<PAGE>

                                                                     Exhibit 4.7

                                    AGREEMENT

         THIS AGREEMENT made and entered into as of the 26th day of April, 1995,
by and among RADVISION LTD., an Israeli company of 8 Hanechoshet Street, Tel
Aviv 69710, Israel (the "Company") and (1) Lerosh Investments Ltd., (2) Gevahim
Investments House Limited Ltd., (3) Mr. Yoav Chelouche, (4) Permal Emerging
Growth V Ltd., (5) Maritime - Julex Investment Ltd., (6) Mr. Shraga Blazer and
(7) Mr. Eli Luz, all of them of 35 Achad Ha'am Street, Tel Aviv, Israel (all
seven of them together jointly and severally the "Purchaser") and Yehuda Zisapel
and Zohar Zisapel of 8 Hanechoshet Street, Tel Aviv 69710, Israel (jointly and
severally, the "Present Shareholders").

                              W I T N E S S E T H :

         WHEREAS, the Company is and will be engaged in the business of
developing, manufacturing and marketing of products for video conferencing (the
"Field"); and

         WHEREAS, the Company desires to issue and sell, and the Purchaser
desires to purchase ordinary shares, par value One New Israeli Shekel (NIS
1.00), of the Company ("Ordinary Shares"),

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and conditions herein contained, the Company and the Purchaser hereby
agree as follows:

                                    SECTION 1
                         ISSUANCE AND PURCHASE OF SHARES

                  1.1 The Purchaser undertakes to invest in the Company the
         amount of Four Hundred Ninety-Nine Thousand Nine Hundred Fifty US
         Dollars (US$ 499,950) (hereinafter, the "Investment Amount") on the
         Closing Date as defined in Section 2 hereinbelow. All amounts will be
         deposited in US dollars or their equivalent in NIS to the Company's
         account no. 377906 at Bank Hapoalim B.M., Hadar Yosef Branch (610).

                  1.2 In consideration for and subject to the execution of the
         investment, the Company shall issue on the Closing Date two thousand
         four hundred seventy-five (2,475) ordinary shares (hereinafter, the
         "Shares") to the Purchaser. The Company shall not be obligated to issue
         any shares whatsoever before the full Investment Amount is received by
         it. The Shares, when issued, will have been validly issued, fully paid
         and non-assessable, and will be free of any liens or encumbrances.

                  The above shares will be issued as follows:

                   Lerosh Investments Ltd.                    495 shares
                   Gevahim Investments House Limited Ltd.     100 shares
                   Yoav Chelouche                             246 shares
                   Permal Emerging Growth V Ltd.              965 shares
                   Maritime - Julex Investment Ltd.           495 shares
                   Shraga Blazer                               25 shares
                   Eli Luz                                    149 shares
<PAGE>

                  1.3 The Investment Amount is part of a total amount of
         approximately US $4,930,000 (hereinafter, the "Total Investment")
         intended to be raised by the Company from the Purchaser as well as from
         other investors (hereinafter, the "Other Purchasers") as set forth in
         Exhibit 1 attached hereto. In consideration for the Total Investment,
         the Company will issue 24,453 Ordinary Shares, par value 1.- NIS each.
         After all said shares have been issued, the ownership of the Company
         will be as set forth in Exhibit 1.

                                    SECTION 2
                                  CLOSING DATE

                  The purchase of the Shares by the Purchaser shall take place
         on April 27, 1995 (the "Closing"). The date of the Closing is referred
         to as the "Closing Date" in this Agreement.

                                    SECTION 3
                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

                  The Company and the Present Shareholders hereby represent and
         warrant to the Purchaser the facts hereinafter set forth in this
         Section 3.

                  3.1 CORPORATE POWER. As of the date hereof and as of the
         Closing, the Company has and will have all requisite corporate power to
         enter into and to perform this Agreement.

                  3.2 SUBSIDIARIES. The Company has a wholly owned U.S.
         subsidiary, RADVISION Inc. in New Jersey. The Company has no other
         subsidiaries and does not otherwise own, of record or beneficially, any
         capital stock or equity interest in any other corporation, association
         or business entity.

                  3.3 ORGANIZATION AND STANDING. The Company is a corporation
         duly organized and existing under the laws of the State of Israel and
         is in good standing under such laws. The Company has requisite
         corporate power to own and operate its properties and assets, and to
         carry on its business as presently conducted. The Memorandum of
         Association and Articles of Association and all amendments to date of
         the Company are attached hereto as EXHIBITS "3.3A" AND "3.3B."

                  3.4 CAPITALIZATION. The Company's authorized capital is sixty
         thousand (60,000) Ordinary Shares. The Company's issued capital stock
         immediately prior to the Closing date shall consist of twenty thousand
         seven hundred thirty-two (20,732) Ordinary Shares, all of which are
         duly authorized, validly issued and free of any liens or encumbrances.
         Out of the issued share capital, thirteen thousand eight hundred sixty
         (13,860) shares are fully paid and six thousand eight hundred
         seventy-two (6,872) shares are partially paid. All shares are
         non-assessable, and to the best of the Company's knowledge and belief,
         are beneficially owned by their holders of record. There are no
         preemptive, conversion or other rights, options, or agreements granted
         or issued by, or binding upon, the Company or the shareholders which
         entitle any person, firm or corporation to purchase or acquire any
         shares of the Company's capital stock, except as set forth in this
         Agreement and in particular, in Sections 3.21, 3.22 and 3.23.


                                       2
<PAGE>

                  3.5 AUTHORIZATION. All corporate actions on the part of the
         Company and its directors and shareholders, required for the
         authorization, execution, delivery and performance by the Company of
         this Agreement and the consummation of the transactions contemplated
         herein have been, or will be executed, upon signature of this
         Agreement. This Agreement is and will be valid and binding obligations
         of the Company, enforceable in accordance with its terms. The
         execution, delivery and performance by the Company of this Agreement,
         and compliance therewith, and the consummation of the transactions
         contemplated by this Agreement will not result in any violation of and
         will not conflict with, or result in a breach of any of the terms of,
         or constitute a default under, any document to which the Company is or
         will be a party or by which it is or will be bound, or result in the
         creation of any mortgage, pledge, lien or encumbrance or charge upon
         any of the properties or assets of the Company. To the best of the
         Company's knowledge, no third party's consent is required for the
         Company to become a party to this Agreement. Immediately after the
         Closing Date, the Company will inform all governmental authorities that
         require to be reported of changes in equity, including, but not limited
         to the Israel Investment Center and the Office of the Chief Scientist
         of the execution of this Agreement.

                  3.6 OUTSTANDING DEBT. Except as set forth in the Schedule of
         Exceptions attached hereto as EXHIBIT "A" ("Schedule of Exceptions"),
         the Company has no outstanding indebtedness for borrowed money and is
         not a guarantor of any debt or obligation of another. There exists no
         default by the Company under the provisions of any agreement or other
         instrument evidencing or relating to any indebtedness or obligation.

                  3.7 ABSENCE OF UNDISCLOSED LIABILITIES. Except as set forth in
         the Schedule of Exceptions, the Company has no material liability of
         any nature, direct or indirect, absolute or contingent, not adequately
         reserved against, excluding any liabilities related to damage which may
         have been caused by its products or are related to sales of said
         products (unless the Company knows or should have known of such damages
         or liabilities). The Company has paid, or has made adequate provisions
         for the payment of, all taxes, interest, penalties, assessments or
         deficiencies owing by it to any taxing authority.

