Document:

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                                                                    EXHIBIT 4.11

                            SHARE PURCHASE AGREEMENT

THIS SHARE PURCHASE AGREEMENT (the "Agreement") is made and entered into on this
22nd-day of February 2000.

BY AND BETWEEN:

(1)      The persons whose names and addresses are set out in the first column
         of Exhibit 1 (the "Selling Shareholders"); and

(2)      SIEMENS Aktiengesellschaft of Hofmannstrasse 51, D-81359, Munich,
         Germany (the "Purchaser"); and

(3)      RADVision Ltd. of Raoul Wallenberg Street, Tel Aviv 69719, Israel (the
         "Company" and collectively with the Selling Shareholders, the
         "Sellers").

WHEREAS:

I.       The Company has filed a registration statement with the U.S. Securities
         and Exchange Commission for the purpose of an initial public offering
         (the "IPO") of its ordinary shares, par value NIS 0.1 per share (the
         "Ordinary Shares"); and

II.      The Purchaser desires to purchase an aggregate of 1,625,228 Ordinary
         Shares (the "Shares") from the Selling Shareholders and the Company,
         subject to and in accordance with the terms and conditions set forth
         herein; and

III.     The Selling Shareholders desire to sell to the Purchaser 1,259,461 of
         the Shares (the "Selling Shareholders' Shares") and the Company desires
         to sell to the Purchaser 365,767 of the Shares (the "Company's
         Shares"), in each case subject to the terms and conditions set forth
         herein.

NOW, THEREFORE, THE PARTIES HEREBY AGREE AS FOLLOWS:

1. PREAMBLE AND DEFINITIONS

   1.1. The preamble to this Agreement and the exhibits and schedules attached
        hereto form an integral part of this Agreement.

   1.2. In this Agreement and in the exhibits and schedules hereto, unless the
        context otherwise requires, the following terms shall bear the meanings
        set forth opposite them:

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                "CLOSING"                   The consummation of the transactions
                                            contemplated by this Agreement as
                                            provided in Section 3.

                "REGISTRATION STATEMENT"    The Company's Registration Statement
                                            on Form F-1 (File No. 333-     ), as
                                            amended, initially filed with the
                                            U.S. Securities and Exchange
                                            Commission on February __, 2000
                                            attached hereto as SCHEDULE 1.1.

2. SALE AND PURCHASE OF SHARES

   2.1. Subject to the terms and conditions of this Agreement, (i) the Selling
        Shareholders agree to sell to the Purchaser, and the Purchaser agrees,
        upon the basis of the representations and warranties contained herein,
        to purchase from the Selling Shareholders, the Selling Shareholders'
        Shares free and clear of any pledges, encumbrances, attachments or any
        other third party rights of any nature whatsoever; and (ii) the Company
        agrees to sell to the Purchaser, and the Purchaser agrees, upon the
        basis of the representations and warranties contained herein, to
        purchase from the Company, the Company's Shares free and clear of any
        pledges, encumbrances, attachments or any other third party rights of
        any nature whatsoever; all of the Shares having all of the rights,
        preferences, privileges and restrictions set forth in the form of
        amended Articles of Association of the Company (the "NEW ARTICLES") to
        be adopted immediately prior to the closing of the IPO; PROVIDED, that,
        notwithstanding anything herein to the contrary, the Sellers shall not
        be obligated to sell the Shares to the Purchaser unless the Purchaser
        purchases all 1,625,228 Shares and the Purchaser shall not be obligated
        to buy the Shares from the Sellers unless the Sellers sell all 1,625,228
        Shares. The Purchase and sale of the Shares is intended to be a private
        placement and not a public offering or part of a public offering.

   2.2. Each of the Selling Shareholders hereby waives, with respect to the
        Shares to be sold to the Purchaser hereunder, any right of first
        refusal, pre-emption or any other right which may be conferred on it by
        the Articles of Association of the Company in effect on the date hereof,
        by any agreement relating to the Ordinary Shares or otherwise.

   2.3. To the extent that any of the Selling Shareholders holds Shares as a
        trustee for others, it shall be the responsibility of each such Selling
        Shareholder to procure all releases and/or waivers from all persons for
        whom such Selling Shareholder holds such Shares in trust. The Selling
        Shareholders will deliver at the Closing evidence of such release or
        waiver in a form reasonably satisfactory to the Purchaser.

3. CLOSING

   3.1. The purchase and sale of the Shares shall be held at the Company's
        offices on Raoul Wallenberg Street, Tel Aviv, on the business day of the
        IPO at 15:00 (local time) or, if later, upon satisfaction or waiver by
        the parties hereto of each of the conditions set forth in Section 4
        (such date, the "CLOSING DATE"). At the Closing, the following
        transactions shall occur, which transactions shall be deemed to take
        place simultaneously and none of them shall be completed or deemed to be
        completed until all shall have occurred:

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   3.1.1 Each of the Selling Shareholders shall execute and deliver to the
         Company a share transfer deed, in the form required to effect the
         transfer of the number of the Selling Shareholders' Shares set forth
         opposite their name on Exhibit 2.1 hereto.

   3.1.2 Each of the Selling Shareholders shall deliver to the Company its old
         share certificate or certify in writing that he lost such share
         certificate or the Company shall declare that a share certificate was
         never issued to such Selling Shareholder.

   3.1.3 The Company shall deliver to the Purchaser, to be held in escrow by the
         Escrow Agent as defined below until all Closing conditions have been
         fulfilled, a certified copy of a resolution of the Board of Directors
         of the Company issuing and allotting the Company's Shares to the
         Purchaser, together with a duly completed notice of such issuance to
         the Israel Registrar of Companies in form and substance acceptable for
         immediate filing with the Israel Registrar of Companies.

   3.1.4 The Company shall register the Purchaser in its register of
         shareholders as the owner of the Shares and shall have the American
         stock transfer agent issue to the Purchaser a validly executed share
         certificate representing the Shares within three (3) business days of
         the Closing.

   3.1.5 The Company shall deliver to the Purchaser, to be held in escrow by the
         Escrow Agent as defined below until all Closing conditions have been
         fulfilled, a duly executed certificate of confirmation from the
         Secretary of the Company certifying that the Purchaser has been duly
         registered in the registry of shareholders of the Company as the owner
         of the Shares.

   3.1.6 Each of the Selling Shareholders, the Company and the Purchaser shall
         deliver to the other Parties a written confirmation attesting that all
         of the representations, warranties and undertakings provided in this
         Agreement are true, correct and effective on and as of the Closing
         Date.

   3.1.7 In consideration for the Shares, the Purchaser shall deposit with the
         Escrow Agent (as defined hereunder) for the benefit of the Sellers the
         Purchase Price (as defined hereunder) less any tax which is required to
         be withheld pursuant to law, to be transferred to the Escrow Agent's
         bank account [details of which shall be provided to the Purchaser in
         writing at least 5 business days prior to the Closing Date], in readily
         available liquid funds, such funds shall be credited to such account
         immediately by bank transfer executed at the Closing.

         For purposes of this Agreement, the "PURCHASE PRICE" shall equal the
         number of the Shares (transferred and issued) multiplied by the Per
         Share Purchase Price (as defined hereinafter). The "PER SHARE PURCHASE
         PRICE" shall equal the per share price of the Company's Ordinary Shares
         to be offered to the public in the IPO prior to any public trading,
         excluding any underwriting discounts and commissions, PROVIDED that in
         no event shall the Per Share Purchase Price exceed U.S.$17.00.

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   3.2.  The Sellers hereby irrevocably appoint Advocate Israel Kantor as
         trustee (the "ESCROW AGENT") to receive the Purchase Price due by the
         Purchaser to the Sellers hereunder. The Escrow Agent shall transfer the
         Purchase Price to RAD Data Communications Ltd. (the "Payment Agent")
         once all of the Closing conditions have been fulfilled. The Sellers
         confirm and acknowledge that payments made by the Purchaser or the
         Escrow Agent to the Payment Agent and acknowledged as received by the
         Payment Agent shall constitute good and sufficient receipt of such
         payments as if the payments were made directly to the Sellers. The
         Purchaser shall have no responsibility for the allocation by the
         Payment Agent among the Sellers of any sum paid by the Purchaser to the
         Payment Agent.

   3.3.  For the avoidance of doubt and without derogating from any other
         documents and agreements which may exist between the parties, it is
         hereby clarified that the Purchase Price to be paid at the Closing
         shall be full and complete consideration for the Shares and the
         Sellers, or any of them, shall not be entitled to any other payment of
         any nature whatsoever with respect to the Shares.

4. CLOSING CONDITIONS

   4.1.  The obligation of the Purchaser to purchase the Shares, and of the
         Sellers to sell the Shares, at the Closing shall be subject to the
         satisfaction or waiver of the following conditions precedent on or
         prior to the Closing Date:

         4.1.1. The Voting Agreement among the Purchaser and certain of the
                Selling Shareholders, in the form attached hereto as Exhibit
                4.1.1 (the "VOTING AGREEMENT"), shall have been executed and
                delivered by all the parties thereto.

         4.1.2. The Umbrella License Agreement between the Company and the
                Purchaser in the form attached hereto as Exhibit 4.1.2 (the
                "LICENSE AGREEMENT"), shall have been executed and delivered by
                all the parties thereto.

         4.1.3. The execution and the delivery of this Agreement and the
                consummation of the transactions contemplated hereby shall have
                been approved by the following regulatory authorities: (i) the
                Investment Center of the Israeli Ministry of Industry and Trade
                and (ii) the Office of the Chief Scientist of the Ministry of
                Industry and Trade.

         4.1.4. The closing of the IPO of the Company's Ordinary Shares shall
                have occurred.

         4.1.5. All documents to be delivered by the Company and the Selling
                Shareholders pursuant to Section 3 above shall be delivered.

         4.1.6. The New Articles shall have been duly adopted.

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 5. REPRESENTATIONS AND WARRANTIES OF THE COMPANY The Company hereby represents
    and warrants to the Purchaser as follows:

   5.1.  ORGANIZATION AND GOOD STANDING. The Company is a corporation duly
         organized, validly existing and in good standing under the laws of the
         State of Israel and has all requisite corporate power and authority to
         carry on its business as now conducted.

