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                                                                    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

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                                       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

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                  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

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                           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.

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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

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                  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

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                  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

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         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

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                                       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

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                                       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