Document:

EXHIBIT 4.2.3

THESE SECURITIES AND THE SECURITIES ISSUABLE UPON THEIR EXERCISE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933 AND MAY NOT BE TRANSFERRED UNLESS
COVERED BY AN EFFECTIVE REGISTRATION STATEMENT UNDER SAID ACT, A TRANSFER
MEETING THE REQUIREMENTS OF RULE 144 OF THE SECURITIES AND EXCHANGE COMMISSION,
OR AN OPINION OF COUNSEL SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY SUCH
TRANSFER IS EXEMPT FROM SUCH REGISTRATION.

                               AMBIENT CORPORATION

                          COMMON STOCK PURCHASE WARRANT

            1. Issuance; Certain Definitions. In consideration of good and
valuable consideration, the receipt of which is hereby acknowledged by AMBIENT
CORPORATION, a Delaware corporation (the "Company"), ENGLEWOOD HOLDING, INC or
registered assigns (the "Holder") is hereby granted the right to purchase at any
time until 5:00 P.M., New York City time, on February 28, 2002 (the "Expiration
Date"), One Million Three Hundred Thousand (1,300,000) fully paid and
nonassessable shares of the Company's Common Stock, par value $.001 per share
(the "Common Stock") at an initial exercise price per share (the "Exercise
Price") of One Dollar ($1.00), subject to further adjustment as set forth
herein.

            2. Exercise of Warrants.

                  2.1 General. This Warrant is exercisable in whole or in part
at any time and from time to time at the Exercise Price per share of Common
Stock payable hereunder, payable in cash or by certified or official bank check,
by means of tendering this Warrant Certificate to the Company. Upon surrender of
this Warrant Certificate with the annexed Notice of Exercise Form duly executed
(which Notice of Exercise Form may be submitted either by delivery to the
Company or by facsimile transmission as provided in Section 8 hereof), together
with payment of the Exercise Price for the shares of Common Stock purchased, the
Holder shall be entitled to receive a certificate or certificates for the shares
of Common Stock so purchased.

                  2.2 Limitation on Exercise. Notwithstanding the provisions of
this Warrant, in no event (except 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 exercise this Warrant, or shall the Company have the obligation, to
issue shares upon such exercise of all or any portion of this Warrant, to the
extent that, after such exercise, 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
unexercised portion of the Warrants), and (2) the number of shares of Common
Stock issuable upon the exercise of the Warrants 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 4.99% of the outstanding
shares

<PAGE>

of Common Stock (after taking into account the shares to be issued to the Holder
upon such exercise). 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 Warrant, further agrees that if the Holder transfers or
assigns any of the Warrants 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 2.2
as if such transferee or assignee were the original Holder hereof.

            3. Reservation of Shares. The Company hereby agrees that at all
times during the term of this Warrant there shall be reserved for issuance upon
exercise of this Warrant such number of shares of its Common Stock as shall be
required for issuance upon exercise of this Warrant (the "Warrant Shares").

            4. Mutilation or Loss of Warrant. Upon receipt by the Company of
evidence satisfactory to it of the loss, theft, destruction or mutilation of
this Warrant, and (in the case of loss, theft or destruction) receipt of
reasonably satisfactory indemnification, and (in the case of mutilation) upon
surrender and cancellation of this Warrant, the Company will execute and deliver
a new Warrant of like tenor and date and any such lost, stolen, destroyed or
mutilated Warrant shall thereupon become void.

            5. Rights of the Holder. The Holder shall not, by virtue hereof, be
entitled to any rights of a stockholder in the Company, either at law or equity,
and the rights of the Holder are limited to those expressed in this Warrant and
are not enforceable against the Company except to the extent set forth herein.

            6. Protection Against Dilution.

                  6.1 Adjustment Mechanism. If an adjustment of the Exercise
Price is required pursuant to this Section 6, the Holder shall be entitled to
purchase such number of additional shares of Common Stock as will cause (i) the
total number of shares of Common Stock Holder is entitled to purchase pursuant
to this Warrant, multiplied by (ii) the adjusted purchase price per share, to
equal (iii) the dollar amount of the total number of shares of Common Stock
Holder is entitled to purchase before adjustment multiplied by the total
purchase price before adjustment.

