RADVISION LTD
F-1/A, 2000-03-13
COMPUTER COMMUNICATIONS EQUIPMENT
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<PAGE>

     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MARCH 13, 2000

                                                      REGISTRATION NO. 333-30916
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                           --------------------------


                                AMENDMENT NO. 3
                                       TO
                                    FORM F-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

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

                                 RADVISION LTD.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

<TABLE>
<S>                                       <C>                                       <C>
                 ISRAEL                                     3576                                 NOT APPLICABLE
    (STATE OR OTHER JURISDICTION OF             (PRIMARY STANDARD INDUSTRIAL                    (I.R.S. EMPLOYER
     INCORPORATION OR ORGANIZATION)             CLASSIFICATION CODE NUMBER)                   IDENTIFICATION NO.)
</TABLE>

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

                            24 RAOUL WALLENBERG ST.
                             TEL AVIV 69719, ISRAEL
                                 972-3-645-5220
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                         ------------------------------

                                RADVISION, INC.
                              575 CORPORATE DRIVE
                            MAHWAH, NEW JERSEY 07430
                                  201-529-4300
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER OF AGENT FOR SERVICE)
                           --------------------------

                                   COPIES TO:

<TABLE>
<S>                               <C>                               <C>
      DAVID P. STONE, ESQ.                                              BRIAN B. MARGOLIS, ESQ.
   WEIL, GOTSHAL & MANGES LLP                                       BROBECK, PHLEGER & HARRISON LLP
        767 FIFTH AVENUE                                                     1633 BROADWAY
       NEW YORK, NY 10153                                                  NEW YORK, NY 10019
          212-310-8000                   YAEL LANGER, ADV.                    212-581-1600
    FACSIMILE: 212-310-8007                RADVISION LTD.               FACSIMILE: 212-586-7878
                                     24 RAOUL WALLENBERG STREET
        ODED ERAN, ADV.                TEL AVIV 69719, ISRAEL              DAN SHAMGAR, ADV.
  ASHOK J. CHANDRASEKHAR, ADV.             972-3-645-5292            MEITAR, LIQUORNIK, GEVA & CO.
   GOLDFARB, LEVY, ERAN & CO.        FACSIMILE: 972-3-649-8248         16 ABBA HILLEL SILVER ROAD
      2 IBN GVIROL STREET                                               RAMAT GAN 52506, ISRAEL
     TEL AVIV 64077, ISRAEL                                                  972-3-610-3100
         972-3-608-9999                                                FACSIMILE: 972-3-610-3111
   FACSIMILE: 972-3-608-9909
</TABLE>

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

    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the Registration Statement becomes effective.

    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, please check the following box. / /

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration number of the earlier effective
registration statement for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If the delivery of the prospectus is expected to be made pursuant to
Rule 434, please check the following box. / /

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                    PROPOSED MAXIMUM
                                                                     OFFERING PRICE      PROPOSED MAXIMUM
           TITLE OF EACH CLASS OF                AMOUNT TO BE         PER ORDINARY      AGGREGATE OFFERING        AMOUNT OF
        SECURITIES TO BE REGISTERED              REGISTERED(1)          SHARE(2)             PRICE(2)         REGISTRATION FEE
<S>                                           <C>                  <C>                  <C>                  <C>
ORDINARY SHARES, NIS 0.1 PER SHARE..........       4,370,000             $20.00             $87,400,000          $23,074(3)
</TABLE>

(1) Includes 570,000 Ordinary Shares subject to the Underwriters' over-allotment
    option.

(2) Estimated solely for the purpose of calculating the registration fee.


(3) Previously paid.


    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY THESE SECURITIES IN
ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.
<PAGE>

                  SUBJECT TO COMPLETION, DATED MARCH 13, 2000
PROSPECTUS


                                3,800,000 SHARES

                                     [LOGO]

                                ORDINARY SHARES

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

This is our initial public offering of ordinary shares. We are offering
3,800,000 ordinary shares. No public market currently exists for our ordinary
shares.

We propose to list the ordinary shares on the Nasdaq National Market under the
symbol RVSN. We anticipate the public offering price to be between $18.00 and
$20.00 per ordinary share.

INVESTING IN THE ORDINARY SHARES INVOLVES RISKS. RISK FACTORS BEGIN ON PAGE 4.

<TABLE>
<CAPTION>
                                                              Per Share       Total
                                                              ----------   -----------
<S>                                                           <C>          <C>
Public Offering Price.......................................  $            $
Underwriting Discount.......................................  $            $
Proceeds to RADVision.......................................  $            $
</TABLE>

We have granted the underwriters the right to purchase up to 570,000 additional
ordinary shares within 30 days to cover over-allotments.

Upon the sale of the ordinary shares in the initial public offering, we and some
of our existing shareholders will sell an additional 1,625,228 ordinary shares
to Siemens and an additional 1,000,000 ordinary shares to Samsung in a
concurrent private placement at $17.00 per ordinary share.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

THE ISRAEL SECURITIES AUTHORITY HAS GRANTED US AN EXEMPTION FROM ISRAEL'S
PROSPECTUS DELIVERY REQUIREMENTS APPLICABLE TO THIS OFFERING. YOU SHOULD NOT
INTERPRET THAT EXEMPTION AS ENDORSING THE MATTERS CONTAINED IN THIS PROSPECTUS
OR AS AN APPROVAL OF THEIR RELIABILITY OR ADEQUACY, NOR SHOULD YOU INTERPRET
THAT EXEMPTION AS AN EXPRESSION OF OPINION CONCERNING THE QUALITY OF THE
SECURITIES OFFERED BY THIS PROSPECTUS.

Lehman Brothers, on behalf of the underwriters, expects to deliver the ordinary
shares to purchasers on or about          , 2000.

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

LEHMAN BROTHERS

             SALOMON SMITH BARNEY

                           U.S. BANCORP PIPER JAFFRAY

                                         FIDELITY CAPITAL MARKETS
                           A DIVISION OF NATIONAL FINANCIAL SERVICES CORPORATION

                , 2000
<PAGE>
               [Picture of packet network depicting deployment of
                       RADVision products and technology]
<PAGE>
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                          PAGE
                                          ----
<S>                                     <C>
Prospectus Summary....................      1
Risk Factors..........................      4
Forward-Looking Statements............     13
Note to Investors.....................     13
Private Placement.....................     14
Use Of Proceeds.......................     14
Dividend Policy.......................     14
Capitalization........................     15
Dilution..............................     16
Selected Consolidated Financial
  Data................................     17
Management's Discussion And Analysis
  Of Financial Condition And Results
  Of Operations.......................     18
Business..............................     30
Management............................     45
</TABLE>

<TABLE>
<CAPTION>
                                          PAGE
                                          ----
<S>                                     <C>
Principal Shareholders................     55
Related Party Transactions............     57
Shares Eligible For Future Sale.......     61
Description Of Share Capital..........     63
Conditions In Israel..................     66
Taxation And Government Programs......     68
Underwriting..........................     77
Legal Matters.........................     80
Experts...............................     80
Enforceability Of Civil Liabilities...     80
Where You Can Find Additional
  Information.........................     81
Index To Consolidated Financial
  Statements..........................    F-1
</TABLE>

    Until           , 2000, 25 days after the date of this prospectus, all
dealers that buy, sell or trade our ordinary shares, whether or not
participating in this offering, may be required to deliver a prospectus. This is
in addition to the dealers' obligation to deliver a prospectus when acting as
underwriters and when selling their unsold allotments or subscriptions.

                                       i
<PAGE>
                               PROSPECTUS SUMMARY

    THIS SUMMARY HIGHLIGHTS INFORMATION CONTAINED IN THIS PROSPECTUS. BEFORE YOU
DECIDE TO INVEST IN OUR ORDINARY SHARES, YOU SHOULD CAREFULLY READ THE ENTIRE
PROSPECTUS, INCLUDING THE SECTION ENTITLED "RISK FACTORS" AND OUR CONSOLIDATED
FINANCIAL STATEMENTS AND THE NOTES TO THOSE FINANCIAL STATEMENTS.

                                   RADVISION

    We are a leading designer, developer and supplier of products and technology
that enable real-time voice, video and data communications over packet networks,
including the Internet and other networks based on the Internet protocol or IP.
We have over 250 customers including Alcatel, Bosch, Cisco Systems, Madge
Networks, Nippon Telegraph & Telephone, Nortel Networks, Philips Electronics,
Shanghai Bell, Siemens and 3Com. Our products and technology are used by our
customers to develop systems that enable enterprises and service providers to
migrate their voice and video communications from traditional telephone networks
to next generation packet networks.

    The use of packet networks for real-time voice, video and data
communications is expected to grow dramatically. This anticipated growth is due
to the inherent benefits of packet networks and the advent of new technologies
and standards that have enabled real-time communications over these networks.
ICM Global Intelligence, a market research firm, forecasts that revenues for
network equipment associated with voice-over-IP, or IP telephony, will grow from
$477 million in 1999 to $7.1 billion in 2004. Perey Research & Consulting, an
industry consulting firm, forecasts revenues for network equipment associated
with IP video communications to grow from $22 million in 1999 to more than
$643 million in 2003.

    We are one of the few companies to offer customers IP communications
products and technology that support both real-time voice and video as well as
voice-only packet-based communications. Our products and technology consist of:

    - RADVision gateways, which interface between traditional telephone networks
      and IP networks;

    - RADVision gatekeepers, which control, manage and monitor real-time voice,
      video and data traffic over packet networks;

    - RADVision IP conferencing bridges, which enable voice and multimedia
      conferencing over packet networks among three or more participants; and

    - RADVision software development kits, which provide the core technology
      necessary to build interoperable, standards-compliant products,
      applications and services for real-time voice and video communication over
      packet networks.

    We believe that we have established ourselves as a technology leader in
providing enabling technology and products for a broad range of standards-based
IP communications products and services. Our goal is to continue to be the
leading provider of innovative products and technology for real-time IP
communications. Our customers rely on our accumulated expertise with IP
communications standards and technology to significantly reduce their
development cycle and improve their time to market in the rapidly growing market
for IP-based voice and video communication. Our customers can deploy our
products as a complete network solution for real-time IP communications,
integrate our products into their own IP communications systems, or use our
technology to build their own standards-compliant IP communications products,
systems and applications for enterprises and service providers.

    We were incorporated under the laws of the State of Israel in 1992 and began
operations in October 1992. Our principal executive offices are located at 24
Raoul Wallenberg St., Tel Aviv 69719, Israel and our telephone number is
011-972-3-645-5220.

                                       1
<PAGE>
                                  THE OFFERING

<TABLE>
<S>                                            <C>

Ordinary shares offered in this offering.....  3,800,000 shares

Private placement

  Ordinary shares offered by us to Siemens...  365,767 shares

  Ordinary shares offered by us to Samsung...  225,055 shares

Ordinary shares to be outstanding after this
  offering and the private placement.........  18,028,596 shares

Use of proceeds..............................  We expect to use the net proceeds from this
                                               offering to finance the continued growth of
                                               our business and for general corporate
                                               purposes.

Proposed Nasdaq National Market symbol.......  RVSN
</TABLE>

    The number of ordinary shares referred to in the preceding table to be
outstanding after this offering excludes:

    - 3,048,873 shares issuable upon the exercise of outstanding options under
      our share option plans; and

    - up to 61,900 additional ordinary shares reserved for issuance under our
      share option plans.

                               PRIVATE PLACEMENT

    Concurrently with this offering, Samsung Electro-Mechanics Co. Ltd. and
Samsung Venture Investment Corporation, members of the Samsung group, and
Siemens Aktiengesellschaft have agreed to purchase an aggregate of 2,625,228 of
our ordinary shares at $17.00 per ordinary share in a private placement. Of the
2,625,228 ordinary shares, we will sell 590,822 ordinary shares in the private
placement and the remaining 2,034,406 ordinary shares will be sold by some of
our existing shareholders, including our chairman of the board, our chief
executive officer and some of our other directors.

                             ABOUT THIS PROSPECTUS

    Unless otherwise indicated, all information contained in this prospectus:

    - gives effect to the sale of an aggregate of 590,822 ordinary shares by us
      to Siemens and Samsung in a private placement concurrent with this
      offering at $17.00 per ordinary share to be effected immediately after the
      closing of this offering;

    - assumes no exercise of the underwriters' option to purchase from us up to
      570,000 additional ordinary shares to cover over-allotments;

    - reflects the conversion of all our preferred shares into ordinary shares
      on a 1-to-1 basis before the share recapitalization referred to below;

    - reflects the conversion of 2,770 ordinary shares into deferred shares
      before the share dividend referred to below;

    - assumes an initial offering price of $19.00 per ordinary share, the
      midpoint of the estimated initial public offering price range; and

    - reflects a 211-for-1 share recapitalization of our ordinary shares,
      following the conversion of our preferred shares into ordinary shares, as
      the result of a share split and share dividend that will be effected
      before this offering.
                            ------------------------

    We have a registered trademark for RADVision-Registered Trademark-. All
other trademarks and trade names appearing in this prospectus are owned by their
holders.

                                       2
<PAGE>
                      SUMMARY CONSOLIDATED FINANCIAL DATA

<TABLE>
<CAPTION>
                                                                      YEAR ENDED DECEMBER 31,
                                                        ----------------------------------------------------
                                                          1995       1996       1997       1998       1999
                                                        --------   --------   --------   --------   --------
                                                               (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                     <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenues..............................................  $   871    $ 1,491    $ 4,899    $ 8,894    $17,550
Gross profit..........................................      301        721      3,689      7,482     14,697
Operating loss........................................   (1,497)    (2,067)    (1,062)      (852)    (2,801)
Net loss..............................................   (1,499)    (2,025)    (1,056)      (829)    (2,696)
Basic and diluted net loss per ordinary share.........  $ (0.21)   $ (0.21)   $ (0.10)   $ (0.08)   $ (0.26)
Weighted average number of ordinary shares used in
  computing basic and diluted net loss per ordinary
  share...............................................    7,217      9,499     10,234     10,492     10,538
Pro forma basic and diluted net loss per ordinary
  share...............................................                                              $ (0.20)
Weighted average number of ordinary shares used in
  computing pro forma basic and diluted net loss per
  ordinary share......................................                                               13,496
</TABLE>

<TABLE>
<CAPTION>
                                                               AS OF DECEMBER 31, 1999
                                                              --------------------------
                                                                              PRO FORMA
                                                               ACTUAL        AS ADJUSTED
                                                              ---------      -----------
                                                                    (IN THOUSANDS)
<S>                                                           <C>            <C>
CONSOLIDATED BALANCE SHEET DATA:
Cash and cash equivalents...................................   $ 2,605         $77,857
Working capital.............................................       814          76,066
Total assets................................................    13,261          88,513
Total bank debt, net of current maturities..................        67              67
Total shareholders' equity..................................     3,481          78,734
</TABLE>

    Pro forma basic and diluted net loss per ordinary share gives effect to the
conversion of all outstanding preferred shares into ordinary shares, which will
take place before the completion of this offering.

    The pro forma as adjusted information included above in the consolidated
balance sheet data gives effect to:

    - the conversion of our preferred shares;

    - the issuance of 52,750 ordinary shares upon the exercise of options after
      December 31, 1999 and the receipt of $62,500 in proceeds from the option
      exercise;

    - this offering of our ordinary shares; and

    - the private placement by us of 590,822 ordinary shares to Siemens and
      Samsung at $17.00 per ordinary share.

                                       3
<PAGE>
                                  RISK FACTORS

    INVESTING IN OUR ORDINARY SHARES INVOLVES A HIGH DEGREE OF RISK. BEFORE
PURCHASING OUR ORDINARY SHARES, YOU SHOULD CAREFULLY CONSIDER THE RISKS
DESCRIBED BELOW IN ADDITION TO THE OTHER INFORMATION IN THIS PROSPECTUS. OUR
BUSINESS, OPERATING RESULTS AND FINANCIAL CONDITION MAY BE MATERIALLY AND
ADVERSELY AFFECTED DUE TO ANY OF THE FOLLOWING RISKS. THE TRADING PRICE OF OUR
ORDINARY SHARES COULD DECLINE DUE TO ANY OF THESE RISKS, AND YOU COULD LOSE ALL
OR PART OF YOUR INVESTMENT.

RISKS RELATING TO OUR BUSINESS

WE HAVE A HISTORY OF LOSSES AND WE CANNOT ASSURE YOU THAT WE WILL OPERATE
PROFITABLY IN THE FUTURE.

    We incurred significant losses in every fiscal year from our inception and
we may continue to incur losses in the future. We reported net losses of
$829,000 and $2,696,000 for 1998 and 1999. As of December 31, 1999, our
accumulated deficit was $9,277,000. We cannot assure you that we will operate
profitably in the future.

OUR QUARTERLY FINANCIAL PERFORMANCE IS LIKELY TO VARY SIGNIFICANTLY IN THE
FUTURE. OUR REVENUES AND OPERATING RESULTS IN ANY QUARTER MAY NOT BE INDICATIVE
OF OUR FUTURE PERFORMANCE AND IT MAY BE DIFFICULT FOR INVESTORS TO EVALUATE OUR
PROSPECTS.

    Our quarterly revenues and operating results have varied significantly in
the past and are likely to continue to vary significantly in the future.
Fluctuations in our quarterly financial performance may result from the fact
that we may receive a small number of relatively large orders in any given
quarter. Because these orders generate disproportionately large revenues, our
revenues and the rate of growth of our revenues for that quarter may reach
levels that may not be sustained in subsequent quarters. In addition, some of
our products have lengthy sales cycles. For example, it typically takes from
three to twelve months after we first begin discussions with a prospective
customer before we receive an order from that customer. We also have a limited
order backlog, which makes revenues in any quarter substantially dependent upon
orders we deliver in that quarter. Because of these factors, our revenues and
operating results in any quarter may not meet market expectations or be
indicative of future performance and it may be difficult for investors to
evaluate our prospects.

UNLESS OUR REVENUES GROW IN EXCESS OF OUR INCREASING EXPENSES, WE WILL NOT BE
PROFITABLE.

    We expect that our operating expenses will increase significantly in the
future, both to finance the planned expansion of our sales and marketing and
research and development activities and to fund the anticipated growth in our
revenues. However, our revenues may not grow apace or even continue at their
current level. If our revenues do not increase as anticipated or if expenses
increase at a greater pace than our revenues, we will not be profitable. Even if
we achieve profitability, we may not be able to sustain or increase
profitability on a quarterly or annual basis.

IF THE USE OF PACKET-BASED NETWORKS AS A MEDIUM FOR REAL-TIME VOICE, VIDEO AND
DATA COMMUNICATIONS DOES NOT CONTINUE TO GROW, THE DEMAND FOR OUR PRODUCTS AND
TECHNOLOGY WILL SLOW AND OUR REVENUES WILL DECLINE.

    Our future success depends on the growth in the use of packet-based
networks, including the Internet and other IP networks, as a medium for
real-time voice, video and data communications. If the use of packet-based
networks does not expand, the demand for our products and technology will slow
and our revenues will decline. Market acceptance of packet-based networks as a
viable alternative to circuit-switched networks for the transmission of
real-time voice and video communications is not proven and may be inhibited by
concerns about quality of service and potentially inadequate development of the
necessary infrastructure.

                                       4
<PAGE>
WE MUST DEVELOP NEW PRODUCTS AND TECHNOLOGY AND ENHANCEMENTS TO EXISTING
PRODUCTS AND TECHNOLOGY TO REMAIN COMPETITIVE. IF WE FAIL TO DO SO, WE MAY LOSE
MARKET SHARE TO OUR COMPETITORS AND OUR REVENUES MAY DECLINE.

    The market for our products and technology is characterized by rapid
technological change, new and improved product introductions, changes in
customer requirements and evolving industry standards. Our future success will
depend to a substantial extent on our ability to:

    - timely identify new market trends; and

    - develop, introduce and support new and enhanced products and technology on
      a successful and timely basis.

    If we fail to develop and deploy new products and technology or product and
technology enhancements on a successful and timely basis, we may lose market
share to our competitors and our revenues may decline.

    We are currently developing new products and technology and enhancements to
our existing products and technology. For example, we are currently developing
technology in the form of a software development kit designed to be compatible
with the new Media Gateway Control Protocol industry standard, commonly referred
to as MGCP, a standard complementary to the H.323 standard designed for larger
networks, as well as a gatekeeper software development kit designed for
telecommunications carriers. We expect to commercially introduce these software
development kits in 2000. We may not be successful in developing or introducing
to the market these or any other new products or technology.


WE HAVE INVESTED, AND WILL CONTINUE TO INVEST, IN PRODUCTS AND TECHNOLOGY WHICH
COMPLY WITH THOSE INDUSTRY STANDARDS WHICH WE BELIEVE HAVE BEEN, OR WILL BE,
BROADLY ADOPTED. IF ONE OR MORE ALTERNATIVE STANDARDS WERE TO GAIN GREATER
ACCEPTANCE THAN THE STANDARDS WHICH WE BELIEVE HAVE OR WILL BE BROADLY ADOPTED,
SALES OF OUR PRODUCTS AND TECHNOLOGY MIGHT SUFFER.


    Currently, all of our revenues are derived from the sale of products and
technology which comply with the H.323 industry standard for real-time voice,
video and data communications over packet networks. If one or more alternative
standards, including, for example, Session Initiation Protocol, commonly
referred to as SIP, were to gain general acceptance, our sales of
H.323-compliant products and our anticipated sales of MGCP-compliant products
might suffer. Because of our concentration on developing H.323 and
MGCP-compliant products and technology, we might be at a disadvantage in
developing and marketing products and technology compliant with alternative
standards and our revenues might decline if alternative standards were to gain
general acceptance. In addition, we intend to invest substantial resources to
develop new products and technology to address industry standards that we expect
to be adopted and to address markets which we expect to develop. If these
expectations ultimately prove to be incorrect, our investments may be of little
or no value, even if we are successful in developing the new products or
technology.

COMPETITION IN THE MARKETS FOR OUR PRODUCTS AND TECHNOLOGY IS INTENSE. WE MAY
NOT BE ABLE TO COMPETE EFFECTIVELY IN THESE MARKETS AND WE MAY LOSE MARKET SHARE
TO OUR COMPETITORS.

    The markets for our products and technology are highly competitive and we
expect competition to intensify in the future. We may not be able to compete
effectively in these markets and we may lose market share to our competitors.
The principal competitors in the market for our products currently include
Ezenia!, formerly known as Video-Server, White Pine Software and the in-house
developers employed by manufacturers of telecommunications equipment and
systems. Other companies, including Accord Networks, have announced products
that may compete with our products. The principal competitors in the market for
our technology, primarily sold in the form of software development kits,

                                       5
<PAGE>
currently include DataBeam, a subsidiary of Lotus/IBM; DynamicSoft; Elemedia, a
subsidiary of Lucent; and Trillium Digital Systems. Additional competitors may
enter each of our markets at any time. Moreover, our customers may seek to
develop internally the products that we currently sell to them and compete with
us.

OUR SOFTWARE DEVELOPMENT KIT REVENUES WILL DECREASE IF OUR CUSTOMERS CHOOSE TO
USE SOURCE CODE WHICH IS AVAILABLE FOR FREE.

    Both Vovida Networks, Inc. and OpenH323 offer H.323 source code for free. In
addition, Vovida offers MGCP and SIP source code for free. If our customers
choose to use the free source code offered by these organizations instead of
purchasing our technology, our revenues from the sale of our software
development kits will decline.

MOST OF OUR COMPETITORS HAVE GREATER RESOURCES THAN WE DO. THIS MAY LIMIT OUR
ABILITY TO COMPETE EFFECTIVELY WITH THEM AND DISCOURAGE CUSTOMERS FROM
PURCHASING OUR PRODUCTS AND TECHNOLOGY.