                  3.8 ABSENCE OF CERTAIN CHANGES. Since December 31, 1994, the
         business of the Company has at all times been conducted in the ordinary
         course. There has not been any event or condition of any character
         which has materially adversely affected the Company's business,
         prospects or plans.

                  3.9 CONTRACTS AND CONTRACTUAL ARRANGEMENTS. The Company is a
         party to several material agreements, all of which are described in the
         Schedule of Exceptions attached hereto. Each of such agreements is in
         full force and effect and, to the Company's knowledge, no party thereto
         is in breach thereof. The Company is of the opinion that it receives
         services from affiliated companies for fair consideration as described
         in the Schedule of Exceptions attached hereto. The Company is not
         obligated to receive services from said affiliated companies.

                  3.10 INDEBTEDNESS OF OR TO SHAREHOLDERS, ETC.; CONFLICTS OF
         INTEREST.


                                       3
<PAGE>

                   (a) Except as set forth in the Schedule of Exceptions, none
         of the Company's shareholders, directors, officers or employees or any
         of their affiliates or families is indebted to the Company and the
         Company has no debt to any of them except for accrued wages for the
         current period.

                  (b) Except as set forth in the Schedule of Exceptions, to the
         best of the Company's knowledge, none of the Company's directors,
         officers, employees or consultants, or their affiliates or families,
         directly or indirectly, own any material interest in any entity which
         is a competitor of the Company.

                  3.11 LITIGATION; INSOLVENCY PROCEEDINGS. To the best of the
         Company's knowledge and belief, there are no pending or threatened
         actions, suits, proceedings or any investigations against or affecting
         the Company involving the possibility of any judgment or liability
         which would adversely affect its business.

                  3.12 INSURANCE. The Company maintains insurance through
         RAD-Bynet insurance policies, adequately covering the perils normally
         insured against by companies similarly situated. All policies of
         insurance maintained by the Company are attached hereto as EXHIBIT
         "3.12." To the best of the Company's knowledge, all such policies are
         in full force and effect.

                  3.13 TITLE TO PROPERTIES; LIENS AND ENCUMBRANCES. Except as
         set forth in the Schedule of Exceptions, the Company owns, or holds
         under lease, all real and personal property used by it in its business.
         All property owned by the Company (all of which is listed on EXHIBIT
         "3.13" hereto) is so owned free and clear of all mortgages, pledges,
         liens or charges.

                  3.14 LEASES. EXHIBIT "3.14" hereto contains a correct and
         complete list and description (including the amount of rents) of all
         leases under which the Company leases property, real or personal.

                  3.15 BUSINESS OF THE COMPANY. The Company has no knowledge of
         (i) the existence of any pending or planned patent, or any statute,
         rule, law, regulation, standard or codes which would materially
         adversely affect the condition, financial or otherwise, or the business
         operations, of the Company; or (ii) the existence of any other factor
         which would materially adversely affect the financial condition, or the
         operations, of the Company.

                  3.16 COMPLIANCE WITH OTHER INSTRUMENTS. The Company is not in
         violation of the terms of its Memorandum or Articles of Incorporation,
         and it is not in violation of the terms of any judgment, decree, order,
         statute, rule or regulation to which it is subject.

                  3.17 EMPLOYEES. All the key employees of the Company are
         listed on EXHIBIT "3.17" hereto. To the best of the Company's
         knowledge, no such employee is in violation of any material term of any
         employment contract, patent disclosure agreement, non-competition
         agreement, or any other contract or agreement or any restrictive
         covenant or any other obligation to a former employer relating to the
         right of any such employee to be employed by the Company. To date, all
         payments due to the Company's employees have


                                       4
<PAGE>

         been paid regularly. In addition, the Company made all allowances
         required by law to cover the amounts due to its employees and/or
         officers in connection with their employment and/or termination of
         employment, as reflected in Exhibit "3.20a."

                  3.18 DISCLOSURE. This Agreement and the Schedule of Exceptions
         delivered to the Purchaser do not contain any material untrue statement
         and do not omit to state a material fact necessary in order to make the
         statements contained herein not misleading in the light of the
         circumstances under which they were made, and such documents represent
         full disclosure by the Company of the material facts with respect to
         the business, prospect and plans of the Company. The Company confirms
         that to the date of this Agreement, the Business Plan dated August,
         1994, which was provided to the Purchaser, does not contain any
         materially untrue information as far as same relates to the Company
         itself. The other information contained therein may have changed since
         August, 1994.

                  3.19 PRODUCTS AND OWNERSHIP. A description of the products is
         enclosed as EXHIBIT 3.19. To the best of the knowledge and belief of
         the Company and as set forth in the Schedule of Exceptions, the Company
         possesses, or is proceeding with due diligence to obtain, all patents,
         patent rights, trademarks, trademark names, trade name rights and
         copyrights the Company believes are necessary to conduct its business
         as now being conducted and as planned to be conducted (without conflict
         with, or infringement upon, any valid rights of others), the lack of
         which could affect the operations or condition, financial or otherwise,
         of the Company. The Company has no knowledge of any infringement by the
         Company or claimed infringement upon, or any conflict with, the patent
         rights, trademarks, trademark rights, trade names, trade name rights,
         copyrights, intellectual property rights or other rights of any person,
         form or corporation.

                  3.20 FINANCIAL STATEMENTS. The audited financial statements of
         the Company as of December 31, 1994 are attached hereto as EXHIBIT
         "3.20A" and adequately reflect the financial situation of the Company.
         The unaudited financial statements of the Company as of February 28,
         1995 are attached hereto as Exhibit "3.20b." As of December 31, 1994 to
         date, the Company did not enter into any material transaction or
         undertake any material commitment which was not in the normal course of
         business, and there was no material change for the worse in the
         Company's position, liabilities and assets.

                  3.21 The agreements with the other purchasers will resemble
         the Agreement with Purchaser.

                  3.22 In the event of any contradiction between this Agreement
         and the Inception Agreement, attached hereto as EXHIBIT "3.22," the
         current Memorandum of Association and the Current Articles of
         Association, this Agreement shall prevail.

                  3.23 On January 1, 1995, a trust in favor of employees of the
         Company and certain employees of the RAD-Bynet group was created. Said
         Trust Agreement is attached hereto as EXHIBIT "3.23."

                  3.24 As of the date of this Agreement, the directors of the
         Company are: Yehuda Zisapel, Zohar Zisapel and Amos Amir.


                                       5
<PAGE>

                                    SECTION 4
                 REPRESENTATIONS AND WARRANTIES OF THE PURCHASER

                  Each of the Purchaser represents and warrants to the Company
         as follows:

                  4.1 LEGAL POWER. As of the date hereof and as of the Closing,
         the Purchaser has and will have all requisite power to enter into and
         to perform this Agreement.

                  4.2 EXPERIENCE. The Purchaser has sufficient experience and
         expertise to evaluate the suitability of its investment in the Company
         to its needs and has the capacity to protect its interests with the
         purchase of the Shares.