   5.2.  AUTHORIZATION. All corporate action on the part of the Company and its
         officers, directors and shareholders necessary for the authorization,
         execution and delivery of this Agreement, the performance of the
         obligations of the Company hereunder and the authorization, issuance
         and delivery of the Company's Shares has been taken or will be taken
         prior to the Closing. Except as set forth in Section 4.1.3 hereof, no
         consent, approval, order, license, permit, action by, or authorization
         of or designation, declaration, or filing with any governmental
         authority, domestic or foreign, is required in connection with the
         valid execution, delivery and performance of this Agreement or the
         offer, sale and/or issuance of the Shares.

   5.3.  BINDING EFFECT. This Agreement constitutes a valid and binding
         agreement of the Company, enforceable against the Company in accordance
         with its terms.

   5.4.  NO CONFLICTS. The execution and delivery of this Agreement, the
         consummation of the transactions contemplated hereby and the compliance
         with the terms and provisions hereof will not conflict with, result in
         a breach or violation of, or constitute a default under (i) the
         Company's Memorandum of Association, and the New Articles; (ii) any
         contract, agreement, lease, license or commitment to which the Company
         is a party or to which it is subject; (iii) any judgment, order,
         injunction, decree or ruling of any court or governmental authority,
         domestic or foreign, to which the Company is subject; and/or (iv)
         applicable law.

   5.5.  COMPANY'S SHARES. The Company's Shares, when issued, sold and delivered
         in accordance with the terms hereof for the consideration expressed,
         will be duly and validly issued, fully paid and nonassessable.
         Furthermore, the Company's Shares, when issued, shall be free and clear
         of any pledges, encumbrances, attachments or any other third party
         rights of any nature whatsoever.

   5.6.  EXEMPTION FROM REGISTRATION. Assuming the accuracy of the Purchaser's
         representations set forth in Section 7 hereof, the offer, sale and
         issuance of the Company's Shares to the Purchaser on the Closing Date
         as contemplated by this Agreement are exempt from the registration
         requirements of the Securities Act of 1933, as amended (the "Securities
         Act").

   5.7.  DISCLOSURE. On the Closing Date, the Registration Statement: (i) does
         not include any untrue statement of a material fact or omits to state
         any material fact required to be stated therein or necessary to make
         the statements therein, in light of the circumstances under which they
         were made, not misleading.

   5.8.  ACCOUNTANTS AND FINANCIAL STATEMENTS. The accountants who have
         certified or shall certify the financial statements filed or to be
         filed with the Securities and Exchange Commission as part of the
         Registration Statement are independent accountants as are required by
         the Securities Act. The consolidated financial statements (including
         all related notes and schedules) of the

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         Company and its subsidiaries contained in the Registration Statement
         are complete and correct and fairly present the financial position and
         results of operations of the Company and its subsidiaries at the
         respective dates and for the respective periods to which they apply.
         Such financial statements have been prepared in accordance with
         generally accepted principles of accounting consistently applied
         throughout the periods involved.

   5.9.  TAX REPORTS AND LIABILITY. The Company has timely complied with all
         requirements pertaining to the filing of tax returns and tax reports
         and supplied the tax authorities with all required documentation and
         information. The Company has duly and timely paid in full all taxes
         shown as due on such returns and reports, except for such untimely
         payment that would not have a material adverse effect on the Company,
         or to the extent such taxes are accrued but not yet due, has adequately
         reserved for the timely payment of any and all such taxes when due. The
         Company is unaware of any unpaid tax liability or potential tax
         liability of the Company pertaining to any period or event prior to the
         date of the execution of this Agreement.

6. REPRESENTATIONS AND WARRANTIES OF THE SELLING SHAREHOLDERS Each of the
   Selling Shareholders hereby represents and warrants to the Purchaser as
   follows:

   6.1.  ORGANIZATION AND GOOD STANDING. Such Seller is a corporation, limited
         partnership or limited liability company, as applicable, duly
         organized, validly existing and in good standing under the laws of its
         jurisdiction of organization.

   6.2.  AUTHORIZATION. All corporate action on the part of such Seller, and its
         officers, directors and shareholders necessary for the authorization,
         execution and delivery of this Agreement, the performance of all
         obligations of such Seller hereunder, and the transfer and delivery of
         such Selling Shareholders' Shares has been taken or will be taken prior
         to the Closing.

   6.3.  BINDING EFFECT. This Agreement constitutes a valid and binding
         agreement of such Selling Shareholder, enforceable against such Selling
         Shareholder in accordance with its terms.

   6.4.  NO CONFLICTS. The execution and delivery of this Agreement, the
         consummation of the transactions contemplated hereby and the compliance
         with the terms and provisions hereof will not conflict with, result in
         a breach or violation of, or constitute a default under (i) such
         Selling Shareholders' organizational documents; or(ii) any contract or
         agreement to which such Selling Shareholder is a party, except in the
         case of clause (ii) for such conflict, breach, violation or default
         which would not have a material adverse effect on such Selling
         Shareholders' business, financial condition or results of operations.

   6.5.  REGISTRATION STATEMENT. Such Selling Shareholder is familiar with the
         Registration Statement and has no knowledge of any material fact,
         condition or information not disclosed in the Registration Statement
         which has materially adversely affected or may materially adversely
         affect the business of the Company or any of its subsidiaries; and the
         sale of the Selling Shareholders' Shares owned by such Selling
         Shareholder pursuant hereto is not prompted by any information
         concerning the Company or any of its subsidiaries which is not set
         forth in the Registration Statement.

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   6.6.  TITLE. Such Seller is the record owner of the number of the Selling
         Shareholders' Shares set forth opposite the name of such Selling
         Shareholder on Exhibit 2.1 hereto and has good and marketable title to
         such Shares, free and clear of any pledges, encumbrances, attachments
         or any other third party right of any nature whatsoever with respect to
         such Shares.

7. REPRESENTATIONS AND WARRANTIES OF THE PURCHASER The Purchaser hereby
   represents and warrants to each of the Sellers as follows:

   7.1.  ORGANIZATION AND GOOD STANDING. The Purchaser is a corporation duly
         organized, validly existing and in good standing under the laws of
         Germany.

   7.2.  AUTHORIZATION. All corporate action on the part of the Purchaser, and
         its officers, directors and shareholders necessary for the purchase of
         the Shares pursuant to this Agreement and the performance of its
         obligations hereunder has been taken or will be taken prior to the
         Closing.

   7.3.  BINDING EFFECT. This Agreement constitutes a valid and binding
         agreement of the Purchaser, enforceable against the Purchaser in
         accordance with its terms.

   7.4.  NO CONFLICTS. The execution and delivery of this Agreement, the
         consummation of the transactions contemplated hereby and the compliance
         with the terms and provisions hereof will not conflict with, result in
         a breach or violation of, or constitute a default under (i) the
         Purchaser's organizational documents; and (ii) any contract or
         agreement to which the Purchaser is a party, except in the case of
         clause (ii) for such conflict, breach, violation or default which would
         not have a material adverse effect on the Purchaser's business,
         financial condition or results of operations.

   7.5.  PURCHASE ENTIRELY FOR OWN ACCOUNT. The Shares will be acquired for
         investment for the Purchaser's own account, not as a nominee or agent,
         and not with a view to the immediate resale or distribution of any part
         thereof, and the Purchaser has no present intention of selling,
         granting any participation in, or otherwise distributing the Shares.

   7.6.  AVAILABLE INFORMATION. The Purchaser has received the following
         information: the Registration Statement, audited financial statements
         for the year ending December 31, 1999 included in the Registration
         Statement and the Business Plan for Year 2000 prior to making its
         decision to purchase the Shares.

   7.7.  INVESTMENT EXPERIENCE. The Purchaser is experienced in evaluating and
         investing in securities of companies in the software and information
         technology industry. and acknowledges that it is able to fend for
         itself, can bear the economic risk of the investment in the Shares, and
         has such knowledge and experience in financial and business matters
         that it is capable of evaluating the merits and risks of the investment
         in the Shares. The Purchaser has not been organized solely for the
         purpose of acquiring the Shares.

   7.8.  ACCREDITED INVESTOR. The Purchaser is an "accredited investor," as that
         term is defined in Rule 501 of Regulation D of the Securities Act.

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   7.9.  PURCHASER NOT A U.S. PERSON. The Purchaser is not a "U.S. Person"
         within the meaning of Rule 902(k) of Regulation S of the Securities
         Act.

   7.10. PURCHASE MADE IN AN "OFFSHORE TRANSACTION" WITH "NO DIRECTED SELLING
         EFFORTS WITHIN THE UNITED STATES." The Purchaser was not physically
         present in the United States when the Purchaser was offered the Shares
         and the offer was not accompanied by any form of advertising in the
         United States or other "directed selling efforts" within the United
         States within the meaning of Rule 902(c) of Regulation S of the
         Securities Act.

   7.11. BROKERAGE COMMISSIONS. No broker's commissions were, or will be
         required to be, paid by the Purchaser in connection with this
         transaction.

8. REGISTRATION RIGHTS AND STAMP DUTY

   8.1   The Selling Shareholders shall assign to the Purchaser the registration
         rights attached to the Shares sold by them. Said assignment shall be
         effectuated at the Closing.

   8.2   The Company shall pay the stamp duty due on the issuance of the
         Company's Shares.

9. COVENANTS OF THE PURCHASER

   9.1.  LOCK UP. Prior to the date which is 270 days after the closing of the
         IPO (the "Lockup Date"), the Purchaser shall not, directly or
         indirectly, Transfer (as defined below) or offer to Transfer any of the
         Shares, and the Purchaser shall sign an undertaking addressed to the
         underwriters in the form set forth in Exhibit 8.1 to such effect. In
         order to enforce the transfer restrictions set forth in the prior
         sentence, the Company may impose stop-transfer instructions with
         respect to the Shares until the Lockup Date. As used in this Agreement,
         the term "Transfer" shall mean any sale, transfer, assignment,
         hypothecation, encumbrance or other disposition, whether voluntary or
         involuntary, of any of the Shares. In the case of a hypothecation, the
         Transfer shall be deemed to occur both at the time of the initial
         pledge and at any pledgee's sale or a sale by any secured creditor or a
         retention by the secured creditor of the pledged Shares in complete or
         partial satisfaction of the indebtedness for which the Shares are
         security.