    Most of our competitors have greater financial, personnel and other
resources than we do, which may limit our ability to compete effectively with
them. These competitors may be able to respond more quickly to new or emerging
technologies or changes in customer requirements. These competitors may also:

    - benefit from greater economies of scale;

    - offer more aggressive pricing; or

    - devote greater resources to the promotion of their products.

    Any of these advantages may discourage customers from purchasing our
products and technology. If we are unable to compete successfully against our
existing or potential competitors, our revenues and margins will decline.

OUR AGREEMENTS WITH OUR CUSTOMERS DO NOT HAVE MINIMUM PURCHASE REQUIREMENTS. IF
OUR CUSTOMERS DECREASE OR CEASE PURCHASING OUR PRODUCTS AND TECHNOLOGY, OUR
REVENUES WILL DECLINE.

    Our agreements with our customers do not have minimum purchase requirements
nor do they require our customers to purchase any products from us. If any or
all of our customers cease to purchase or reduce their purchases of our products
and technology at any time, our revenues will decline. We cannot assure you that
our customers will not choose to independently develop for themselves, or
purchase from others, products and technology similar to our products and
technology. Moreover, if our customers do not successfully market and sell the
systems and products into which they incorporate our products and technology,
the demand of these customers for our products and technology will decline. Our
customers' sales of systems and products containing our products and technology
may be adversely affected by circumstances over which we have no control and
over which our customers may have little, if any, control.

WE ARE DEPENDENT UPON A LIMITED NUMBER OF SUPPLIERS OF KEY COMPONENTS. IF THESE
SUPPLIERS DELAY OR DISCONTINUE MANUFACTURE OF THESE COMPONENTS, WE MAY
EXPERIENCE DELAYS IN SHIPMENTS, INCREASED COSTS AND CANCELLATION OF ORDERS FOR
OUR PRODUCTS.

    We currently obtain key components used in the manufacture of our products
from a single supplier or from a limited number of suppliers. We do not have
long-term supply contracts with our suppliers. Any delays in delivery of or
shortages in these components could interrupt and delay manufacturing of our
products and result in the cancellation of orders for our products. In addition,
these suppliers could discontinue the manufacture or supply of these components
at any time. We may

                                       6
<PAGE>
not be able to identify and integrate alternative sources of supply in a timely
fashion or at all. Any transition to alternate suppliers may result in delays in
shipment and increased expenses and may limit our ability to deliver products to
our customers. Furthermore, if we are unable to identify an alternative source
of supply, we would have to modify our products to use a substitute component,
which may cause delays in shipments, increased design and manufacturing costs
and increased prices for our products.

    Recently, we have experienced shortages in the supply of flash memory
components that we integrate into our gateway and IP conferencing bridges as a
result of an earthquake in Taiwan, the location of the manufacturer who supplies
our principal supplier of flash memory components. We cannot assure you that we
will be able to obtain sufficient supplies of flash memory components in a
timely manner or at all. If we cannot obtain sufficient supplies of these
components, the shipment of our products may be delayed and we may lose
customers. Even if sufficient supplies are available, we cannot assure you that
these supplies will be available to us on favorable terms.

WE INTEND TO MANUFACTURE AND MAINTAIN AN INVENTORY OF CUSTOMIZED PRODUCTS FOR
SOME CUSTOMERS WHO WILL HAVE NO OBLIGATION TO PURCHASE THESE PRODUCTS. IF THESE
CUSTOMERS FAIL TO PURCHASE THESE PRODUCTS, OUR FINANCIAL RESULTS MAY BE HARMED.

    To satisfy the timing requirements of some of our larger customers, we
intend to manufacture and maintain an inventory of some of our products that we
will customize to the specifications of these customers. The size of this
inventory will be based upon the purchasing history and forecasts of these
customers, which we currently estimate to be approximately two months of sales
to these customers. These customers will have no obligation to purchase the
inventoried products at any time. If the customers for whom the inventoried
products are manufactured do not purchase them, we may be required to modify the
products for sale to others and we may be unable to find other purchasers. In
either case, the value of the products may be materially diminished which may
have a negative impact on our financial results.

UNDETECTED ERRORS MAY INCREASE OUR COSTS AND IMPAIR THE MARKET ACCEPTANCE OF OUR
PRODUCTS AND TECHNOLOGY.

    Our products and technology have occasionally contained, and may in the
future contain, undetected errors when first introduced or when new versions are
released. Our customers integrate our products and technology into systems and
products that they develop themselves or acquire from other vendors. As a
result, when problems occur in equipment or a system into which our products or
technology have been incorporated, it may be difficult to identify the cause of
the problem. Regardless of the source of these errors, we must divert the
attention of our engineering personnel from our research and development efforts
to address the errors. We cannot assure you that we will not incur warranty or
repair costs, be subject to liability claims for damages related to product
errors or experience delays as a result of these errors in the future. Any
insurance policies that we may have may not provide sufficient protection should
a claim be asserted. Moreover, the occurrence of errors, whether caused by our
products or technology or the products of another vendor, may result in
significant customer relations problems and injury to our reputation and may
impair the market acceptance of our products and technology.

WE RELY ON THIRD PARTY TECHNOLOGY LICENSES. IF WE ARE UNABLE TO CONTINUE TO
LICENSE THIS TECHNOLOGY ON REASONABLE TERMS, WE MAY FACE DELAYS IN RELEASES OF
OUR PRODUCTS AND MAY BE REQUIRED TO REDUCE THE FUNCTIONALITY OF OUR PRODUCTS
DERIVED FROM THIS TECHNOLOGY.

    We rely on technology that we license from third parties, including software
that is integrated with internally developed software and used in our products
to perform key functions. For example, we

                                       7
<PAGE>
license T.120 data collaboration software from Data Connection Limited and voice
compression technology from Siemens. If we are unable to continue to license any
of this software on commercially reasonable terms, we will face delays in
releases of our products or will be required to reduce the functionality of our
products until equivalent technology can be identified, licensed or developed,
and integrated into our current products.

THIRD PARTIES MAY INFRINGE UPON OR MISAPPROPRIATE OUR INTELLECTUAL PROPERTY,
WHICH COULD IMPAIR OUR ABILITY TO COMPETE EFFECTIVELY AND NEGATIVELY AFFECT OUR
PROFITABILITY.

    Our success depends upon the protection of our technology, trade secrets and
trademarks. Our profitability could suffer if third parties infringe upon our
intellectual property rights or misappropriate our technology and other assets.
To protect our rights to our intellectual property, we rely on a combination of
trade secret protection, trademark law, confidentiality agreements and other
contractual arrangements. The protective steps we have taken may be inadequate
to deter infringement or misappropriation. We may be unable to detect the
unauthorized use of our intellectual property or take appropriate steps to
enforce our intellectual property rights. Policing unauthorized use of our
products and technology is difficult. In addition, the laws of some foreign
countries in which we currently or may in the future sell our products do not
protect our proprietary rights to as great an extent as do the laws of the
United States. Failure to adequately protect or to promptly detect unauthorized
use of our intellectual property could devalue our proprietary content and
impair our ability to compete effectively. Further, defending our intellectual
property rights could result in the expenditure of significant financial and
managerial resources, whether or not the defense is successful.

OUR PRODUCTS MAY INFRINGE ON THE INTELLECTUAL PROPERTY RIGHTS OF OTHERS, WHICH
COULD INCREASE OUR COSTS AND NEGATIVELY AFFECT OUR PROFITABILITY.

    Third parties may assert against us infringement claims or claims that we
have infringed a patent, copyright, trademark or other proprietary right
belonging to them. For example, in 1998, Lucent alleged that some products
manufactured by us infringed specified Lucent patents. See "Business--Legal
Proceedings." Any infringement claim, even if not meritorious, could result in
the expenditure of significant financial and managerial resources and could
negatively affect our profitability.

OUR GROWTH WILL CONTINUE TO PLACE A SIGNIFICANT STRAIN ON OUR RESOURCES AND MUST
BE MANAGED EFFECTIVELY. IF WE ARE UNABLE TO MANAGE OUR EXPANDING OPERATIONS
EFFECTIVELY, OUR REVENUES MAY NOT INCREASE, OUR COST OF OPERATIONS MAY RISE AND
WE MAY REMAIN UNPROFITABLE.

    Because of the growth in our revenues, we are actively expanding our
operations. If we are unable to manage our expanding operations effectively, our
revenues may not increase, our cost of operations may rise and we may remain
unprofitable. From January 1, 1998 through December 31, 1999, the number of our
employees increased from 42 to 192. This growth has placed, and will continue to
place, a significant strain on our managerial, operational and financial
resources. We cannot assure you that:

    - we have made adequate allowance for the costs and risks associated with
      this expansion; or

    - our systems, procedures or controls will be adequate to support our
      expanding operations.

    Any delay in implementing, or transitioning to, new or enhanced systems,
procedures or controls may seriously harm our ability to forecast sales demand
accurately, manage our product inventory and record and report financial and
management information on a timely and accurate basis.

                                       8
<PAGE>
OUR BUSINESS COULD BE ADVERSELY AFFECTED IF OUR SENIOR MANAGERS, INCLUDING OUR
CHIEF FINANCIAL OFFICER WHO RECENTLY JOINED US, DO NOT WORK TOGETHER EFFECTIVELY
AS A TEAM.

    Our chief financial officer joined us in November 1999 and has not
previously worked with us. If our senior managers do not work together
effectively as a team to successfully manage our growth, our business could be
adversely affected.

WE ARE DEPENDENT ON OUR SENIOR MANAGEMENT, PARTICULARLY AMI AMIR, OUR CO-FOUNDER
AND CHIEF EXECUTIVE OFFICER. ANY LOSS OF THE SERVICES OF OUR SENIOR MANAGEMENT
WOULD NEGATIVELY AFFECT OUR BUSINESS.

    Our future success depends to a large extent on the continued services of
our senior management and key personnel. In particular, we are highly dependent
on the services of Ami Amir, our co-founder and chief executive officer. We do
not carry key-man life insurance for any of our senior management. Any loss of
the services of Mr. Amir, other members of senior management or other key
personnel would negatively affect our business.

OUR FAILURE TO RETAIN AND ATTRACT PERSONNEL COULD HARM OUR BUSINESS, OPERATIONS
AND PRODUCT DEVELOPMENT EFFORTS.

    Our products require sophisticated research and development, marketing and
sales, and technical customer support. Our success depends on our ability to
attract, train and retain qualified research and development, marketing and
sales and technical customer support personnel. We intend to increase
substantially the number of our employees who perform these functions.
Competition for personnel in all of these areas is intense and we may not be
able to hire sufficient personnel to achieve our goals or support the
anticipated growth in our business. The market for the highly-trained personnel
we require is very competitive, due to the limited number of people available
with the necessary technical skills and understanding of our products and
technology. If we fail to attract and retain qualified personnel, our business,
operations and product development efforts would suffer.

OUR NON-COMPETITION AGREEMENTS WITH OUR EMPLOYEES MAY NOT BE ENFORCEABLE. IF ANY
OF THESE EMPLOYEES LEAVES US AND JOINS A COMPETITOR, OUR COMPETITOR COULD
BENEFIT FROM THE EXPERTISE OUR FORMER EMPLOYEE GAINED WHILE WORKING FOR US.

    We currently have non-competition agreements with all of our employees in
Israel. These agreements prohibit our employees, if they cease to work for us,
from directly competing with us or working for our competitors. Under current
U.S. and Israeli law, we may not be able to enforce these non-competition
agreements. If we are unable to enforce any of these agreements, our competitors
that employ our former employees could benefit from the expertise our former
employees gained while working for us. In addition, we do not have
non-competition agreements with our employees outside of Israel.

GOVERNMENT REGULATION COULD DELAY OR PREVENT PRODUCT OFFERINGS, RESULTING IN
DECREASED REVENUES.

    Our products are designed to operate with local telephone systems throughout
the world and therefore must comply with the regulations of the Federal
Communications Commission and other regulations affecting the transmission of
voice, video and data over telecommunications and other media. Each time we
introduce a new product, we are required to obtain regulatory approval in the
countries in which it is offered. In addition, we must periodically obtain
renewals of the regulatory approvals for the use of our products in countries
where we have already obtained approval. We cannot assure you that regulatory
approval for our current products will be renewed or that regulatory approval
for future products will be obtained. If we do not obtain the necessary
approvals and renewals, we may be required to delay the sales of our products in
those countries until approval for use is granted or renewed. This could result
in decreased revenues.

                                       9
<PAGE>
RISKS RELATING TO THIS OFFERING


SOME OF OUR SHAREHOLDERS, INCLUDING YEHUDA AND ZOHAR ZISAPEL, DUE TO A VOTING
AGREEMENT AND THE SIZE OF THEIR SHAREHOLDINGS, WILL HAVE SIGNIFICANT INFLUENCE
OVER MATTERS REQUIRING SHAREHOLDER APPROVAL, WHICH COULD DELAY OR PREVENT A
CHANGE OF CONTROL.



    After this offering and the private placement, Yehuda and Zohar Zisapel, who
are brothers, will beneficially own, directly or through entities they control,
approximately 25.0% of the ordinary shares then outstanding. In addition,
concurrent with the private placement, Yehuda and Zohar Zisapel, Ami Amir,
Siemens and some of our other existing shareholders, who will collectively own
approximately 47.7% of the ordinary shares after this offering and the private
placement, have agreed to enter into a voting agreement under which they will
act together in the nomination and election of directors. As a result, these
shareholders may control the outcome of various actions that require shareholder
approval. For example, they may be able to elect most of our directors, delay or
prevent a transaction in which shareholders might receive a premium over the
prevailing market price for their shares or prevent changes in control or
management.


A TOTAL OF 14,228,596, OR 78.9%, OF OUR OUTSTANDING ORDINARY SHARES FOLLOWING
THIS OFFERING AND THE CONCURRENT PRIVATE PLACEMENT ARE RESTRICTED FROM IMMEDIATE
RESALE, BUT MAY BE SOLD INTO THE MARKET IN THE NEAR FUTURE. THIS COULD CAUSE THE
MARKET PRICE OF OUR ORDINARY SHARES TO DROP SIGNIFICANTLY, EVEN IF OUR BUSINESS
IS DOING WELL.

    After this offering and the concurrent private placement, we will have
18,028,596 ordinary shares outstanding. This includes the 3,800,000 ordinary
shares we are selling in this offering, which may be resold in the public market
immediately after this offering. The remaining 14,228,596 ordinary shares,
representing approximately 78.9% of our total outstanding ordinary shares
following this offering, will become available for resale in the public market
as shown in the chart below. As restrictions on resale end, the market price of
our ordinary shares could drop significantly if the holders of these restricted
shares sell them or are perceived by the market as intending to sell them.

<TABLE>
<CAPTION>
 NUMBER OF SHARES/
PERCENTAGE OF TOTAL
    OUTSTANDING            DATE OF AVAILABILITY FOR RESALE INTO PUBLIC MARKET
- -------------------   ------------------------------------------------------------
<C>                   <S>
     569,334 / 3.1%   90 days after the date of this prospectus due to the
                      requirements of the U.S. securities laws.
 10,875,784 / 60.3%   180 days after the date of this prospectus, due to an
                      agreement these shareholders have with the underwriters.
                      However, the underwriters may waive this restriction and
                      allow these shareholders to sell their shares at any time.
  2,625,228 / 14.6%   270 days after the date of this prospectus, due to an
                      agreement these shareholders will enter into with us in
                      connection with the private placement.
     158,250 / 0.9%   More than 270 days after the date of this prospectus due to
                      the requirements of the U.S. securities laws.
</TABLE>

OUR MANAGEMENT WILL HAVE BROAD DISCRETION CONCERNING THE USE OF THE PROCEEDS OF
THIS OFFERING, AND IF THE PROCEEDS ARE NOT APPLIED EFFECTIVELY, OUR RESULTS OF
OPERATIONS MAY SUFFER.

    Our management will have broad discretion concerning the use of the proceeds
of this offering. Investors will be relying on the judgment of management for
the application of the proceeds of this offering. The results and the
effectiveness of the application of the proceeds are uncertain and if the
proceeds are not applied effectively, our results of operations may suffer.

                                       10
<PAGE>
YOU WILL EXPERIENCE IMMEDIATE AND SIGNIFICANT DILUTION OF BOOK VALUE PER SHARE
FROM THE PRICE YOU PAY FOR ANY ORDINARY SHARES YOU PURCHASE IN THIS OFFERING.

    The initial public offering price of our ordinary shares will be
substantially higher than the net tangible book value per ordinary share of the
outstanding ordinary shares immediately after this offering. Assuming an initial
public offering price of $19.00 per ordinary share, you will incur immediate
dilution of $14.63 in the net tangible book value per ordinary share from the
price you pay for any ordinary shares you purchase in this offering.

IF WE ARE CHARACTERIZED AS A PASSIVE FOREIGN INVESTMENT COMPANY, OUR U.S.
SHAREHOLDERS MAY SUFFER ADVERSE TAX CONSEQUENCES, INCLUDING HIGHER TAX RATES AND
POTENTIALLY PUNITIVE INTEREST CHARGES ON THE PROCEEDS OF SHARE SALES.

    Generally, if for any taxable year 75% or more of our gross income is
passive income, or at least 50% of our assets are held for the production of, or
produce, passive income, we may be characterized as a passive foreign investment
company for U.S. federal income tax purposes. If we are characterized as a
passive foreign investment company, our U.S. shareholders may suffer adverse tax
consequences, including having gains realized on the sale of our shares be
treated as ordinary income, rather than capital gain income, and having
potentially punitive interest charges apply to the proceeds of share sales. For
purposes of determining if we are a passive foreign investment company, the
proceeds of this offering will constitute a passive asset and the income
generated by the proceeds will, until we employ it in the course of our
business, constitute passive income. Therefore, the timeliness of our use of the
proceeds of this offering may affect our status as a passive foreign investment
company.

RISKS RELATING TO OUR LOCATION IN ISRAEL

CONDITIONS IN ISRAEL AFFECT OUR OPERATIONS AND MAY LIMIT OUR ABILITY TO PRODUCE
AND SELL OUR PRODUCTS, WHICH COULD DECREASE OUR REVENUES.

    We are incorporated under Israeli law and our principal offices, our
manufacturing facilities and our research and development facilities are located
in Israel. Political, economic and military conditions in Israel directly affect
our operations. Since the establishment of the State of Israel in 1948, a number
of armed conflicts have taken place between Israel and its Arab neighbors and a
state of hostility, varying in degree and intensity, has led to security and
economic problems for Israel. We could be adversely affected by any major
hostilities involving Israel, the interruption or curtailment of trade between
Israel and its trading partners, a significant increase in inflation, or a
significant downturn in the economic or financial condition of Israel. Despite
the progress towards peace between Israel and its Arab neighbors, the future of
these peace efforts is uncertain. Several Arab countries still restrict business
with Israeli companies. We could be adversely affected by restrictive laws or
policies directed towards Israel or Israeli businesses.

BECAUSE ALL OF OUR REVENUES ARE GENERATED IN U.S. DOLLARS OR ARE LINKED TO THE
U.S. DOLLAR WHILE A PORTION OF OUR EXPENSES ARE INCURRED IN NEW ISRAELI SHEKELS,
OUR RESULTS OF OPERATIONS WOULD BE ADVERSELY AFFECTED IF INFLATION IN ISRAEL IS
NOT OFFSET ON A TIMELY BASIS BY A DEVALUATION OF THE NEW ISRAELI SHEKEL AGAINST
THE U.S. DOLLAR.

    All of our revenues are in dollars or are linked to the dollar, while a
portion of our expenses, principally salaries and the related personnel
expenses, are in new Israeli shekels, or NIS. As a result, we are exposed to the
risk that the rate of inflation in Israel will exceed the rate of devaluation of
the NIS in relation to the dollar or that the timing of this devaluation lags
behind inflation in Israel. This would have the effect of increasing the dollar
cost of our operations. In 1997 and 1998, the rate of devaluation of the NIS
against the dollar exceeded the rate of inflation, a reversal from prior years.
However, in 1999, while the rate of inflation was low, there was a devaluation
of the dollar against the NIS. We cannot predict any future trends in the rate
of inflation in Israel or the rate of devaluation of

                                       11
<PAGE>
the NIS against the dollar. If the dollar cost of our operations in Israel
increases, our dollar-measured results of operations will be adversely affected.

THE GOVERNMENT GRANTS WE HAVE RECEIVED FOR RESEARCH AND DEVELOPMENT EXPENDITURES
RESTRICT OUR ABILITY TO MANUFACTURE PRODUCTS AND TRANSFER TECHNOLOGIES OUTSIDE
OF ISRAEL AND REQUIRE US TO SATISFY SPECIFIED CONDITIONS THAT WE MAY FAIL TO
SATISFY. IF WE FAIL TO SATISFY THESE CONDITIONS, WE MAY BE REQUIRED TO REFUND
GRANTS PREVIOUSLY RECEIVED.

    We currently receive grants from the government of Israel through the Office
of the Chief Scientist of the Ministry of Industry and Trade, commonly referred
to as the Chief Scientist, for the financing of a significant portion of our
research and development expenditures in Israel. In 1998 and 1999, we received
grants from the Chief Scientist totaling approximately $1.1 million and
$1.1 million, representing 26.0% and 14.3% of our total research and development
expenditures in these periods. The terms of the Chief Scientist grants restrict
our ability to manufacture products, or transfer technologies, developed using
Chief Scientist grants outside of Israel. This restriction may impair our
ability to enter into original equipment manufacturer agreements or similar
arrangements for those products or technologies. In the past, we obtained
approvals from the Chief Scientist for the licensing of source code of some of
our products and we expect that similar approvals will be required in the
future. We cannot assure you that the approvals of the Chief Scientist will be
obtained on terms that are acceptable to us. In addition, if we fail to comply
with any of the conditions imposed by the Chief Scientist, we may be required to
refund any payments previously received, together with interest and penalties.

THE TAX BENEFITS THAT WE CURRENTLY RECEIVE FROM OUR APPROVED ENTERPRISE PROGRAMS
REQUIRE US TO SATISFY SPECIFIED CONDITIONS. IF WE FAIL TO SATISFY THESE
CONDITIONS, WE MAY BE REQUIRED TO PAY ADDITIONAL TAXES AND WOULD LIKELY BE
DENIED THESE BENEFITS IN THE FUTURE.

    The Investment Center of the Ministry of Industry and Trade has granted
approved enterprise status to several investment programs at our manufacturing
facility. The portion of our income derived from these approved enterprise
programs commencing when we begin to generate net income from these programs
will be exempt from tax for a period of two years and will be subject to a
reduced tax for an additional five to eight years, depending on the percentage
of our share capital held by non-Israelis. The benefits available to an approved
enterprise program are dependent upon the fulfillment of conditions stipulated
in applicable law and in the certificate of approval. If we fail to comply with
these conditions, in whole or in part, we may be required to pay additional
taxes for the period in which we benefited from the tax exemption or reduced tax
rates and would likely be denied these benefits in the future.

THE TAX BENEFITS AVAILABLE TO APPROVED ENTERPRISE PROGRAMS MAY BE REDUCED OR
ELIMINATED IN THE FUTURE. THIS WOULD LIKELY INCREASE OUR TAXES.

    From time to time, the government of Israel has discussed reducing or
eliminating the benefits available to approved enterprise programs. We cannot
assure you that these tax benefits will be continued in the future at their
current levels or at all. If these tax benefits were reduced or eliminated, our
taxes would likely increase.

IT MAY BE DIFFICULT TO ENFORCE A U.S. JUDGMENT AGAINST US, OUR OFFICERS AND
DIRECTORS AND THE ISRAELI EXPERTS NAMED IN THIS PROSPECTUS OR TO ASSERT U.S.
SECURITIES LAWS CLAIMS IN ISRAEL OR SERVE PROCESS ON SUBSTANTIALLY ALL OF OUR
OFFICERS AND DIRECTORS AND THESE EXPERTS.