                  4.3 INVESTMENT. The Purchaser is acquiring the Shares for
         investment for its own account.

                  4.4 ACCESS TO DATA. The Purchaser hereby represents that it
         has had the full opportunity to discuss management and financial
         affairs of the Company with its management and key employees and has
         had the opportunity to review the business plan and the Company's
         facilities. The Purchaser has not been denied any information that has
         been requested, and based on the said information has made a diligent
         examination of the aspects of the Company's business. The Purchaser has
         heretofore received all information that the Purchaser has deemed
         necessary and appropriate to enable the Purchaser to evaluate the
         financial risk inherent in making an investment in the shares of the
         Company and the Purchaser has received satisfactory and complete
         information concerning the business and financial condition of the
         Company in response to all inquiries in respect thereof. The Purchaser
         is aware that the Company has been in the development stage since its
         inception in October 1992, that no sales of its products have taken
         place, and that due to the short operating history of the Company there
         can be no assurance that the Company will attain profitability. Nothing
         contained in this Section 4.4 shall derogate from the liability of the
         Company with respect to the representations and warranties made in
         Section 3 above.

                  4.5 AUTHORIZATION. All corporate or partnership action on the
         part of the Purchaser, its respective directors, partners and/or
         shareholders necessary for the authorization, execution, delivery,
         payment and performance by the Purchaser of this Agreement and the
         consummation of the transactions contemplated herein, has been taken.

                  4.6 Purchaser has sufficient financial resources to enable it
         to fulfill its obligations under this Agreement and commits to make its
         investment in the Company as set forth in Section 1 hereinabove.

                                    SECTION 5
                     CONDITIONS OF THE PURCHASER TO CLOSING

                  The obligations of the Purchaser at the Closing, as referred
         to in Section 1 hereof, are subject to the fulfillment of each of the
         following conditions:


                                       6
<PAGE>

                  5.1 REPRESENTATIONS AND WARRANTIES CORRECT. The
         representations and warranties made by the Company in Section 3 hereof
         shall be true and correct when made, and shall be true and correct in
         all material respects on Closing with the same force and effect as if
         they had been made immediately prior to the Closing and as of such time
         except for such changes which result from the obligations of the
         parties to this Agreement.

                  5.2 PERFORMANCE. All covenants, agreements and conditions
         contained in this Agreement to be performed or complied with by the
         Company on or prior to Closing shall have been performed or complied
         with in all respects.

                  5.3 LEGAL INVESTMENT. At the time of the Closing, the purchase
         and issuance of the Shares shall be legally permitted by all laws and
         regulations to which the Purchaser and the Company are subject.

                  5.4 PROCEEDINGS AND DOCUMENTS. All corporate and other
         proceedings in connection with the transactions contemplated hereby and
         all documents and instruments incident to such transactions shall have
         been completed to the satisfaction (as to substance and form) of the
         Purchaser.

                  5.5 PROPRIETARY INFORMATION AND NON-COMPETITION AGREEMENT.
         Each of the Company's employees shall have executed and delivered to
         the Company an Employment Agreement, substantially in the form attached
         hereto as EXHIBIT "5.5A" or EXHIBIT "5.5B," which agreement contains
         non-disclosure and non-competition provisions therein.

                  5.6 RETENTION OF KEY EMPLOYEES. All the persons listed in
         EXHIBIT "3.17" shall either be employees of the Company as of the
         Closing and to the best of the Company's knowledge, have not informed
         them that they intend to leave the Company, or if an employee has left
         the Company or intends to leave the Company, the latter has notified
         the Purchaser of same.

                  5.7 OPINION OF COMPANY'S COUNSEL. The Purchaser shall have
         received from Nehama Sneh, corporate counsel to the Company, a
         satisfactory opinion in substantially the form attached as EXHIBIT
         "5.7."

                                    SECTION 6
                        CONDITIONS OF COMPANY TO CLOSING

                  The obligations of the Company at the Closing, as referred to
         in Section 1 hereof, are subject to the fulfillment of each of the
         following conditions:

                  6.1 REPRESENTATION. The representations and warranties made by
         the Purchaser in Section 4 hereof shall be true and correct when made
         and shall be true and correct on Closing with the same force and effect
         as if they had been made immediately prior to the Closing and as of
         such time.

                  6.2 Purchaser has fulfilled any and all of its obligations set
         forth in Section 1.1.


                                       7
<PAGE>

                                   SECTION 6A

                               BOARD OF DIRECTORS

                  Subsequent to the Closing, the Board of Directors will consist
         of six (6) directors, three of whom will be appointed by Zohar Zisapel,
         Yehuda Zisapel and RAD Data Communications Ltd., the fourth will be
         Amos Amir in his capacity as Managing Director of the Company, and the
         fifth and the sixth are entitled to be appointed by The Trust Company
         of Maritime Bank of Israel ("Maritime") and Clal Venture Capital LP
         ("Clal"). Lannet Data Communications Ltd. ("Lannet") and Finovelec,
         will have the right to designate one observer each to the Board of
         Directors. Upon reasonable notice, Lannet will be permitted to change
         the status of its observer to that of director, in which event the
         number of directors will be eight (8), Lannet's observer will become
         the seventh director and Yehuda Zisapel and Zohar Zisapel will be
         entitled to appoint another director (the eighth).

                                    SECTION 7
                            COVENANTS OF THE COMPANY

                  For as long as the Purchaser's equity interest in the Company
         will amount to at least five (5%) percent of the outstanding capital
         securities therein and Purchaser has the right to appoint a director or
         an observer under Section 6A hereinabove, except where stated otherwise
         in this Section 7 and in Section 8, and without derogating from any
         rights or obligations conferred upon shareholders, or obligations
         conferred upon corporations, under applicable law, the Company hereby
         covenants and agrees as follows. For the purposes of calculating Clal's
         percentage of ownership set forth above, ECI Telecom Ltd.'s ("ECI")
         equity interest in the Company at the time will be taken into account
         and added to that of Clal for as long as Clal is a shareholder of ECI.

                  7.1 ADDITIONAL INFORMATION. The Company will permit an
         employee of the Purchaser to visit upon a mutually convenient time and
         inspect any of the properties of the Company, including its books of
         account, and to discuss its affairs, finances and accounts with the
         Company's officers and the Auditor.

                  (a) As soon as available after approval by the Board of
         Directors, the Company will provide Purchaser with a summary of the
         budget, including projected yearly profit and loss accounts and balance
         sheet, as contained in its Operating Plan and as approved by its Board
         of Directors, as well as information about material changes in the
         budget, all as approved by the Board of Directors.

                  (b) With reasonable promptness, the Company agrees to provide
         to Purchaser such information and data with respect to the Company, as
         the Purchaser may from time to time reasonably request.

                  The foregoing provisions of this Section 7.1 shall not be in
         limitation of any rights which the Purchaser may have to inspect and
         copy the books and records of the Company or to inspect its properties
         or discuss its affairs, finances and accounts, under the laws of the
         State of Israel.


                                       8
<PAGE>

                  7.2 USE OF PROCEEDS. The Company will use the proceeds of the
         issuance and sale of the Shares mainly to fund its activities and its
         business subject to any resolutions made by its Board of Directors from
         time to time.

                  7.3 BOARD APPROVAL. Without derogating from the Company's
         Articles of Association, or any law or practice limiting the authority
         of the management of the Company, the Company shall ensure that the
         approval of the Board of Directors of the Company shall be required for
         the following, (i) designation of all authorized signatories; (ii)
         approval of the Company's or the subsidiaries' budget and Operating
         Plan; (iii) selection of legal counsel of the Company; (iv) terms of
         employment of the Managing Director of the Company; and (v) any and all
         other matters with regard to which the Board of Directors of the
         Company resolves that its prior approval shall be required.