   9.2.  MARKET STAND-OFF. In addition to the transfer restrictions set forth in
         Section 8.1 (which shall in no way be limited by the following), in
         connection with any underwritten public offering by the Company of its
         equity securities pursuant to an effective registration statement filed
         under the Securities Act, the Purchaser shall not Transfer or offer to
         Transfer any of the Shares without the prior written consent of the
         Company and its underwriters. Such restriction (the "Market Stand-Off")
         shall be in effect for such period of time from and after the effective
         date of the final prospectus for the offering as may be requested by
         the Company or such underwriters; PROVIDED, HOWEVER, that such Market
         Stand-Off shall not exceed 270 days from the Closing. In order to
         enforce the Market Stand-Off, the Company may impose stop-transfer
         instructions with respect to the Shares until the end of the applicable
         stand-off period.

   9.3.  The Purchaser hereby declares that it will not make an hostile takeover
         of the Company.

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   9.4.  LEGAL OBLIGATIONS. Immediately after the Closing, the Purchaser
         undertakes to file all the necessary documents and reports required to
         be filed by the Purchaser by any relevant authority, in Israel, the US
         or elsewhere, and to abide by all the appropriate rules, regulations
         and laws applying to a foriegn equity holder, including, without
         limitation, undertaking towards the Office of Chief Scientist to comply
         with the Research and Development Law and timely filing a Schedule 13D
         reporting the acquisition of securities of a public company with the US
         Securities and Exchange Commission.

   9.5.  RIGHT TO A DIRECTOR AND VOTING AGREEMENT. Upon the Closing, the
         Purchaser shall be entitled to nominate one director on his behalf to
         the Company's Board of Directors by way of a voting agreement. The
         Board of Directors meetings, and the minutes thereof, shall be in the
         English language. Directors of the Company and of its subsidiaries
         shall be entitled to attend meetings of the Board of Directors by means
         of a conference call, videoconference or similar means of
         telecommunication which ensure that all participating directors are
         able to hear each other simultaneously. The Purchaser and the Sellers
         listed on Schedule 7 hereto agree to enter into an agreement under
         which the foregoing rights of the Purchaser shall be included and to
         vote the Ordinary Shares of the Company owned by each of them in favor
         of the nomination of one representative of the Purchaser to the Board
         of Directors of the Company, and as many other representatives of such
         Sellers shall indicate (but in no event less then the number of
         representatives as they have immediately prior to the IPO), as more
         fully set forth in the Voting Agreement attached hereto (including
         certain instances whereby the board members may exclude a member).

10. DEFAULTING SELLING SHAREHOLDER. If, on the Closing Date, any Selling
    Shareholder defaults in the performance of its obligations under this
    Agreement, any of the remaining non-defaulting Selling Shareholders shall
    have the option to sell the Selling Shareholders' Shares which the
    defaulting Selling Shareholders agreed but failed to sell on such Closing
    Date in the respective proportions which the number of Selling Shareholders'
    Shares set forth opposite the name of each Selling Shareholder in Exhibit
    2.1 hereto who elects to sell additional Ordinary Shares as a result of such
    default bears to the total number of Selling Shareholders' Shares set forth
    opposite the names of all the Selling Shareholders on Exhibit 1 hereto who
    elect to sell additional Ordinary Shares as a result of such default. If
    none (or an insufficient number) of the non-defaulting Selling Shareholders
    elect to sell the Shares which the defaulting Selling Shareholders agreed
    but failed to sell on the Closing Date, this Agreement shall terminate
    without liability on the part of any non-defaulting Selling Shareholders,
    the Company or the Purchaser. Nothing herein shall derogate from the rights
    of the Purchaser, in law or equity, against such a defaulting Selling
    Shareholder.

11. NOTICES

    11.1. Any notice, declaration or other communication required or authorized
          to be given by any party under this Agreement to any other party shall
          be in writing and shall be personally delivered or sent by facsimile
          transmission (with a copy by registered mail in either case) addressed
          to the other party at the address stated below or such other address
          as shall be specified by the party concerned by notice in accordance
          with the provisions of this Section. Any notice shall be deemed to
          have been received on the next following business day.

    11.2. Addresses for the purposes of this Section are as follows:

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Company:        Yael Langer, Adv.
                RADVision Ltd.
                Raoul Wallenberg Street
                Tel-Aviv 69719, Israel
                Fax: (3) 6498248

Sellers:        As appearing in the first column of Exhibit 1

with a copy to: Yael Langer, Adv.
                RADVision Ltd. Legal Department
                24 Raoul Wallenberg Street
                Tel-Aviv 69719, Israel
                Fax: (3) 6498248

Siemens:        Hofmannstrasse 51
                D-81359 Munich
                Germany
                Attention: Mr. Guenther Barth
                Fax: (89) 7222 3365

With a copy to: Israel Kantor, Adv. and/or Royi Nachimzon, Adv.
                Kantor, Elhanani, Tal & Co.
                74-76 Rothschild Blvd.
                Tel-Aviv 65785, Israel
                Fax: (3) 5662960

Payment Agent:  RAD Data Communications Ltd.
                24 Raoul Wallenberg Street
                Tel Aviv 69719
                Attention: Eitan Abramovitch
                Fax: (3) 648 7350

Escrow Agent:   Israel Kantor, Adv.
                Kantor, Elhanani, Tal & Co.
                74-76 Rothschild Blvd.
                Tel-Aviv 65785, Israel
                Fax: (3) 5662960

12. GENERAL

    12.1 This Agreement shall (except for any obligation fully performed prior
         to or at the Closing Date) continue in full force and effect (except
         for provisions which, in accordance with their express terms, are
         limited in time or otherwise, insofar as they are so limited) after the
         Closing Date notwithstanding that the Closing shall have occurred.

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    12.2 All of the parties to this Agreement will after, as well as before and
         upon, the Closing Date do all acts and things and sign and execute all
         documents and deeds required for the purpose of implementing the terms
         of this Agreement.

    12.3 None of the rights or obligations under or pursuant to this Agreement
         may be assigned or transferred to any other person or entity without
         the written consent of all the parties hereto except that the Sellers
         and the Purchaser may so transfer or assign to their respective
         affiliates or between themselves, PROVIDED that: (i) the assignee shall
         be an affiliate of the relevant party at the time it exercises any of
         its rights or obligations hereunder; (ii) the assignor shall inform the
         other parties hereto of such assignment at least 5 business days prior
         to it being effected; (iii) the assignee shall agree in writing to be
         bound by all of the terms hereof; (iv) the assignor shall remain liable
         for any and all of its obligations under this Agreement.

    12.4 This Agreement contains the whole agreement between the parties
         relating to the transactions provided for in this Agreement and
         supersedes all previous agreements, if any, between such parties in
         respect of such matters and each of the parties to this Agreement
         acknowledges that in agreeing to enter into this Agreement it has not
         relied on any representations or warranties except for those contained
         in this Agreement.

    12.5 No failure or delay by any party hereto in exercising any claim,
         remedy, right, power or privilege under this Agreement shall operate as
         a waiver nor shall any single or partial exercise of any claim, remedy,
         right, power or privilege preclude any further exercise thereof or
         exercise of any other claim, right, power or privilege.

    12.6 This Agreement may be executed in two or more counterparts each of
         which shall be deemed an original but all of which constitute one and
         the same instrument.

    12.7 Except as expressly provided herein, this Agreement may be amended or
         terminated, and any of the terms hereof waived, only by a document in
         writing specifically referring to this Agreement and executed by the
         parties hereto or, in the case of a waiver, by the party waiving
         compliance. The failure of any party hereto at any time or times to
         require performance of any provisions hereof shall in no manner affect
         this right at a later time. No waiver by any party hereto of a breach
         of any term contained in this Agreement, in any one or more instance,
         shall be deemed or construed as a further or continuing waiver of any
         such breach or a waiver of any breach of any other form.

    12.8 All Ordinary Share numbers in this Agreement give effect to the stock
         split and distribution of bonus shares which will take place
         immediately prior to the closing of the IPO.

    12.9 The timing and text of any public announcement regarding the existence
         of this Agreement or the terms hereof shall be agreed between the
         parties hereto, such agreement not to be unreasonably withheld and
         shall also be approved by the Lead Underwriters of the IPO.

    12.10 This Agreement shall not be construed as granting any rights to any
         third party. In this Agreement, third party shall mean any person or
         entity that is not a party to this Agreement.

13. GOVERNING LAW AND SERVICE OF PROCESS

                                       11
<PAGE>

    13.1 This Agreement is subject to and shall be interpreted in accordance
         with the laws of the State of Israel.

    13.2 For the purposes of any claim under this Agreement, the addresses of
         the Selling Shareholders for the purposes of service of process shall
         be their addresses as set forth in the first column of Exhibit 1, or
         such other address as any Selling Shareholder shall notify the
         Purchaser in writing.

14. ARBITRATION

    14.1 All disputes arising out of or in connection with this Agreement and
         other agreements resulting herefrom, including any question regarding
         its existence, validity or termination, shall be finally settled under
         the Rules of Arbitration of the International Chamber of Commerce,
         Paris France, by three arbitrators in accordance with the said rules.
         The seat of arbitration shall be Tel Aviv, Israel. The procedural law
         of Israel shall apply where the rules are silent. The language to be
         used in the arbitration proceeding shall be English

    14.2 The parties undertake to abide by and fully implement the arbitration
         award rendered, and this Section 14 shall be deemed to be an
         arbitration agreement in accordance with the Arbitration Law-1968.

    14.3 Each of the parties or, if there are more than one plaintiff or
         defendant, each of Yehuda Zisapel and Zohar Zisapel together on behalf
         of the Sellers and the Purchaser shall nominate one arbitrator for
         confirmation by the competent authority under the applicable rules
         ("APPOINTING AUTHORITY") within thirty (30) days. Both arbitrators
         shall agree on the third arbitrator within 30 days. In the event that
         an arbitrator is to be appointed by more than one party, and they fail
         to agree upon the identity of such arbitrator within the aforesaid time
         period, any other party to the arbitration may request that such
         arbitrator be appointed by the Appointing Authority. Should the two
         arbitrators fail, within the above time-limit, to reach agreement on
         the third arbitrator, he shall be appointed by the Appointing
         Authority.