                  6.2 Capital Adjustments. In case of any stock split or reverse
stock split, stock dividend, reclassification of the Common Stock,
recapitalization, merger or consolidation, or like capital adjustment affecting
the Common Stock of the Company, the provisions of this Section 6 shall be
applied as if such capital adjustment event had occurred immediately prior to
the date of this Warrant and the original purchase price had been fairly
allocated to the stock resulting from such capital adjustment; and in other
respects the provisions of this Section shall be applied in a fair, equitable
and reasonable manner so as to give effect, as nearly as may be, to the purposes
hereof.

                                       2
<PAGE>

A rights offering to stockholders shall be deemed a stock dividend to the extent
of the bargain purchase element of the rights.

                  6.3 Adjustment for Spin Off. If, for any reason, prior to the
exercise of this Warrant in full, the Company spins off or otherwise divests
itself of a part of its business or operations or disposes 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 (a) 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
unexercised Warrants 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 Warrants") been exercised as
of the close of business on the trading day immediately before the Record Date
(the "Reserved Spin Off Shares"), and (b) to be issued to the Holder on the
exercise of all or any of the Outstanding Warrants, such amount of the Reserved
Spin Off Shares equal to (i) the Reserved Spin Off Shares multiplied by (ii) a
fraction, of which (x) the numerator is the amount of the Outstanding Warrants
then being exercised, and (y) the denominator is the amount of the Outstanding
Warrants.

            7. Transfer to Comply with the Securities Act; Registration Rights.

                  7.1 Transfer. This Warrant has not been registered under the
Securities Act of 1933, as amended, (the "Act") and has been issued to the
Holder for investment and not with a view to the distribution of either the
Warrant or the Warrant Shares. Neither this Warrant nor any of the Warrant
Shares or any other security issued or issuable upon exercise of this Warrant
may be sold, transferred, pledged or hypothecated in the absence of an effective
registration statement under the Act relating to such security or an opinion of
counsel satisfactory to the Company that registration is not required under the
Act. Each certificate for the Warrant, the Warrant Shares and any other security
issued or issuable upon exercise of this Warrant shall contain a legend on the
face thereof, in form and substance satisfactory to counsel for the Company,
setting forth the restrictions on transfer contained in this Section.

                  7.2 Registration Rights. (a) The Company hereby grants to the
Holder piggyback registration rights with respect to the Warrant Shares. In the
event the Company is filing a Registration Statement for itself or on behalf of
any of its shareholders, the Company shall notify the Holder in writing
reasonably in advance of such filing (but at least five business days) and give
the Holder the opportunity to include all or any party of the Warrant Shares
(whether or not previously issued, to the extent permissible under the Act or
any regulation promulgated thereunder. Upon the Holder's notification that the
Holder desires to have all or any portion of the Warrant Shares included in such
registration, the Company shall, at no cost or expense to the Holder, include or
cause to be included in such registration statement the Warrant Shares so
identified by the Holder. The Company's obligations under the foregoing
provisions of this Section 7.2 will be satisfied by

                                       3
<PAGE>

the inclusion of the Warrant Shares in the Registration Statement contemplated
by that certain Registration Rights Agreement, dated as of February 17, 2000
(the "Registration Rights Agreement"), to which the Company and certain
purchasers of the Company's 10% Convertible Debentures are parties, provided
such Registration Statement is declared effective and remains effective for the
term contemplated in the Registration Rights Agreement.

                  (b) In addition to the registration rights referred to in the
preceding provisions of Section 7.2(a), effective after the expiration of the
effectiveness of the Registration Statement as contemplated by the Registration
Rights Agreement, the Holder shall have demand piggy-back registration rights
with respect to the Warrant Shares then held by the Holder or then subject to
issuance upon exercise of this Warrant (collectively, the "Remaining Warrant
Shares"), subject to the conditions set forth below. If, at any time after the
Registration Statement has ceased to be effective, the Company participates
(whether voluntarily or by reason of an obligation to a third party) in the
registration of any shares of the Company's stock, the Company shall give
written notice thereof to the Holder and the Holder shall have the right,
exercisable within ten (10) business days after receipt of such notice, to
demand inclusion of all or a portion of the Holder's Remaining Warrant Shares in
such registration statement. If the Holder exercises such election, the
Remaining Warrant Shares so designated shall be included in the registration
statement at no cost or expense to the Holder (other than any costs or
commissions which would be borne by the Holder under the terms of the
Registration Rights Agreement). The Holder's rights under this Section 7.2(b)
are subject to the following conditions:

      (x) under no circumstances will the Aggregate Remaining Warrant Shares (as
      defined below) included in such registration statement exceed twenty
      percent (20%) of the all the shares (including the Aggregate Remaining
      Warrant Shares) included in such registration statement; and

      (y) if there is a managing underwriter of the offering of shares referred
      to in the registration statement and such managing underwriter advises the
      Company in writing that the number of shares proposed to be included in
      the offering will have an adverse effect on its ability to successfully
      conclude the offering and, as a result, the number of shares to be
      included in the offering is to be reduced, the number of Remaining Warrant
      Shares of the Holder which were to be included in the registration (before
      such reduction) will be reduced pro rata with the number of shares
      included for all other parties whose shares are being registered.