    We are incorporated in Israel. Substantially all of our executive officers
and directors and the Israeli experts named in this prospectus are nonresidents
of the United States, and a substantial portion of our assets and the assets of
these persons are located outside the United States. Therefore, it may be
difficult for an investor, or any other person or entity, to enforce a U.S.
court judgment based upon the civil liability provisions of the U.S. federal
securities laws in an Israeli court against us or any of those persons or to
effect service of process upon these persons in the United States. Additionally,
it may be difficult for an investor, or any other person or entity, to enforce
civil liabilities under U.S. federal securities laws in original actions
instituted in Israel.

                                       12
<PAGE>
                           FORWARD-LOOKING STATEMENTS

    This prospectus contains forward-looking statements that address our
strategy; the anticipated development of our products and technology; our
anticipated use of proceeds; our projected capital expenditures and liquidity;
our development of additional revenue sources; the market acceptance of our
products and technology; and our technological advancement. These statements may
be found in the sections of this prospectus entitled "Prospectus Summary," "Risk
Factors," "Use of Proceeds," "Management's Discussion and Analysis of Financial
Condition and Results of Operations" and "Business" and in this prospectus
generally, including the section of this prospectus entitled "Business--Industry
Background" which contains information obtained from independent industry
sources. Actual results could differ materially from those anticipated in these
forward-looking statements as a result of various factors, including all the
risks discussed in "Risk Factors" and elsewhere in this prospectus.

    In addition, statements that use the terms believe, do not believe, expect,
plan, intend, estimate, anticipate and similar expressions are intended to
identify forward-looking statements. All forward-looking statements in this
prospectus reflect our current views about future events and are based on
assumptions and are subject to risks and uncertainties. Except as required by
applicable law, including the securities laws of the United States, we do not
intend to update or revise any forward-looking statements.

                               NOTE TO INVESTORS

    Investors may rely only on the information contained in this prospectus. We
and the underwriters have not authorized anyone to provide any different or
additional information. This prospectus is not an offer to sell or a
solicitation of an offer to buy ordinary shares in any jurisdiction where it is
unlawful. The information contained in this prospectus is accurate only as of
the date of this prospectus, regardless of the time of delivery of this
prospectus or of any sale of ordinary shares.

                                       13
<PAGE>
                               PRIVATE PLACEMENT

    Siemens and Samsung have agreed to purchase in a private placement
concurrently with this offering an aggregate of 2,625,228 ordinary shares from
us and some of our existing shareholders, including our chairman of the board,
our chief executive officer and some of our other directors. Each shareholder
participating in the private placement will sell approximately 19.3% of its
holdings. The price per share in the private placement will be equal to the
initial public offering price, net of the underwriting discount, up to a maximum
of $17.00 per share. Siemens and Samsung have represented that they will be
purchasing our ordinary shares for investment and not with a view to resale, and
have agreed to a 270-day lock-up following the closing of this offering. Based
on an assumed initial public offering price of $19.00 per share, the price per
share in the private placement will be $17.00. The number of shares they will
purchase from us and our existing shareholders and the aggregate purchase price
they will pay to us and our existing shareholders are as follows:

<TABLE>
<CAPTION>
                                       NUMBER OF ORDINARY SHARES            AGGREGATE PURCHASE PRICE
                                   ---------------------------------   ----------------------------------
                       PRICE PER   PURCHASED    PURCHASED FROM OUR                   PAID TO OUR EXISTING
                         SHARE      FROM US    EXISTING SHAREHOLDERS   PAID TO US        SHAREHOLDERS
                       ---------   ---------   ---------------------   -----------   --------------------
<S>                    <C>         <C>         <C>                     <C>           <C>
Siemens..............   $17.00      365,767          1,259,461         $ 6,218,039        $21,410,837
Samsung..............    17.00      225,055            774,945           3,825,935         13,174,065
                                    -------          ---------         -----------        -----------
                                    590,822          2,034,406         $10,043,974        $34,584,902
                                    =======          =========         ===========        ===========
</TABLE>

    Concurrent with Siemen's investment in us, we will enter into a licensing
agreement with Siemens to license our technology to Siemens worldwide. In
addition, we have entered into a letter of intent with Samsung to jointly
develop voice over IP products and solutions. We believe that the private
placement and the associated business agreements will enhance our ongoing
relationships with these key strategic customers and will help us sustain our
market leadership position.

                                USE OF PROCEEDS

    We estimate that we will receive net proceeds of approximately
$75.2 million from:

    - the sale by us of 3,800,000 ordinary shares in this offering, after
      deducting the underwriting discount and the estimated offering expenses;
      and

    - the sale by us of 590,822 ordinary shares to Siemens and Samsung in the
      concurrent private placement at $17.00 per ordinary share.

    We expect to use the net proceeds to finance the continued growth of our
business and for general corporate purposes. Our principal purposes for
conducting this offering are to:

    - provide working capital for general corporate purposes;

    - fund possible acquisitions of additional businesses and technologies or
      investments in public or private companies in related businesses or the
      establishment of joint ventures that are complementary to our current or
      future business; and

    - provide a public market for our ordinary shares, which would facilitate
      our issuing equity securities as consideration for acquisitions and
      incentive compensation to employees.

    We have no plans or commitments for any specific acquisition, investment or
joint venture and we cannot be sure that we will complete any acquisition,
investment or joint venture.

    Pending use of the net proceeds as described above, we intend to invest the
net proceeds in short-term, interest-bearing, investment-grade instruments, or
bank deposits with interest and principal linked to the U.S. dollar or the
Israel consumer price index, or deposit the net proceeds in U.S. dollar bank
accounts in Israel or outside of Israel.

                                DIVIDEND POLICY

    We have never declared or paid any cash dividend on our ordinary shares and
we do not anticipate paying any cash dividends on our ordinary shares in the
future. We currently intend to retain all future earnings to finance our
operations and to expand our business.

                                       14
<PAGE>
                                 CAPITALIZATION

    The following table presents our capitalization as of December 31, 1999:

    - on an actual basis;

    - on a pro forma basis to give effect to the conversion of all outstanding
      preferred shares into ordinary shares, which will take place before this
      offering, and the issuance of 52,750 ordinary shares upon the exercise of
      options after December 31, 1999 and the receipt of $62,500 in proceeds
      from the option exercise; and

    - on a pro forma as adjusted basis to give effect to:

       - the conversion of preferred shares referred to above;

       - the sale by us of 3,800,000 ordinary shares in this offering at the
         initial public offering price and the receipt by us of the estimated
         net proceeds of this offering, after deducting the underwriting
         discount and estimated offering expenses payable by us; and

       - the sale by us of 590,822 ordinary shares in the concurrent private
         placement to Siemens and Samsung at $17.00 per ordinary share and the
         receipt by us of the proceeds of the private placement.


<TABLE>
<CAPTION>
                                                                      AS OF DECEMBER 31, 1999
                                                              ---------------------------------------
                                                                                           PRO FORMA
                                                               ACTUAL      PRO FORMA      AS ADJUSTED
                                                              --------   --------------   -----------
                                                                         (IN THOUSANDS)
<S>                                                           <C>        <C>              <C>
Long term debt, excluding current maturities................   $   67        $   67         $    67
Shareholders' equity:
  Preferred shares:
    Authorized actual--5,275,000 shares; authorized pro
      forma and pro forma as adjusted--none; issued and
      outstanding actual--2,957,165 shares; issued and
      outstanding pro forma and pro forma as
      adjusted--none........................................        4            --              --
  Ordinary shares:
    Authorized actual--12,332,317 shares; authorized pro
      forma and pro forma as adjusted--24,984,470 shares;
      issued and outstanding actual--10,627,859 shares;
      issued and outstanding pro forma--13,637,774 shares;
      issued and outstanding pro forma as
      adjusted--18,028,596 shares...........................       17            21             128
  Additional paid-in capital................................   13,789        13,789          88,935
  Deferred compensation.....................................   (1,052)       (1,052)         (1,052)
  Accumulated deficit.......................................   (9,277)       (9,277)         (9,277)
                                                               ------        ------         -------
    Total shareholders' equity..............................    3,481         3,481          78,734
                                                               ------        ------         -------
      Total capitalization..................................   $3,548        $3,548         $78,801
                                                               ======        ======         =======
</TABLE>


    The actual, pro forma and pro forma as adjusted information presented in the
table excludes:

    - 3,048,873 ordinary shares issuable upon exercise of options outstanding
      under our share option plans as of the date of this prospectus at a
      weighted average exercise price of $2.86 per ordinary share; and


    - up to 61,900 additional ordinary shares reserved for issuance under our
      share option plans.


    The number of ordinary shares in the table are presented on an actual basis
after giving effect to the conversion of 2,770 ordinary shares into deferred
shares which will occur before completion of this offering. The 2,770 deferred
shares reflect the 10-for-1 stock split that will be effected before this
offering but do not reflect the 20.1 share dividend which will not be
distributed to holders of deferred shares.

    Immediately before the completion of this offering, we will increase our
authorized share capital to 24,984,470 ordinary shares and 15,530 deferred
shares.

                                       15
<PAGE>
                                    DILUTION

    Our pro forma consolidated net tangible book value as of December 31, 1999
was approximately $3.5 million, or $0.26 per ordinary share. We have calculated
our pro forma consolidated net tangible book value per share by:

    - subtracting our consolidated liabilities from our consolidated tangible
      assets; and

    - dividing the difference by the number of ordinary shares outstanding on a
      pro forma basis after giving effect to the conversion of all outstanding
      preferred shares into ordinary shares, the share recapitalization that
      will be effected before this offering and the issuance of 52,750 ordinary
      shares upon the exercise of options after December 31, 1999.

    After giving effect to:

    - the sale by us of 3,800,000 ordinary shares in this offering at the
      initial public offering price and receipt by us of the estimated net
      proceeds of this offering, after deducting the underwriting discount and
      estimated offering expenses; and

    - the sale by us of 590,822 ordinary shares in the aggregate to Siemens and
      Samsung in the concurrent private placement at $17.00 per ordinary share
      and receipt by us of the proceeds of the private placement,

our pro forma consolidated net tangible book value as of December 31, 1999 would
have been approximately $78.7 million, or $4.37 per ordinary share. This
represents an immediate increase in pro forma consolidated net tangible book
value of $4.11 per ordinary share to existing shareholders and an immediate
dilution of $14.63 per ordinary share to new investors purchasing ordinary
shares in this offering.

    Dilution per share represents the difference between the price per share to
be paid by new investors for the ordinary shares sold in this offering and the
pro forma consolidated net tangible book value per share immediately after this
offering and the private placement. The following table illustrates this per
share dilution:

<TABLE>
<S>                                                           <C>        <C>
Assumed initial public offering price per share.............              $19.00
  Pro forma consolidated net tangible book value per share
    before this offering....................................   $0.26
  Increase in pro forma consolidated net tangible book value
    per share attributable to new investors in this
    offering................................................    3.61
  Increase in pro forma consolidated net tangible book value
    per share attributable to the private placement to
    Siemens and Samsung.....................................    0.50
                                                               -----
Pro forma consolidated net tangible book value per share
  after this offering and the private placement.............                4.37
                                                                          ------
Dilution per share to new investors.........................              $14.63
                                                                          ======
</TABLE>

    The following table presents the differences between the total consideration
paid to us and the average price per share paid by existing shareholders, by the
investors in the private placement and by new investors purchasing ordinary
shares in this offering:

<TABLE>
<CAPTION>
                                               SHARES PURCHASED       TOTAL CONSIDERATION      AVERAGE
                                             ---------------------   ----------------------     PRICE
                                               NUMBER     PERCENT      AMOUNT      PERCENT    PER SHARE
                                             ----------   --------   -----------   --------   ---------
<S>                                          <C>          <C>        <C>           <C>        <C>
Existing shareholders......................  13,637,774     75.6%    $12,242,500     13.0%     $ 0.90
Siemens and Samsung........................     590,822      3.3%     10,043,974     10.6%      17.00
New investors..............................   3,800,000     21.1%     72,200,000     76.4%      19.00
                                             ----------    -----     -----------    -----
  Total....................................  18,028,596    100.0%    $94,486,474    100.0%
                                             ==========    =====     ===========    =====
</TABLE>

    The above table does not reflect:

    - 3,048,873 ordinary shares issuable upon exercise of options outstanding
      under our share option plans; and

    - up to 61,900 additional ordinary shares reserved for issuance under these
      plans.

    To the extent outstanding options are exercised, there will be further
dilution to new investors.

                                       16
<PAGE>
                      SELECTED CONSOLIDATED FINANCIAL DATA

    We have derived the following selected consolidated financial data from our
consolidated financial statements.

    The following data were derived from our audited consolidated financial
statements presented elsewhere in this prospectus:

    - consolidated statement of operations data for the years ended December 31,
      1997, 1998 and 1999; and

    - consolidated balance sheet data as of December 31, 1998 and 1999.

    The following data were derived from our audited consolidated financial
statements not included in this prospectus:

    - consolidated statement of operations data for the years ended December 31,
      1995 and 1996; and

    - consolidated balance sheet data as of December 31, 1995, 1996, 1997.

    Our consolidated financial statements have been prepared in U.S. dollars and
according to generally accepted accounting principles in the United States.

    You should read the selected consolidated financial data together with the
section of this prospectus entitled "Management's Discussion and Analysis of
Financial Condition and Results of Operations" and our consolidated financial
statements included elsewhere in this prospectus.

    We have calculated pro forma basic and diluted net loss per share assuming
the conversion of all outstanding preferred shares into ordinary shares. Please
see notes 2 and 17 of the notes to our consolidated financial statements for an
explanation of the number of shares used in computing per share data.

<TABLE>
<CAPTION>
                                                                            YEAR ENDED DECEMBER 31,
                                                              ----------------------------------------------------
                                                                1995       1996       1997       1998       1999
                                                              --------   --------   --------   --------   --------
                                                                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                           <C>        <C>        <C>        <C>        <C>
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenues....................................................  $   871    $ 1,491    $ 4,899     $8,894    $17,550
Cost of revenues............................................      570        770      1,211      1,412      2,853
                                                              -------    -------    -------     ------    -------
Gross profit................................................      301        721      3,689      7,482     14,697
                                                              -------    -------    -------     ------    -------
Operating expenses:
  Research and development..................................    1,331      1,775      2,763      4,379      7,667
  Less participation by the Chief Scientist.................      438        497        890      1,140      1,097
                                                              -------    -------    -------     ------    -------
  Research and development, net.............................      893      1,278      1,873      3,239      6,570
  Marketing and selling, net................................      660      1,260      2,384      4,425      9,502
  General and administrative................................      242        250        494        670      1,426
                                                              -------    -------    -------     ------    -------
Total operating expenses....................................    1,795      2,788      4,751      8,334     17,498
                                                              -------    -------    -------     ------    -------
Operating loss..............................................   (1,494)    (2,067)    (1,062)      (852)    (2,801)
Financing income (expenses), net............................       (5)        42          6         23        105
                                                              -------    -------    -------     ------    -------
Net loss....................................................  $(1,499)   $(2,025)   $(1,056)    $ (829)   $(2,696)
                                                              =======    =======    =======     ======    =======
Basic and diluted net loss per ordinary share...............  $ (0.21)   $ (0.21)   $ (0.10)    $(0.08)   $ (0.26)
Weighted average number of ordinary shares used in computing
  basic and diluted net loss per ordinary share.............    7,217      9,499     10,234     10,492     10,538
Pro forma basic and diluted net loss per ordinary share.....                                              $ (0.20)
Weighted average number of ordinary shares used in computing
  pro forma basic and diluted net loss per ordinary share...                                               13,496
</TABLE>

<TABLE>
<CAPTION>
                                                                               AS OF DECEMBER 31,
                                                              ----------------------------------------------------
                                                                1995       1996       1997       1998       1999
                                                              --------   --------   --------   --------   --------
                                                                                 (IN THOUSANDS)
<S>                                                           <C>        <C>        <C>        <C>        <C>
CONSOLIDATED BALANCE SHEET DATA:
Cash and cash equivalents...................................   $  481     $1,349     $  435     $3,305    $ 2,605
Working capital.............................................    2,088      1,071        873      4,318        814
Total assets................................................    3,006      3,073      3,704      9,371     13,261
Total bank debt, less current maturities....................       --         23        106        130         67
Shareholders' equity........................................    2,361      1,453      1,363      5,450      3,481
</TABLE>

                                       17
<PAGE>
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

OVERVIEW

    We are a leading designer, developer and supplier of products and technology
that enable real-time voice, video and data communications over packet networks,
including the Internet and other IP networks.

    We were incorporated in January 1992, commenced operations in October 1992
and commenced sales of our products in the fourth quarter of 1994. Before that
time, our operations consisted primarily of research and development and
recruiting personnel. In 1995, we established a wholly owned subsidiary in the
United States, RADVision Inc., which conducts our sales and marketing activities
in North America.

    All of our revenues are generated in U.S. dollars or are linked to the
dollar and a majority of our expenses are incurred in dollars. Consequently, we
use the dollar as our functional currency. Transactions and balances in other
currencies are converted into dollars according to the principles in Financial
Accounting Standards Board Statement No. 52. Gains and losses arising from
conversion are recorded as interest income or expense, as applicable. Our
consolidated financial statements are prepared in dollars and according to
generally accepted accounting principles in the United States.

    REVENUES.  We generate revenues from the sale of our products and our
technology, which is primarily sold in the form of software development kits, as
well as related maintenance and support services. We generally recognize
revenues from the sale of our products and technology upon shipment and when
collection is probable. Revenues generated from maintenance and support services
are deferred and recognized ratably over the period of the term of service. We
price our products on a per unit basis, and grant discounts based upon unit
volumes. We price our software development kits on the basis of a fixed-fee plus
royalties from products developed using the software development kits. We expect
our revenues from the sale of both our products and our technology to increase,
though we expect that the rate of growth of our revenues from the sale of our
products will exceed the rate of growth of our revenues from the sale of our
technology.

    We sell our products and technology through direct sales and various
indirect distribution channels in North America, Europe, the Far East and
Israel. For the year ended December 31, 1999, approximately 52% of our revenues
were generated in the United States.

    COST OF REVENUES.  Our cost of revenues consists of component and material
costs, direct labor costs, subcontractor fees, overhead related to manufacturing
and depreciation of manufacturing equipment. Our gross margin is affected by the
selling prices for our products as well as the proportion of our revenues
generated from the sale of our technology. Our revenues from the sale of our
technology have higher gross margins than our revenues from the sale of our
products and we offer greater discounts to our high volume OEM customers. As the
relative proportion of our revenues from our products increases as a percentage
of our total revenues and we generate a higher percentage of our revenues from
sales to our high volume OEM customers, our gross margins will decline.

    RESEARCH AND DEVELOPMENT EXPENSES, NET.  Our research and development
expenses consist primarily of compensation and related costs for research and
development personnel, expenses for testing facilities and depreciation of
equipment. All of our research and development costs are expensed as incurred.
Research and development expenses are presented net of payments received from
the Chief Scientist. We do not currently intend to apply for a material amount
of grants from the Chief Scientist in the future. However, we expect to continue
to make substantial investments in research and development.

                                       18
<PAGE>
    MARKETING AND SELLING EXPENSES, NET.  Our marketing and selling expenses
consist primarily of compensation and related costs for sales personnel,
marketing personnel, sales commissions, marketing programs, public relations,
promotional materials, travel expenses, trade show exhibit expenses and
royalties paid to the government of Israel. Marketing and selling expenses are
presented net of marketing grants received from the government of Israel.

    GENERAL AND ADMINISTRATIVE EXPENSES.  Our general and administrative
expenses consist primarily of salaries and related expenses for executive,
accounting and human resources personnel, professional fees, provisions for
doubtful accounts and other general corporate expenses.

    Operating expenses also include amortization of stock-based compensation,
which is allocated among research and development expenses, marketing and
selling expenses and general and administrative expenses based on the division
in which the recipient of the option grant is employed. Amortization of
stock-based compensation results from the granting of options to employees with
exercise prices per share determined to be below the fair market value per share
of our ordinary shares on the dates of grant. The stock-based compensation is
being amortized to operating expenses over the vesting period of the individual
options.

    FINANCING INCOME, NET.  Our financing income consists primarily of interest
earned on bank deposits, gains and losses from the conversion of monetary
balance sheet items denominated in non-dollar currencies into dollars and
interest expense incurred on outstanding debt.

    TAXES.  Israeli companies are generally subject to income tax at the
corporate tax rate of 36%. However, several of our investment programs at our
manufacturing facility in Tel Aviv have been granted approved enterprise status
and, therefore, we are eligible for the reduced tax benefits described later in
this section in "--Corporate Tax Rate." These benefits should result in income
recognized by us being tax exempt or taxed at a lower rate for a specified
period after we begin to report taxable income and exhaust any net operating
loss carry-forwards. However, these benefits may not be applied to reduce the
tax rate for any income derived by our U.S. subsidiary.

RESULTS OF OPERATIONS

    The following table presents consolidated statement of operations data for
the periods indicated as a percentage of total revenues.

<TABLE>
<CAPTION>
                                                                  YEAR ENDED DECEMBER 31,
                                                              --------------------------------
                                                                1997        1998        1999
                                                              --------    --------    --------
<S>                                                           <C>         <C>         <C>
Revenues....................................................   100.0%      100.0%      100.0%
Cost of revenues............................................    24.7        15.9        16.3
                                                               -----       -----       -----
Gross profit................................................    75.3        84.1        83.7
Operating expenses:
  Research and development..................................    56.4        49.2        43.7
  Less participation by the Chief Scientist.................    18.2        12.8         6.3
                                                               -----       -----       -----
  Research and development, net.............................    38.2        36.4        37.4
  Marketing and selling, net................................    48.7        49.8        54.1
  General and administrative................................    10.1         7.5         8.1
                                                               -----       -----       -----
    Total operating expenses................................    97.0        93.7        99.6
                                                               -----       -----       -----
Operating loss..............................................   (21.7)       (9.6)      (15.9)
Financing income, net.......................................     0.1         0.3         0.6
                                                               -----       -----       -----
Net loss....................................................   (21.6)%      (9.3)%     (15.3)%
                                                               =====       =====       =====
</TABLE>

                                       19
<PAGE>
YEARS ENDED DECEMBER 31, 1998 AND 1999

  CONSOLIDATED STATEMENT OF OPERATIONS

    REVENUES.  Revenues increased from $8.9 million for the year ended
December 31, 1998 to $17.6 million for the year ended December 31, 1999, an
increase of $8.7 million, or 97.3%. This increase was due to an increase of
$1.5 million, or 214.3%, in sales of RADVision IP conferencing bridges, an
increase of $283,000, or 52.9%, in sales of our standards-compliant version of
RADVision video interface units, which we introduced in 1998, an increase of
$2.9 million, or 67.4%, in sales of H.323 software development kits, as well as
an increase in sales of our other products and technology in response to
increased market demand.

    Revenues from IP conferencing bridges increased from $699,000 for the year
ended December 31, 1998 to $2.2 million for the year ended December 31, 1999.
The increase in revenues from IP conferencing bridges was primarily attributable
to an increase in the sales price of our IP conferencing bridges.

    Revenues from video interface units increased from $535,000 for the year
ended December 31, 1998 to $818,000 for the year ended December 31, 1999. The
increase in revenues from video interface units was primarily attributable to a
global growth in demand for these units as customers moved from integrated
services digital networks, or ISDN, to IP-based networks.

    Revenues from H.323 software development kits increased from $4.3 million
for the year ended December 31, 1998 to $7.2 million for the year ended
December 31, 1999. This increase in revenues from H.323 software development
kits was primarily attributable to increased market demand for this technology.