                  Without derogating from the first sentence of Section 7
         hereof, it is further provided that the Purchaser's rights hereunder
         shall expire upon a public offering of the Company's shares regardless
         of Purchaser's percentage of ownership at that time.

                  7.4 Resolutions of the Board of the Company regarding the
         following subject matters shall require the consent of five out of six
         directors. In the event that the Board will consist of 8 directors as
         per Section 6.2 hereinabove, then the following subject matters will
         require the consent of 6 out of 8 directors, including consent of two
         directors out of the following: "Clal" Director, "Maritime" Director,
         "Lannet" Director:

                  (a) A merger of the Company with any other entity;

                  (b) Acquisition or disposition, including mortgage, of other
         corporations, real estate, and any material assets out of the ordinary
         course of the Company's business;

                  (c) Replacement of the Company's Managing Director;

                  (d) Replacement of the auditors of the Company;

                  (e) Approval of the distribution of dividends by the Company.

                  (f) Loans by the Company or any of its subsidiaries to their
         directors or officers, or to their relatives or other affiliates, with
         the exception of employees receiving shares under the trust as set
         forth in subsection 3.23 hereinabove;

                  (g) Transactions in excess of $20,000 not included in the
         approved Operating Plan between the Company or its affiliates and their
         directors, officers and employees or their relatives or other
         affiliates, with the exception of employees receiving shares under the
         trust as set forth in subsection 3.23 hereinabove;

                  (h) All material transactions or obligations not contemplated
         in the budget by the Company or its subsidiaries; and

                  (i) Resolution to enter a new business field unrelated to the
         present field.


                                       9
<PAGE>

                  Notwithstanding anything to the contrary contained herein, in
         the event that a director is not allowed under a specific section of
         this Agreement to participate in a board meeting and/or discussion, the
         majority required will be (1) 4 out of 5, or (2) 5 out of 7, including
         only one of the following:
         the Clal Director, Maritime Director, or Lannet Director.

                  7.5 RIGHT OF FIRST REFUSAL FOR IPO. The Company agrees that in
         the event that the Board of Directors resolves:

                  (a) to initially offer shares of the Company on the Israeli
         Stock Exchange, then the following will apply:

                           (1) The Company will inform Clal Issuing Ltd. of said
         resolution;

                           (2) Clal Issuing Ltd. will have an option for twenty
         (20) days as of said notice date by the Company to make a proposal to
         underwrite the offering (hereinafter, the "Clal Proposal");

                           (3) The Board of Directors will consider the Clal
         Proposal and will, in its sole discretion, resolve whether it is
         acceptable or not; and

                           (4) In the event that the Board resolves not to
         accept the Clal Proposal, then the Company will be free to negotiate
         and agree with any underwriter whatsoever.

                           (5) Within five (5) working days after the written
         notice of the Company of the best proposal from the underwriter as in
         (4) above, Clal will have the option to improve the Clal Proposal to
         match the underwriter's proposal. In the event that Clal Issuing Ltd.
         either fails to respond or to match the other proposal, Clal's option
         under this Section 7.5(a) will terminate and the Board will be free to
         proceed as it deems fit.

                  (b) In the event that the Board of Directors resolves to
         initially offer shares of the Company on NASDAQ, with some of the
         shares intended for the Israeli public, then the following will apply:

                           (1) The Company will inform Clal Issuing Ltd. of said
         resolution;

                           (2) The Company will be free to negotiate and agree
         with any underwriting house to underwriter the offering, provided that
         the Company notifies said underwriter that Clal Issuing Ltd. has a
         right of first refusal concerning the offering of the shares of the
         Company to the Israeli public.

                  (c) In the event that the Board of Directors resolves to
         engage a placement agent for a private offering in the Israeli market,
         and such agent is entitled to a commission in return for his services
         (whether by form of money or options), then the following will apply:

                           (1) The Company will inform Clal Venture Capital LP
         of said resolution;


                                       10
<PAGE>

                           (2) Clal Issuing Ltd. will have an option for ten
         (10) days as of said notice date by the Company to make a proposal to
         head the offering as a placement agent (hereinafter, the "Clal
         Proposal");

                           (3) Within five (5) working days after the written
         notice of the Company of a proposal from another placement agent, Clal
         and Clal Issuing Ltd. will have the option to improve the Clal Proposal
         to match the other proposal. In the event that Clal Issuing Ltd. either
         fails to respond or to match the other proposal, Clal's option under
         this Section 7.5(c) will terminate and the Board will be free to
         proceed as it deems fit;

                           (4) The Board of Directors will consider the Clal
         Proposal as well as the other proposal(s) and will, in its sole
         discretion, resolve whether it is acceptable or not; and

                           (5) In the event the Board accepts Clal Issuing
         Ltd.'s proposal and Clal Issuing Ltd. acts as the said placement agent,
         then, notwithstanding anything to the contrary contained herein, the
         Board, in its sole discretion, by simple majority, will be free
         thereafter to resolve that the services of Clal Issuing Ltd. as a
         placement agent are not satisfactory, to terminate such services and to
         receive such services from any other placement agent without any
         further rights or obligations with respect to Clal Issuing Ltd. or the
         Purchasers.

                  (d) It is specifically agreed that:

                           (1) all discussions concerning the identity of
         underwriter or placement agent as well as the terms of the offer under
         Section 7.5 will be without the presence of Clal's appointed director;

                           (2) Clal Venture Capital LP's and Clal Issuing Ltd.'s
         rights under Section 7.5 will terminate upon acceptance or rejection by
         the Board of Directors of the Clal Proposal;

                           (3) It is further provided that the rights of Clal
         Issuing Ltd., and Clal Venture Capital LP under Section 7.5 shall
         expire upon a public offering of the Company's shares regardless of
         Purchaser's percentage of ownership at that time.

                           (4) For the purposes of this Agreement, the address
         of Clal Issuing Ltd. is 5 Druianov Street, Tel-Aviv 63143.

                                    SECTION 8

                  For as long as the Purchaser's equity interest in the Company
         amounts to at least two (2%) percent of the outstanding share capital
         of the Company therein, and without derogating from any rights
         conferred upon shareholders, or obligations conferred upon corporations
         under applicable law, the Company hereby covenants and agrees as
         follows:

                  8.1 PRE-EMPTIVE RIGHTS. If the Company should at any time or
         from time to time propose to issue and sell New Securities, as defined
         in subsection 8.1(a), a pro rata


                                       11
<PAGE>

         portion of such New Securities shall first be offered (as hereinafter
         provided) to the shareholders of the Company (each of whom shall
         hereinafter be referred to as "offeree"). For purposes of this Section
         8.1, the pro rata portion of each Offeree shall mean a fraction of the
         New Securities to be issued, of which the aggregate number of shares
         which are held by the Offeree on the date of the Company's written
         notification referred to in subsection 8.1(b) below (the "Notice Date")
         shall be the numerator and the aggregate number of shares held by all
         the Offerees shall be the denominator. The aforesaid rights of the
         Offerees shall be subject to the following provisions:

                           (a) "New Securities" shall mean any capital stock of
         the Company, whether or not now authorized, and rights, options or
         warrants to purchase capital stock, and securities of any type
         whatsoever that are, or may become, convertible into capital stock;
         provided that the term "New Securities" shall not include (i)
         securities purchased under this Agreement; (ii) securities offered to
         the public; (iii) securities issued pursuant to the acquisition of
         another corporation by the Company by merger, purchase of substantially
         all the assets of another corporation or any other reorganization
         whereby the Company owns not less than fifty-one percent (51%) of the
         voting power of such corporation; (iv) securities issued to employees,
         consultants or directors of the Company pursuant to any stock option
         plan or stock purchase or stock bonus arrangement approved by the Board
         of Directors of the Company; or (v) securities issued pursuant to
         payment of any dividend or distribution with respect to the Company's
         issued and outstanding capital stock.