15. TERMINATION At any time prior to the Closing Date, the Company
shall have the right, in its sole reasonable discretion, to terminate this
Agreement AB INITIO without any liability or adverse affect or without it being
considered a breach of this Agreement, if the Company can substantiate by
reasonable proof that the applicable governmental authorities may prevent the
IPO from going forward or substantially delay the IPO process as a result of the
transactions contemplated by this Agreement. If the closing of the IPO does not
occur within sixty days of the effective date of this Agreement, the Purchaser
shall have a right, in its sole and absolute discretion, to terminate this
Agreement AB INITIO without any penalty, liability or adverse affect, and
without such termination being considered a breach of this Agreement.

                                       12
<PAGE>

          IN WITNESS WHEREOF, the parties have caused this Agreement to be
signed by its duly authorized representatives as of the date first above
written.

SIEMENS Aktiengesellschaft

By:  /s/ Anthony Maher                         By:  /s/ Christoph Ferner
    ----------------------------                   ----------------------------
Name:  Anthony Maher                               Christoph Ferner
Title: President ICN Siemens                       Vice President ICN Siemens

RADVision Ltd.

By:  /s/ Yehuda Zisapel
    ----------------------------
Name:  Yehuda Zisapel
Title: Chairman of the Board of Directors

                THE REST OF THIS PAGE IS LEFT INTENTONALLY BLANK

                                       13
<PAGE>

Name and address of Selling Shareholder                  Signature
---------------------------------------                  ---------

Yehuda Zisapel                                  By:              *
                                                     ---------------------------
23 Kisufim Street                               Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Zohar Zisapel                                   By:              *
                                                     ---------------------------
54 Pinchas Street                               Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Michael & Klil Properties (93) Ltd.             By:              *
                                                     ---------------------------
12 Hanechoshet Street                           Name: __________________________
Tel Aviv 69710 Israel                           Title: _________________________

Lomsha Ltd.                                     By:              *
                                                     ---------------------------
12 Hanechoshet Street                           Name: __________________________
Tel Aviv 69710 Israel                           Title: _________________________

Amos Amir                                       By:              *
                                                     ---------------------------
9 Eliahu Hacham Street                          Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Plonit Achzakot Ltd.                            By:              *
                                                     ---------------------------
9 Eliahu Hacham Street                          Name: __________________________
Tel Aviv, Israel                                Title: _________________________

                                       14
<PAGE>

Nichsei Almonit Ltd.                            By:              *
                                                     ---------------------------
12 Hanechoshet Street                           Name: __________________________
Tel Aviv 69710 Israel                           Title: _________________________

RAD Data Communications Ltd.                    By:              *
                                                     ---------------------------
12 Hanechoshet Street                           Name: __________________________
Tel Aviv 69710 Israel                           Title: _________________________

Efraim Wachtel                                  By:              *
                                                     ---------------------------
20 Hagefen Street                               Name: __________________________
Raanana, Israel                                 Title: _________________________

Daniella Ilan                                   By:              *
                                                     ---------------------------
12 Eliahu Hakim Street                          Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Yoram Holtz                                     By:              *
                                                     ---------------------------
18 Hakotzer Street                              Name: __________________________
Ramat Hasharon, Israel                          Title: _________________________

Dario Zipris                                    By:              *
                                                     ---------------------------
9/5 Ussiskin Street                             Name: __________________________
Ramat Hasharon, Israel                          Title: _________________________

Ilan Seidner                                    By:              *
                                                     ---------------------------
3A Kushani Street                               Name: __________________________
Ramat Aviv                                      Title: _________________________

Arie Oren                                       By:              *
                                                     ---------------------------
8 Tana Street                                   Name: __________________________
Rosh Haayin, Israel                             Title: _________________________

Aaron Strossberg                                By:              *
                                                     ---------------------------
16 Brodetsky Street                             Name: __________________________
Rishon Lezion, Israel                           Title: _________________________

Eitan Abramovitch                               By:              *
                                                     ---------------------------
27 Hahatzav Street                              Name: __________________________
Mevasseret Zion, Israel                         Title: _________________________

Eli Luz                                         By:              *
                                                     ---------------------------

                                       15
<PAGE>

c/o Trust Company of Maritime Bank of           Name: _________________________
Israel Ltd.                                     Title: ________________________
35 Ahad Ha'am Street
Tel Aviv, Israel

Lerosh Investments Ltd.                         By:              *
                                                     ---------------------------
c/o Trust Company of Maritime Bank of           Name: __________________________
Israel Ltd.                                     Title: _________________________
35 Ahad Ha'am Street
Tel Aviv, Israel

Trust Company of Maritime Bank of Israel        By:              *
Ltd.                                                 ---------------------------
35 Ahad Ha'am Street                            Name: __________________________
Tel Aviv, Israel                                Title: _________________________

ECI Telecom Ltd.                                By:              *
                                                     ---------------------------
30 Hasivim Street                               Name: __________________________
Petach Tikva, Israel                            Title: _________________________

Factory Systemes SA                             By:              *
                                                     ---------------------------
22, Rue Vladimir Jankelevitch                   Name: __________________________
Emerainville, 77437 Marne La Vallee             Title: _________________________
Cedex 2, France

Clal Venture Capital LP                         By:              *
                                                     ---------------------------
Atidim Technology Park, Bldg. 4                 Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Robert Freeman                                  By:              *
                                                     ---------------------------
407 Robbins Road                                Name: __________________________
Neptune, New Jersey                             Title: _________________________

Shrem Pudim Kelner Trust Company Ltd.           By:              *
                                                     ---------------------------
21 Haarbaah Street                              Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Evergreen Canada Israel Management Ltd.         By:              *
                                                     ---------------------------
c/o Evergreen Israel                            Name: __________________________
96 Rothschild Blvd.                             Title: _________________________
Tel Aviv, Israel

IJT Technologies Ltd.                           By:              *
                                                     ---------------------------
c/o Evergreen Israel                            Name: __________________________
96 Rothschild Blvd.                             Title: _________________________
Tel Aviv, Israel

                                       16
<PAGE>

Periscope I Fund LP, an Israeli partnership     By:              *
c/o Evergreen Israel                                 ---------------------------
96 Rothschild Blvd.                             Name: __________________________
Tel Aviv, Israel                                Title: _________________________

Periscope I Fund LP, a Delaware partnership     By:              *
c/o Evergreen Israel                                 ---------------------------
96 Rothschild Blvd.                             Name: __________________________
Tel Aviv, Israel                                Title: _________________________

* By:  /s/ Yehuda Zisapel
      ----------------------------
           Yehuda Zisapel
           Attorney-in-fact

                                       17

<PAGE>

                                 EXHIBIT 4.1.1

                                VOTING AGREEMENT

         THIS VOTING AGREEMENT (the "Agreement") made and entered into as of the
____ day of _________, 2000 by and between (1) the persons listed in Schedule I
hereto (the "Existing Shareholders"); and (2) Siemens Aktiengesellschaft (the
"New Shareholder", and together with the Existing Shareholders, collectively
referred to herein as the "Parties").

         WHEREAS, the Existing Shareholders, RADVision Ltd. (the "Company") and
the New Shareholder have entered into a Share Purchase Agreement of even date
herewith (the "Share Purchase Agreement"), under which the New Shareholder is
acquiring ordinary shares of the Company, par value NIS 0.1 per share (the
"Ordinary Shares") from the Existing Shareholders and the Company; and

         WHEREAS, pursuant to the terms of the Share Purchase Agreement, the
Parties have agreed to enter into an agreement with respect to the voting of the
Ordinary Shares held by each of the Parties.

         NOW, THEREFORE, the Parties agree as follows:

1. INTERPRETATION

   1.1.  The recitals to this Agreement constitute an integral part hereof.

   1.2.  In this Agreement, all capitalized terms which are not defined herein
         shall have the meaning ascribed to such terms in the Share Purchase
         Agreement.

2. TERM

         Subject to Section 4 hereof, the initial term of this Agreement shall
be for three years from the Closing Date, and thereafter shall be automatically
extended for two successive additional one year periods, unless terminated by
any of the Parties upon written notice to the other Parties given at least sixty
(60) days prior to the expiration date of the then current term.

3. Agreement to Vote for Directors

3.1 Each of the Parties hereby agrees to vote, either in person of by its
    nominee or proxy, all Ordinary Shares beneficially owned, directly or
    indirectly, by such Party on the date hereof or hereafter acquired, at a
    regular or special meeting of the Company's shareholders (or by written
    consent) at which the directors ("Directors") of the Company's board of
    directors (the "Board") are to be elected, in favor of a slate of directors
    consisting of: (i) one nominee of the New Shareholder to the Board, and (ii)
    as many other representatives that such Selling Shareholders shall
    unanimously

<PAGE>

    indicate (but in no event less then the number and identity of
    representatives as they have immediately prior to the IPO).

    The Parties further agree to cause the existing Board, and future Boards, to
    nominate for election such persons in any proxy statement and written ballot
    sent to the shareholders of the Company in connection with such election or
    meeting.

3.2 At least three days in advance of each regular or special meeting of the
    Company's shareholders at which the Directors of the Board are to be
    elected, the Parties entitled to select nominees to the Board will notify
    the other Parties of the identity of the nominee(s) to be elected to the
    Board in accordance with Section 3.1 above.

3.3 Upon the Closing, the nominee of the New Shareholder shall be appointed as a
    Director to the Board in accordance with Article 88 of the Company's
    Articles of Association, or by the convention of a regular or special
    meeting.

4. TERMINATION OF DIRECTORSHIP

In the event that all Directors, except for one Director, decide in good faith
and believing it to be in the best interests of the Company and can substantiate
their decision by reasonable proof that the continuing presence of any Director
appointed by a Party pursuant to Section 3 hereof as a director of the Board may
damage the business prospects of the Company, then (i) the right of such Party
to appoint a Director under this Agreement shall immediately terminate and such
Board Member shall immediately resign from the Board, (ii) the other Parties
shall be released from any obligation to vote their Ordinary Shares in favor of
such Party's nominee, and such party shall be released from its obligations to
vote as well and (iii) the Parties shall take all actions necessary, including,
without limitation, convening a meeting of shareholders, to effect the removal
of such Director from the Board.