    Revenue from sales to customers in the United States increased from
$4.6 million, or 51.7% of revenue, for the year ended December 31, 1998, to
$9.1 million, or 51.6% of revenue, for the year ended December 31, 1999, an
increase of $4.5 million, or 97.8%. This increase in sales to customers in the
United States was primarily attributable to the more rapid adoption of our
technology in the United States as compared to the rest of the world.

    Revenue from sales to customers in Europe increased from $2.3 million, or
25.8% of revenue, for the year ended December 31, 1998, to $4.0 million, or
23.1% of revenue, for the year ended December 31, 1999, an increase of
$1.7 million, or 73.9%.

    Revenue from sales to customers in the Far East increased from $942,000, or
10.6% of revenue, for the year ended December 31, 1998, to $2.7 million, or
15.2% of revenue, for the year ended December 31, 1999, an increase of
$1.8 million, or 191.1%. This increase in sales to customers in the Far East as
a percentage of total sales was primarily attributable to increased sales
efforts in this region.

    COST OF REVENUES.  Cost of revenues increased from $1.4 million for the year
ended December 31, 1998 to $2.9 million for the year ended December 31, 1999, an
increase of $1.5 million, or 107.1%. This increase was attributable to the
increase in our revenues. Gross profit as a percentage of revenues decreased
from 84.1% for the year ended December 31, 1998 to 83.7% for the year ended
December 31, 1999.

    RESEARCH AND DEVELOPMENT, NET.  Research and development expenses, net
increased from $3.2 million for the year ended December 31, 1998 to
$6.6 million for the year ended December 31, 1999, an increase of $3.4 million,
or 106.3%. This increase was primarily attributable to an increase in the number
of research and development personnel whom we employed. We have increased our
research and development personnel to support our existing and expected new
product lines and to accommodate the growth of our business. Research and
development expenses, net as a percentage of

                                       20
<PAGE>
revenues increased from 36.4% for the year ended December 31, 1998 to 37.4% for
the year ended December 31, 1999.

    MARKETING AND SELLING, NET.  Marketing and selling expenses, net increased
from $4.4 million for the year ended December 31, 1998 to $9.5 million for the
year ended December 31, 1999, an increase of $5.1 million, or 115.9%. This
increase was primarily attributable to a $2.5 million, or 114.7%, increase in
personnel-related expenses resulting from our increasing the number of our sales
and marketing employees in 1999 and to an increase of $836,000, or 78.8%, in
promotional expenses. We have increased our sales and marketing expenses in
response to current and expected growth in the market for our products.
Marketing and selling expenses, net as a percentage of revenues increased from
49.8% for the year ended December 31, 1998 to 54.1% for the year ended
December 31, 1999. We expect that marketing and selling expenses will continue
to increase in proportion to our continued growth.

    GENERAL AND ADMINISTRATIVE.  General and administrative expenses increased
from $670,000 for the year ended December 31, 1998 to $1.4 million for the year
ended December 31, 1999, an increase of $730,000, or 109.0%. This increase was
primarily attributable to an increase of $340,000, or 89.5%, in personnel
expenses and occupancy costs and to an increase of $96,000, or 114.3%, in
recruitment costs. General and administrative expenses as a percentage of
revenues increased from 7.5% for the year ended December 31, 1998 to 8.1% for
the year ended December 31, 1999. We expect that general and administrative
expenses will increase due to our recruiting efforts as we continue to increase
the number of our employees.

    NET LOSS.  Net loss increased from $829,000 for the year ended December 31,
1998 to $2.7 million for the year ended December 31, 1999, an increase of
$1.9 million, or 229.2%. Net loss increased as a percentage of revenues from
9.3% for the year ended December 31, 1998 to 15.3% for the year ended
December 31, 1999.

  CONSOLIDATED BALANCE SHEET

    TRADE RECEIVABLES.  Trade receivables increased from $2.6 million for the
year ended December 31, 1998 to $3.2 million for the year ended December 31,
1999, an increase of $0.6 million, or 23.1%. This increase was primarily
attributable to an increase in sales of our products during the year ended
December 31, 1999.

    ALLOWANCE FOR DOUBTFUL ACCOUNTS.  Allowance for doubtful accounts increased
from $73,000 for the year ended December 31, 1998 to $225,000 for the year ended
December 31, 1999, an increase of $152,000, or 208.2%. This increase was
primarily attributable to an increase in sales of our products during the year
ended December 31, 1999. Allowance for doubtful accounts as a portion of trade
receivables increased from 2.77% for the year ended December 31, 1998 to 6.54%
for the year ended December 31, 1999. This increase was primarily attributable
to an outstanding debt from one customer for $105,000.

    OTHER RECEIVABLES AND PREPAID EXPENSES.  Other receivables and prepaid
expenses increased from $887,000 for the year ended December 31, 1998 to
$1.5 million for the year ended December 31, 1999, an increase of $0.6 million,
or 67.6%. This increase was primarily attributable to an increase in grants from
the Chief Scientist, which increased other receivables and prepaid expenses from
$336,000 for the year ended December 31, 1998 to $731,000 for the year ended
December 31, 1999, an increase of $395,000, or 117.6%.

    INVENTORIES.  Inventories increased from $873,000 for the year ended
December 31, 1998 to $2.4 million for the year ended December 31, 1999, an
increase of $1.5 million, or 171.8%. This

                                       21
<PAGE>
increase was primarily attributable to an increase in inventory in response to
anticipated growth in sales.

    TRADE PAYABLES.  Trade payables increased from $0.6 million for the year
ended December 31, 1998 to $2.6 million for the year ended December 31, 1999, an
increase of $2.0 million, or 333.3%. This increase was primarily attributable to
an increase in trade payables resulting from the increase in inventory.

    OTHER PAYABLES AND ACCRUED EXPENSES.  Other payables and accrued expenses
increased from $2.6 million for the year ended December 31, 1998 to
$6.3 million for the year ended December 31, 1999, an increase of $3.7 million,
or 142.3%. This increase was primarily attributable to an increase of $788,000
in accrued employee expenses, an increase of $699,000 in accrued deferred income
and an increase of $710,000 in development costs paid by customers which will be
recognized only after all criteria for revenue recognition according to
SOP 97-2 are met.

YEARS ENDED DECEMBER 31, 1997 AND 1998

    REVENUES.  Revenues increased from $4.9 million for the year ended
December 31, 1997 to $8.9 million for the year ended December 31, 1998, an
increase of $4.0 million, or 81.6%. This increase was due primarily to an
increase in sales of RADVision H.323 software development kits and related
support services, as well as the receipt of several large orders in 1998 for our
products and technology. Revenue from H.323 software development kits and
related support services increased from $2.4 million for the year ended
December 31, 1997 to $4.4 million for the year ended December 31, 1998, an
increase of $2.0 million, or 83.3%. This increase in revenues from sales of
H.323 software development kits was primarily attributable to the release of an
enhanced version of the software development kits during the first quarter of
1998, which resulted in increased sales.

    Revenue from sales to customers in the United States increased from
$3.0 million, or 61.2% of revenue, for the year ended December 31, 1997, to
$4.6 million, or 51.7% of revenue, for the year ended December 31, 1998, an
increase of $1.6 million, or 53.3%.

    Revenue from sales to customers in Europe increased from $632,000, or 12.9%
of revenue, for the year ended December 31, 1997, to $2.3 million, or 25.8% of
revenue, for the year ended December 31, 1998, an increase of $1.7 million, or
263.9%.

    Revenue from sales to customers in the Far East increased from $332,000, or
6.8% of revenue, for the year ended December 31, 1997, to $942,000, or 10.6% of
revenue, for the year ended December 31, 1998, an increase of $610,000, or
183.7%.

    This increase in sales to customers in Europe and the Far East as a
percentage of total sales was primarily attributable to the increased adoption
of our technologies in those regions. These technologies had been adopted in the
United States in the previous year. As a result, sales to customers in the
United States as a percentage of total sales decreased, despite the growth in
actual sales to these customers.

    COST OF REVENUES.  Cost of revenues increased from $1.2 million for the year
ended December 31, 1997 to $1.4 million for the year ended December 31, 1998, an
increase of $200,000, or 16.7%. This increase was due to the increase in our
revenues, which was partially offset by a decrease in our cost of materials.
Gross profit as a percentage of revenues increased from 75.3% for 1997 to 84.1%
for 1998. This increase was due to the increase in our sales of technology,
which generated higher margins.

    RESEARCH AND DEVELOPMENT, NET.  Research and development expenses, net
increased from $1.9 million for the year ended December 31, 1997 to
$3.2 million for the year ended December 31, 1998, an increase of $1.3 million,
or 68.4%. This increase was attributable to an increase in personnel-related
expenses resulting from our increasing the number of our research and
development employees

                                       22
<PAGE>
in 1998 associated with new product and technology development. Research and
development expenses, net decreased as a percentage of revenues from 38.2% for
the year ended December 31, 1997 to 36.4% for the year ended December 31, 1998.

    MARKETING AND SELLING, NET.  Marketing and selling expenses, net increased
from $2.4 million for the year ended December 31, 1997 to $4.4 million for the
year ended December 31, 1998, an increase of $2.0 million, or 83.3%. This
increase was primarily attributable to an increase of $1.1 million, or 101.8%,
in personnel and related expenses and an increase of $513,000, or 93.6%, in
public relations, advertising and other promotional expenses. Marketing and
selling expenses, net increased as a percentage of revenues from 48.7% for the
year ended December 31, 1997 to 49.8% for the year ended December 31, 1998.

    GENERAL AND ADMINISTRATIVE.  General and administrative expenses increased
from $494,000 for the year ended December 31, 1997 to $670,000 for the year
ended December 31, 1998, an increase of $176,000, or 35.6%. This increase was
primarily attributable to an increase of $54,000, or 17.3%, in personnel
expenses and to an increase of $81,000, or 2,700%, in travel expenses. General
and administrative expenses as a percentage of revenues decreased from 10.1% for
the year ended December 31, 1997 to 7.5% for the year ended December 31, 1998.

    NET LOSS.  Net loss decreased from $1,056,000 for the year ended
December 31, 1997 to $829,000 for the year ended December 31, 1998, a decrease
of $227,000, or 21.5%. Net loss decreased as a percentage of revenues from 21.6%
for the year ended December 31, 1997 to 9.3% for the year ended December 31,
1998.

                                       23
<PAGE>
QUARTERLY RESULTS OF OPERATIONS

    The following tables present consolidated statements of operations data for
each of the eight fiscal quarters ended December 31, 1999, in dollars and as a
percentage of revenues. In management's opinion, this unaudited information has
been prepared on the same basis as our audited consolidated financial statements
and includes all adjustments, consisting only of normal recurring adjustments,
necessary for fair presentation of the unaudited information for the quarters
presented. The results of operations for any quarter are not necessarily
indicative of results that we might achieve for any subsequent periods.

<TABLE>
<CAPTION>
                                                                 THREE MONTHS ENDED
                            ---------------------------------------------------------------------------------------------
                            MAR. 31,    JUNE 30,    SEPT. 30,    DEC. 31,    MAR. 31,    JUNE 30,    SEPT. 30,   DEC. 31,
                              1998        1998        1998         1998        1999        1999        1999        1999
                            --------    --------    ---------    --------    --------    --------    ---------   --------
                                                                   (IN THOUSANDS)
<S>                         <C>         <C>         <C>          <C>         <C>         <C>         <C>         <C>
CONSOLIDATED STATEMENT OF
  OPERATIONS DATA:
Revenues..................   $1,357      $1,657      $2,875       $3,006      $3,393      $3,979      $4,623     $ 5,555
Cost of revenues..........     (216)       (284)       (458)        (454)       (454)       (592)       (642)     (1,165)
                             ------      ------      ------       ------      ------      ------      ------     -------
Gross profit..............    1,141       1,373       2,417        2,552       2,939       3,387       3,981       4,390
Operating expenses:
  Research and
    development...........      844       1,085       1,133        1,317       1,408       1,917       2,124       2,217
  Less participation by
    the Chief Scientist...     (193)       (298)       (309)        (339)       (208)       (318)       (245)       (325)
                             ------      ------      ------       ------      ------      ------      ------     -------
  Research and
    development, net......      651         787         824          978       1,200       1,599       1,879       1,892
  Marketing and selling,
    net...................      865       1,000       1,204        1,357       1,661       1,844       2,327       3,670
  General and
    administrative........      112         147         195          216         240         291         299         596
                             ------      ------      ------       ------      ------      ------      ------     -------
Operating income (loss)...     (487)       (561)        194            1        (162)       (347)       (524)     (1,768)
Financing income
  (expenses), net.........        7         (14)         26            3          97          (1)         20         (11)
                             ------      ------      ------       ------      ------      ------      ------     -------
Net income (loss).........   $ (480)     $ (575)     $  220       $    4      $  (65)     $ (348)     $ (504)    $(1,779)
                             ======      ======      ======       ======      ======      ======      ======     =======
AS A PERCENTAGE OF
  REVENUES:
Revenues..................      100%        100%        100%         100%        100%        100%        100%        100%
Cost of revenues..........      (16)        (17)        (16)         (15)        (13)        (15)        (14)        (21)
                             ------      ------      ------       ------      ------      ------      ------     -------
Gross profit..............       84          83          84           85          87          85          86          79
Operating expenses:
  Research and
    development...........       62          66          39           44          42          48          46          40
  Less participation by
    the Chief Scientist...      (14)        (18)        (11)         (11)         (6)         (8)         (5)         (6)
                             ------      ------      ------       ------      ------      ------      ------     -------
  Research and
    development, net......       48          48          28           33          36          40          41          34
  Marketing and selling,
    net...................       64          60          42           45          49          47          50          66
  General and
    administrative........        8           9           7            7           7           7           6          11
                             ------      ------      ------       ------      ------      ------      ------     -------
Operating income (loss)...      (36)        (34)          7            0          (5)         (9)        (11)        (32)
Financing income
  (expenses), net.........        1          (1)          1            0           3           0           0          (0)
                             ------      ------      ------       ------      ------      ------      ------     -------
Net income (loss).........      (35)%       (35)%         8%           0%         (2)%        (9)%       (11)%       (32)%
                             ======      ======      ======       ======      ======      ======      ======     =======
</TABLE>

    We expect our operating results to fluctuate significantly in the future as
a result of various factors, many of which are outside our control.
Consequently, we believe that period-to-period comparisons of

                                       24
<PAGE>
our operating results may not necessarily be meaningful and, as a result, you
should not rely on them as an indication of future performance.

LIQUIDITY AND CAPITAL RESOURCES

    Since our inception, we have financed our operations through cash generated
by operations and a combination of private placements of our share capital and
borrowings under lines of credit. Through December 31, 1999, we have raised a
total of approximately $12.2 million in aggregate net proceeds in four private
placements. As of December 31, 1999, we had approximately $2.6 million in cash
and cash equivalents. As of December 31, 1999, our working capital was $814,000.

    In December 1999, we issued 158,250 ordinary shares to Intel for $250,000,
or $1.58 per share, which is $17.42 less than the assumed initial public
offering price of $19.00 per share. The shares were issued under an agreement
entered into with Intel in 1996 under which Intel agreed to invest $1.0 million
in us through the purchase of ordinary shares in three installments of $500,000,
$250,000 and $250,000 upon our achieving specified milestones or, in the case of
the third installment, at Intel's option before the initial public offering of
our ordinary shares.

    Net cash used in operating activities was approximately $1.0 million for the
year ended December 31, 1997 and $0.8 million for the year ended December 31,
1998. Net cash provided by operating activities was $1.4 million for the year
ended December 31, 1999.

    For the year ended December 31, 1997, cash used in operating activities was
primarily attributable to a net loss of $1.1 million and an increase in trade
receivables of $1.4 million, offset in part by an increase in other payables and
accrued expenses of $1.1 million. For the year ended December 31, 1997, the
increase in accounts receivable was attributable to our increase in sales.

    For the year ended December 31, 1998, cash used in operating activities was
attributable primarily to a net loss of approximately $829,000, an increase in
trade receivables of $724,000, an increase in other receivables and prepaid
expenses of $626,000 and an increase in inventory of $447,000. These increases
in cash used in operating activities were offset in part by depreciation of
approximately $360,000 and an increase in other payables and accrued expenses of
approximately $964,000. For the year ended December 31, 1998, the increase in
accounts receivable was primarily attributable to higher sales levels during the
fourth quarter.

    For the year ended December 31, 1999, cash provided by operating activities
was primarily attributable to an increase in trade payables of $1.9 million, an
increase of $3.5 million in other payables and accrued expenses and an increase
in depreciation of $718,000. These increases in cash provided by operating
activities were offset in part by a net loss of approximately $2.7 million, an
increase in trade receivables of $647,000, an increase in other receivables and
prepaid expenses of $430,000 and an increase in inventory of $1.6 million.

    The increase in inventory for the year ended December 31, 1999 was primarily
in anticipation of expected growth in product revenue as well as a greater need
for evaluation units. The increase in accounts receivable for the year ended
December 31, 1999 was primarily the result of increased sales as compared to the
previous year. In addition, we increased our allowance for doubtful accounts to
address the increase in our accounts receivable balance. The increase in
payables for the year ended December 31, 1999 was primarily due to a change in
the timing of some of our accounts payable.

    Net cash used in investing activities was approximately $428,000 for the
year ended December 31, 1997, $1.1 million for the year ended December 31, 1998
and $2.3 million for the year ended December 31, 1999. For the year ended
December 31, 1999, $2.4 million of cash used in investing activities was for
purchases of property and equipment, partially offset by $74,000 in proceeds
from the sale of property and equipment.

    Net cash provided by financing activities was $484,000 for the year ended
December 31, 1997, $4.8 million for the year ended December 31, 1998, and
$177,000 for the year ended December 31,

                                       25
<PAGE>
1999. For the year ended December 31, 1997, cash provided by financing
activities was attributable to $889,000 in proceeds from the issuance of
ordinary shares, offset in part by $525,000 in decrease in short term credit.
For the years ended December 31, 1998 and 1999, cash provided by financing
activities was attributable principally to proceeds from the issuance of
preferred shares.

    As of December 31, 1999, our principal commitments consisted of obligations
outstanding under operating leases. Although we have no material commitments for
capital expenditures, we anticipate an increase in capital expenditures and
lease commitments consistent with our anticipated growth in operations,
infrastructure and personnel. We also may establish additional operations as we
expand globally.

    As of December 31, 1999, we had $131,000 outstanding under an equipment term
loan facility. As of December 31, 1999, we had a $2.5 million line of credit,
all of which was unused.

    Our capital requirements are dependent on many factors, including market
acceptance of our products and the allocation of resources to our research and
development efforts, as well as our marketing and sales activities. In the last
three years, we have experienced substantial increases in our expenditures as a
result of the growth in our operations and personnel. We intend to increase our
expenditures in the future consistent with our anticipated growth. We anticipate
that our cash resources will be used primarily to fund our operating activities,
as well as for capital expenditures.

    We believe that the net proceeds from this offering and the private
placement, together with our current cash, cash equivalents and borrowing
capacity, will be sufficient to meet our anticipated cash needs for working
capital and capital expenditures for at least the next 12 months. During and
after this period, if cash generated from operations is insufficient to satisfy
our liquidity requirements, we may seek to sell additional equity or increase
the available borrowings under our line of credit. If we are unable to obtain
this additional financing, we may be required to reduce the scope of our planned
product development and marketing efforts, which could harm our business,
financial condition and operating results.

CORPORATE TAX RATE

    Israeli companies are generally subject to income tax at the corporate tax
rate of 36%. However, several investment programs at our manufacturing facility
in Tel Aviv have been granted approved enterprise status and we are, therefore,
eligible for tax benefits under the Law for the Encouragement of Capital
Investments, 1959. We have derived, and expect to continue to derive, a
substantial portion of our income from the approved enterprise programs at our
manufacturing facility.

    Subject to compliance with applicable requirements, the portion of our
income derived from the approved enterprise programs will be eligible for the
following tax benefits commencing in the first year in which it generates
taxable income:

<TABLE>
<CAPTION>
        YEAR AFTER WE
       BEGIN GENERATING
        TAXABLE INCOME           TAX BENEFIT
       ----------------          -----------
<S>                              <C>
   1-2........................   Tax-exempt
   3-7........................   Corporate tax of up to 25%
   8-10.......................   Corporate tax of up to 25% if more than 25% of
                                   our shares are held by non-Israeli investors
</TABLE>

    The period of tax benefits for our approved enterprise programs has not yet
commenced, because we have yet to realize taxable income. These benefits should
result in income recognized by us being tax exempt or taxed at a lower rate for
a specified period after we begin to report taxable income and exhaust any net
operating loss carry-forwards. However, these benefits may not be applied to
reduce the tax rate for any income derived by our U.S. subsidiary.

                                       26
<PAGE>
    As of December 31, 1999, our net operating loss carry-forwards for Israeli
tax purposes amounted to approximately $2.3 million. Under Israeli law, these
net operating losses may be carried forward indefinitely and offset against
future taxable income. We expect that, during the period in which these tax
losses are utilized, our income will be substantially tax exempt. Therefore,
there will be no tax benefit available from these losses and no deferred income
taxes have been included in our financial statements. Deferred taxes for other
temporary differences are immaterial.

    As of December 31, 1999, the net operating loss carry-forwards of our U.S.
subsidiary for U.S. tax purposes amounted to approximately $2.2 million. These
losses are available to offset any future U.S. taxable income of our U.S.
subsidiary and will expire in the years 2010 through 2014.

IMPACT OF INFLATION AND CURRENCY FLUCTUATIONS

    The dollar cost of our operations is influenced by the extent to which any
inflation in Israel is offset, is offset on a lagging basis, or is not offset by
the devaluation of the NIS in relation to the dollar. When the rate of inflation
in Israel exceeds the rate of devaluation of the NIS against the dollar,
companies experience increases in the dollar cost of their operations in Israel.
Unless offset by a devaluation of the NIS, inflation in Israel will have a
negative effect on our profitability as we receive payment in dollars or
dollar-linked NIS for all of our sales while we incur a portion of our expenses,
principally salaries and related personnel expenses, in NIS.

    The following table presents information about the rate of inflation in
Israel, the rate of devaluation of the NIS against the U.S. dollar, and the rate
of inflation of Israel adjusted for the devaluation:

<TABLE>
<CAPTION>
                                                                              ISRAELI INFLATION
     YEAR ENDED             ISRAELI INFLATION       ISRAELI DEVALUATION         ADJUSTED FOR
    DECEMBER 31,                 RATE %                   RATE %                DEVALUATION %
    ------------            -----------------       -------------------       -----------------
<S>                         <C>                     <C>                       <C>
        1995                        8.1                     3.9                       4.1
        1996                       10.6                     3.7                       6.6
        1997                        7.0                     8.8                      (1.7)
        1998                        8.6                    17.6                      (7.7)
        1999                        1.3                    (0.1)                      1.3
</TABLE>

    We cannot assure you that we will not be materially and adversely affected
in the future if inflation in Israel exceeds the devaluation of the NIS against
the dollar or if the timing of the devaluation lags behind inflation in Israel.

    A devaluation of the NIS in relation to the dollar has the effect of
reducing the dollar amount of any of our expenses or liabilities which are
payable in NIS, unless these expenses or payables are linked to the dollar. This
devaluation also has the effect of decreasing the dollar value of any asset
which consists of NIS or receivables payable in NIS, unless the receivables are
linked to the dollar. Conversely, any increase in the value of the NIS in
relation to the dollar has the effect of increasing the dollar value of any
unlinked NIS assets and the dollar amounts of any unlinked NIS liabilities and
expenses.