The term "Aggregate Remaining Warrant Shares" means the aggregate of all
Remaining Warrant Shares of the Holder and of the holders of all other Warrants
originally issued pursuant to and as contemplated by the Securities Purchase
Agreement, to the extent such Remaining Warrant Shares are to be included in a
registration statement pursuant to this Section 7.2(b).

            8. Notices. Any notice or other communication required or permitted
hereunder shall be in writing and shall be delivered personally, telegraphed,
telexed, sent by facsimile

                                       4
<PAGE>

transmission or sent by certified, registered or express mail, postage pre-paid.
Any such notice shall be deemed given when so delivered personally, telegraphed,
telexed or sent by facsimile transmission, or, if mailed, two days after the
date of deposit in the United States mails, as follows:

                  (i)   if to the Company, to:

                        Ambient Corporation
                        270 Madison Avenue
                        New York, NY 10016
                        Attn:
                        Telephone No.: (888) 861-0205
                        Telecopier No.: (212)

                        with a copy to:

                        Baer Marks & Upham LLP.
                        805 Third Avenue
                        New York, NY 10022
                        Attn: Samuel Ottensosser Esq.
                        Telephone No.: (212) 702-5700
                        Telecopier No.: (212) 702-5941

                        and with a copy to:

                        Aboudi & Brounstein
                        3 Gavish St.
                        P.O.B. 2432
                        Kfar Saba Industrial Zone, Israel 44641
                        Attn: David Aboudi, Esq.
                        Telephone No.: (011 972 9) 764-4833
                        Telecopier No.: (011 972 9) 764-4834

                  (ii)  if to the Holder, to:

                        ENGLEWOOD HOLDING, INC.

                        Telephone No.: (     )
                        Telecopier No.: (     )

                                       5
<PAGE>

                        with a copy to:

                        Krieger & Prager,  LLP.
                        Suite 1440
                        39 Broadway
                        New York, New York 10006
                        Attn: Sam Krieger, Esq.
                        Telecopier No.  (212) 363-2999
                        Telephone No.: (212) 363-2900

Any party may be notice given in accordance with this Section to the other
parties designate another address or person for receipt of notices hereunder.

            9. Supplements and Amendments; Whole Agreement. This Warrant may be
amended or supplemented only by an instrument in writing signed by the parties
hereto. This Warrant of even date herewith contain the full understanding of the
parties hereto with respect to the subject matter hereof and thereof and there
are no representations, warranties, agreements or understandings other than
expressly contained herein and therein.

            10. Governing Law. This Warrant shall be deemed to be a contract
made under the laws of the State of Delaware for contracts to be wholly
performed in such state and without giving effect to the principles thereof
regarding the conflict of laws. Each of the parties consents to the jurisdiction
of the federal courts whose districts encompass any part of the City of
Wilmington or the state courts of the State of Delaware sitting in the City of
Wilmington in connection with any dispute arising under this Warrant and hereby
waives, to the maximum extent permitted by law, any objection, including any
objection based on forum non conveniens, 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 fees and disbursements incurred by
the Buyer in enforcement of or protection of any of its rights under any of the
Transaction Agreements.

            11. Counterparts. This Warrant may be executed in any number of
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument.

                                       6
<PAGE>

            12. Descriptive Headings. Descriptive headings of the several
Sections of this Warrant are inserted for convenience only and shall not control
or affect the meaning or construction of any of the provisions hereof.

      IN WITNESS WHEREOF, the parties hereto have executed this Warrant as of
the17th day of February 2000.

                                    AMBIENT CORPORATION

                                    By:_________________________________
                                         Name:
                                         Its:

Attest:

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

                                       7
<PAGE>

                         NOTICE OF EXERCISE OF WARRANT

      The undersigned hereby irrevocably elects to exercise the right,
represented by the Warrant Certificate dated as of ___________________, 200_, to
purchase ________ shares of the Common Stock, par value $.001 per share, of
AMBIENT CORPORATION and tenders herewith payment in accordance with Section 1 of
said Common Stock Purchase Warrant.