                           (b) In the event the Company proposes to undertake an
         issuance of New Securities, it shall give each Offeree written notice
         of its intention, describing the type of New Securities and the price
         and the terms upon which the Company proposes to issue the same, and
         offering its pro rata portion thereof to such Offerees at such price
         and on such terms. Each Offeree shall have twenty-one (21) days from
         the date of such notice to accept such offer, in whole or in part, by
         written notice to the Company, that has to be received by the Company
         during the above mentioned 21 days period. All New Securities as to
         which such offers have not been accepted in whole or in part by one or
         more of the Offerees (of which fact the Company shall give immediate
         written notice to all other Offerees), shall be re-offered to each of
         the Offerees who have accepted in full the original offer, and each
         such Offeree shall have the right, within ten (10) days of the date of
         such written notice, to purchase the respective pro rata portions of
         such new Securities, the same to be computed as aforesaid but without
         regard to the shares held by any Offeree which had not accepted the
         original offer in full.

                           (c) In the event any Offeree fails to accept such
         offers, the Company shall have the right to sell within six (6) months
         or enter into an agreement, to sell such New Securities as to which
         such offers were not accepted, provided, however, that no such sale be
         effected at a price or upon terms more favorable to the purchasers
         thereof than those specified in the Company's notice pursuant to
         Section 8.1(b).

                           (d) Each of Yehuda Zisapel, Zohar Zisapel and RAD
         Data Communications Ltd. shall have a right to allocate any unused
         portion of the New Securities offered to him to the other.


                                       12
<PAGE>

                            (e) The Purchaser shall have the right to allocate
         any unused portion of the New Securities offered to him to its owners
         or to a company affiliated to Purchaser, provided that such recipient
         of shares will join in this Agreement as if it had become a party to it
         as of the receipt of shares.

                           (f) Notwithstanding anything to the contrary
         contained herein, Amos Amir, so long as he is the Managing Director of
         the Company, will be entitled to be an Offeree under this Section 8.1.

                           (g) Each of Lerosh Investments Ltd., Gevahim
         Investments House Limited Ltd., Mr. Yoav Chelouche, Permal Emerging
         Growth V Ltd., Maritime-Julex Investment Ltd., Mr. Shraga Blazer and
         Mr. Eli Luz shall have a right to allocate any unused portion of the
         New Securities offered to him to the other.

                  8.2 REGISTRATION RIGHTS. If the Company should elect to offer
         any of its securities to the public, the Purchaser and the Present
         Shareholders shall have registration rights as set forth in Exhibit
         "8.2" attached hereto.

                  8.3 RESTRICTIONS. Unless otherwise required by applicable law
         or under this Agreement, the Company shall not without the approval of
         at least 75% of the shareholders:

                           (a) amend or repeal any provision of, or add any
         provision to, the Company's Articles of Association;

                           (b) create any new class or classes of securities of
         the Company having any preference or priority as to dividends or assets
         superior to any such preference or priority of the Ordinary Shares, or
         reclassify any of its existing securities into such superior
         securities; or

                           (c) approve a merger of the Company with any other
         entity;

                           Without derogating from the first sentence of Section
         8, it is further provided that each shareholder's rights under Section
         8 (except for 8.2) shall expire upon the initial public offering of the
         Company's shares, regardless of that shareholder's percentage of
         ownership at that time.

                                   SECTION 8A

                  The Company agrees and undertakes as follows:

                  8A.1 BASIC FINANCIAL INFORMATION. The Company will furnish to
         the Purchaser the following reports certified, when so required herein,
         by the Company's auditors:

                           (a) As soon as practicable after the end of each
         calendar quarter, and in any event within forty-five (45) days
         thereafter, a balance sheet and a profit and loss account and of cash
         flow (including opening cash, income, expenses and closing cash) of


                                       13
<PAGE>

         the Company as of the end of such quarterly period, and for the current
         fiscal year to date, prepared in accordance with generally accepted
         accounting principles consistently applied and setting forth in
         comparative form the figures for the corresponding periods of the
         previous fiscal year, subject to changes resulting from year-end audit
         adjustments, all in reasonable detail, signed by the principal
         financial or accounting officer of the Company. There shall be appended
         to such materials a report of the management as to the business of the
         Company and its activities during the quarter.

                           (b) Not later than forty-five (45) days after the end
         of each quarter, sales figures, backlog and new orders for such
         quarter.

                           Without derogating from the first sentence of Section
         7, it is further provided that the Company will not be required to
         furnish any information under the provisions of this Section 8A.1 and
         of Section 8A.2 below subsequent to the initial public offering.

                  8A.2 INSURANCE. The Company shall continue to maintain
         insurance policies similar to those described in Section 3.12 above.

                  8A.3 ACCOUNTS AND RECORDS. The Company will keep true records
         and books of account in which full, true and correct entries will be
         made of all dealings or transactions in relation to its business and
         affairs in accordance with generally accepted accounting principles
         applied on a consistent basis.

                  8A.4 PROPRIETARY INFORMATION AND NON-COMPETITION AGREEMENTS.
         The Company will not employ, or continue to employ, any person who will
         have access to confidential information with respect to the Company and
         its operations unless such person has executed and delivered the
         Company's standard Employment agreement then in force containing
         proprietary information and non-competition sections to the
         satisfaction (as to substance and form) of the Company's counsel.

                                    SECTION 9
                  RESTRICTIONS ON TRANSFERABILITY OF SECURITIES

                  Except as set forth in this Section 9, the Present
         Shareholders and the Purchaser agree not to sell or transfer any of
         their shares and rights in the Company to a third party. This Section 9
         will terminate upon the initial offering of the Company's shares to the
         public.

                  9.1 For the purpose of this Section 9, the shareholders, the
         Purchaser and the Other Purchasers will be regarded as the following
         Groups:

                  (a)      Zisapel Group - Yehuda Zisapel, Zohar Zisapel, the
                           Trust and RAD Data Communications Ltd.

                  (b)      Clal Group - Clal Venture Capital LP, ECI Telecom
                           Ltd.

                  (c)      Finovelec Group - Finovelec, Factory Systemes,
                           Houston Venture Partners Ltd.


                                       14
<PAGE>

                  (d)      Capital Group - Zohar Gilon, Avraham Neuman, Yair
                           Tauman, W.S.P. Capital

                  (e)      Maritime Group - Lerosh Investments Ltd., Gevahim
                           Investments House Limited Ltd., Mr. Yoav Chelouche,
                           Permal Emerging Growth V Ltd., Maritime-Julex
                           Investment Ltd., Mr. Shraga Blazer and Mr. Eli Luz.