    Because exchange rates between the NIS and the dollar fluctuate
continuously, with a historically declining trend in the value of the NIS,
exchange rate fluctuations and especially larger periodic devaluations will have
an impact on our profitability and period-to-period comparisons of our results.
The effects of foreign currency re-measurements are reported in our consolidated
financial statements in current operations.

MARKET RISK

    We currently do not invest in, or hold for trading or other purposes, any
financial instruments subject to market risk. We currently pay interest on our
equipment term loan facility based on the London interbank offered rate. As a
result, changes in the general level of interest rates directly affect

                                       27
<PAGE>
the amount of interest payable by us under this facility. However, because our
outstanding debt under this facility has never exceeded $218,000, we do not
expect our exposure to market risk from changes in interest rates to be
material.

GOVERNMENT GRANTS

    We principally conduct our research and development operations in Israel.
Our research and development efforts have been financed through internal
resources and grants from the Chief Scientist. For the years ended December 31,
1998 and 1999, the Chief Scientist provided grants for research and development
efforts of approximately $1.1 million in 1998 and 1999, representing 26.0% and
14.3% of our total research and development expenses in these periods. We do not
intend to apply for a material amount of grants from the Chief Scientist in the
future.

    Under Israeli law, royalties on the revenues derived from sales of products
and services developed using Chief Scientist grants are payable to the Israeli
government, generally at the rate of 3.0% during the first three years, 4.0%
over the following three years and 5.0% in or after the seventh year. The
maximum aggregate royalties payable generally cannot exceed 100%-150% of the
dollar-linked value of the total grants received. Royalties payable for grants
received under programs approved after January 1, 1999, however, will be subject
to interest on the dollar-linked value of the total grants received at an annual
rate of the London interbank offered rate applicable to 12-month dollar
deposits. Based upon the aggregate grants received to date, we expect that we
will continue to pay royalties to the Israeli government on sales of our
products and related services for the next few years. For the last three years,
we have paid or accrued royalties to the Israeli government as follows:

<TABLE>
<CAPTION>
 YEAR ENDED          ROYALTIES PAID
DECEMBER 31,           OR ACCRUED
- ------------         --------------
<S>                  <C>
   1997                 $ 83,000
   1998                  178,000
   1999                  495,000
</TABLE>

    The government of Israel does not own proprietary rights in technology
developed using its funding and there is no restriction on the export of
products manufactured using the technology. The technology is, however, subject
to other legal restrictions, including the obligation to manufacture the product
based on this technology in Israel and to obtain the Chief Scientist's consent
to transfer the technology to a third party. This restriction may impair our
ability to enter into original equipment manufacturer agreements or similar
arrangements for those products and technologies. In the past, we obtained
approvals from the Chief Scientist for the licensing of source code of some of
our products and we expect that similar approvals will be required in the
future. These restrictions continue to apply even after we have paid the full
amount of royalties payable for the grants.

    The Israeli government, through the Fund for the Encouragement of Marketing
Activities, awards grants to Israeli companies for overseas marketing expenses,
including expenses for maintaining branches, advertising, catalogs, exhibitions
and surveys, up to a maximum rate of 33% of these expenses, not to exceed
$1.2 million annually. In 1998, we received grants from the marketing fund
totaling approximately $178,000, and are required to pay royalties in connection
with these grants at a rate of 3.0% of the increase in our sales generated
outside of Israel from the date of the grant up to the total dollar-linked
amount of the grants. Marketing grants are currently awarded only to companies
whose annual exports in the year preceding the application did not exceed
$15.0 million. As of December 31, 1999, our contingent liability to the Israeli
government for grants received from the marketing fund was $199,000. If we fail
to satisfy the terms and conditions of the grants, we may be required to refund
the grants already received and would likely be denied these grants in the
future.

                                       28
<PAGE>
YEAR 2000

    The year 2000 issue is the result of computer programs being written using
two digits rather than four to define the applicable year. Any computer programs
or hardware that have date-sensitive software may recognize a date using 00 as
the year 1900 rather than the year 2000. This could result in system failures or
miscalculations, causing disruptions of operations for any company using these
computer programs or hardware. As a result, many companies' computer systems may
need to be upgraded or replaced to avoid year 2000 issues.

    Our products and technology are generally integrated into larger networks
involving sophisticated hardware and software products supplied by other
vendors. Each of our customers' networks involves different combinations of
third-party products. We cannot evaluate whether all of their products are year
2000 compliant. We may face claims based on year 2000 problems in other
companies' products or based on issues arising from the integration of multiple
products within the overall network. Although no claims have been made, we may
in the future be required to defend our products and technology in legal
proceedings that could be expensive regardless of the merits of these claims.

    Our internal systems have not suffered any interruptions following
December 31, 1999. In addition, we have not been made aware that any of our
major suppliers or manufacturers have suffered disruptions in their systems.

    We have not indentified any year 2000 problems that could adversely affect
our business operations. However, we believe that it is not possible to
determine with complete certainty that all year 2000 problems affecting us have
been identified or corrected. The number of devices that could be affected and
the interactions among these devices are simply too numerous. As a result, we
believe that the following consequences are possible:

    - operational inconveniences and inefficiencies for us, our suppliers, our
      manufacturers and our customers that will divert management's time and
      attention and financial and human resources from ordinary business
      activities;

    - business disputes and claims for pricing adjustments or penalties due to
      year 2000 problems by our customers; and

    - business disputes alleging that we failed to comply with the terms of
      contracts or industry standards of performance, some of which could result
      in litigation or contract termination.

    To date, we have not experienced any material interruptions in our
operations related to year 2000 issues and do not expect that future costs will
be material. We have not incurred any significant expenses to date, and we do
not anticipate that the total costs associated with our year 2000 remediation
efforts, including both expenses incurred and any to be incurred in the future,
will be of any significance to our operations. However, if we, our customers,
our suppliers, or our customers' third-party providers fail to remedy any year
2000 issues, our business could be interrupted and we could experience a
material loss of revenues.

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS

    In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
Accounting for Derivative Instruments and Hedging Activities. SFAS No. 133
established accounting and reporting standards requiring that every derivative
instrument be recorded on the balance sheet at its fair value. SFAS No. 133
requires that changes in the derivative's fair value be recognized currently in
earnings unless specific hedge accounting criteria are met. Special accounting
for qualifying hedges allows a derivative's gains and losses to offset related
results on the hedged item in the statement of operations. SFAS No. 133 is
effective for fiscal years beginning after June 15, 2000. We believe that the
adoption of SFAS No. 133 will not have a material effect on our financial
statements.

                                       29
<PAGE>
                                    BUSINESS

OVERVIEW

    We are a leading designer, developer and supplier of products and technology
that enable real-time voice, video and data communications over packet networks,
including the Internet and other networks based on the Internet protocol or IP.
Our products and technology are used by our customers to develop systems that
enable enterprises and service providers to use next generation packet networks
for real-time IP communications. We have over 250 customers including Alcatel,
Bosch, Cisco, Madge, NTT, Nortel, Philips, Shanghai Bell, Siemens and 3Com.

INDUSTRY BACKGROUND

GROWTH IN COMMUNICATIONS

    In recent years, communications networks have experienced dramatic growth in
traffic. This growth is expected to continue due to a number of factors,
including:

    - an increasing need for enterprises to expand their networks to enable them
      to send, access and receive information quickly, economically and
      globally;

    - an increasing use of the Internet and other packet networks for
      communicating and engaging in commercial transactions;

    - an increase in available bandwidth at declining prices; and

    - the introduction of new voice, video and data communications services and
      applications.

LIMITATIONS OF TRADITIONAL NETWORKS

    Traditionally, circuit-switched networks have been the principal medium for
the transmission of communications. Circuit-switched technology dedicates a
circuit with a fixed amount of bandwidth for the duration of the connection,
regardless of a user's actual bandwidth usage. The recent growth in data
communications traffic, particularly the growth in the number of Internet users,
has placed significant strains on the capacity of traditional circuit-switched
networks. Circuit-switched networks were initially deployed to handle only voice
communications. These networks were not designed to handle data efficiently and
cannot scale cost-effectively to accommodate the growth in data traffic.
Moreover, circuit-switched networks were built based on proprietary, complex
technologies which have historically limited the entrance of new competitors and
hindered the development and introduction of new services.

ADVANTAGES OF PACKET-BASED NETWORKS

    While circuit-switched networks were principally designed to handle analog
voice traffic, packet-based networks were principally designed for transmitting
digital information. Packet-based networks, including IP networks, transmit
voice, video and data information in the form of small digital packages called
packets. Voice, video and data packets are sent over a single network
simultaneously and reassembled at the destination. Packet switching enables more
efficient utilization of available network bandwidth than circuit-switching,
allowing more calls to travel through a packet network at the same time.
Moreover, packet networks allow for the cost-efficient expansion of capacity as
communications traffic increases. In addition, packet networks are built using
open standards, like IP, which promote competition by allowing different vendors
to build products and applications that can interoperate with one another. By
using packet technologies based on open standards, new services can be deployed
rapidly and economically.

                                       30
<PAGE>
THE NEED FOR INDUSTRY STANDARDS FOR REAL-TIME IP COMMUNICATIONS

    Originally, enterprises and communications service providers deployed packet
networks primarily for handling data traffic and not for real-time IP
communications. Technical barriers initially hampered the use of packet networks
for real-time communications. For example, packet networks were not designed to
guarantee the sequential delivery of packets and packets could be lost. In
addition, the time of delivery of packets was dependent upon the amount of
packet traffic being transmitted over the network. For real-time communications,
it is critical that the packets associated with a specific voice or video
communication be transmitted in the correct sequence and in a timely manner.
Early attempts at real-time IP communications solved these technical problems by
using proprietary solutions developed by individual vendors. However,
proprietary solutions from different vendors meant that different vendor
products could not inter-operate with one another.

    To enable the global deployment of real-time IP communications networks,
industry standards and protocols were developed to promote interoperability of
real-time communications over packet networks. H.323 is currently the most
widely deployed industry-wide protocol for real-time IP communications. H.323
was developed by a team of computing, telephony and networking experts under the
direction and auspices of the International Telecommunications Union, or ITU-T,
a United Nations organization, with the goal of specifying a universal real-time
standard that would ensure interoperability of all packet-based networks and
products. H.323 provides the technical framework for developing
standards-compliant products and systems for real-time voice and video
communication over packet networks. All components of an H.323 compliant
network, including terminals, gateways, gatekeepers and conferencing bridges,
use the H.323 protocol to communicate.

    Today, H.323 is the standard of choice for the builders of real-time IP
communications solutions for enterprises. The ITU-T is continuously enhancing
H.323 and publishing new versions to support the evolving requirements of next
generation packet networks. Other emerging standards like MGCP, or Media Gateway
Control Protocol, and SIP, or Session Initiation Protocol, are also being
developed to address the complex requirements of multi-protocol packet networks.
The widespread acceptance of industry protocols and standards for IP
communications has enabled the deployment of packet networks for real-time
communications by ensuring interoperability and is facilitating the migration to
IP communications.

GROWTH IN REAL-TIME VOICE AND VIDEO IP COMMUNICATIONS

    Due to the inherent benefits of packet networks and the advent of new
technologies and standards that have enabled real-time communications over these
networks, the use of packet networks for real-time voice, video and data
communications is expected to grow dramatically. ICM Global Intelligence, a
market research firm, forecasts that revenues for network equipment associated
with voice-over-IP, or IP telephony, will grow from $477 million in 1999 to
$7.1 billion in 2004. Perey Research & Consulting, an industry consulting firm,
forecasts revenues for network equipment associated with IP video communications
to grow from $22 million in 1999 to more than $643 million in 2003.

    This anticipated growth in real-time IP communications is expected to be
driven primarily by enterprises and communications service providers migrating
to packet networks. As enterprises move from centralized organizations to
distributed networks of employees, customers, suppliers and business partners,
they require more effective communications capabilities to support their
operations and remain competitive in a global and rapidly changing market.
Packet networks are well-suited for enterprises because they provide enterprises
with the following advantages:

    - cost-effective increases in capacity to meet increasing communications
      traffic demands;

                                       31
<PAGE>
    - support for new communications applications, like video conferencing and
      data collaboration, for improved workforce productivity;

    - interoperability with different network configurations of their customers,
      suppliers and partners; and

    - cost savings associated with simplified network management resulting from
      creating a single network that handles all communications, rather than
      having to maintain separate telephone and computer networks.

    Communications service providers have also begun to deploy packet networks
in an effort to compete more effectively in a deregulated market. Global
deregulation and rapid technological advances have resulted in the emergence of
many new communications service providers, increased competition among
traditional telecommunications carriers, lower prices, innovative new product
and service offerings and accelerated customer turnover. To remain competitive,
communications service providers must be able to develop and introduce new
services to differentiate themselves in the market and attract and maintain
customers. Packet networks are well-suited to accomplish these objectives
because they enable the rapid deployment of new and differentiated solutions. In
addition, packet-based technology allows new competitors to enter the market
quickly without substantial investment in infrastructure.

KEY ATTRIBUTES OF REAL-TIME VOICE AND VIDEO IP COMMUNICATIONS SOLUTIONS

    To migrate their voice and video communications to packet networks,
enterprises and communications service providers require a real-time IP
communications solution that provides:

    - reliable real-time voice, video and data communications functionality;

    - interoperability with the existing circuit-switched networks as well as
      with other IP equipment and systems;

    - applications, features and functionality comparable to those available
      over traditional telephone networks, including call transfer, conferencing
      and caller identification;

    - scalability to permit cost-effective increases in capacity to meet demand;

    - standards compliance, so that products from different vendors can work
      together in one network; and

    - flexibility to adapt to rapidly changing network environments in response
      to the evolving needs of enterprises and to accommodate a mobile business
      environment.

OUR SOLUTION

    We provide standards-based products and technology for real-time voice,
video and data communications over packet networks for enterprises and service
providers. Our products and technology offer the following benefits:

    REAL-TIME VOICE, VIDEO AND DATA COMMUNICATIONS FUNCTIONALITY.  We are one of
the few companies that offer IP communications products which support both
voice-only, as well as combined voice, video and data communications. We believe
that this dual functionality is attractive to enterprises and service providers
that seek a flexible IP communications solution which can provide enhanced
multimedia functionality in addition to IP telephony capabilities. We believe
our products enable developers of IP communications solutions to offer features
and functions generally unavailable in competitive solutions.

    MARKET LEADING TECHNOLOGY FOR STANDARDS BASED REAL-TIME IP
COMMUNICATIONS.  We were one of the original five members of the ITU-T committee
responsible for defining the H.323 standard which has

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been adopted worldwide for real-time packet-based communications. We believe our
technology is recognized as the market-leading implementation of the H.323
industry standard for real-time voice, video and data communications over packet
networks. We have been actively involved in the development of protocols for
real-time communications since the inception of the industry in 1994 and were
the first-to-market with enabling products and technology for voice, video and
data communications over IP networks. We believe that our technology has become
the technology of choice among developers of standards-compliant IP
communications systems. Because we were first to market and have achieved broad
market penetration, our customers benefit from our ability to develop and
provide them market-tested, proven products and technology. Using our products
and technology, our customers can develop unique capabilities with increased
functionality that will differentiate their IP communications solutions in the
market. We believe that the accumulated knowledge that we have gained
participating in the development of industry standards provides us with a
competitive advantage and positions us to be among the first to market products
and technology based on the latest technological advances.

    INTEROPERABILITY.  We provide our customers with products and technology
that are interoperable across a broad range of IP communications systems. Our
products and technology have been integrated into IP communications systems
developed by more than 250 communications equipment providers. Because our
products and technology are broadly deployed across various segments of the IP
communications industry, we believe that the interoperability of our products
and technology with products from different vendors is virtually assured. We
believe that our long-standing involvement in the definition of standards and
accumulated experience with product development across our broad customer base
provides us with a competitive advantage in addressing interoperability needs.
We continue to participate actively in defining industry standards by working
closely with industry consortia on a broad spectrum of IP communications
protocols to ensure continued interoperability of our products and technology
across multiple protocols.

    IMPROVED TIME TO MARKET.  Our customers rely on our accumulated expertise
with IP communications standards and core technology to significantly reduce
their development cycle and improve time to market. Communications equipment
providers seeking to market standards-compliant systems for real-time voice and
video communications over packet networks require standards-compliant building
blocks to develop their products. Implementing standards as deployable products
and technology is a complex task that requires significant technical knowledge
and expertise as well as substantial investments of time and resources. Our
products and technology enable our customers to shorten their own development
time by integrating our proven enabling products and technology into their
solutions. Rather than dedicate in-house resources to implementing industry
standards, these developers can use our products and technology and focus their
core competencies on building enhanced systems, products and applications.

    BROAD RANGE OF PRODUCT ENVIRONMENTS.  Our products and technology provide
our customers with flexibility to design individual products and applications or
complete systems. Our customers can build a complete network solution for
real-time IP communications using our full suite of products or integrate
RADVision products with their own products or other vendor products into their
real-time IP communications solution. Similarly, our technology has been
designed to enable the development of a broad range of products and
applications, from those that can service single users, including hand held
devices and residential IP phones, to multi-user products, like highly complex,
powerful carrier class gateways. Taken together, our products and technology
provide all of the key network components necessary to build a real-time IP
communications solutions.

    DISTRIBUTED ARCHITECTURE.  We designed our products based on a distributed
architecture. With a distributed architecture, the core functions needed for
real-time IP communications are dispersed throughout the network at the site of
each gateway, IP conferencing bridge and gatekeeper, rather than

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<PAGE>
aggregated at a single centralized location. This distributed approach offers
several advantages compared to a traditional centralized architecture. The
distributed architecture of our products enables better utilization of network
bandwidth, because communications need not be routed through a centralized
location but rather can be routed over the shortest path to minimize bandwidth
usage. Similarly, our distributed architecture is a scalable solution, allowing
a network manager to add network resources at distributed locations
incrementally as the network grows. Our distributed architecture also provides
redundancy and increased fault tolerance and reliability because, unlike a
centralized architecture, failure at one location will not compromise the entire
network.

OUR STRATEGY

    Our goal is to be the leading provider of innovative products and technology
that enable real-time voice and video communications over packet networks. Key
elements of our strategy include the following:

    - MAINTAIN AND EXTEND OUR TECHNOLOGY LEADERSHIP. We believe that we have
      established ourselves as a technology leader in providing core-enabling
      technology for a broad range of IP communications products and services.
      We have accumulated extensive knowledge and expertise as designers and
      developers of commercial products and technology for real-time
      packet-based communications. We place considerable emphasis on research
      and development to expand the capabilities of our existing products, to
      develop new products and to improve our existing technology and
      capabilities. We believe that our future success will depend upon our
      ability to maintain our technological leadership, to enhance our existing
      products and to introduce on a timely basis new commercially viable
      products addressing the needs of our customers. We intend to continue to
      devote a significant portion of our personnel and financial resources to
      research and development.

    - STRENGTHEN AND EXPAND OUR RELATIONSHIPS WITH OEM CUSTOMERS. We have
      established and continue to maintain collaborative working relationships
      with many OEMs in the IP communications market, including Bosch, Cisco,
      Nortel, Philips, Polycom and Siemens. We work closely with our OEM
      customers to integrate our products and core technology into their
      solutions. Our core technology and our system design expertise enable us
      to assist these customers in the development of complete solutions that
      contain enhanced features and functionality compared to competitive
      alternatives. We have generally established long-term relationships with
      our OEM customers by starting with a few products and subsequently
      expanding these relationships by increasing the number and range of
      products sold to these customers. We intend to expand the depth and
      breadth of our existing OEM relationships while initiating similar new
      relationships with leading OEMs focused on the IP communications market.

    - CONTINUE TO OFFER NEW AND ENHANCED PRODUCTS AND FEATURES. We believe we
      have consistently been either first, or among the first, to market
      products that support real-time voice, video and data communications over
      packet networks. We were the first to market with IP gateways that provide
      combined voice, video and data functionality, and first to market with
      software development kits for the development of H.323-compliant IP
      communications products and applications. We intend to utilize our
      technological expertise as a basis for market leadership by continuing to
      be first-to-market with new and enhanced products and features that
      address the increasingly sophisticated needs of our customers and the
      evolving markets they serve. In addition, we believe that our
      participation in the drafting of industry standards gives us the ability
      to quickly identify emerging trends to develop new products and
      technologies that are at the forefront of technological evolution in the
      IP communications industry. We currently expect to introduce several new
      or enhanced products in 2000, including our MGCP software development kits
      and carrier class gatekeepers for large-scale networks.

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<PAGE>
    - EXPAND THE DISTRIBUTION CHANNELS FOR OUR PRODUCTS. We intend to continue
      to focus our sales and marketing efforts on expanding our distribution
      channels, including broadening the number of systems integrators that
      distribute our products. Systems integrators provide us a channel for
      feedback from their customers, the end-users of our products, which gives
      us valuable insight into evolving industry trends and customer
      requirements. Systems integrators represent an important independent
      marketing channel for our products that provides us with increased market
      presence through the relationships and existing customer base of these
      systems integrators. In addition, endorsements by leading systems
      integrators strengthen our brand name awareness. As part of this strategy
      to expand our distribution channels, we intend to open an office in Asia
      in 2000.

    - CONTINUE OUR ACTIVE INVOLVEMENT IN SHAPING INDUSTRY STANDARDS FOR IP
      COMMUNICATIONS. We actively participate in and contribute to the
      formulation of standards for IP communications. We intend to continue our
      active involvement in the organizations that define the standards for
      real-time communications over next generation packet networks. Our
      knowledge and expertise gained in participating in the development of
      these industry standards enable us to be among the first to market
      products based on new standards adopted. We are continually improving and
      enhancing our core enabling H.323 technology to ensure that we maintain
      our leadership position as a provider of superior H.323 software
      development kits. We are also investing significant resources in
      developing other emerging protocols, like MGCP. Because of our involvement
      in defining these IP communications standards, we believe we are
      well-positioned to quickly develop enhanced functionality and new products
      based on multiple protocols.

OUR PRODUCTS AND TECHNOLOGY

    RADVision products and technology provide the core building blocks needed
for standards-based real-time voice, video and data communications over packet
networks. Our customers can deploy our products as a complete network solution
for IP communications, integrate our products into their own IP communications
systems or use our technology to build their own standards-compliant IP
communications products, systems and applications for enterprises and service
providers.

    Our products and technology consist of:

    - RADVision gateways, which interface between traditional circuit-switched
      networks and IP networks;

    - RADVision gatekeepers, which control, manage and monitor real-time voice,
      video and data traffic over packet networks;

    - RADVision IP conferencing bridges, which enable voice or multimedia
      conferencing over packet networks among three or more participants; and

    - RADVision software development kits, which provide the core technology
      necessary to build interoperable, standards-compliant products, systems
      and applications for real-time voice and video communication over packet
      networks.

      RADVISION GATEWAYS

    To achieve the successful deployment of IP communications systems by
enterprises and service providers, users who are connected to packet networks
must be able to communicate with users who are connected to circuit-switched
telephone networks. RADVision gateways provide an interface between traditional
circuit-switched telephone networks and the new packet-based networks. A gateway
converts voice, video and data signals received from a circuit-switched network
into packets, that it then transmits in real-time over a packet-based network.
When the direction of the communication is reversed, the gateway converts the
packets back into circuit-switched signals.

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<PAGE>
    We offer RADVision multimedia gateways, which support real-time voice, video
and data communications, and RADVision voice gateways, which support voice-only
communications.

      RADVISION MULTIMEDIA GATEWAYS

    Our RADVision multimedia gateways can support up to 30 voice calls or 15
multimedia calls simultaneously. We sell these gateways principally to systems
integrators and OEMs who offer IP communications solutions to enterprises for
next generation networks. These gateways provide the following benefits:

    - REAL-TIME VOICE, VIDEO AND DATA COMMUNICATIONS. Our multimedia gateways
      support real-time voice and video calls, data collaboration as well as
      voice-only calls.