      Please deliver the stock certificate to:

Dated:______________________

____________________________
[Name of Holder]

                                       8
<PAGE>

By:_________________________

|_| CASH: $ _______________________

                                       9Exhibit 10.5
                              EMPLOYMENT AGREEMENT

      THIS EMPLOYMENT AGREEMENT is entered into as of the 27th day of March,
2000 between Michael Braunold (the "Employee") and PLT Solutions Inc., a
Delaware company (the "Company").

                               W I T N E S S E T H

      WHEREAS, the Company is wishes to employ the Employee in accordance with
the terms and conditions of this Agreement, and the Employee wishes to be so
employed.

NOW THEREFORE the parties hereto agree as follows:

1. Employment. With effect from the effective date (as defined in section 2),
the Company hereby engages Employee to serve as chief executive officer who
shall perform such duties, undertake such responsibilities and exercise such
authority as the Board of Directors.

2. Term.

      2.1 Employee's employment under this Agreement shall commence not later
than March 27th, 2000 (the "Effective Date") and, unless otherwise provided,
shall end on the earlier of (i) the death or disability (as defined herein ) of
the Employee, (ii) termination of Employee's employment by Company with cause
(as defined herein); (iii) after one year from the Effective Date (the "initial
term"), (vi) termination of Employee's employment without cause by the Company
or Employee upon 90 days prior written notice any time. After the expiration of
such initial term (other than for reasons set forth in clauses (i), (ii) and
(vi) this Agreement shall automatically be renewed for an additional one (1)
year periods on the same terms and conditions set forth herein (unless mutually
agreed otherwise).

Notwithstanding the foregoing, in the event that Company or Employee shall have
terminated this Agreement without cause, upon the request of the Company the
Employee shall vacate his position and the premises on a date specified by the
Company which is earlier than the end of the notice period specified in (vi)
above upon payment to Employee, in one lump sum on the effective date of
termination, the amount of pro rata Gross Salary payable under Section 3.1 from
the effective date of termination until the end of such notice period.

      2.2 For the purpose of this paragraph 2, "disability" shall mean any
physical or mental illness or injury as a result of which Employee remains
absent from work for a period of two (2) successive months, or an aggregate of
two (2) months in any twelve (12) month period. Disability shall occur at the
end of any such period.

      2.3 For the purpose of this paragraph 2, "cause" shall exist if Employee
(i) breaches any of the material terms or conditions of this Agreement; (ii)
substantially fails to perform the Employee's areas of responsibility set forth
herein, (iii) engages in willful misconduct or acts in bad faith with respect to
the Company, in connection with and related to the employment hereunder, (iv) is
convicted of a felony, (v) fails to comply with the

<PAGE>
                                       2

instructions of the Company's Board; provided that with respect to clauses (i)
and (ii), if Employee has cured any such condition within 15 days following
delivery of the advance notice, then "cause" shall be deemed not to exist. For
purposes of this Paragraph 2, "advance notice" shall constitute a written notice
delivered to Employee that sets forth with particularity the facts and
circumstances relied upon by the Company as the basis for cause.

3. Compensation

      3.1 During the term hereof, and subject to the performance of the services
required to be performed hereunder by Employee, the Company shall pay to the
Employee for all services rendered hereunder, as salary, payable not less often
than once per month and in accordance with the Company's normal and reasonable
payroll practices, a monthly gross amount equal to $3000 payable (the "Gross
Salary") less required employee deductions under law.

      3.2 (i) Employee shall be issued options to acquire up to 100,000 shares
of Common Stock of the Company's parent company, Ambient Corporation ("Options")
exercisable at par value of the shares. At the option of the Company, these
Options may be issued from and pursuant to a Company employee stock option plan
or otherwise. Such Options shall vest in the Employee equally over three (3)
years, so long as Employee remains in the employ of the Company and in
accordance with the terms and subject to Employee executing the Company's
standard Employee Stock Option Plan. The options shall vest in the Employee
pro-rata to the number of complete months which Employee was employed hereunder.

If the Company sells all or substantially all of its assets, the Employee shall
be entitled to exercise, immediately prior to such sale the Options which have
not yet vested.

      3.3 Upon the execution of this Agreement the Company shall pay to Employee
the sum of $12,000, less required deductions.

4. Vacation. The Employee shall be entitled to 21 working days of paid vacation
during each fiscal year that this Agreement is in effect to be taken at times as
agreed upon by the parties.