5. TRANSFER AND PLEDGE OF ORDINARY SHARES

         5.1 Ordinary Shares of a Party to this Agreement transferred to an
Affiliate or to another Party to this Agreement shall continue to be bound by
this Agreement.

         For purposes of this Agreement, an "Affiliate" shall mean a 'relative'
(as such term is defined in the Companies Law-1999) and/or any entity in which a
Party hereto, or a 'relative' of a Party hereto, holds an equity interest.

         5.2 Any pledge, mortgage, hypothecation, encumbrance and the like
(collectively referred as the "Pledge") of the Ordinary Shares owned by the
Parties hereto shall be subject to: (i) the inclusion of the provisions of this
Agreement in the Pledge documents; and (ii) the written commitment of the
Pledgee to be bound by, and comply with, the provisions of this Agreement,
including the commitment of the Pledgee to bind any transferees to such a
commitment should it exercise the Pledge.

                                       2
<PAGE>

6. REMEDIES

         The Parties acknowledge that time is of the essence under this
Agreement for the performance of the acts contemplated hereunder and that this
Agreement, and each provision contained herein, is subject to specific
performance by any court of competent jurisdiction.

7. NOTICES

         All notices or other communications required or permitted hereunder
shall be in writing (except as otherwise provided herein) and shall be deemed
duly given when received by delivery in person, by facsimile, telex or telegram
or by an overnight courier service addressed to the address of the respective
Party set forth opposite the name of such Party on Schedule I hereto.

8. SUCCESSORS

         The terms and conditions of this Agreement shall inure to the benefit
and be binding upon the respective successors of the Parties. Nothing in this
Agreement, express or implied, is intended to confer upon any party other than
the Parties or their respective successors and assigns, any rights, remedies,
obligations, or liabilities under or by reason of this Agreement, except as
expressly provided in this Agreement.

9. GOVERNING LAW AND ARBITRATION

         9.1 This Agreement is subject to and shall be interpreted in accordance
with, the laws of the State of Israel.

         9.2 Without derogating from that stated in section 6 above, the Parties
hereto agree that the Arbitration provision of the Share Purchase Agreement
shall be binding upon them with respect to this Agreement and any and all issues
and disputes arising hereunder.

                                       3
<PAGE>

         IN WITNESS WHEREOF, the Parties have executed this Agreement, as of the
date first above-mentioned.

Siemens Aktiengesellschaft               Amos Amir

By:_______________________               ____________________________
Name:
Title:

Yehuda Zisapel                           Zohar Zisapel

__________________________               ____________________________

Plonit Achzakot Ltd.                     Nichsei Almonit Ltd.

By:_______________________               By:_________________________
Name:                                    Name:
Title:                                   Title:

Michael and Klil Holdings (93) Ltd.      Evergreen Canada Israel Management Ltd.

By:_______________________               By:_________________________
Name:                                    Name:
Title:                                   Title:

Lomsha Ltd.                              Periscope I Fund, Israeli Partnership

By:_______________________               By:_________________________
Name:                                    Name:
Title:                                   Title:

RAD Data Communications Ltd.             Periscope I Fund, LP

By:_______________________               By:_________________________
Name:                                    Name:
Title:                                   Title:

Clal Venture Capital Fund LP             IJT Technologies Ltd.

By:_______________________               By:_________________________
Name:                                    Name:
Title:                                   Title:

                                       4
<PAGE>

                                   SCHEDULE I

                PARTY                                   ADDRESS
--------------------------------------------------------------------------------
Siemens Aktiengesellschaft

Yehuda Zisapel                              Atidim Technllogical Park, Building
                                            No. 4, Tel-Aviv

--------------------------------------------------------------------------------
Zohar Zisapel                               12, Hanechoshet Street, Tel-Aviv

--------------------------------------------------------------------------------
Michael and Klil Holdings (93) Ltd.         12, Hanechoshet Street, Tel-Aviv

--------------------------------------------------------------------------------
Lomsha Ltd.                                 12, Hanechoshet Street, Tel-Aviv

--------------------------------------------------------------------------------
RAD Data Communications Ltd.                12, Hanechoshet Street, Tel-Aviv

--------------------------------------------------------------------------------
Amos Amir                                   Eliahu Hakim 9/3,  Tel-Aviv

--------------------------------------------------------------------------------
Plonit Achzakot Ltd.                        Eliahu Hakim 9/3,  Tel-Aviv

--------------------------------------------------------------------------------
Nichsei Almonit Ltd.                        Eliahu Hakim 9/3,  Tel-Aviv

--------------------------------------------------------------------------------
Clal Venture Capital Fund LP                Atidim Technllogical Park, Building
                                            No. 4, Tel-Aviv

--------------------------------------------------------------------------------
Evergreen Canada Israel Management Ltd.     96 Rothschild Blvd.
                                            Tel-Aviv  65224

--------------------------------------------------------------------------------
Periscope I Fund, Israeli Partnership       96 Rothschild Blvd.
                                            Tel-Aviv  65224

--------------------------------------------------------------------------------
Periscope I Fund, LP                        96 Rothschild Blvd.
                                            Tel-Aviv  65224

--------------------------------------------------------------------------------
IJT Technologies Ltd.                       96 Rothschild Blvd.
                                            Tel-Aviv  65224

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

                                       5<PAGE>

                                                                    Exhibit 4.12

                            SHARE PURCHASE AGREEMENT

THIS SHARE PURCHASE AGREEMENT (the "Agreement") is made as of the 22nd day of
February 2000

BETWEEN:

(1)      The persons whose names and addresses are set out in the first column
         of Exhibit 1 (the "Selling Shareholders");

(2)      Samsung Electro-Mechanics Co.Ltd., a company organized under the laws
         of the Republic of Korea, of 314 Maetan 3-Dong, Paldal-Gu, Suwon,
         Kyunggi-Do, Korea 442-743 Korea and Samsung Venture Investment Corp., a
         company organized under the laws of the Republic of Korea, of and 16th
         Floor Samsung Yeok Sam Bldg. 647-9, Yeok Sam-Dong, KangNam-Gu, Korea
         135-080 (collectively referred to as the "Purchaser"); and

(3)      RADVision Ltd. of Raoul Wallenberg Street, Tel Aviv 69719, Israel (the
         "Company" and collectively with the Selling Shareholders, the
         "Sellers").

WHEREAS:

A.       The Company has filed a registration statement with the U.S. Securities
         and Exchange Commission for the purpose of an initial public offering
         (the "IPO") of its ordinary shares, par value NIS 0.1 per share (the
         "Ordinary Shares");

B.       The Purchaser desires to purchase an aggregate of 1,000,000 Ordinary
         Shares (the "Shares") from the Sellers according to the following
         proportion: Samsung Electro-Mechanics Co., Four Hundred Thousand
         (400,000) Shares and Samsung Venture Investment Corp Six Hundred
         thousand (600,000) Shares. The purchase of the Shares shall be at a
         price per share equal to the initial public offering price of the
         Ordinary Shares, subject to the terms and conditions set forth herein;
         and

C.       The Selling Shareholders desire to sell to the Purchaser Seven Hundred
         Seventy Four Thousand Nine Hundred and Forty Five (774,945) of the
         Shares (the "Selling Shareholders' Shares") and the Company desires to
         sell to the Purchaser Two Hundred Twenty Five Thousand and Fifty Five
         (225,055) of the Shares (the "Company's Shares"), in each case subject
         to the terms and conditions set forth herein.

NOW, THEREFORE, THE PARTIES HEREBY AGREE AS FOLLOWS:

1.       Definitions

         1.1.     In this Agreement and in the exhibits and schedules hereto,
                  unless the context otherwise requires, the following terms
                  shall bear the meanings set forth opposite them:

                  "Closing"                  The consummation of the
                                             transactions contemplated by this
                                             Agreement as provided in Section 6.

                  "Registration Statement"   The Company's Registration
                                             Statement on Form F-1 (File No.
                                             333-     ), as amended, initially
                                             filed with the U.S. Securities and

<PAGE>
                                       2

                                             Exchange Commission on February __,
                                             2000 attached hereto as Schedule
                                             1.1.

2.       Sale and Purchase of Shares

         2.1.     Subject to the terms and conditions of this Agreement, (i) the
                  Selling Shareholders agree to sell to the Purchaser, and the
                  Purchaser agrees to purchase from the Selling Shareholders,
                  the Selling Shareholders' Shares and (ii) the Company agrees
                  to sell to the Purchaser, and the Purchaser agrees to
                  purchasers agree to purchase from the Company, the Company's
                  Shares having the rights, preferences, privileges and
                  restrictions set forth in the form of amended Articles of
                  Association of the Company (the "New Articles") to be adopted
                  immediately prior to the closing of the IPO; provided, that,
                  notwithstanding anything herein to the contrary, the Sellers
                  shall not be obligated to sell the Shares to the Purchaser
                  unless the Purchaser purchases all 1,000,000 Shares. The
                  purchase and sale of the Shares is intended to be a private
                  placement and not a public offering or part of a public
                  offering. The Selling Shareholders and the number of Shares
                  sold is detailed in Schedule 2.1 attached hereto.

         2.2.     Each of the Selling Shareholders hereby waives, with respect
                  to the Shares to be sold to the Purchaser hereunder, any right
                  of first refusal, pre-emption or any other right which may be
                  conferred on it by the Articles of Association of the Company
                  in effect on the date hereof or by any agreement relating to
                  the Ordinary Shares.

         2.3.     The Selling Shareholders agree to assign to the Purchaser all
                  registration rights, including piggyback rights, if any, which
                  were attached to the Shares sold by them, prior to the
                  Effective Date.

         2.4.     The Purchaser respective Shares as noted above may change in
                  the event any Korean law governing the transaction under this
                  Agreement dictates so, provided that the aggregate number of
                  Shares purchased by the Purchaser is 1,000,000 Shares.

         To the extent that any of the Selling Shareholder holds Shares as a
         trustee for others, it shall be the responsibility each such Selling
         Shareholder to procure all releases and/or waivers from all persons for
         whom such Selling Shareholder hold such Shares in trust. The Selling
         Shareholders will deliver at the Closing evidence of such release or
         waiver in a form reasonably satisfactory to the Purchaser.