                  9.2 Group Members are entitled to transfer shares among
         themselves for consideration or without consideration without any
         restrictions.

                  9.3 Except as set forth in sections 9.9, 9.10 and 9.11
         hereinbelow, any shareholder who shall elect to transfer (hereinafter
         "Seller") all or part of his shares, not in accordance with subsection
         9.2 (hereinafter "Offered Shares") shall offer them first to the other
         registered shareholders of the Company at that time (hereinafter
         "Offerees") on a pro rata basis based on their share in the share
         capital of the Company.

                  9.4 In the event any such Offeree fails to exercise his right
         to purchase his Offered Shares within forty-five (45) days from the
         date the offer is made, then the Seller shall have the right to offer
         the Offered Shares to a third party at the same price and upon the same
         terms of sale as those offered to the other shareholders under section
         9.3 and provided that said third party shall undertake all of Seller's
         obligations under this Agreement. (Such third party to be called
         hereunder, the "Transferee"). In the event that the shares are not sold
         to said party within six (6) months as of the offer to such said third
         party, then Section 9.3 will apply anew.

                  9.5 The Board of Directors shall have the right to not approve
         the transfer of shares to a third party in each of the following
         events:

                  (i)      If the third party is a competitor of the Company;

                  (ii)     If there is a possibility of conflict of interest
                           between the third party and the Company;

                  (iii)    For any other reason, in which case such approval
                           shall not be unreasonably withheld.

                  9.6 In the event that Yehuda Zisapel and/or Zohar Zisapel
         and/or RAD will sell more than a total of 25% of their shares in the
         Company the to third parties, then Purchaser will have the right to
         sell the same portion of Purchaser's shares in the Company under the
         same terms and conditions (hereinafter, the "Tag Along Right").
         Purchaser will inform Zisapel in writing by fax and by confirmation by
         mail if it intends to exercise its Tag Along Right within ten (10) days
         after the date of notice by Zisapel to Purchaser. Failure to respond
         will be deemed as a decision not to Tag Along.

                  9.7 This Section 9 will supersede Section 14 of the Inception
         Agreement.

                  9.8 The terms of the Trust Agreement, EXHIBIT 3.23, will have
         priority over this Section 9.


                                       15
<PAGE>

                  9.9 Finovelec, in its discretion, shall be permitted to freely
         transfer up to 5% of its shares (at that time) in the Company to up to
         6 of Finovelec executives, as well as up to an additional 5% of its
         shares (at that time) in the Company to IDI (if then an affiliate of
         Finovelec). Such transfer shall be considered a transfer among the
         Finovelec Group, provided that each Transferee, upon receipt of the
         shares, will join this Agreement and undertake all of Finovelec's
         obligations hereunder and will be considered henceforth a member in the
         Finovelec Group for the purpose of this Section 9.

                  9.10 Clal Venture Capital LP is entitled to transfer all of
         its shares in the Company to its partners, provided that each
         Transferee, upon receipt of the shares, will join this Agreement and
         undertake all of Purchaser's obligations hereunder and will be
         considered henceforth a member in the Clal Group for the purpose of
         this Section 9.

                  9.11 Each of Zohar Gilon, Avraham Neuman and Yair Tauman is
         entitled, once, to transfer his shares to a company directly under the
         total control of said person, provided that each Transferee, upon
         receipt of the shares, will join this Agreement and undertake all of
         Purchaser's obligations hereunder and will be considered henceforth a
         member in the Capital Group for the purpose of this Section 9.

                                   SECTION 9A
                                  ANTI-DILUTION

                  (a) In the event that any time prior to the earlier of the
         Closing of the Company's initial public offering or three (3) years
         from the date of this Agreement, the Company issues or sells any
         Ordinary Shares to third parties upon a private placement (excluding
         Company employees) for consideration per share of less than US $135 (an
         "Offering"), then prior to said private placement the Purchaser shall
         be given the option to purchase Ordinary Shares of the Company at par
         value (NIS 1.- per share), in an amount computed as set forth below.

                  (b) The amount of shares to be issued to Purchaser will be
         computed according to the following table:

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------
  SHARE PRICE AT NEXT PRIVATE PLACEMENT   ADDITIONAL SHARES ISSUED TO ALL PURCHASERS (DISTRIBUTED
                                                            ON A PRO-RATA BASIS)
---------------------------------------------------------------------------------------------------
<S>                                                            <C>
           * $134.99 to $101.01                                   7,489 *
---------------------------------------------------------------------------------------------------
           * $101.00 to $50.51                                    17,959 *
---------------------------------------------------------------------------------------------------
            * Less than $50.5                                     33,642 *
---------------------------------------------------------------------------------------------------
</TABLE>

                  * The number and price of shares will be adjusted in the event
         of any restructuring of the Company's share capital.

                      (c) Upon the occurrence of each event giving rise to a
         right pursuant to this Section, the Company will, at its expense,
         promptly compute the number of Ordinary Shares that each Purchaser is
         entitled to purchase in accordance with the terms hereof, and


                                       16
<PAGE>

         furnish to the Purchaser, a notice of such right and the number of
         shares Purchaser is entitled to.

                      (d) Any and all of Purchaser's rights under this Section
         9A will terminate within the earliest of: (i) the Closing of the
         Company's initial public offering or (ii) three (3) years from the date
         of this Agreement or (iii) upon the first private placement
         contemplated after the Closing set forth in Section 9A hereinabove.

                                   SECTION 10
                                  MISCELLANEOUS

                  10.1 ARBITRATION. All disputes arising under this Agreement or
         in connection with the transactions hereunder shall be resolved between
         the parties in good faith; however, if these efforts fail, the dispute
         shall be resolved by arbitration by a sole arbitrator within sixty (60)
         days. The arbitrator shall be chosen by agreement of the parties
         hereto. If they fail to so agree within twenty (20) days after a party
         shall have requested such arbitration, the arbitrator shall be
         appointed by the Chairman of the Israeli Bar who shall also determine
         the place of the arbitration proceedings based on the convenience of
         the parties involved; provided, however, that the arbitrator chosen
         shall be from the jurisdiction chosen by the above-mentioned Chairman.
         The arbitrator shall not be bound by any judicial rules of evidence or
         procedure. The arbitral award shall be final and binding upon the
         parties, and judgment upon the award may be entered in any court having
         jurisdiction, or application may be made to such court for a judicial
         acceptance of the award or for an order of enforcement, as the case may
         be. The provisions of this Section 10.1 shall apply to all disputes
         arising in connection with this Agreement. Each party shall bear its
         own expenses, subject to the arbitration judgment on the issue of
         expenses.

                  10.2 SURVIVAL. The representations, warranties, covenants and
         agreements made herein shall survive (i) any investigation made by the
         Purchaser and (ii) the Closing.

                  10.3 SUCCESSORS AND ASSIGNS. Except as otherwise expressly
         provided herein, the provisions hereof shall inure to the benefit of,
         and be binding upon, the successors, assigns, heirs, executors and
         administrators of the parties hereto; provided, however, that no party
         may assign its rights hereunder without the prior written consent of
         the other parties hereto.

                  10.4 ENTIRE AGREEMENT; AMENDMENT. This Agreement (including
         the Schedules and Exhibits hereto) and the other documents delivered
         pursuant hereto constitute the full and entire understanding and
         agreement between the parties with regard to the subject matters hereof
         and thereof and supersede all prior agreements and understandings
         relating thereto. Neither this Agreement nor any term hereof may be
         amended, waived, discharged or terminated except by an instrument in
         writing signed by all the parties hereto.