    - INTEROPERABILITY. Our multimedia gateways are H.323 compliant and are
      designed to be fully interoperable with other IP network components.

    - EMBEDDED GATEKEEPER. Our multimedia gateways contain an embedded
      gatekeeper that provides the gateway with similar functionality to that of
      a corporate telephone system, known as a private branch exchange, or PBX,
      including call and network management capabilities such as controlling how
      calls are routed, who may use the networks and how bandwidth is allocated.
      This embedded gatekeeper is offered free to the customer who may choose to
      use it or disable it. Customers who disable the embedded gatekeeper can
      purchase a gatekeeper from us or from another gatekeeper vendor.

    - ADVANCED CALL FUNCTIONALITY. Our multimedia gateways can support advanced
      PBX-like functions including call transfer and call forwarding.

    A typical configuration of our RADVision multimedia gateways in a packet
network is shown below.

                                     [LOGO]

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<PAGE>
        RADVISION VOICE GATEWAYS

    Our RADVision voice gateways are optimized for voice-only functionality. Our
RADVision voice gateways can support up to 30 voice calls simultaneously. These
gateways were developed based upon the technology contained in our multimedia
gateways for voice and video calls and can be easily up-graded to a multimedia
gateway. We sell our RADVision voice gateways to OEMs that build solutions for
enterprises and require gateways to interface voice calls between traditional
circuit-switched telephone networks and packet networks.

    Our voice gateways are designed for two principal applications:

    - as gateways to connect traditional PBXs for circuit-switched networks with
      new PBXs built for packet-based networks, also known as IP/PBXs, and

    - as gateways to interconnect two circuit-switched PBX systems over a packet
      network, thus bypassing the circuit-switched network.

    Our RADVision voice gateways contain embedded gatekeepers and are
interoperable with other H.323 compliant network components. Our RADVision voice
gateways also provide the advanced call functionality of our multimedia
gateways.

    A configuration of our RADVision voice gateways demonstrating both
applications of these gateways is shown below.

                                     [LOGO]

        RADVISION VIDEO INTERFACE UNITS

    Enterprises have invested significant resources in outdated, or legacy,
videoconferencing equipment that are designed to function only over
circuit-switched networks. Our RADVision video interface unit

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<PAGE>
was designed to extend the life of this equipment by allowing legacy
videoconferencing systems to be connected directly to a packet network rather
than the circuit-switched network. Our RADVision video interface units are
affordable, single user gateways designed specifically to interconnect legacy
video equipment with packet networks. Because most new videoconferencing systems
are designed to connect directly to packet networks, we expect that the market
for these units will decrease significantly over time.

        RADVISION GATEKEEPERS

    Gatekeepers perform the essential network function of controlling and
managing real-time voice, video and data communications on a packet-based
network. Gatekeepers define and control how traffic is routed over a
packet-based network by identifying the IP destination address and routing the
traffic to that destination. Gatekeepers also enable the provisioning of
advanced PBX-like functions, including call forwarding, multi-point conferencing
and call transfer. Network managers use gatekeepers to configure, monitor and
manage the voice and video call activity on a packet network to ensure optimal
implementation of the network. Gatekeepers log and track call activity and
maintain details of network activity which permit the network manager to monitor
IP communications activity on the network, including number of calls, number of
users and bandwidth usage.

    We provide a free embedded gatekeeper in our gateways. We also sell a
stand-alone gatekeeper software application that is designed to be installed on
any computer that supports the Microsoft Windows NT operating system. We sell
this off-the-shelf application to systems integrators as a complementary product
to our family of gateways and IP conferencing bridges. These customers combine
RADVision gatekeeper application software with other IP network components to
build complete IP communications solutions. These customers typically purchase
our gatekeeper application in conjunction with the purchase of our gateways or
IP conferencing bridges to use instead of our free embedded gatekeeper.

    We also sell gatekeeper technology in the form of software development kits
that enable our OEM customers to build and customize their own gatekeeper
applications. Our gatekeeper software development kit offers the software
developer full control over a wide range of gatekeeper functions and the
flexibility to customize and further differentiate the gatekeeper to respond to
the needs of their particular market. By using RADVision software development
kits, our customers can build upon our proven technology and bring their
gatekeeper products to market quickly.

        RADVISION IP CONFERENCING BRIDGES

    While communications between two parties involves point-to-point
connections, conferencing between multiple parties involves multipoint
communications among three or more participants. In traditional circuit-switched
networks, conferencing bridges connect callers to each other through a central
bridge that conducts the conference call. As enterprises migrate to packet
networks, IP conferencing bridges are needed to conduct conference calls over
these next generation networks. We were one of the first and remain one of a few
companies to offer IP conferencing bridges for multipoint communications.

    Traditionally, voice or video conferencing required the conference to be
arranged in advance by a network administrator and remain attended by an
operator for the duration of the conference. Our RADVision IP conferencing
bridges allow voice or video conferencing among multiple participants over IP
networks without any advance arrangements or the assistance of an operator.
Participants simply dial a number and the conferencing bridge automatically
arranges the conference call. Additional participants can join the conference
while it is in progress or by being added to the conference by any party already
participating in the conference. Traditional conferencing bridges were primarily
built as large complex carrier class bridges that were not appropriate for
installation within an enterprise, requiring enterprises to contract with
external service providers to conduct conference calls. Our

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<PAGE>
RADVision IP conferencing bridges are substantially less expensive and are
designed to be deployed locally within an enterprise network, eliminating the
need to contract with a service provider for conferencing services.

    Our RADVision IP conferencing bridges can support up to 15 simultaneous
voice and video calls or 24 voice-only calls. Like our gateways, our
conferencing bridges include an embedded gatekeeper. Multiple conferencing
bridges can be combined to increase the number of simultaneous conferences, and
conferencing bridges can be linked together to provide a solution for very large
conferences, allowing for multiple conference panels with many remote viewers.

    A configuration of our RADVision IP conferencing bridges for multipoint
conferencing between three or more participants is shown below.

                                     [LOGO]

        RADVISION H.323 SOFTWARE DEVELOPMENT KIT

    H.323 is currently the most widely deployed standard for real-time IP
communications. All components of an H.323-compliant network, including
terminals, gateways, gatekeepers and conferencing bridges, use the H.323
protocol to communicate. As a result, communications equipment providers seeking
to market H.323-compliant IP telephony and multimedia products, systems and
applications need H.323 core software to develop their solutions. Rather than
dedicate in-house resources to developing H.323 technology, these providers seek
to build upon our proven enabling technologies.

    We sell the core enabling technology for real-time IP communications in the
form of software development kits. Our RADVision H.323 software development kits
provide developers with the core software building blocks needed to develop
H.323-compliant products, systems and applications. Our RADVision H.323 software
development kit is an integrated set of software programs which execute

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<PAGE>
the H.323 protocol and perform the functions necessary to establish and maintain
real-time voice, video and data communications over packet-based networks. Our
technology enables our customers to focus on their core competencies and
dramatically reduces the time to market of H.323-compliant IP communications
products, systems and applications. Our RADVision H.323 software development
kits can be used to develop a broad spectrum of products, including gateways,
gatekeepers, conferencing bridges, IP telephones and other H.323-compliant
products.

        PRODUCTS AND TECHNOLOGY UNDER DEVELOPMENT

    We intend to capitalize upon our technological leadership in real-time IP
communications to develop new products and technology that meet the evolving
needs of the IP communications market. Our future product and technology
offerings are expected to include:

    RADVISION MGCP SOFTWARE DEVELOPMENT KITS.  Media gateway control protocol,
commonly referred to as MGCP, provides functions that complement H.323 and has
been developed for large packet networks operated by telecommunications carriers
and service providers that require gateways that can support a practically
unlimited number of calls. MGCP is the protocol by which a centralized gateway
controller communicates with and controls the numerous gateways throughout a
packet network and manages the network traffic through those gateways. MGCP has
been adopted by large telecommunications companies and Internet service
providers as well as by cable television companies building IP communications
solutions over their networks. Our RADVision MGCP software development kit will
be used to build MGCP compliant gateways. We intend to commercially release our
MGCP software development kit in 2000. We may also develop and introduce in the
future products that are based on other industry standards such as SIP,or
Session Initiation Protocol, to the extent we believe that these products are
feasible and there is a market opportunity for these products.

    RADVISION CARRIER CLASS GATEKEEPERS.  Gatekeepers are generally designed to
manage hundreds of simultaneous voice calls. Large packet networks operated by
telecommunications carriers and service providers require gatekeepers that can
support a practically unlimited number of calls. We are currently enhancing our
RADVision gatekeeper to provide core functionality necessary for large IP
communications networks operated by telecommunications carriers and services
providers. Our carrier class gatekeeper software development kit release will
support high performance, high reliability, carrier class platforms, including
network platforms developed by Cisco, Compaq and Hewlett-Packard. We expect our
customers to introduce systems for creating new IP-based services incorporating
our carrier class gatekeeper in 2000.

CUSTOMERS

    We sell our products to OEMs, systems integrators and value added resellers,
or VARs. Our OEM customers purchase our products to integrate with products that
they developed in-house to build complete IP communications solutions. Our
systems integrator customers either purchase our full suite of products or
integrate our individual products with products of other manufacturers to build
complete IP communications solutions. Our VAR customers purchase our products to
resell to end-users as separate units, or as part of a family of related product
offerings, either under our RADVision label or under their private label.

    We sell our technology in the form of software development kits to
developers of IP communications products, systems and applications for
developing their own IP communications solutions based on our core enabling
technology.

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<PAGE>
    The following is a representative list of our customers who have purchased
more than $200,000 of our products or technology since January 1, 1999:

<TABLE>
<S>                                       <C>                                       <C>
Alcatel                                   Frebon International                      PictureTel
Bosch Telecommunications                  LG Information and                        Philips
Cisco Systems                             Communications                            Shanghai Bell
Computer and Communications               Madge Networks                            Siemens
  Laboratory                              NTT                                       3Com
France Telecom                            Nortel                                    VCON
</TABLE>

SALES AND MARKETING

    SALES ORGANIZATION.  We market and sell our products through multiple
channels in North America, Europe, the Far East and Israel. Our products are
sold to end-users principally through indirect channels by OEMs, system
integrators and value added resellers. We market and sell our technology,
primarily in the form of software development kits, directly to developers of IP
communications products and applications. In Taiwan, Korea and Japan, we sell
our software development kits indirectly through local sales representatives.

    Our sales organization is managed from our corporate headquarters in Tel
Aviv. We currently have sales offices in Tel Aviv, Israel, in Mahwah, New Jersey
and in Sunnyvale, California. We intend to establish a sales office in Asia in
the year 2000. North America is currently our largest market, contributing
approximately 54% of our total sales for the year ended December 31, 1999.

    We have dedicated sales teams to support our larger strategic accounts as
well as to identify potential strategic customers who would deploy our products
on large scales and generate significant revenues for us.

    MARKETING ORGANIZATION.  Our marketing organization develops strategies and
implements programs to support the sale of our products and technology and to
support and enhance our market position as an industry leader. Our current
marketing efforts include various programs designed to increase industry
visibility, including press/analyst tours, trade shows and events, speaking
engagements and ongoing interaction with analysts and the media as well as
targeted marketing programs. Additional programs include technical seminars
where customers and other industry participants are educated in real-time IP
communications technology and the benefits of our products and technology. We
also view our web site as an important marketing tool. We intend to enhance our
web site to create a reference site for IP communications, featuring broad-based
coverage of issues relevant to the IP communications industry, as well as
important product and market trends.

    To reinforce and further strengthen our market position as a technology
leader in the field of real-time IP communications, we actively participate in
key industry consortia. We are a member of the board of directors of the
International Multimedia Telecommunications Consortia, or IMTC, a global
organization to promote interoperable multimedia communications solutions based
on international standards, and are responsible for directing its marketing
activities. We regularly participate in IMTC-sponsored InterOP events, a
vendor-neutral forum where IMTC members test the interoperability of their
products.

    We are also active in defining and reviewing evolving IP communications
standards that are being developed by international standards bodies including:

    - the ITU-T, which has published the H.323 standard;

    - the Internet Engineering Task Force, or IETF, which has published the SIP
      standard; and

    - CableLabs, an organization of cable operators which is currently working
      on defining the MGCP standard.

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<PAGE>
CUSTOMER CARE AND SUPPORT

    Our ability to provide our customers with responsive and qualified customer
care and support services globally is essential to attract and retain customers,
build brand loyalty and maintain our leadership position in the market. We
believe our customer care and support organizational structure enables us to
provide superior technical support and customer service on a cost- and
time-efficient basis.

    We provide global customer care and support for our products and technology.
Our customer care and technical support teams are located in Tel Aviv, Israel,
in Mahwah, New Jersey and in Sunnyvale, California. We assist our customers with
the initial installation, set-up and training. In addition, our technical
support team trains and certifies our customers to provide local support in each
of the geographical areas in which our products are sold. We also provide
customers the option of obtaining, for a fee, 24 hours a day, 7 days a week
help-desk support.

    In addition, customers who purchase our software development kits generally
request that we provide them ongoing engineering and technical support services
to integrate our technology into their products, although these services are not
essential for the use of our software development kits. Our standard software
development kit contract provides for one year of support services, renewable
annually at the customer's option. Customers who have contracted for support
services receive all relevant software updates and enhancements as well as
access to our customer care and technical support teams.

RESEARCH AND DEVELOPMENT

    We place considerable emphasis on research and development to expand the
capabilities of our existing products and technology, to develop new products
and to improve our existing technologies and capabilities. We believe that our
future success will depend upon our ability to maintain our technological
leadership, to enhance our existing products and technology and to introduce on
a timely basis new commercially viable products and technology addressing the
needs of our customers. We intend to continue to devote a significant portion of
our personnel and financial resources to research and development. As part of
our product development process, we seek to maintain close relationships with
our customers to identify market needs and to define appropriate product
specifications.

    As of December 31, 1999, our research and development staff consisted of
approximately 94 employees. Our research and development activities are
conducted at our facilities in Tel Aviv, Israel and in our office in Mahwah, New
Jersey. To introduce new, high quality products, we deploy procedures for the
design, development and quality assurance of our new product developments. Our
team is divided according to our existing product lines. Each product line team
is headed by a team leader and includes software or hardware engineers and
quality control technicians.

MANUFACTURING AND ASSEMBLY

    Our manufacturing operations consist of materials planning and procurement,
out-sourcing of sub-assemblies, final assembly, product assurance testing,
quality control and packaging and shipping. We assemble and test our products at
our facilities in Tel Aviv, Israel. We test our products both during and after
the assembly process using internally developed product assurance testing
procedures. We have a flexible assembly process that enables us to configure our
products at the final assembly stage for customers who require that our products
be modified to bear their private label. This flexibility is designed to reduce
our assembly cycle time and reduce our need to maintain a large inventory of
finished goods. We use an enterprise resource planning, or ERP, system that we
purchased from BAAN Systems that we modified to our specific needs. This system
allows us to use just in time procurement and manufacturing procedures. We
believe that the efficiency of our assembly process to date is largely due to
our product architecture and our commitment to assembly process design. We
manufacture our

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<PAGE>
software development kits on CD-ROMs and package and ship them accompanied by
relevant documentation.

    As part of our commitment to quality, we have been certified as an ISO 9002
supplier. The ISO 9002 standard defines the procedures required for the
manufacture of products with predictable and stable performance and quality. We
are continuously trying to improve our quality based on the guidelines dictated
by the ISO 9002 standard.

INTELLECTUAL PROPERTY

    We rely on copyright, trademark and trade secret laws, confidentiality
agreements and other contractual arrangements with our customers, third-party
distributors, employees and others to protect our intellectual property.

    Despite our efforts to protect our proprietary rights, unauthorized parties
may attempt to copy aspects of our products and technology or obtain and use
information that we regard as proprietary. Policing unauthorized use of our
products and technology is difficult. In addition, the laws of some foreign
countries in which we currently or may in the future sell products do not
protect our proprietary rights to as great an extent as do the laws of the
United States. Our means of protecting our proprietary rights may not be
adequate and our competitors may independently develop similar technology,
duplicate our products or design around our intellectual property.

    We rely on technology that we license from third parties, including software
that is integrated with internally developed software and used in our products
to perform key functions. For example, we license T.120 data collaboration
software from Data Connection Limited and voice compression technology from
Siemens. If we are unable to continue to license any of this software on
commercially reasonable terms, we will face delays in releases of our products
or will be required to reduce the functionality of our products until equivalent
technology can be identified, licensed or developed, and integrated into our
current products.

COMPETITION

    We compete in a new, rapidly evolving and highly competitive and fragmented
market. We expect competition to intensify in the future. We believe that the
main competitive factors in our market are time to market, product quality,
features, cost, technological performance, scalability, compliance with industry
standards and customer relationships.

    The principal competitors in the market for our products and software
development kits currently include:

<TABLE>
<CAPTION>
PRODUCTS                                        SOFTWARE DEVELOPMENT KITS
- ---------------------------------------         ------------------------------------------------------
<S>                                             <C>
- - Ezenia!, formerly known as Video-             - DataBeam, a subsidiary of Lotus/IBM
  Server                                        - DynamicSoft
- - White Pine Software                           - Elemedia, a subsidiary of Lucent
- - In-house developers employed by               - Trillium Digital Systems
  manufacturers of telecommunications
  equipment and systems
</TABLE>

    Other companies, including Accord Networks, have announced products that may
compete with ours. Additional competitors may enter each of our markets at any
time.

    Both Vovida Networks, Inc. and OpenH323 offer H.323 source code for free. In
addition, Vovida offers MGCP and SIP source code for free. If our customers
choose to use the free source code offered by these organizations instead of
purchasing our technology, our revenues from the sale of our software
development kits will decline.

                                       43
<PAGE>
FACILITIES

    Our headquarters and principal administrative, finance, sales and marketing
and promotion operations are located in approximately 25,481 square feet of
leased office space in Tel Aviv, Israel. The expiration dates of the lease of
our principal offices range from August 2000 to December 2000. We intend to
relocate our corporate headquarters in Tel Aviv, Israel to new facilities in
2000. In the United States, we lease approximately 9,000 square feet in Mahwah,
New Jersey expiring in May 2002 and approximately 1,232 square feet in
Sunnyvale, California expiring in December 2002.

EMPLOYEES

    As of December 31, 1999, we had 192 employees worldwide, of whom 94 were
employed in research and development, 53 in sales and marketing, 10 in
management and administration and 35 in operations. We have standard employment
agreements with all of our employees located in Israel. Of our employees, 153
are based in Israel and 39 are based in the United States.

    None of our employees is represented by a labor union. To date, we have not
experienced any work stoppages.

LEGAL PROCEEDINGS

    We are not party to any material legal proceedings.

    In 1998, Lucent sent correspondence to our affiliate, RAD Data
Communications Ltd., alleging that some products manufactured by RAD and some of
its affiliates, including us, infringe upon specified Lucent patents and
offering to license these patents to RAD and its affiliates. In subsequent
correspondence, RAD requested that Lucent specifically substantiate each
allegation of infringement before RAD or any of its affiliates would be prepared
to enter into any licensing arrangements. RAD has recently received further
correspondence from Lucent in which Lucent has reiterated its claims. RAD does
not believe Lucent has substantiated its claims and has communicated this belief
to Lucent. RAD advises us that the alleged infringement claims are unresolved.

    The elements of our products that Lucent has alleged infringe upon its
patents are contained within components which we obtain from a third party
manufacturer. We believe that the third party manufacturer has a license to use
these patents and that we may be entitled to the benefits of this license.

    In addition, based on Lucent's fee and royalty schedule for licensing the
relevant patents, we believe that any licensing fee and royalty payments that we
may be required to pay for the right to use Lucent's patents would not have a
material impact on our earnings. As a result, we do not believe that Lucent's
allegations will have a material adverse effect upon us, our business, financial
condition or liquidity.

                                       44
<PAGE>
                                   MANAGEMENT

DIRECTORS AND EXECUTIVE OFFICERS

    The following table lists our current directors and executive officers:

<TABLE>
<CAPTION>
NAME                            AGE                              POSITION
- ----                          --------   --------------------------------------------------------
<S>                           <C>        <C>
Yehuda Zisapel                   57      Chairman of the Board of Directors

Ami Amir                         55      Chief Executive Officer, President and Director

Eli Doron                        47      Chief Technical Officer and Executive Vice President

Yeshayahu Gordon                 43      Vice President, Global Sales

Michelle Blank                   45      Vice President, Global Marketing

David Seligman                   41      Chief Financial Officer

Yael Langer                      35      General Counsel and Secretary

Zohar Zisapel                    50      Director

Adi Gan                          31      Director

Dan Goldstein                    45      Director

Hillel E. Milo                   49      Director

Efraim Wachtel                   54      Director

Andreas Mattes                   38      Director Nominee
</TABLE>

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

    Adi Gan, Dan Goldstein and Hillel Milo are independent directors.

    Andreas Mattes shall become a director upon the closing of the private
placement.

    YEHUDA ZISAPEL has served as a director of RADVision since November 1992 and
as our chairman of the board of directors since August 1999. Mr. Zisapel is also
a founder and a director of RAD Data Communications Ltd., a leading worldwide
data communications company headquartered in Israel, of which he has served as a
director since 1979, and its affiliate, BYNET Data Communications Ltd.
Mr. Zisapel also serves as the chairman of the board of RIT Technologies Ltd.
and RADWARE Ltd. and as a director of other companies in the RAD-BYNET group,
including SILICOM Ltd. and RADCOM Ltd. Mr. Zisapel has a B.Sc. and an M.Sc.
degree in electrical engineering from the Technion, Israel Institute of
Technology and an M.B.A. degree from Tel Aviv University. Yehuda Zisapel and
Zohar Zisapel are brothers.

    AMI AMIR, our co-founder, has served as our chief executive officer,
president and a director since November 1992. From March 1987 to November 1992,
Mr. Amir was the president of RAD Data Communications Inc. Before March 1987,
Mr. Amir held senior engineering positions for Simtech Advanced Training and
Simulation Systems, Tadiran Electronic Industries and Elbit Systems Ltd.
Mr. Amir has a B.Sc. degree in electronics and computer science from the
Technion Israel Institute of Technology.

    ELI DORON, our co-founder, has served as our executive vice president and
chief technical officer since July 1998. From October 1992 to July 1998,
Mr. Doron was our vice president of research and development. From October 1983
to October 1992, Mr. Doron held senior engineering positions at Simtech Advanced
Training and Simulation Systems. Mr. Doron has a B.Sc. degree in electronics and
computer science from Ben Gurion University.

                                       45
<PAGE>
    YESHAYAHU GORDON has served as our vice president of global sales since May
1999 and as our vice president of sales and marketing since August 1997. From
April 1995 to July 1997, Mr. Gordon was president of RADVision Inc. From
May 1994 to April 1995, Mr. Gordon was president of Radlinx Inc. From
August 1990 to May 1994, Mr. Gordon was the district sales manager for
Orbotech Inc. and, before August 1990, sales representative for DEC Israel.
Mr. Gordon has a B.Sc. degree in physics and computer science from Tel Aviv
University.

    MICHELLE BLANK has served as our vice president of global marketing since
May 1999. From June 1997 to May 1999, Ms. Blank was president of RADVision Inc.
From September 1990 to June 1997, Ms. Blank acted as an independent consultant
to several technology companies. Ms. Blank has a Ph.D. degree in cognitive
science from The University of Texas.

    DAVID SELIGMAN has served as our chief financial officer since
November 1999. From July 1996 until November 1999, Mr. Seligman was the chief
financial officer and secretary of LanOptics Ltd. From October 1993 until
June 1996, Mr. Seligman was a senior financial analyst for Fidelity Investments
Systems Company. Mr. Seligman has a B.A. in political science and geography and
an M.B.A. in accounting and finance from Tel Aviv University.