3.       Closing

         3.1.     The purchase and sale of the Shares shall be held at the
                  Company's offices on Raoul Wallenberg Street, Tel Aviv, on the
                  day of the closing of IPO or, if later, upon satisfaction or
                  waiver of each of the conditions set forth in Sections 4 and 5
                  (such date, the "Closing Date"), unless otherwise agreed to by
                  the Sellers and the Purchaser. However, the share certificates
                  issued by the American Stock Transfer and Trust Company shall
                  be delivered within 3 business days as of the Closing Date. At
                  the Closing, each of the Selling Shareholders shall deliver to
                  the Purchaser the number of the Selling Shareholders' Shares
                  set forth opposite their name on Exhibit 2.1 hereto and the
                  Company shall issue and deliver to the Purchaser the Company's
                  Shares, in each case against payment of the purchase price
                  therefor by wire transfer of immediately available funds to an
                  account specified by the Payment Agent prior to the Closing
                  Date as set forth in Section 3.2. The per share purchase price
                  for the Shares (the "Per Share Purchase Price") shall be equal
                  to the per share price paid by the public for the Company's
                  Ordinary Shares in the IPO, less any underwriting

<PAGE>
                                       3

                  discounts and commissions; provided that in no event shall the
                  Per Share Purchase Price exceed U.S.$17.00.

         3.2.     The Sellers hereby appoint RAD Data Communications Ltd. (the
                  "Payment Agent") to receive the payment due by the Purchaser
                  to the Sellers hereunder. The Sellers confirm and acknowledge
                  that payments made by the Purchaser to the Payment Agent and
                  acknowledged as received by the Payment Agent shall constitute
                  good and sufficient receipt of such payments as if the
                  payments were made directly to the Sellers. Except as
                  specifically set forth in this Agreement, the Purchaser shall
                  have no responsibility for the allocation by the Payment Agent
                  among the Sellers of any sum paid by the Purchaser to the
                  Payment Agent.

4.       Closing Conditions

         4.1.     The obligation of the Purchaser to purchase the Shares at the
                  Closing shall be subject to the satisfaction or waiver of the
                  following conditions precedent on or prior to the Closing
                  Date:

                  4.1.1.   Reserved.

                  4.1.2.   Reserved.

                  4.1.3.   The execution and the delivery of this Agreement and
                           the consummation of the transactions contemplated
                           hereby shall have been approved by the following
                           regulatory authorities: (i) the Investment Center of
                           the Israeli Ministry of Industry and Trade and (ii)
                           the Office of the Chief Scientist of the Ministry of
                           Industry and Trade; (iii) the Finance Supervisory
                           Commission of Korea and (iv) the Ministry of Finance
                           and Economy of Korea.(provided the approval mentioned
                           in sub-sections (iii) and (iv) shall be obtained by
                           the Purchaser).

                  4.1.4.   The Sellers shall have delivered to the Purchaser
                           share certificates representing the Shares (in the
                           amounts set out in Exhibit 2.1) and, with respect to
                           the Selling Shareholders' Shares, stock powers duly
                           executed by the registered holders in favor of the
                           Purchaser.

                  4.1.5.   The representations and warranties made by the
                           Selling Shareholders in Section 5 hereof and the
                           Company in Section 6 hereof shall be true and correct
                           in all material respects on the date hereof and as of
                           the Closing Date with the same force and effect as if
                           they had been made on and as of such date.

                  4.1.6.   The closing of the initial public offering of the
                           Company's Ordinary Shares shall have occurred.

         4.2.     The obligation of each of the Sellers and the Company to sell
                  the Shares to the Purchaser at the Closing shall be subject to
                  the satisfaction or waiver of the following conditions
                  precedent on or prior to the Closing Date:

                  4.2.1.   Reserved

                  4.2.2.   Reserved

                  4.2.3.   The execution and the delivery of this Agreement and
                           the consummation of the transactions contemplated
                           hereby shall have been approved by the following
                           regulatory

<PAGE>
                                       4

                           authorities: (i) the Investment Center of the Israeli
                           Ministry of Industry and Trade and (ii) the Office of
                           the Chief Scientist of the Ministry of Industry and
                           Trade; ; (iii) the Finance Supervisory Commission of
                           Korea and (iv) the Ministry of Finance and Economy of
                           Korea.(provided the approval mentioned in
                           sub-sections (iii) and (iv) shall be obtained by the
                           Purchaser).

                  4.2.4.   The Purchaser shall have delivered to the Payment
                           Agent on behalf of the Sellers by wire transfer of
                           immediately available funds the aggregate purchase
                           price for the Shares.

                  4.2.5.   The representations and warranties made by the
                           Purchaser in Section 7 hereof shall be true and
                           correct in all material respects on the date hereof
                           and as of the Closing Date with the same force and
                           effect as if they had been made on and as of such
                           date.

                  4.2.6.   The closing of the initial public offering of the
                           Company's Ordinary Shares shall have occurred.

5.       Representations and Warranties of the Company The Company hereby
         represents and warrants to the Purchaser as follows:

         5.1.     Organization and Good Standing. The Company is a corporation
                  duly organized, validly existing and in good standing under
                  the laws of the State of Israel and has all requisite
                  corporate power and authority to carry on its business as now
                  conducted.

         5.2.     Authorization. All corporate action on the part of the Company
                  and its officers, directors and shareholders necessary for the
                  authorization, execution and delivery of this Agreement, the
                  performance of the obligations of the Company hereunder and
                  the authorization, issuance and delivery of the Company's
                  Shares has been taken or will be taken prior to the Closing.

         5.3.     Binding Effect. This Agreement constitutes a valid and binding
                  agreement of the Company, enforceable against the Company in
                  accordance with its terms.

         5.4.     No Conflicts. The execution and delivery of this Agreement,
                  the consummation of the transactions contemplated hereby and
                  the compliance with the terms and provisions hereof will not
                  conflict with, result in a breach or violation of, or
                  constitute a default under (i) the Company's Memorandum of
                  Association and the New Articles or (ii) any contract or
                  agreement to which the Company is a party, except in the case
                  of clause (ii) for such conflict, breach, violation or default
                  which would not have a material adverse effect on the
                  Company's business, financial condition or results of
                  operations.

         5.5.     Company's Shares. The Company's Shares, when issued, sold and
                  delivered in accordance with the terms hereof for the
                  consideration expressed, will be duly and validly issued,
                  fully paid and nonassessable.

         5.6.     Exemption from Registration. Assuming the accuracy of the
                  Purchaser's representations set forth in Section 7 hereof, the
                  offer, sale and issuance of the Company's Shares to the
                  Purchaser on the Closing Date as contemplated by this
                  Agreement are exempt from the registration requirements of the
                  Securities Act of 1933, as amended (the "Securities Act").

         5.7.     Disclosure. On the Closing Date, the Registration Statement
                  will not contain any untrue statement of a material fact or
                  omit to state a material fact necessary to make the statements
                  therein (in light of the circumstances under which they were
                  made) not misleading.

<PAGE>
                                       5

6.       Representations and Warranties of the Selling Shareholders Each of the
         Selling Shareholders hereby represents and warrants to the Purchaser as
         follows:

         6.1.     Organization and Good Standing. Such Seller is a corporation,
                  limited partnership or limited liability company, as
                  applicable, duly organized, validly existing and in good
                  standing under the laws of its jurisdiction of organization.

         6.2.     Authorization. All corporate action on the part of such
                  Seller, and its officers, directors and shareholders necessary
                  for the authorization, execution and delivery of this
                  Agreement, the performance of all obligations of such Seller
                  hereunder, and the transfer and delivery of such Selling
                  Shareholders' Selling Shareholders' Shares has been taken or
                  will be taken prior to the Closing.

         6.3.     Binding Effect. This Agreement constitutes a valid and binding
                  agreement of such Selling Shareholder, enforceable against
                  such Selling Shareholder in accordance with its terms.

         6.4.     No Conflicts. The execution and delivery of this Agreement,
                  the consummation of the transactions contemplated hereby and
                  the compliance with the terms and provisions hereof will not
                  conflict with, result in a breach or violation of, or
                  constitute a default under (i) such Selling Sharholders'
                  organizational documents or (ii) any contract or agreement to
                  which such Selling Shareholder is a party, except in the case
                  of clause (ii) for such conflict, breach, violation or default
                  which would not have a material adverse effect on such Selling
                  Shareholders' business, financial condition or results of
                  operations.

         6.5.     Registration Statement. Such Selling Shareholder is familiar
                  with the Registration Statement and has no knowledge of any
                  material fact, condition or information not disclosed in the
                  Registration Statement which has materially adversely affected
                  or may materially adversely affect the business of the Company
                  or any of its subsidiaries; and the sale of Selling
                  Shareholders' Shares owned by such Selling Shareholder
                  pursuant hereto is not prompted by any information concerning
                  the Company or any of its subsidiaries which is not set forth
                  in the Registration Statement.

         6.6.     Title. Such Seller is the record owner of the number of the
                  Selling Shareholders' Shares set forth opposite the name of
                  such Selling Shareholder on Exhibit 2.1 hereto and has good
                  and marketable title to such Shares, free and clear of any
                  lien or encumbrance and no third party has any rights with
                  respect to such Shares.

7.       Representations and Warranties of the Purchaser The Purchaser hereby
         represents and warrants to each of the Sellers as follows:

         7.1.     Organization and Good Standing. The Purchaser is a corporation
                  duly organized, validly existing and in good standing under
                  the laws of the Republic of Korea and has the power and
                  authority to carry on its business as it is now being
                  conducted.

         7.2.     Authorization. All corporate action on the part of the
                  Purchaser, and its officers, directors and shareholders
                  necessary for the purchase of the Shares pursuant to this
                  Agreement and the performance of its obligations hereunder has
                  been taken or will be taken prior to the Closing.

         7.3.     Binding Effect. This Agreement constitutes a valid and binding
                  agreement of the Purchaser, enforceable against the Purchaser
                  in accordance with its terms.

         7.4.     No Conflicts. The execution and delivery of this Agreement,
                  the consummation of the transactions contemplated hereby and
                  the compliance with the terms and provisions hereof

<PAGE>
                                       6

                  will not conflict with, result in a breach or violation of, or
                  constitute a default under (i) the Purchaser's organizational
                  documents or (ii) any contract or agreement to which the
                  Purchaser is a party, except in the case of clause (ii) for
                  such conflict, breach, violation or default which would not
                  have a material adverse effect on the Purchaser's business,
                  financial condition or results of operations.