                  10.5 NOTICES. All notices and other communications required or
         permitted to be given or sent hereunder shall be in writing and shall
         be deemed to have been sufficiently


                                       17
<PAGE>

         given or delivered for all purposes if mailed by registered airmail,
         transmitted by telex or telecopier, or delivered by hand to the
         following respective addresses until otherwise directed by notice as
         aforesaid:

                                  To the Purchaser:

                                  The Trust Company of Maritime Bank of Israel
                                  35 Achad Ha'am Street
                                  Tel Aviv, Israel

                                  Attention: Mr. Yosi Ben-Yosef

                                  To the Company:

                                  RADVISION Ltd.
                                  8 Hanechoshet Street
                                  Tel Aviv 69710, Israel

                                  Attention: Mr. Amos Amir

         provided, however, that notice of change of address shall be
         effective only upon actual receipt.

                  All notices sent by registered mail shall be deemed to have
         been received within seventy-two (72) hours of posting. If delivered by
         hand, upon their delivery.

                  10.6 DELAYS OR OMISSIONS. No delay or omission to exercise any
         right, power or remedy upon any breach or default under this Agreement
         shall impair any such right, power or remedy of such holder nor shall
         it be construed to be a waiver of any such breach or default, or in
         acquiescence therein, or of any similar breach or default thereafter
         occurring; nor shall any waiver of any single breach or default be
         deemed a waiver of any other breach or default theretofore or
         thereafter occurring. Any waiver, permit, consent or approval of any
         kind or character on the part of any holder of any breach or default
         under this Agreement, or any waiver on the part of any holder of any
         holder of any provisions or conditions of this Agreement shall be
         effective only if made in writing and only to the extent specifically
         set forth in such writing. All remedies, either under this Agreement or
         by virtue of law or otherwise afforded to any holder, shall be
         cumulative and not alternative.

                  10.7 WAIVER OF DEFAULT. No waiver with respect to any breach
         or default in the performance of any obligation under the terms of this
         Agreement shall be deemed to be a waiver with respect to any subsequent
         breach or default, whether of similar or different nature.

                  10.8 RIGHTS; SEVERABILITY. In case any provision of the
         Agreement shall be invalid, illegal or unenforceable, the validity,
         legality and enforceability of the remaining provisions shall not in
         any way be affected or impaired thereby. The parties hereto shall


                                       18
<PAGE>

         be obliged to draw up an arrangement in accordance with the meaning and
         the object of the invalid provision.

                  10.9 CONFIDENTIAL INFORMATION. The Purchaser acknowledges that
         the information received by it and such information which will be
         received pursuant hereto shall be confidential and is intended for the
         Purchaser's use only for the purpose of this Agreement, and the
         Purchaser will not use or allow the use of such confidential
         information or reproduce, disclose or disseminate such information to
         any other person (other than the Purchaser's employees or agents having
         a need to know the contents of such information, and the Purchaser's
         attorneys), except in connection with the exercise of rights under this
         Agreement, unless the Company has made such information available to
         the public generally or the Purchaser is required to disclose such
         information by a governmental body or by judicial order, but only to
         the persons and the extent so required.

                  10.10 TITLES AND SUBTITLES. The titles of the sections and
         subsections of this Agreement are for convenience of reference only and
         are not to be considered in construing this Agreement.

                  10.11 GOVERNING LAW. This Agreement shall be governed
         exclusively by, and construed solely in accordance with, the laws of
         the State of Israel.

                  10.12 Purchaser and any Transferee under Section 9 are
         represented by the Managing Director of Maritime, presently Mr. Yosi
         Ben-Yosef. Notice sent to the Managing Director of Maritime will be
         deemed as notice sent to Purchaser and/or any such Transferee. A
         resolution or request given by the Managing Director of Maritime to the
         Company will be deemed as if given by Purchaser and any such
         Transferee. The Company will have no obligation to provide information
         or notice whatsoever except to the Managing Director of Maritime.

                  10.13 Purchaser agrees that the Company will issue to Mr.
         Eliezer Manor forty-nine (49) shares against payment of their nominal
         value.

                  10.14 Following the Closing, the Company will amend its
         Memorandum and Articles of Association to reflect this Agreement. The
         Present shareholders and the Purchasers agree to such amendments.

                  10.15 The Company will bear the cost of stamp tax due in
         connection with the issuance of shares according to this Agreement.

                  IN WITNESS WHEREOF, the parties hereto have executed this
         Agreement in three (3) original copies, one to the Company, one to the
         Purchaser and one of the Present Shareholders, as of the date first
         above-mentioned.

         THE COMPANY                         THE PURCHASER
         RADVISION LTD.                      Lerosh Investments Ltd.


         By: /s/ AMOS AMIR                   By: /s/ LEROSH INVESTMENTS LTD.
            ------------------------------      -------------------------------
            Amos Amir, Managing Director


                                       19
<PAGE>

                               Gevahim Investments House Limited Ltd.

                               By: /s/  GEVAHIM INVESTMENTS HOUSE LIMITED LTD.
                                   ---------------------------------------------

                               /s/ YOAV CHLOUCHE
                               -------------------------------------------------
                               Yoav Chelouche

                               Permal Emerging Growth V Ltd.

                               By: /s/  PERMAL EMERGING GROWTH V LTD.
                                   ---------------------------------------------

                               Maritime - Julex Investment Ltd.

                               By: /s/  MARITIME-JULEX INVESTMENT LTD.
                                   ---------------------------------------------

                               /s/ SHRAGA BLAZER
                               -------------------------------------------------
                               Shraga Blazer

                               /s/ ELI LUZ
                               -------------------------------------------------
                               Eli Luz

THE PRESENT SHAREHOLDERS:

                               /s/ ZOHAR ZISAPEL
                               -------------------------------------------------
                               Zohar Zisapel

                               /s/ YEHUDA ZISAPEL
                               -------------------------------------------------
                               Yehuda Zisapel


                                       20
<PAGE>

                                    EXHIBIT 1

<TABLE>
<CAPTION>
                      No. of Shares                         Shares           Total No.
Name of               prior to             Invested         Issued           After         Ownership
Shareholder           Investment           Amount           at Closing       Closing       after Closing
--------------------------------------------------------------------------------------------------------
<S>                   <C>                  <C>              <C>              <C>           <C>
Yehuda Zisapel        6,930                                                  6,930         15.34%

Zohar Zisapel         6,930                                                  6,930         15.34%

Yehuda Zisapel        5,940                                                  5,940         13.15%
and Zohar
Zisapel
(as trustees)

Amos Amir               932                                                    932          2.06%

RAD Data                                   710,030                           3,515          7.78%
Communications
Ltd.

Zohar Gilon                                 60,600                             300          0.66%

Avraham Neuman                              60,600                             300          0.66%

Yair Tauman                                 60,600                             300          0.66%

W.S.P. Capital                              37,976                             188          0.42%
Investments Ltd.

Lannet Data                                999,900                           4,950         10.95%
Communications Ltd.

Lerosh Investments Ltd.                     99,990                             495          1.10%

Gevahim Investments                         20,200                             100          0.22%
House Limited Ltd.