    YAEL LANGER has served as our general counsel since July 1998. Ms. Langer is
also general counsel and secretary of RAD and other companies in the RAD-BYNET
group. From December 1995 to July 1998, Ms. Langer served as assistant general
counsel to companies in the RAD-BYNET group. From September 1993 until
July 1995, Ms. Langer was a member of the legal department of Poalim Capital
Markets and Investments Ltd. Ms. Langer has an LL.B. degree from the Hebrew
University in Jerusalem.

    ZOHAR ZISAPEL has served as a director of RADVision since November 1992 and
was chairman of the board of directors until August 1999. Mr. Zisapel is also a
founder and a director of RAD, of which he has served as president since
January 1982, and a director of other companies in the RAD-BYNET group,
including RADCOM, SILICOM, RIT and RADWARE. Mr. Zisapel previously served as
head of the electronics research department in the Israeli Ministry of Defense.
Mr. Zisapel received B.Sc. and M.Sc. degrees in electrical engineering from the
Technion, Israel Institute of Technology and an M.B.A. degree from Tel Aviv
University. Zohar Zisapel and Yehuda Zisapel are brothers.

    ADI GAN has served as a director of RADVision since August 1998. Since
January 1998, Mr. Gan has been an investment manager with Evergreen's Venture
Capital Group. From August 1995 until January 1998, Mr. Gan was employed by
TesCom Ltd., initially as a project manager and then as a manager of the
real-time system division of TesCom Ltd. Mr. Gan has a B.Sc. in physics from the
Technion, Israel Institute of Technology, and a M.Sc. in chemistry from Tel Aviv
University.

    DAN GOLDSTEIN has served as a director of RADVision since January 2000. In
1985, Mr. Goldstein founded Formula Systems (1985) Ltd. and has been its chief
executive officer and chairman of the board of directors since that time.
Mr. Goldstein is also the chairman of the board of directors of other companies
in the Formula Systems group, including ForSoft Ltd., Sintec Advanced
Technologies Ltd., F.C.T. Formula Computer Technologies Ltd. and Applicom
Software Industries (1990) Ltd., and is a director of Crystal Systems Solutions
Ltd. Mr. Goldstein has a B.Sc. degree in mathematics and computer science and an
M.B.A. in business administration from Tel Aviv University.

    HILLEL E. MILO has served as a director of RADVision since May 1995. Until
July 1999, Mr. Milo was president and chief executive officer of Israel Infinity
Venture Capital Fund. Since January 1995, Mr. Milo has been chief executive
officer and managing director of Clal Venture Capital Fund L.P. In 1993,
Mr. Milo co-founded Walden Israel Venture Capital fund and has been the general
partner of that fund since that time. Mr. Milo has a B.Sc. in mechanical
engineering and a M.A. in management science from the University of Alabama.

                                       46
<PAGE>
    EFRAIM WACHTEL has served as a director of RADVision since March 1998.
Mr. Wachtel has been president and chief executive officer of RAD since
November 1997. From October 1985 to November 1997, Mr. Wachtel was vice
president of sales and marketing of RAD. Before October 1985, Mr. Wachtel held
various research and development positions in several companies in Israel and in
the U.S. Mr. Wachtel has a B.Sc. degree in electrical engineering from the
Technion, Israel Institute of Technology.

    ANDREAS MATTES will be appointed a director of RADVision effective upon the
closing of the private placement. Since April 1999, Mr. Mattes has been the
president of enterprise networks of Siemens ICN. From October 1998 until April
1999, Mr. Mattes was the president of central sales of Siemens ICN. From June
1997 until October 1998, Mr. Mattes was the president of international sales of
Siemens PN. From January 1996 until June 1997, Mr. Mattes was the vice president
of product management of Siemens PN. From October 1985 until January 1996,
Mr. Mattes held various sales, marketing and business administration positions
at Siemens.

BOARD OF DIRECTORS

    Our articles of association to be adopted before the consummation of this
offering provide that directors are elected at our annual general meeting of the
shareholders by a vote of the holders of a majority of the voting power
represented at that meeting. Each director, except for the external directors
described below, holds office until the next annual general meeting of the
shareholders.

INDEPENDENT DIRECTORS

    Upon the completion of this offering, our ordinary shares will be listed for
quotation on the Nasdaq National Market and we will be subject to the rules of
the Nasdaq National Market applicable to listed companies. Under the Nasdaq
rules, we are required to appoint a minimum of three independent directors. The
independence standard under the Nasdaq rules excludes any person who is a
current or former employee of a company or its affiliates as well as the
immediate family members of an executive officer of a company or its affiliates.
Our three independent directors, Adi Gan, Dan Goldstein and Hillel Milo, meet
the independence standard of the Nasdaq rules.

ISRAELI COMPANIES LAW

    We are subject to the provisions of the new Israeli Companies Law,
5759-1999, which became effective on February 1, 2000 and supersedes most of the
provisions of the Israeli Companies Ordinance (New Version), 5743-1983. The
Companies Law authorizes the minister of justice to adopt regulations exempting
from the provisions described below companies, like us, whose shares are traded
outside of Israel.

EXTERNAL DIRECTORS

    QUALIFICATIONS OF EXTERNAL DIRECTORS

    Under the Companies Law, companies incorporated under the laws of Israel
whose shares have been offered to the public in or outside of Israel are
required to appoint two external directors. The Companies Law provides that a
person may not be appointed as an external director if he or his relative,
partner, employer or any entity under his control has or had during the two
years preceding the date of appointment any affiliation with:

    - the company;

    - any entity controlling the company; or

    - any entity controlled by the company or by this controlling entity.

                                       47
<PAGE>
    The term affiliation includes:

    - an employment relationship;

    - a business or professional relationship maintained on a regular basis;

    - control; and

    - service as an office holder.

    No person can serve as an external director if the person's position or
other business creates, or may create, conflict of interests with the person's
responsibilities as an external director.

    Until the lapse of two years from termination of office, a company may not
engage an external director to serve as an office holder and cannot employ or
receive services from that person, either directly or indirectly, including
through a corporation controlled by that person.

    ELECTION OF EXTERNAL DIRECTORS

    External directors are to be elected by a majority vote at a shareholders'
meeting, provided that either:

    - the majority of shares voted at the meeting, including at least one third
      of the shares of non-controlling shareholders voted at the meeting, vote
      in favor of the election; or

    - the total number of shares voted against the election of the external
      director does not exceed one percent of the aggregate voting rights in the
      company.

    The initial term of an external director is three years and may be extended
for an additional three years. Each committee of a company's board of directors
is required to include at least one external director. Under the provisions of
the Companies Law, we are required to designate the initial external directors
at a shareholders' meeting to be convened no later than August 1, 2000. We
intend to elect two directors as external directors after this offering.

AUDIT COMMITTEE

    NASDAQ REQUIREMENTS

    Under the Nasdaq rules, we are required to form an audit committee
consisting of at least three independent directors, all of whom are financially
literate and one of whom has accounting or related financial management
expertise. The responsibilities of the audit committee under the Nasdaq rules
include evaluating the independence of a company's outside auditors. Our current
audit committee complies with the Nasdaq rules. In addition, we are required to
adopt an audit committee charter. We have adopted an audit committee charter
that complies with Nasdaq specifications.

    COMPANIES LAW REQUIREMENTS

    Under the Companies Law, the board of directors of any company that is
required to nominate external directors must also appoint an audit committee,
comprised of at least three directors including all of the external directors,
but excluding a:

    - chairman of the board of directors;

    - general manager;

    - chief executive officer; and

    - controlling shareholder and any director employed by the company or who
      provides services to the company on a regular basis.

                                       48
<PAGE>
    The role of the audit committee is to examine flaws in the business
management of the company, in consultation with the internal auditor and the
company's independent accountants, and suggest appropriate course of action.

    APPROVAL OF INTERESTED PARTY TRANSACTIONS

    The approval of the audit committee is required to effect specified actions
and transactions with office holders and interested parties. An interested party
is defined in the Companies Law as a 5% or greater shareholder, any person or
entity who has the right to designate one director or more or the general
manager of the company or any person who serves as a director or as a general
manager. An audit committee may not approve an action or a transaction with an
interested party or with an office holder unless at the time of approval the two
external directors are serving as members of the audit committee and at least
one of whom was present at the meeting in which an approval was granted.

INTERNAL AUDITOR

    Under the Companies Law, the board of directors must appoint an internal
auditor proposed by the audit committee. The role of the internal auditor is to
examine, whether the company's actions comply with the law, integrity and
orderly business procedure. Under the Companies Law, the internal auditor may
not be an interested party, an office holder, or an affiliate, or a relative of
an interested party, an office holder or affiliate, nor may the internal auditor
be the company's independent accountant or its representative. We intend to
appoint an internal auditor that complies with the requirements of the Companies
Law after this offering.

APPROVAL OF SPECIFIED RELATED PARTY TRANSACTIONS UNDER ISRAELI LAW

    FIDUICIARY DUTIES OF OFFICE HOLDERS

    The Companies Law imposes a duty of care and a duty of loyalty on all office
holders of a company, including directors and executive officers. The duty of
care requires an office holder to act with the level of care which a reasonable
office holder in the same position would have acted under the same
circumstances. The duty of care includes a duty to use reasonable means to
obtain:

    - information on the appropriateness of a given action brought for his
      approval or performed by him by virtue of his position; and

    - all other important information pertaining to these actions.

    The duty of loyalty of an office holder includes a duty to:

    - refrain from any conflict of interest between the performance of his
      duties in the company and his personal affairs;

    - refrain from any activity that is competitive with the company;

    - refrain from exploiting any business opportunity of the company to receive
      a personal gain for himself or others; and

    - disclose to the company any information or documents relating to a
      company's affairs which the office holder has received due to his position
      as an office holder.

    Each person listed in the table under "--Directors and Executive Officers"
above is an office holder.

                                       49
<PAGE>
    DISCLOSURE OF PERSONAL INTERESTS OF AN OFFICE HOLDER

    The Companies Law requires that an office holder of a company promptly
disclose any personal interest that he may have and all related material
information known to him relating to any existing or proposed transaction by the
company. If the transaction is an extraordinary transaction, the office holder
must also disclose any personal interest held by:

    - the office holder's spouse, siblings, parents, grandparents, descendants,
      spouse's descendants and the spouses of any of these people; or

    - any corporation in which the office holder is a 5% or greater shareholder,
      director or general manager or in which he has the right to appoint at
      least one director or the general manager.

    Under Israeli law, an extraordinary transaction is a transaction:

    - other than in the ordinary course of business;

    - otherwise than on market terms; or

    - that is likely to have a material impact of the company's profitability,
      assets or liabilities.

    Under the Companies Law, once an office holder complies with the above
disclosure requirement, the board of directors may approve a transaction between
the company and an office holder, or a third party in which an office holder has
a personal interest, unless the articles of association provide otherwise. A
transaction that is adverse to the company's interest may not be approved.

    If the transaction is an extraordinary transaction, both the audit committee
and the board of directors must approve the transaction. Under specific
circumstances, shareholder approval may also be required. An office holder who
has a personal interest in a matter, which is considered at a meeting of the
board of directors or the audit committee, may not be present at this meeting or
vote on this matter.

    DISCLOSURE OF PERSONAL INTERESTS OF A CONTROLLING SHAREHOLDER

    Under the Companies Law, the disclosure requirements which apply to an
office holder also apply to a controlling shareholder of a public company. A
controlling shareholder includes a shareholder that holds 25% or more of the
voting rights in a public company if no other shareholder owns more than 50% of
the voting rights in the company. Extraordinary transactions with a controlling
shareholder or in which a controlling shareholder has a personal interest, and
the terms of compensation of a controlling shareholder who is an office holder,
require the approval of the audit committee, the board of directors and the
shareholders of the company. The shareholder approval may include either:

    - at least one-third of the shareholders who have no personal interest in
      the transaction and are present and voting, in person, by proxy or by
      written ballot, at the meeting; or

    - a majority of the voting power present and voting, provided that the
      shareholders who have no personal interest in the transaction who vote
      against the transaction do not represent more than one percent of the
      voting rights in the company.

EXCULPATION, INSURANCE AND INDEMNIFICATION OF DIRECTORS AND OFFICERS

    Under the Companies Law, an Israeli company may not exempt an office holder
from liability for a breach of his duty of loyalty, but may exempt in advance an
office holder from his liability to the company, in whole or in part, for a
breach of his duty of care.

                                       50
<PAGE>
    OFFICE HOLDER INSURANCE

    Our articles of association provide that, subject to the provisions of the
Companies Law, we may enter into a contract for the insurance of the liability
of any of our office holders for:

    - a breach of his duty of care to us or to another person;

    - a breach of his duty of loyalty to us, provided that the office holder
      acted in good faith and had reasonable cause to assume that his act would
      not prejudice our interests; or

    - a financial liability imposed upon him in favor of another person
      concerning an act performed by him in his capacity as an office holder.

    INDEMNIFICATION OF OFFICE HOLDERS

    Our articles of association provide that we may indemnify an office holder
against:

    - a financial liability imposed on him in favor of another person by any
      judgment concerning an act performed in his capacity as an office holder;
      and

    - reasonable litigation expenses, including attorneys' fees, expended by the
      office holder or charged to him by a court relating to an act performed in
      his capacity as an office holder, resulting from:

       - proceedings we institute against him or instituted on our behalf or by
         another person;

       - a criminal charge from which he was acquitted; or

       - a criminal charge in which he was convicted for a criminal offense that
         does not require proof of intent.

    Our articles of association also include the following:

    - We are authorized to grant in advance an undertaking to indemnify an
      office holder, provided that the undertaking is:

       - limited to specified events which the board of directors determines to
         be anticipated; and

       - limited in amount determined by the board of directors to be reasonable
         under the circumstances.

    - We are authorized to indemnify retroactively an office holder.

    LIMITATIONS ON INSURANCE AND INDEMNIFICATION

    The Companies Law provides that a company may not indemnify an office holder
nor enter into an insurance contract which would provide coverage for any
monetary liability incurred as a result of any of the following:

    - a breach by the office holder of his duty of loyalty unless the office
      holder acted in good faith and had a reasonable basis to believe that the
      act would not prejudice the company;

    - a breach by the office holder of his duty of care if the breach was done
      intentionally or recklessly;

    - any act or omission done with the intent to derive an illegal personal
      benefit; or

    - any fine levied against the office holder.

                                       51
<PAGE>
    In addition, under the Companies Law, indemnification of, and procurement of
insurance coverage for, our office holders must be approved by our audit
committee and our board of directors and, in specified circumstances, by our
shareholders.

    We have agreed to indemnify our office holders to the fullest extent
permitted under the Companies Law. Before this offering, we intend to obtain
directors and officers liability insurance for the benefit of our office
holders.

COMMITTEES

    Our board of directors has formed an audit committee, a share incentive
committee, an option committee, an executive committee and a compensation
committee.

    Our audit committee, which consists of Adi Gan, Dan Goldstein and Hillel
Milo, our three independent directors, exercises the powers of the board of
directors in matters relating to our accounting, reporting and financial control
practices. Upon the appointment of our external directors under the Companies
Law, the external directors will also serve on our audit committee.

    Our share incentive committee, which consists of Yehuda Zisapel, Hillel Milo
and Ami Amir, administers our key employee share incentive plan.

    Our option committee, which consists of Yehuda Zisapel, Hillel Milo and Ami
Amir, administers our consultants option plan.

    Our executive committee, which consists of Yehuda Zisapel, Hillel Milo and
Ami Amir, is responsible for managing our daily operations and acting on behalf
of our board of directors in exigent circumstances.

    Our compensation committee, which consists of Yehuda Zisapel and Hillel
Milo, sets the annual compensation for Ami Amir, our chief executive officer.

COMPENSATION OF DIRECTORS AND OFFICERS

    The following table presents all compensation we paid to all of our
directors and officers as a group for the year ended December 31, 1999. The
table does not include any amounts we paid to reimburse any of our affiliates
for costs incurred in providing us with services during this period, including
services provided by Yael Langer who is also our officer.

<TABLE>
<CAPTION>
                                                                                 PENSION,
                                                                                RETIREMENT
                                                              SALARIES, FEES,   AND OTHER
                                                              COMMISSIONS AND    SIMILAR
                                                                  BONUSES        BENEFITS
                                                              ---------------   ----------
<S>                                                           <C>               <C>
All directors and officers as a group, consisting of eleven
  persons...................................................      $628,000        $73,000
</TABLE>

    As of December 31, 1999, our directors and executive officers as a group,
consisting of eleven persons, held options to purchase an aggregate of 320,298
ordinary shares. All our officers work full time for us except Yael Langer, who
is also an officer of other companies in the RAD-BYNET group. Ms. Langer devotes
between 15% to 30% of her time to us. Other than reimbursement for expenses, we
do not compensate our directors for serving on our board of directors.

    Under the Companies Law, the board of directors must approve all
compensation arrangements of office holders who are not directors. Directors'
compensation arrangements also require audit committee approval before board
approval and shareholder approval.

                                       52
<PAGE>
KEY EMPLOYEE SHARE INCENTIVE PLAN

    GENERAL

    In April 1996, we adopted our key employee share incentive plan. Employees
of RADVision and its subsidiaries or of affiliates of RADVision belonging to the
RAD-BYNET group are eligible to participate in the plan. Options granted under
this plan are for a term of sixty-two months from the date of the grant of the
option. The following table presents option grant information for this plan as
of December 31, 1999:

<TABLE>
<CAPTION>
ORDINARY SHARES RESERVED                     WEIGHTED AVERAGE
   FOR OPTION GRANTS       OPTIONS GRANTED    EXERCISE PRICE
- ------------------------   ---------------   ----------------
<S>                        <C>               <C>
       3,163,523              3,038,323           $2.86
</TABLE>

    The 3,163,523 ordinary shares indicated in the table as having been reserved
for option grants reflect the total number of ordinary shares reserved for
grants under this plan and our consultants option plan in the aggregate. After
December 31, 1999, 52,750 of the 3,038,323 options granted were exercised. We
intend to grant further options under this plan to our executive officers and
employees.

    PLAN ADMINISTRATION

    The share incentive committee of our board of directors administers the
plan. Under the plan, the committee has the authority to determine, in its
discretion:

    - the persons to whom options are granted;

    - the number of shares underlying each option award;

    - the time or times at which the award shall be made;

    - the exercise price, vesting schedule and conditions under which the
      options may be exercised; and

    - any other matter necessary or desirable for the administration of the
      plan.

    OPTION TRUST

    Under the plan, all options, or shares issued upon exercise of options, are
held in trust and registered in the name of a trustee selected by the share
incentive committee. The trustee may not release the options or ordinary shares
to the beneficiaries of these options or shares before the later of:

    - the second anniversary of the registration of the options in the name of
      the trustee; and

    - the initial public offering of our ordinary shares.

    During this period, voting rights attached to the ordinary shares issued
upon exercise of the options may be exercised by the trustee.

    TERMINATION AND AMENDMENT

    Our board of directors may terminate or amend the plan, provided that any
action by our board of directors, which will alter or impair the rights of an
option holder, requires the prior consent of that option holder.

CONSULTANTS OPTION PLAN

    GENERAL

    In March 1999, we adopted our consultants option plan. Our employees and
directors and consultants employed by us are eligible to participate in the
plan. Options granted under the plan are

                                       53
<PAGE>
for a term of sixty-two months from the date of grant of the option. The
following table presents option grant information for this plan as of
December 31, 1999:

<TABLE>
<CAPTION>
ORDINARY SHARES RESERVED                     WEIGHTED AVERAGE
   FOR OPTION GRANTS       OPTIONS GRANTED    EXERCISE PRICE
- ------------------------   ---------------   ----------------
<S>                        <C>               <C>
       3,163,523               63,300             $1.18
</TABLE>

    The 3,163,523 ordinary shares indicated in the table as having been reserved
for option grants reflect the total number of ordinary shares reserved for
grants under this plan and our key employee share incentive plan in the
aggregate.

    PLAN ADMINISTRATION

    The option committee of our board of directors administers the plan. Under
the plan, the committee has the authority to determine, in its discretion:

    - the persons to whom options are granted;

    - the number of shares underlying each option award;

    - the time or times at which the award shall be made;

    - the exercise price, vesting schedule and conditions under which the
      options may be exercised; and

    - any other matter necessary or desirable for the administration of the
      plan.

    OPTION TRUST

    Under the plan, all options, or shares issued upon exercise of options, are
held in trust and registered in the name of a trustee selected by the option
committee. The trustee may not release the options or ordinary shares to the
beneficiaries of these options or shares before the initial public offering of
our ordinary shares.

    During this period, voting rights attached to the ordinary shares issued
upon exercise of the options may be exercised by the trustee.

    TERMINATION AND AMENDMENT

    Our board of directors may terminate or amend the plan, provided that any
action by our board of directors, which will alter or impair the rights of an
option holder, requires the prior consent of that option holder.

EMPLOYMENT AGREEMENTS

    At the start of their employment, our employees in North America generally
sign offer letters specifying basic terms and conditions of employment as well
as non-disclosure agreements. At the start of their employment, our employees in
Israel generally sign written employment agreements that include confidentiality
and non-compete provisions.

                                       54
<PAGE>
                             PRINCIPAL SHAREHOLDERS

    The following table presents information covering the beneficial ownership
of our ordinary shares as of the date of this prospectus, as adjusted to reflect
the sale of the ordinary shares in this offering and the concurrent private
placement, by:

    - each person who is known to own beneficially more than 5% of the
      outstanding ordinary shares; and

    - all directors and executive officers as a group.

    The percentage of ordinary shares in the table below is based on:

    - 13,637,774 ordinary shares outstanding before this offering and the
      concurrent private placement; and

    - 18,028,596 ordinary shares outstanding immediately following this offering
      and the concurrent private placement.

    Total shares beneficially owned in the table below include shares that may
be acquired upon the exercise of options that are exercisable within 60 days of
the date of this prospectus. The shares that may be issued under these options
are treated as outstanding only for purposes of determining the percent owned by
the person or group holding the options but not for the purpose of determining
the percentage ownership of any other person or group.

    Unless otherwise noted below, each shareholder's address is c/o
RADVision Ltd., 24 Raoul Wallenberg St., Tel Aviv 69719, Israel.

<TABLE>
<CAPTION>
                                                      TOTAL SHARES                      PERCENTAGE OF
                                                   BENEFICIALLY OWNED                  ORDINARY SHARES
                                            --------------------------------   --------------------------------
                                            BEFORE OFFERING   AFTER OFFERING   BEFORE OFFERING   AFTER OFFERING
                                              AND PRIVATE      AND PRIVATE       AND PRIVATE      AND PRIVATE
NAME                                           PLACEMENT        PLACEMENT         PLACEMENT        PLACEMENT
- ----                                        ---------------   --------------   ---------------   --------------
<S>                                         <C>               <C>              <C>               <C>
Yehuda Zisapel (1)........................     3,000,209         2,432,097           22.0%            13.5%
Zohar Zisapel (2).........................     3,141,368         2,545,977           23.0             14.1
Siemens Aktiengesellschaft (3)............            --         1,625,228             --              9.0
Clal Venture Capital Fund LP (4)..........     1,244,900         1,004,330            9.1              5.6
Evergreen group (5).......................     1,167,463           941,858            8.6              5.2
Samsung entities (6)......................            --         1,000,000             --              5.5
All directors and executive officers as a
  group
  (12 persons) (7)........................     9,075,110         7,983,278           66.5             44.3
</TABLE>

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

(1) After giving effect to the private placement, includes 470,249 ordinary
    shares owned of record by RAD Data Communications Ltd.