5. Development Rights. The Employee agrees and declares that all proprietary
information including but not limited to trade secrets, know-how, patents and
other rights in connection therewith developed by or with the contribution of
Employee's efforts during his employment with the Company shall be the sole
property of the Company. Upon the Company's request (whenever made), Employee
shall execute and assign to the Company all the rights in the proprietary
information.

6. Secrecy and Nondisclosure The Employee shall treat as secret and confidential
all of the processes, methods, formulas, procedures, techniques, software,
designs, know-how, data, and other information which are not of public knowledge
or record pertaining to the Company's business (existing, potential, and
future), including without limitation all business information relating to
customers and supplies and products of which the employee becomes aware during
and as a result of employment with the Company, and Employee shall not

<PAGE>
                                       3

disclose, use, publish, or in any other manner reveal, directly or indirectly,
at any time during and after the term of this Agreement, any such information
detailed herein.

7. Non-Competition & Poaching

      7.1 During the term of this Agreement and for a term of one (1) year after
Employee ceases to be employed by the Company, Employee will not, directly or
indirectly, for his own account or as an employee, officer, director, partner,
joint venturer, shareholder, investor, consultant or otherwise (except as an
investor in a corporation whose stock is publicly traded and in which Employee
holds less than 5% of the outstanding shares) engage in or contribute his
knowledge to any work or activity that involves a product, process, service or
development which directly competes with the business of the Company, now or
hereafter existing or which relates to internet security.

      7.2 Employee acknowledges that the restricted period of time and
geographical location specified under this Section 7 are reasonable, in view of
the nature of the business in which the Company is engaged and Employee's
knowledge of the Company's business and products. If such period of time or
geographical location should be determined to be unreasonable in any judicial
proceeding, then the period of time and area of restriction shall be reduced so
that this Agreement may be enforced in such area and during such period of time
as shall be determined to be reasonable by such judicial proceeding.

      7.3 The Employee shall not at any time during the period from the
termination of this Agreement or any extension hereof, to the expiry of six (6)
months, employ or attempt to employ or solicit or endeavor to entice away from
or discourage from being employed by the Company any person who is, or shall at
any time until the termination of this Agreement or any extension hereof, one of
the employees of the Company.

8. Miscellaneous

      8.1 Employee Representations. The Employee represents and warrants to the
Company that the execution and delivery of this Agreement and the fulfillment of
the terms hereof (i) will not constitute a breach of any agreement or other
instrument to which he is party, (ii) does not require the consent of any
person, and (iii) shall not utilize during the term of his employment any
proprietary information of any third party, including prior employers of the
Employee.

      8.2 Entire Agreement. This Agreement constitutes the entire understanding
and agreement between the parties and supersedes any and all prior discussions
and agreements and correspondence, and may not be amended or modified in any
respect except by a subsequent writing executed by both parties.

      8.3 Notices. All notices or other communications required or desired to be
sent to either Party shall be in writing and shall be sent by hand or by
Registered or Certified mail, postage prepaid, return receipt requested, or sent
by telegram or facsimile to the address set forth in the Preamble to this
Agreement or to such other address as the recipient may designate by notice in
accordance with the provisions of this Clause. Any such notice shall

<PAGE>
                                       4

have been deemed to have been delivered if served by hand when delivered, if by
Registered or Certified Mail 48 hours after posting if within the same country
or 14 days if posted from another country, and by telex or facsimile
transmission when dispatched and receipt confirmed by recipient party.

      8.4 Severability. Any term or provision of this Agreement which is found
by a court, tribunal or arbitration panel to be invalid or unenforceable shall
be ineffective to the extent of such invalidity or unenforceability without
rendering invalid or unenforceable the remaining terms or provisions of this
Agreement or affecting the validity or enforceability of any of the other terms
or provisions of this Agreement. In the event that any term or provision of this
Agreement is found to be unenforceable or ineffective, then the reviewing court,
tribunal or arbitration panel may modify such term or provision to the extent
necessary to render it enforceable and the parties agree to be bound by and
perform this Agreement as modified.

      8.5 Applicable Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York.

      IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
signed by the date stated above.

PLT Solutions Inc.

S/Michael Braunold                              S/Michael Braunold
------------------                              ------------------
                                                Michael Braunold

Ambient Corporation hereby agrees to section 3.2 herein.

Ambient Corporation

S/Michael Braunold
------------------

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00007-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00007-of-00352.parquet"}]]