Yoav Chelouche                              49,692                             246          0.54%

Permal Emerging Growth                     194,930                             965          2.14%
V Ltd.

Maritime - Julex                            99,990                             495          1.10%
Investment Ltd.

Shraga Blazer                                5,050                              25          0.06%

Eli Luz                                     30,098                             149          0.33%

<PAGE>

Clal Venture Capital                       999,900                           4,950         10.95%
LP

ECI Telecom Ltd.                           499,950                           2,475          5.48%

Eliezer Manor                                                                   49          0.11%

Finovelec                                  550,046                           2,723          6.03%

Factory Systemes                           250,076                           1,238          2.74%

Houston Venture                            199,980                             990          2.19%
Partners Ltd.

                     20,732              4,929,608                          45,185        100.00%
</TABLE>


                                       2
<PAGE>

                                   EXHIBIT 5.7

To:      Purchaser
         (as defined in the attached Agreement
         dated April 26, 1995)

                                     OPINION

I, the undersigned, as counsel to RADVision Ltd., hereby give my opinion, to the
best of my knowledge at this time as follows:

                  1. ORGANIZATION AND STANDING. RADVision Ltd. ("RADVision") is
a company duly organized and existing under the laws of the State of Israel
and is in good standing under such laws. RADVision has the requisite
corporate power to own and operate its properties and assets and to carry on
its business as presently conducted.

                  2. CAPITALIZATION. The RADVision `s authorized capital is
sixty thousand (60,000) Ordinary Shares. The RADVision's issued capital stock
immediately prior to the Closing date shall consist of twenty thousand seven
hundred thirty--two (20,732) Ordinary Shares, all of which are duly
authorized, validly issued and free of any liens or encumbrances. Out of the
issued share capital, thirteen thousand eight hundred sixty (13,860) shares
are fully paid and six thousand eight hundred seventy--two (6,872) shares are
partially paid. All shares are non-assessable, and to the best of RADVision'
s knowledge and belief, are beneficially owned by their holders of record.
There are no preemptive, conversion or other rights, options, or agreements
granted or issued by, or binding upon, RADVision or the shareholders which
entitle any person, firm or corporation to purchase or acquire any shares of
RADVision' s capital stock, except as set forth in this Agreement.

                  The rights, restrictions, privileges and preferences with
respect to RADVision's shares, as set forth in its Memorandum of Association
and Articles of Association, are valid and enforceable. To the best of my
knowledge, there are no outstanding rights, options, warrants, conversion
rights or agreements for the purchase or acquisition from RADVision of any
shares of its capital stock, except as stated in its Memorandum and Articles
of Association.

                  3. COMPLIANCE WITH LAW AND OTHER INSTRUMENTS. The execution,
delivery and performance of the Agreement dated April 26, 1995 between
RADVision and the Purchaser (the "Agreement") will not result in any
violation of, or be in conflict with or constitute a default under, any
applicable law, regulation or order, RADVision's Memorandum of Association or
Articles of Association. To the best of my knowledge, the execution, delivery
and performance of the Agreement and consummation of the transactions
contemplated thereby, will not result in any violation of, or be in conflict
with or constitute a default under, any term of any mortgage, indenture,
contract, agreement, instrument, judgment, decree or order applicable to
RADVision, or result in the creation of any mortgage, pledge, lien,
encumbrance or charge upon any of the properties or assets of RADVision
pursuant to any such term. <PAGE>

                  4. LITIGATION. To the best of my knowledge, there are neither
any actions, proceedings nor investigations pending or threatened against
RADVision or its assets or properties.

                  5. EMPLOYMENT AGREEMENTS. The agreements between RADVision
and its employees (except for Danny Levin) as referred to in Sections 5.5 and
5.6 of the Agreement have been duly executed and delivered by, and constitute
valid and binding obligations of, all such employees, enforceable by
RADVision in accordance with their terms.

                  6. STATEMENTS AND FACTS. Nothing has come to my attention
that would lead me to believe that the Agreement contains any untrue
statement of a material fact or omits to state a material fact necessary to
make the statements therein not misleading.

                                          /s/ NEHAMA SNEH
                                          -----------------------------
                                          Nehama Sneh
                                          Advocate

Dated: April 26, 1995

(opinion/6)
<PAGE>

                                   EXHIBIT 8.2

                               REGISTRATION RIGHTS

         1. INCIDENTAL REGISTRATION. If the Company shall elect to offer any of
its securities to the public, it shall give notice to the Purchaser of such
intention and shall include in such offering a portion of all shareholders
shares equal to the total amount of shares registered, multiplied by an amount
derived by dividing the number of Shares held by each shareholder by the total
number of shares outstanding at that time. In the event the public offering
involves an underwriting, the rights of the shareholders hereunder shall be
conditional upon the underwriter's determination as to marketing factors
requiring the limitation of such right, and the underwriter may preclude from
the offering any or all securities which could have otherwise been included in
the offering.

         2. DEMAND REGISTRATION. At any time commencing one year following the
closing of the Company's initial public offering, and for a period of three (3)
years thereafter, each group of shareholders as defined in section 9.1 and/or
Lannet Data Communications Ltd. shall be entitled to demand one registration of
any or all of its shares held at the time of the initial public offering for
trading on any securities exchange; PROVIDED, however, that such request must
cover Shares representing a market value at the time of such request equal to a
minimum of three million Dollars ($3,000,000); and PROVIDED FURTHER, however,
that such request may not include Shares which within three months from the date
of such request could be sold to the public without restriction, for example
pursuant to the provisions of Rule 144 of the Securities and Exchange
Commission. Within 20 days after receipt, the Company shall give written notice
of such request to the other shareholders and shall include in such registration
all Shares held by them with respect to which the Company receives written
requests for inclusion therein within 15 days after the receipt of the Company's
notice. Thereupon, the Company shall use its best efforts to effect the
registration as soon as possible of all Shares (as to which it has received
requests for registration) for trading on a securities exchange, where the
Shares are then traded, specified in the request for registration. In the event
the registration involves an underwriting, the rights of the shareholders
hereunder shall be conditional upon the underwriter's determination as to
marketing factors requiring the limitation of such right, and the underwriter
may preclude from the offering any or all securities which could have otherwise
been included in the offering. Notwithstanding any other provision of this
clause 2 of Exhibit 8.2, after the Company has effected one such registrations
pursuant to this clause 2, and such registrations have been declared or ordered
effective, in the event that the Company shall furnish to such shareholder(s)
delivering a request for registration a certificate signed by the President of
the Company stating that in the good faith judgment of the Board of Directors of
the Company it would be seriously detrimental to the Company or its shareholders
for a registration statement to be filed in the near future, the Company's
obligation to use its best efforts to register, qualify or comply under this
clause 2 shall be deferred for a period not to exceed 120 days from the date of
receipt of such request.

         3. EXPENSES. All expenses incurred in connection with a registration
under Section 2 shall be borne by the selling shareholders participating in such
registration on a pro rata basis; PROVIDED, however, that the Company shall pay
any expenses associated with such registration which the Company would have
incurred in the ordinary course of business. All expenses incurred in connection
with a registration under Section 1 shall be borne by the
<PAGE>

Company; PROVIDED, however, that each of the shareholders participating in such
registration shall pay its pro rata portion of the fees, discounts or
commissions payable to any underwriter.


                                       2