         7.5.     Purchase Entirely for Own Account. The Shares will be acquired
                  for investment for the Purchaser's own account, not as a
                  nominee or agent, and not with a view to the resale or
                  distribution of any part thereof, and the Purchaser has no
                  present intention of selling, granting any participation in,
                  or otherwise distributing the Shares.

         7.6.     Available Information. The Purchaser has received all the
                  information, including, but not limited to, the Registration
                  Statement , it considers necessary or appropriate for deciding
                  whether to purchase the Shares and has had the opportunity to
                  ask questions and receive answers from the Company regarding
                  the business, properties, prospects, and financial condition
                  of the Company and to obtain additional information necessary
                  to verify the accuracy of any information furnished to the
                  Purchaser or to which the Purchaser has had access.

         7.7.     Investment Experience. The Purchaser is experienced in
                  evaluating and investing in securities of companies in the
                  software and information technology industry and acknowledges
                  that it is able to fend for itself, can bear the economic risk
                  of the investment in the Shares, and has such knowledge and
                  experience in financial and business matters that it is
                  capable of evaluating the merits and risks of the investment
                  in the Shares. The Purchaser has not been organized solely for
                  the purpose of acquiring the Shares.

         7.8.     Accredited Investor. The Purchaser is an "accredited
                  investor," as that term is defined in Rule 501 of Regulation D
                  of the Securities Act.

         7.9.     Purchaser not a U.S. Person. The Purchaser is not a "U.S.
                  Person" within the meaning of Rule 902(k) of Regulation S of
                  the Securities Act.

         7.10.    Purchase made in an "offshore transaction" with "no directed
                  selling efforts within the United States." The Purchaser was
                  not physically present in the United States when the Purchaser
                  was offered the Shares and the offer was not accompanied by
                  any form of advertising in the United States or other
                  "directed selling efforts" within the United States within the
                  meaning of Rule 902(c) of Regulation S of the Securities Act.

         7.11.    Brokerage Commissions. No broker's commissions were, or will
                  be required to be, paid by the Purchaser in connection with
                  this transaction.

8.       Covenants of the Purchaser

         8.1.     Lock Up. Prior to the date which is 270 days after the Closing
                  (the "Lockup Date"), the Purchaser shall not, directly or
                  indirectly, Transfer (as defined below) or offer to Transfer
                  any of the Shares, and the Purchaser shall sign an undertaking
                  addressed to the underwriters in the form set forth in Exhibit
                  8.1 to such effect. In order to enforce the transfer
                  restrictions set forth in the prior sentence, the Company may
                  impose stop-transfer instructions with respect to the Shares
                  until the Lockup Date. As used in this Agreement, the term
                  "Transfer" shall mean any sale, transfer, assignment,
                  hypothecation, encumbrance or other disposition, whether
                  voluntary or involuntary, of any of the Shares. In the case of
                  a hypothecation, the Transfer shall be deemed to occur both at
                  the time of the initial pledge and at any pledgee's sale or a
                  sale by any secured creditor or a retention by the secured

<PAGE>
                                       7

                  creditor of the pledged Shares in complete or partial
                  satisfaction of the indebtedness for which the Shares are
                  security.

         8.2.     Market Stand-Off. In addition to the transfer restrictions set
                  forth in Section 8.1 (which shall in no way be limited by the
                  following), in connection with any underwritten public
                  offering by the Company of its equity securities pursuant to
                  an effective registration statement filed under the Securities
                  Act, the Purchaser shall not Transfer or offer to Transfer any
                  of the Shares without the prior written consent of the Company
                  and its underwriters. Such restriction (the "Market
                  Stand-Off") shall be in effect for such period of time from
                  and after the effective date of the final prospectus for the
                  offering as may be requested by the Company or such
                  underwriters; provided, however, that such Market Stand-Off
                  shall not exceed 270 days. In order to enforce the Market
                  Stand-Off, the Company may impose stop-transfer instructions
                  with respect to the Shares until the end of the applicable
                  stand-off period.

         8.3.     Standstill. The Purchaser agrees that, prior to the third
                  anniversary of the Closing, unless specifically invited by the
                  Company, the Purchaser will not, in any manner, directly or
                  indirectly, effect any acquisition of Voting Securities (as
                  defined below), or beneficial ownership thereof if,
                  immediately after any such acquisition, the Purchaser would
                  beneficially own, in the aggregate, Voting Securities
                  representing more than ten percent (10%) of the outstanding
                  Ordinary Shares of the Company. The Purchaser also agrees
                  during such period not to make any public request (or
                  publicize any request) of the Company (or its directors,
                  officers, employees or agents), directly or indirectly, to
                  amend or waive any provision of this Section 8.3, including
                  this sentence. The Purchaser also agrees not to form, join or
                  in any way participate in a "group" (as defined under the
                  Securities Exchange Act of 1934, as amended (the "Exchange
                  Act")), or take any other action, in order to circumvent the
                  provisions of this Section 8.3. For purposes of this
                  Agreement, (i) the term "Voting Securities" shall refer to all
                  securities of the Company entitled to vote generally for the
                  election of directors, and (ii) the term "beneficial
                  ownership" shall have the meaning set forth in Rule 13d-3
                  under the Exchange Act. The restrictions set forth in this
                  Section 8.3 shall be ineffective if an officer of the Company,
                  duly authorized by the Company's Board of Directors, has
                  informed the Purchaser in writing of the Company's potential
                  interest in entering into a sale of all or substantially all
                  of its assets or shares or a merger in which the Company would
                  not be the surviving corporation; provided, however, that if
                  such acquisition, merger or sale is not consummated within
                  sixty days of such public announcement the restrictions set
                  forth in this Section 8.3 shall be reinstated.

         8.4.     Legal Obligations. Immediately after the Closing, the
                  Purchaser undertakes to file all the necessary documents and
                  reports required by any relevant authority, in Israel, the US
                  or elsewhere, and to abide by all the appropriate rules,
                  regulations and laws applying to a forgien equity holder,
                  including, without limitation, undertaking towards the Office
                  of Chief Scientist to comply with the Research and Development
                  Law and timely filing a Schedule 13D reporting the acquisition
                  of securities of a public company with the US Securities and
                  Exchange Commission. In general, the Purchaser will comply
                  with the continued restrictions which will apply to it as long
                  as it is a major shareholder, nominating a Board member and an
                  affiliate of the Company.

         8.5.     Reserved.

9.       Defaulting Selling Shareholder. If, on the Closing Date, any Selling
         Shareholder defaults in the performance of its obligations under this
         Agreement, any of the remaining non-defaulting Selling Shareholders
         shall have the option to sell the Selling Shareholders' Shares which
         the defaulting Selling Shareholders agreed but failed to sell on such
         Closing Date in the respective

<PAGE>
                                       8

         proportions which the number of Selling Sharholders' Shares set forth
         opposite the name of each Selling Shareholder on Exhibit 2.1 hereto who
         elects to sell additional Ordinary Shares as a result of such default
         bears to the total number of Selling Shareholders' Shares set forth
         opposite the names of all the Selling Shareholders on Exhibit 1 hereto
         who elect to sell additional Ordinary Shares as a result of such
         default. If none (or an insufficient number) of the non-defaulting
         Selling Shareholders elect to sell the Shares which the defaulting
         Selling Shareholders agreed but failed to sell on the Closing Date,
         this Agreement shall terminate without liability on the part of any
         non-defaulting Selling Shareholders, the Company or the Purchaser.

10.      Notices

         10.1.    Any notice, declaration or other communication required or
                  authorized to be given by any party under this Agreement to
                  any other party shall be in writing and shall be personally
                  delivered or sent by facsimile transmission (with a copy by
                  registered mail in either case) addressed to the other party
                  at the address stated below or such other address as shall be
                  specified by the party concerned by notice in accordance with
                  the provisions of this Section. Any notice shall be deemed to
                  have been received on the next following business day.

         10.2.    Addresses for the purposes of this section are as follows:

Company:        Yael Langer, Adv.
                RADVision Ltd.
                24 Raoul Wallenberg Street
                Tel-Aviv 69719, Israel
                Fax: (3) 6498248

Sellers:        As appearing in the first column of Exhibit 1
                with a copy to: Yael Langer, Adv.
                RADVision Ltd. Legal Department
                24 Raoul Wallenberg Street
                Tel-Aviv 69719, Israel
                Fax: (3) 6498248

Purchaser:      Byung Joo Kang, Senior Manager
                Samsung Electro-Mechanics Co., Ltd.
                314 Maetan 3-Dong, Paldal-Gu, Suwon,
                Kyunggi-Do, Korea 442-743
                Fax: (82)331-210-6363

                Tae Young Ha, Senior Manager
                Samsung Venture Investment Corp.
                16th Floor Samsung Yeok Sam Bldg. 647-9,
                Yeok Sam-Dong, KangNam-Gu, Korea 135-080
                Fax: (82)- 2-3430-5577

Payment Agent:  RAD Data Communications Ltd.
                24 Raoul Wallenberg Street
                Tel Aviv 69719
                Attention: Eitan Abramovitch
                Fax: (3) 648 7350

<PAGE>
                                       9

11.      General

         11.1.    This Agreement shall (except for any obligation fully
                  performed prior to or at the Closing Date) continue in full
                  force and effect (except for provisions which, in accordance
                  with their terms, are limited in time or otherwise, insofar as
                  they are so limited) after the Closing Date notwithstanding
                  that the Closing shall have occurred.

         11.2.    All of the parties to this Agreement will after, as well as
                  before and upon, the Closing Date do all acts and things and
                  sign and execute all documents and deeds requisite for the
                  purpose of implementing the terms of this Agreement.

         11.3.    None of the rights or obligations under or pursuant to this
                  Agreement may be assigned or transferred to any other person
                  or entity without the written consent of all the parties
                  except that the Sellers and the Purchaser may so transfer or
                  assign to their respective Affiliates or between themselves,
                  provided that the assignee shall be an Affiliate of the
                  relevant party at the time it exercises any of its rights or
                  obligations hereunder.

         11.4.    This Agreement contains the whole agreement between the
                  parties relating to the transactions provided for in this
                  Agreement and supersedes all previous agreements if any
                  between such parties in respect of such matters and each of
                  the parties to this Agreement acknowledges that in agreeing to
                  enter into this Agreement it has not relied on any
                  representations or warranties except for those contained in
                  this Agreement.

