUTE ARISING
UNDER THIS AGREEMENT SHALL BE RESPONSIBLE FOR


                                       16
<PAGE>

ALL FEES AND EXPENSES, INCLUDING ATTORNEYS' FEES, INCURRED BY THE PREVAILING
PARTY IN CONNECTION WITH SUCH DISPUTE.

            4.7 Certain Amounts. Whenever pursuant to this Debenture the
Borrower is required to pay an amount in excess of the outstanding principal
amount (or the portion thereof required to be paid at that time) plus accrued
and unpaid interest plus Default Interest on such interest, the Borrower and the
Holder agree that the actual damages to the Holder from the receipt of cash
payment on this Debenture may be difficult to determine and the amount to be so
paid by the Borrower represents stipulated damages and not a penalty and is
intended to compensate the Holder in part for loss of the opportunity to convert
this Debenture and to earn a return from the sale of shares of Common Stock
acquired upon conversion of this Debenture at a price in excess of the price
paid for such shares pursuant to this Debenture. The Borrower and the Holder
hereby agree that such amount of stipulated damages is not plainly
disproportionate to the possible loss to the Holder from the receipt of a cash
payment without the opportunity to convert this Debenture into shares of Common
Stock.

            4.8 Allocations of Maximum Share Amount and Reserved Amount. The
Maximum Share Amount and Reserved Amount shall be allocated pro rata among the
Holders of Debentures based on the principal amount of such Debentures issued to
each Holder. Each increase to the Maximum Share Amount and Reserved Amount shall
be allocated pro rata among the Holders of Debentures based on the principal
amount of such Debentures held by each Holder at the time of the increase in the
Maximum Share Amount or Reserved Amount. In the event a Holder shall sell or
otherwise transfer any of such Holder's Debentures, each transferee shall be
allocated a pro rata portion of such transferor's Maximum Share Amount and
Reserved Amount. Any portion of the Maximum Share Amount or Reserved Amount
which remains allocated to any person or entity which does not hold any
Debentures shall be allocated to the remaining Holders of Debentures, pro rata
based on the principal amount of such Debentures then held by such Holders.

            4.9 Damages Shares. The shares of Common Stock that may be issuable
to the Holder pursuant to Sections 1.3 and 1.4(g) hereof and pursuant to Section
2(c) of the Registration Rights Agreement ("Damages Shares") shall be treated as
Common Stock issuable upon conversion of this Debenture for all purposes hereof
and shall be subject to all of the limitations and afforded all of the rights of
the other shares of Common Stock issuable hereunder, including without
limitation, the right to be included in the Registration Statement filed
pursuant to the Registration Rights Agreement. For purposes of calculating
interest payable on the outstanding principal amount hereof, except as otherwise
provided herein, amounts convertible into Damages Shares ("Damages Amounts")
shall not bear interest but must be converted prior to the conversion of any
outstanding principal amount hereof, until the outstanding Damages Amounts is
zero.

            4.10 Denominations. At the request of the Holder, upon surrender of
this Debenture, the Borrower shall promptly issue new Debentures in the
aggregate outstanding principal amount hereof, in the form hereof, in such
denominations of at least $50,000 as the Holder shall request, or in the amount
of the balance of the Debenture.


                                       17
<PAGE>

            4.11 Purchase Agreement. By its acceptance of this Debenture, each
Holder agrees to be bound by the applicable terms of the Purchase Agreement.

            4.12 Notice of Corporate Events. Except as otherwise provided below,
the Holder of this Debenture shall have no rights as a Holder of Common Stock
unless and only to the extent that it converts this Debenture into Common Stock.
The Borrower shall provide the Holder with prior notification of any meeting of
the Borrower's stockholders (and copies of proxy materials and other information
sent to stockholders). In the event of any taking by the Borrower of a record of
its stockholders for the purpose of determining stockholders who are entitled to
receive payment of any dividend or other distribution, any right to subscribe
for, purchase or otherwise acquire (including by way of merger, consolidation,
reclassification or recapitalization) any share of any class or any other
securities or property, or to receive any other right, or for the purpose of
determining stockholders who are entitled to vote in connection with any
proposed sale, lease or conveyance of all or substantially all of the assets of
the Borrower or any proposed liquidation, dissolution or winding up of the
Borrower, the Borrower shall mail a notice to the Holder, at least twenty (20)
days prior to the record date specified therein (or thirty (30) days prior to
the consummation of the transaction or event, whichever is earlier), of the date
on which any such record is to be taken for the purpose of such dividend,
distribution, right or other event, and a brief statement regarding the amount
and character of such dividend, distribution, right or other event to the extent
known at such time. The Borrower shall make a public announcement of any event
requiring notification to the Holder hereunder substantially simultaneously with
the notification to the Holder in accordance with the terms of this Section
4.12.

            4.13 Remedies. The Borrower acknowledges that a breach by it of its
obligations hereunder will cause irreparable harm to the Holder, by vitiating
the intent and purpose of the transaction contemplated hereby. Accordingly, the
Borrower acknowledges that the remedy at law for a breach of its obligations
under this Debenture will be inadequate and agrees, in the event of a breach or
threatened breach by the Borrower of the provisions of this Debenture, that the
Holder shall be entitled, in addition to all other available remedies at law or
in equity, and in addition to the penalties assessable herein, to an injunction
or injunctions restraining, preventing or curing any breach of this Debenture
and to enforce specifically the terms and provisions thereof, without the
necessity of showing economic loss and without any bond or other security being
required.