         11.5.    No failure or delay by any party hereto in exercising any
                  claim, remedy, right, power or privilege under this Agreement
                  shall operate as a waiver nor shall any single or partial
                  exercise of any claim, remedy, right, power or privilege
                  preclude any further exercise thereof or exercise of any other
                  claim, right, power or privilege.

         11.6.    This Agreement may be executed in two or more counterparts
                  each of which shall be deemed an original but all of which
                  constitute one and the same instrument.

         11.7.    Except as expressly provided herein, this Agreement may be
                  amended or terminated, and any of the terms hereof waived,
                  only by a document in writing specifically referring to this
                  Agreement and executed by the parties hereto or, in the case
                  of a waiver, by the party waiving compliance. The failure of
                  any party hereto at any time or times to require performance
                  of any provisions hereof shall in no manner affect this right
                  at a later time. No waiver by any party hereto of a breach of
                  any term contained in this Agreement, in any one or more
                  instance, shall be deemed or construed as a further or
                  continuing waiver of any such breach or a waiver of any breach
                  of any other form.

         11.8.    All Ordinary Share numbers in this Agreement give effect to
                  the stock split and distribution of bonus shares which will
                  take place immediately prior to the closing of the IPO.

11       Governing Law and Service of Process

         12.1     This Agreement is subject to and shall be interpreted in
                  accordance with the laws of the State of Israel.

         12.2     For the purposes of any claim under this Agreement, the
                  addresses of the Selling Shareholders for the purposes of
                  service of process shall be their addresses as set forth in

<PAGE>
                                       10

                  the first column of Exhibit 1, or such other address as any
                  Selling Shareholder shall notify the Purchaser in writing.

13       Arbitration

         13.1     All disputes arising out of or in connection with this
                  Agreement and other agreements resulting herefrom, including
                  any question regarding its existence, validity or termination,
                  shall be finally settled under the Rules of Arbitration of the
                  International Chamber of Commerce, by three arbitrators in
                  accordance with the said rules. The seat of arbitration shall
                  be Tel Aviv, Israel. The procedural law of Israel shall apply
                  where the rules are silent. The language to be used in the
                  arbitration proceeding shall be English.

         13.2     The parties undertake to abide by and fully implement the
                  arbitration award rendered, and this Section 13.1 shall be
                  deemed to be an arbitration agreement in accordance with the
                  Arbitration Law 1968.

         13.3     Each of the parties or, if there are more than one plaintiff
                  or defendant, each of Yehuda Zisapel and Zohar Zisapel
                  together on behalf of the Sellers and the Purchaser shall
                  nominate one arbitrator for confirmation by the competent
                  authority under the applicable rules ("Appointing Authority")
                  within thirty (30) days. Both arbitrators shall agree on the
                  third arbitrator within 30 days. In the event that an
                  arbitrator is to be appointed by more than one party, and they
                  fail to agree upon the identity of such arbitrator within the
                  aforesaid time period, any other party to the arbitration may
                  request that such arbitrator be appointed by the Appointing
                  Authority. Should the two arbitrators fail, within the above
                  time-limit, to reach agreement on the third arbitrator, he
                  shall be appointed by the Appointing Authority.

14       Termination At any time prior to the Closing Date, the Company shall
         have the right, in its sole discretion, to terminate this Agreement
         without any liability or adverse affect or without it being considered
         a breach of this Agreement, if the Company, in its sole discretion,
         believes that consummating the transactions contemplated by this
         Agreement may delay the IPO or have any adverse effect on the IPO
         process.

<PAGE>
                                       11

         IN WITNESS WHEREOF, the parties have caused this Agreement to be signed
by its duly authorized representatives as of the date first above written.

Samsung Electro-Mechanics Co., Ltd

By:     /s/ Hyung-Do Lee
     -------------------------------
Name: Hyung-Do Lee
Title: President and CEO

Samsung Venture Investment Corp.

By:     /s/ Jae Han Lee
     -------------------------------
Name: Jae Han Lee
Title: C.E.O.

RADVision Ltd.

By:     /s/ Yehuda Zisapel
     -------------------------------
Name: Yehuda Zisapel
Title: Chairman of the Board of Directors

                THE REST OF THIS PAGE IS LEFT INTENTONALLY BLANK
<PAGE>
                                       12

                              SELLING SHAREHOLDERS

--------------------------------------------------------------------------------
Name and address of Selling Shareholder                    Signature
---------------------------------------                    ---------
Yehuda Zisapel                               By:                 *
                                                  -----------------------------
23 Kisufim Street                            Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Zohar Zisapel                                By:                 *
                                                  -----------------------------
54 Pinchas Street                            Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Michael & Klil Properties (93) Ltd.          By:                 *
                                                  -----------------------------
12 Hanechoshet Street                        Name: ____________________________
Tel Aviv 69710 Israel                        Title: ___________________________

--------------------------------------------------------------------------------
Lomsha Ltd.                                  By:                 *
                                                  -----------------------------
12 Hanechoshet Street                        Name: ____________________________
Tel Aviv 69710 Israel                        Title: ___________________________

--------------------------------------------------------------------------------
Amos Amir                                    By:                 *
                                                  -----------------------------
9 Eliahu Hacham Street                       Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Plonit Achzakot Ltd.                         By:                 *
                                                  -----------------------------
9 Eliahu Hacham Street                       Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Nichsei Almonit Ltd.                         By:                 *
                                                  -----------------------------
12 Hanechoshet Street                        Name: ____________________________
Tel Aviv 69710 Israel                        Title: ___________________________

--------------------------------------------------------------------------------
RAD Data Communications Ltd.                 By:                 *
                                                  -----------------------------
12 Hanechoshet Street                        Name: ____________________________
Tel Aviv 69710 Israel                        Title: ___________________________

--------------------------------------------------------------------------------
Efraim Wachtel                               By:                 *
                                                  -----------------------------
20 Hagefen Street                            Name: ____________________________
Raanana, Israel                              Title: ___________________________

--------------------------------------------------------------------------------
Daniella Ilan                                By:                 *
                                                  -----------------------------
12 Eliahu Hakim Street                       Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Yoram Holtz                                  By:                 *
                                                  -----------------------------
18 Hakotzer Street                           Name: ____________________________
Ramat Hasharon, Israel                       Title: ___________________________
--------------------------------------------------------------------------------
<PAGE>
                                       13

--------------------------------------------------------------------------------
Dario Zipris                                 By:                 *
                                                  -----------------------------
9/5 Ussiskin Street                          Name: ____________________________
Ramat Hasharon, Israel                       Title: ___________________________

--------------------------------------------------------------------------------
Ilan Seidner                                 By:                 *
                                                  -----------------------------
3A Kushani Street                            Name: ____________________________
Ramat Aviv                                   Title: ___________________________

--------------------------------------------------------------------------------
Arie Oren                                    By:                 *
                                                  -----------------------------
8 Tana Street                                Name: ____________________________
Rosh Haayin, Israel                          Title: ___________________________

--------------------------------------------------------------------------------
Aaron Strossberg                             By:                 *
                                                  -----------------------------
16 Brodetsky Street                          Name: ____________________________
Rishon Lezion, Israel                        Title: ___________________________

--------------------------------------------------------------------------------
Eitan Abramovitch                            By:                 *
                                                  -----------------------------
27 Hahatzav Street                           Name: ____________________________
Mevasseret Zion, Israel                      Title: ___________________________

--------------------------------------------------------------------------------
Eli Luz                                      By:                 *
c/o Trust Company of Maritime Bank                -----------------------------
  of Israel Ltd.                               Name: __________________________
35 Ahad Ha'am Street                           Title: _________________________
Tel Aviv, Israel

--------------------------------------------------------------------------------
Lerosh Investments Ltd.                      By:                 *
c/o Trust Company of Maritime Bank                -----------------------------
  of Israel Ltd.                             Name: ____________________________
35 Ahad Ha'am Stree                          Title: ___________________________
Tel Aviv, Israel

--------------------------------------------------------------------------------
Trust Company of Maritime Bank               By:                 *
  of Israel Ltd.                                  -----------------------------
35 Ahad Ha'am Street                         Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
ECI Telecom Ltd.                             By:                 *
                                                  -----------------------------
30 Hasivim Street                            Name: ____________________________
Petach Tikva, Israel                         Title: ___________________________

--------------------------------------------------------------------------------
Factory Systemes SA                          By:                 *
                                                  -----------------------------
22, Rue Vladimir Jankelevitch Emerainville,  Name: ____________________________
77437 Marne La Vallee Cedex 2, France        Title: ___________________________

--------------------------------------------------------------------------------
Clal Venture Capital LP                      By:                 *
                                                  -----------------------------
Atidim Technology Park, Bldg. 4              Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Robert Freeman                               By:                 *
                                                  -----------------------------
407 Robbins Road                             Name: ____________________________
Neptune, New Jersey                          Title: ___________________________

--------------------------------------------------------------------------------
Shrem Pudim Kelner Trust Company Ltd.        By:                 *
                                                  -----------------------------
21 Haarbaah Street                           Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Evergreen Canada Israel Management Ltd.      By:                 *
                                                  -----------------------------
c/o Evergreen Israel                         Name: ____________________________
96 Rothschild Blvd.                          Title: ___________________________
Tel Aviv, Israel

--------------------------------------------------------------------------------
IJT Technologies Ltd.                        By:                 *
                                                  -----------------------------
c/o Evergreen Israel                         Name: ____________________________
96 Rothschild Blvd.                          Title: ___________________________
Tel Aviv, Israel

--------------------------------------------------------------------------------
Periscope I Fund LP, an Israeli partnership  By:                 *
c/o Evergreen Israel                              -----------------------------
96 Rothschild Blvd.                          Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________

--------------------------------------------------------------------------------
Periscope I Fund LP, a Delaware partnership  By:                 *
c/o Evergreen Israel                              -----------------------------
96 Rothschild Blvd.                          Name: ____________________________
Tel Aviv, Israel                             Title: ___________________________
--------------------------------------------------------------------------------

* By:  /s/ Yehuda Zisapel
    ----------------------------
       Yehuda Zisapel
       Attorney-in-fact

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