                         ARTICLE V. OPTIONAL PREPAYMENT

            5.1 Optional Prepayment. Notwithstanding anything to the contrary
contained in this Article V, for not more than thirty (30) days from the date
hereof, so long as (i) no Event of Default or Trading Market Prepayment Event
shall have occurred and be continuing, and (ii) the Borrower has a sufficient
number of authorized shares of Common Stock reserved for issuance upon full
conversion of the Debentures, then at any time after the Issue Date, the
Borrower shall have the right, exercisable on not less than ten (10) Trading
Days prior written notice to the Holders of the Debentures (which notice may not
be sent to the Holders of the Debentures until the Borrower is permitted to
prepay the Debentures pursuant to this Section 5.1), to prepay all of the
outstanding Debentures in accordance with this Section 5.1. Any notice


                                       18
<PAGE>

of prepayment hereunder (an "Optional Prepayment") shall be delivered to the
Holders of the Debentures at their registered addresses appearing on the books
and records of the Borrower and shall state (1) that the Borrower is exercising
its right to prepay all of the Debentures issued on the Issue Date and (2) the
date of prepayment (the "Optional Prepayment Notice"). On the date fixed for
prepayment (the "Optional Prepayment Date"), the Borrower shall make payment of
the Optional Prepayment Amount (as defined below) to or upon the order of the
Holders as specified by the Holders in writing to the Borrower at least one (1)
business day prior to the Optional Prepayment Date. If the Borrower exercises
its right to prepay the Debentures, the Borrower shall make payment to the
holders of an amount in cash (the "Optional Prepayment Amount") equal to 135%
multiplied by the sum of (w) the then outstanding principal amount of this
Debenture plus (x) accrued and unpaid interest on the unpaid principal amount of
this Debenture to the Optional Prepayment Date plus (y) Default Interest, if
any, on the amounts referred to in clauses (w) and (x) plus (z) any amounts owed
to the Holder pursuant to Sections 1.3 and 1.4(g) hereof or pursuant to Section
2(c) of the Registration Rights Agreement (the then outstanding principal amount
of this Debenture to the date of payment plus the amounts referred to in clauses
(x), (y) and (z) shall collectively be known as the "Optional Prepayment Sum").
Notwithstanding notice of an Optional Prepayment, the Holders shall at all times
prior to the Optional Prepayment Date maintain the right to convert all or any
portion of the Debentures in accordance with Article I and any portion of
Debentures so converted after receipt of an Optional Prepayment Notice and prior
to the Optional Prepayment Date set forth in such notice and payment of the
aggregate Optional Prepayment Amount shall be deducted from the principal amount
of Debentures which are otherwise subject to prepayment pursuant to such notice.
If the Borrower delivers an Optional Prepayment Notice and fails to pay the
Optional Prepayment Amount due to the Holders of the Debentures within two (2)
business days following the Optional Prepayment Date, the Borrower shall forever
forfeit its right to redeem the Debentures pursuant to this Section 5.1.

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                                       19
<PAGE>

            IN WITNESS WHEREOF, Borrower has caused this Debenture to be signed
in its name by its duly authorized officer this ___ day of November, 2003.


                                        AMNIS SYSTEMS  INC.


                                        By:_____________________________________
                                           Scott MacCaughern
                                           Chairman and Chief Executive Officer


                                       20
<PAGE>

                                                                       EXHIBIT A

                              NOTICE OF CONVERSION
                    (To be Executed by the Registered Holder
                       in order to Convert the Debentures)

            The undersigned hereby irrevocably elects to convert
$________principal amount of the Debenture (defined below) into shares of common
stock, par value $.0001 per share ("Common Stock"), of Amnis Systems Inc., a
Delaware corporation (the "Borrower") according to the conditions of the
convertible debentures of the Borrower dated as of November __, 2003 (the
"Debentures"), as of the date written below. If securities are to be issued in
the name of a person other than the undersigned, the undersigned will pay all
transfer taxes payable with respect thereto and is delivering herewith such
certificates. No fee will be charged to the Holder for any conversion, except
for transfer taxes, if any. A copy of each Debenture is attached hereto (or
evidence of loss, theft or destruction thereof).

            The Borrower shall electronically transmit the Common Stock issuable
pursuant to this Notice of Conversion to the account of the undersigned or its
nominee with DTC through its Deposit Withdrawal Agent Commission system ( "DWAC
Transfer").

      Name of DTC Prime Broker:______________________________________

      Account Number:________________________________________________

            In lieu of receiving shares of Common Stock issuable pursuant to
this Notice of Conversion by way of a DWAC Transfer, the undersigned hereby
requests that the Borrower issue a certificate or certificates for the number of
shares of Common Stock set forth below (which numbers are based on the Holder's
calculation attached hereto) in the name(s) specified immediately below or, if
additional space is necessary, on an attachment hereto:

      Name:__________________________________________________________

      Address:_______________________________________________________

            The undersigned represents and warrants that all offers and sales by
the undersigned of the securities issuable to the undersigned upon conversion of
the Debentures shall be made pursuant to registration of the securities under
the Securities Act of 1933, as amended (the "Act"), or pursuant to an exemption
from registration under the Act.

      Date of Conversion:____________________________________________

      Applicable Conversion Price:___________________________________

      Number of Shares of Common Stock to be Issued Pursuant to
      Conversion of the Debentures:__________________________________

      Signature:_____________________________________________________

      Name:__________________________________________________________

      Address:_______________________________________________________

            The Borrower shall issue and deliver shares of Common Stock to an
overnight courier not later than three business days following receipt of the
original Debenture(s) to be converted, and shall make payments pursuant to the
Debentures for the number of business days such issuance and delivery is late.


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