(2) After giving effect to the private placement, includes:

    - 470,249 ordinary shares owned of record by RAD Data Communications Ltd.;

    - 571,106 ordinary shares owned of record by Michael and Klil Holdings
      (93) Ltd.; and

    - 571,106 ordinary shares owned of record by Lomsha Ltd.

(3) The address of Siemens Aktiengesellschaft is Hofmannstrasse 51, D-81359,
    Munich, Germany.

(4) The address of Clal Venture Capital Fund LP is Atidim Technological Park,
    Building No. 4, Tel Aviv, Israel. Hillel Milo, chief executive officer and
    managing director of Clal Venture Capital Fund LP and a director of
    RADVision, disclaims beneficial ownership of the ordinary shares held by
    Clal Venture Capital Fund LP except to the extent of his proportional
    interest in the ordinary shares.

                                       55
<PAGE>
(5) After giving effect to the private placement, consists of:

    - 29,960 ordinary shares owned by Evergreen Canada-Israel Management Ltd.;

    - 127,839 ordinary shares owned by the Periscope I Fund, Israeli
      Partnership;

    - 498,931 ordinary shares owned by the Periscope I Fund, L.P.; and

    - 285,128 ordinary shares owned by IJT Technologies Ltd.

    The address of the Evergreen group is 96 Rothschild Avenue, Tel Aviv,
    Israel. Adi Gan, an investment manager of the Evergreen group's venture
    capital group and a director of RADVision, disclaims beneficial ownership of
    the ordinary shares held by the Evergreen group except to the extent of his
    proportional interest in the ordinary shares.

(6) After giving effect to the private placement, consists of:

    - 510,000 ordinary shares owned by Samsung Electro-Mechanics Co. Ltd.; and

    - 490,000 ordinary shares owned by Samsung Venture Investment Corporation.

   The address of Samsung Electro-Mechanics Co. Ltd. is 314 Maetan 3-Dong,
    Paldal-Gu, Suwon, Kyunggi-D, Korea 442-743. The address of Samsung Venture
    Investment Corporation is Samsung Yeok Sam Bldg. 647-9, Yeok Sam-Dong, Kang
    Nam-Gu, Korea 135-080.

(7) Includes 152,764 ordinary shares issuable upon the exercise of options
    exercisable within 60 days of the date of this prospectus.

                                       56
<PAGE>
                           RELATED PARTY TRANSACTIONS

THE RAD-BYNET GROUP

    Yehuda and Zohar Zisapel are directors and principal shareholders of
RADVision. Individually or together, they are also directors and principal
shareholders of several other companies which, together with us and the other
subsidiaries and affiliates, are known as the RAD-BYNET group. These
corporations include:

    AB-NET Ltd.

    BYNET Data Communications Ltd.

    BYNET Electronics Ltd.

    BYNET SEMECH Ltd.

    BYNET Systems Applications Ltd.

    Commerce.net Ltd.

    Giganet Ltd.

    IP-RAD Ltd.

    RADCOM Ltd.

    RAD Data Communications

    RADGuard Ltd.

    RADLAN Computer Communications Ltd.

    RAD Network Devices

    RAD-OP Ltd.

    RADView Software Ltd.

    RADWARE Ltd.

    RADWIN Ltd.

    RIT Technologies Ltd.

    RND Networks

    SILICOM Ltd.

    In addition to engaging in other businesses, members of the RAD-BYNET group
are actively engaged in designing, manufacturing, marketing and supporting data
communications products, none of which currently compete with our products. Some
of the products of members of the RAD-BYNET group are complementary to, and may
be used in connection with, our products.

    Members of the RAD-BYNET group provide us with legal, human resources and
administrative services, and we reimburse each company for its costs in
providing these services. The aggregate amount of these reimbursements was
approximately $155,000, $152,000 and $196,000 in 1997, 1998 and 1999.

  AGREEMENT WITH RADCOM LTD.

    In January 1999, we entered into an agreement to license our H.323 software
development kit to RADCOM Ltd., an affiliated company controlled by Yehuda and
Zohar Zisapel and a member of the RAD-BYNET group. The agreement, which was
based on our standard form, provides for an aggregate fee of $187,000. This fee
includes maintenance and support services for one year and minimum royalty
payments on sales of products which incorporate the technology contained in the
software development kit during the first two years of the agreement. In
addition, the agreement provides that RADCOM has an option to extend the
maintenance and support services for additional annual periods as well as an
option to purchase additional RADVision products and technology at specified
discounts.

  LEASE ARRANGEMENTS

    We lease from RIT Technologies Ltd., RAD Data Communication Ltd. and several
other companies, all of which are affiliated companies controlled by Yehuda
Zisapel and Zohar Zisapel and members of the RAD-BYNET group, office space of
approximately 21,830 square feet in Tel Aviv, Israel, for an aggregate monthly
rent of approximately $40,000. The expiration dates of these lease agreements
range from August 2000 to December 2000. Under most of these lease agreements,
we have the option to extend the term of the lease for additional periods.

    We lease from RAD Data Communications, an affiliated company controlled by
Yehuda Zisapel and Zohar Zisapel and a member of the RAD-BYNET group,
approximately 9,000 square feet for our facility in New Jersey, for a monthly
rent of approximately $6,500. The term of the lease is five years, commencing
May 1997 and terminating in May 2002. The monthly rent payments include a 15%
intra-group discount. If the property is sold, this discount would no longer
apply and our monthly payments will increase.

                                       57
<PAGE>
  SUPPLY ARRANGEMENT


    We purchase from RAD Data Communications components which we integrate into
our multimedia RADVision products. The aggregate purchase price of these
components was approximately $252,000 for the year ended December 31, 1998, and
approximately $301,000 for the year ended December 31, 1999.


    We generally ascertain the market prices for goods and services that can be
obtained at arms length from unaffiliated third parties before entering into any
transaction with a member of the RAD-BYNET group for those goods and services.
In addition, all of our transactions to date with members of the RAD-BYNET group
were approved unanimously by our shareholders. As a result, we believe that the
terms of the transactions in which we have engaged and are currently engaged
with other members of the RAD-BYNET group are beneficial to us and no less
favorable to us than terms which might be available to us from unaffiliated
third parties. Any future transaction and arrangement with entities, including
other members of the RAD-BYNET group, in which our office holders have a
personal interest will require approval by our audit committee, our board of
directors and, if applicable, our shareholders.

PRIVATE PLACEMENTS

  1995

    In April 1995, we issued in a private placement to investors, including RAD
Data Communications Ltd. and Clal Venture Capital Fund LP, an aggregate of
5,159,583 ordinary shares for an aggregate purchase price of approximately
$4.9 million, or $0.95 per share.

  1996

    In September 1996, we agreed to issue in a private placement to new
investors and existing shareholders, including Clal Venture Capital Fund LP, an
aggregate of 1,030,946 ordinary shares at an aggregate purchase price of
approximately $1.6 million, or $1.55 per share. Out of the aggregate 1,030,946
shares, we issued 714,235 shares during September and October 1996. Under an
agreement with Intel Corporation, we issued an additional 158,461 shares in
November 1997 and an additional 158,250 shares in December 1999 in exchange for
an additional aggregate investment in us of $500,000.

  1997

    In May through July 1997, we issued in a private placement to existing
shareholders, including RAD Data Communications Ltd., Zohar Zisapel and Clal
Venture Capital Fund LP, an aggregate of 269,447 ordinary shares at an aggregate
purchase price of approximately $650,000, or $2.41 per share.

  1998

    In May 1998, we issued in a private placement to new investors and existing
shareholders, including the Evergreen group, Zohar Zisapel, RAD Data
Communications Ltd. and Clal Venture Capital Fund LP, an aggregate of 2,957,165
preferred shares at an aggregate purchase price of approximately $5 million, or
$1.69 per share. We also issued 121,114 ordinary shares at NIS 0.1 per share to
the May 1997 investors as an anti-dilution adjustment to the shares they
purchased in the May 1997 private placement.

                                       58
<PAGE>
REGISTRATION RIGHTS

  1995

    In the private placement of our ordinary shares in April 1995, several of
our shareholders were granted registration rights for their ordinary shares. The
agreements grant registration rights to each of:

    - Yehuda Zisapel, Zohar Zisapel, RAD Data Communications Ltd. and the
      employees' trust, as a group;

    - Clal Venture Capital Fund LP and ECI Telecom Ltd., as a group; and

    - other shareholder groups specified in the agreements.

    Under the agreements, each of these shareholder groups will have the right
to make a single demand for the registration of their ordinary shares
outstanding at the time of this offering, provided that:

    - the shareholder group owns at least 2% of our outstanding share capital;
      and

    - the demand covers shares representing a market value of at least
      $3 million and does not include shares which may be sold without
      restriction within three months from the date of the demand.

    The shareholders' rights will be exercisable at any time commencing on the
first anniversary of the consummation of this offering and for a period of three
years. In addition, each of the investors in the April 1995 private placement
has the right to have its ordinary shares included in some of our registration
statements, provided that the shareholder owns at least 2% of our outstanding
share capital at the time it exercises this right.

  1996

    In the private placement of our ordinary shares in September 1996, Intel
Corporation was granted registration rights for their ordinary shares. The
agreement provides for registration rights on the same terms and conditions as
contained in the private placement agreements of April 1995.

  1998

    In the private placement of our preferred shares in May 1998, several of our
shareholders were granted registration rights for the ordinary shares
outstanding or to be issued upon conversion of their preferred shares, which
represent 2,957,165 ordinary shares in the aggregate.

    The agreement provides that the purchasers of the preferred shares in
May 1998, as a group, will have the right to make a demand on two occasions for
the registration of their ordinary shares outstanding at the time of this
offering, provided that:

    - the demand covers shares representing a market value of at least
      $3 million; and

    - the demand does not include shares which may be sold without restriction
      within three months from the date of the demand.

    The shareholders' rights will be exercisable at any time commencing on the
first anniversary of the consummation of this offering and for a period of three
years or, in specified cases, for a period of five years. In addition, each of
the investors in the May 1998 private placement has the right to have its
ordinary shares included in some of our registration statements. The agreement
also provides that if subsequent investors in RADVision are granted more
favorable terms concerning demand or other registration rights, each of the
investors will be granted identical rights, for so long as they own at least 5%
of our outstanding shares at that time.

                                       59
<PAGE>
AGREEMENTS WITH OUR CHIEF EXECUTIVE OFFICER

  FOUNDERS AGREEMENT

    In January 1992, Messrs. Yehuda and Zohar Zisapel entered into an agreement
with Ami Amir, under which Ami Amir agreed to serve as our chief executive
officer for a period of not less than 5 years. In consideration for his
services, Zohar Zisapel and Yehuda Zisapel transferred 11% of our then
outstanding share capital to Ami Amir. The agreement provides that so long as
Ami Amir is our shareholder or director, he may not engage in business
activities that compete with us or pertain to data communications. In addition,
none of the parties may disclose to third parties information pertaining to our
business. The agreement also gives each of Messrs. Yehuda and Zohar Zisapel and
Ami Amir a right of first refusal if any of them offers to transfer their shares
to a third party.

  GRANT OF SECURITIES

    Under agreements between us, Messrs. Yehuda and Zohar Zisapel and Ami Amir
dated April 7, 1995 and January 1, 1999, we issued 196,652 ordinary shares and
granted 119,848 options to Ami Amir. The shares and options will vest over a
five year period, commencing January 1, 1999. This five-year period will be
reduced by a factor of two upon the consummation of this offering.

  LOAN AGREEMENT

    In July 1997, we entered into an agreement with Ami Amir under which we
loaned him approximately $66,000 at an annual interest rate of 1% linked to the
Israel consumer price index. The loan is scheduled to be repaid upon the earlier
of the termination of his employment with us or the sale by Ami Amir of all or
any portion of his shares of RADVision. As of December 31, 1999, the outstanding
balance of this loan was approximately $65,000, consisting of principal and
accrued interest. Ami Amir's shares of RADVision serve as collateral for the
payment of the loan.

VOTING AGREEMENT

    Upon the completion of the private placement, Siemens and some of our
existing shareholders, including our chairman of the board, our chief executive
officer, the Evergreen group, Clal Venture Capital Fund LP and Zohar Zisapel,
will enter into a voting agreement. The voting agreement provides that, in the
election of our directors, the shareholders party to the agreement will nominate
and vote for a nominee of Siemens to serve as a director and as many other
nominees as the other shareholders party to the agreement shall unanimously
propose to serve as directors. However, the number of directors that the other
shareholders propose to serve as directors shall at a minimum be equal to the
number of directors which these shareholders have appointed to the board at the
date of this prospectus. If all directors, except for one director, decide that
the continuation of a director on our board may damage our business prospects,
then the director shall be removed from our board.

    The voting agreement expires three years following the date of this
prospectus, provided that it shall be automatically extended for two additional
one-year periods, unless any of the parties to the agreement notifies each of
the other parties 60 days before the expiration date of the then current term.
After giving effect to this offering and the concurrent private placement,
8,608,642 ordinary shares, representing approximately 47.7% of the outstanding
shares, will be subject to the voting agreement.

                                       60
<PAGE>
                        SHARES ELIGIBLE FOR FUTURE SALE

    Sales of substantial amounts of our ordinary shares in the public market
could adversely affect prevailing market prices of our ordinary shares.

    Assuming no exercise of outstanding options, we will have an aggregate of
18,028,596 ordinary shares outstanding upon completion of this offering and the
concurrent private placement. Of these shares, the 3,800,000 shares sold in this
offering will be freely tradable without restriction or further registration
under the Securities Act, unless the shares are purchased by affiliates under
Rule 144 of the Securities Act.

    The remaining 14,228,596 ordinary shares will be held by our existing
shareholders and the investors in the concurrent private placement and will be
restricted securities. Restricted securities may be sold in the public market
only if registered or if they qualify for an exemption from registration under
Rule 144 of the Securities Act. These rules are summarized below.

    The following table indicates approximately when the 14,228,596 ordinary
shares that are not being sold in this offering, but which will be outstanding
at the time this offering is complete, will be eligible for sale into the public
market, under the provisions of Rule 144 or 701:

           ELIGIBILITY OF RESTRICTED SHARES FOR SALE IN PUBLIC MARKET

<TABLE>
<S>                                                           <C>
90 days after the date of this prospectus...................     569,334
180 days after the date of this prospectus..................  10,875,784
270 days after the date of this prospectus..................   2,625,228
More than 270 days after the date of this prospectus........     158,250
</TABLE>

LOCK-UP AGREEMENTS

    Our officers and directors, all of our employees and substantially all of
our existing shareholders have signed lock-up agreements under which they agreed
not to dispose of or hedge any ordinary shares or any securities convertible
into or exchangeable for ordinary shares for a period of 180 days after the date
of this prospectus. Dispositions can be made sooner with the prior written
consent of Lehman Brothers Inc. In addition, as a condition to the private
placement, Siemens and Samsung have signed lock-up agreements prohibiting the
disposition of the shares they acquire in the private placement for a period of
270 days after the date of this prospectus.

RULE 144

    In general, under Rule 144 as currently in effect, beginning 90 days after
the date of this prospectus, a person who has beneficially owned ordinary shares
for at least one year would be entitled to sell within any three-month period a
number of shares that does not exceed the greater of:

    - 1% of the number of ordinary shares then outstanding, which will equal
      approximately 180,285 ordinary shares immediately after this offering; or

    - the average weekly trading volume of the ordinary shares on the Nasdaq
      National Market during the four calendar weeks preceding the filing of a
      notice on Form 144 in connection with the sale.

    Sales under Rule 144 are also subject to manner of sale provisions and
notice requirements and to the availability of current public information about
us.

                                       61
<PAGE>
RULE 144(K)

    Under Rule 144(k), a person:

    - who is not considered to have been one of our affiliates at any time
      during the 90 days preceding a sale; and

    - who has beneficially owned the shares proposed to be sold for at least two
      years, including the holding period of any prior owner other than an
      affiliate,

is entitled to sell his shares without complying with the manner of sale, public
information, volume limitation or notice provisions of Rule 144. Therefore,
unless otherwise restricted, these shares may be sold immediately upon the
completion of this offering.

RULE 701

    In general, under Rule 701, any of our employees, directors, officers,
consultants or advisors who purchases ordinary shares from us under a
compensatory stock or option plan or other written agreement before the
effective date of this offering is entitled to resell these shares. These shares
can be resold 90 days after the effective date of this offering in reliance on
Rule 144, without having to comply with restrictions, including the holding
period, contained in Rule 144.

    The Securities and Exchange Commission has indicated that Rule 701 will
apply to typical stock options granted by an issuer before it becomes subject to
the reporting requirements of the Securities Exchange Act of 1934, along with
the shares acquired upon exercise of these options, including exercises after
the date of this prospectus. Securities issued in reliance on Rule 701 are
restricted securities and, subject to the contractual restrictions described
above, beginning 90 days after the date of this prospectus, may be sold:

    - by persons other than affiliates subject only to the manner of sale
      provisions of Rule 144; and

    - by affiliates under Rule 144 without compliance with its one year minimum
      holding period requirement.

OPTIONS

    Following the completion of this offering we intend to file a registration
statement on Form S-8 under the Securities Act covering 3,163,523 ordinary
shares reserved for issuance under our share option plans. The registration
statement on Form S-8 will become effective automatically upon filing. As of
December 31, 1999, options to purchase 3,101,623 ordinary shares were issued and
outstanding, of which options to purchase 542,903 ordinary shares had vested.
After December 31, 1999, 52,750 options were exercised. Ordinary shares
registered under the registration statement will, subject to vesting provisions
and Rule 144 volume limitations applicable to our affiliates, be available for
sale in the open market immediately after the 180-day lock-up agreements expire.

REGISTRATION RIGHTS

    Beginning on the first anniversary of the completion of this offering, the
holders of 13,336,255 ordinary shares are entitled to request that we register
their ordinary shares under the Securities Act. After these ordinary shares are
registered, they will become freely tradable without restriction under the
Securities Act. Any sales of securities by these shareholders could have a
material adverse effect on the trading price of our ordinary shares.

                                       62
<PAGE>
                          DESCRIPTION OF SHARE CAPITAL

    Upon completion of this offering, our authorized share capital will be
25,000,000 shares, of we will be authorized to issue 24,984,470 ordinary shares
and 15,530 deferred shares. On January 18, 2000, our board of directors
declared, and our shareholders approved, effective immediately before this
offering:

    - a share dividend of 20.1 ordinary shares for each ordinary share then
      outstanding; and

    - a 10-for-1 share split.

    In addition, before the share split and the distribution of the share
dividend, each preferred share will automatically convert into one ordinary
share. Immediately following the conversion of our preferred shares, the share
split and the distribution of the share dividend, there will be 13,637,774
ordinary shares issued and outstanding.

    Upon completion of this offering, all outstanding ordinary shares, including
the ordinary shares issued in this offering, will be validly issued and fully
paid and will not have preemptive rights, rights of first refusal, except for a
contractual right of first refusal among the founders, or co-sale rights. The
ownership or voting of ordinary shares by non-residents of Israel is not
restricted in any way by our memorandum of association, our articles of
association or the laws of the State of Israel, except for ownership by
nationals of countries which are, or have been, in a state of war with Israel
may not be recognized as owners of ordinary shares.

DEFERRED SHARES

    As of December 31, 1999, our authorized share capital includes 12,760
deferred shares, as adjusted for the share split, all of which are issued and
outstanding. The deferred shares were created upon the conversion of ordinary
shares allocated to a trust and held on behalf of our employees when the
employees to whom the shares were allocated left us. Our shareholders have
resolved that, effective upon completion of this offering, an additional 2,770
ordinary shares be converted into deferred shares due to additional employee
departures. The deferred shares confer no rights or privileges on their holders
except for the right to receive upon our dissolution or liquidation NIS 0.1 per
deferred share. Holders of deferred shares will not receive the share dividend.

TRANSFER OF SHARES AND NOTICES

    Fully paid ordinary shares are issued in registered form and may be freely
transferred under our articles of association unless the transfer is restricted
or prohibited by another instrument. Our articles of association provide that
each shareholder of record is entitled to receive at least 21 days' prior notice
of any shareholders' meeting.

ELECTION OF DIRECTORS

    Our ordinary shares do not have cumulative voting rights in the election of
directors. As a result, the holders of ordinary shares that represent more than
50% of the voting power represented at a shareholders meeting have the power to
elect most of our directors.

DIVIDEND AND LIQUIDATION RIGHTS

    We may declare a dividend to be paid to the holders of ordinary shares
according to their rights and interests in our profits. In the event of our
liquidation, after satisfaction of liabilities to creditors, our assets will be
distributed to the holders of ordinary shares in proportion to the nominal value
of their holdings. This right may be affected by the grant of preferential
dividend or distribution rights to the holders of a class of shares with
preferential rights that may be authorized in the future. The board of directors
may declare interim dividends and propose the final dividend for any fiscal year
only out of

                                       63
<PAGE>
retained earnings. Under the Companies Law, the declaration of a dividend does
not require the approval of the shareholders of the company, unless the
company's articles of association require otherwise. Our articles of association
provide that the declaration of a dividend must be approved by an ordinary
shareholders' resolution, which may decrease but not increase the amount
proposed by the board of directors.

VOTING

    Holders of ordinary shares have one vote for each ordinary share held on all
matters submitted to a vote of shareholders. These voting rights may be affected
by the grant of any special voting rights to the holders of a class of shares
with preferential rights that may be authorized in the future.

QUORUM

    The quorum required for an ordinary meeting of shareholders consists of at
least two shareholders present in person or by proxy who hold or represent
between them at least 33 1/3% of the issued share capital. A meeting adjourned
for lack of a quorum generally is adjourned to the same day in the following
week at the same time and place or any time and place as the directors designate
in a notice to the shareholders. At the reconvened meeting, the required quorum
consists of any two members present in person or by proxy.

RESOLUTIONS

    An ordinary resolution, like a resolution for the declaration of dividends,
requires approval by the holders of a majority of the voting rights represented
at the meeting, in person, by proxy or by written ballot, and voting on the
resolution. Under our articles of association, a special or extraordinary
resolution requires approval of the holders of 65% of the voting rights
represented at the meeting and voting on the resolution. Special or
extraordinary resolutions include resolutions for:

    - amending our memorandum of association or articles of association;

    - approving changes in capitalization;

    - winding-up; or

    - authorization of a class of shares with special rights.

    Under the Companies Law, unless otherwise provided in the articles of
association or applicable law, all resolutions of the shareholders require a
simple majority and all shareholders meetings require prior notice of at least
21 days. However, companies, such as ours, which have been incorporated before
the Companies Law became effective, must specifically amend their articles of
association to provide for the shareholder voting requirements contained in the
Companies Law. The Companies Law requires that the first amendment of a
company's articles of association following the effective date of the Companies
Law be approved by holders of 75% of the voting rights represented at the
meeting, in person, by proxy or by written ballot, and voting on the amendment.

SHAREHOLDER DUTIES

    Under the Companies Law, a shareholder has a duty to act in good faith
towards the company in which he hold shares and towards the company's other
shareholders and to refrain from abusing his power in the company. This duty
extends to voting in the general meeting of shareholders on the following
matters:

    - any amendment to the articles of association;

    - an increase of the company's authorized share capital;

                                       64
<PAGE>
    - a merger; or

    - approval of some of the acts and transactions which require shareholder
      approval.

    In addition, a shareholder has the general duty to refrain from depriving
rights of other shareholders. Furthermore, any controlling shareholder, any
shareholder who knows that it possesses the power to determine the outcome of a
shareholder vote and any shareholder that, under the provisions of the articles
of association, has the power to appoint an office holder in the company, is
under a duty to act in fairness towards the company. The Companies Law does not
describe the substance of these duties.

REGISTRATION RIGHTS

    For a discussion of registration rights we have granted to shareholders,
please see the section of this prospectus entitled "Related Party
Transactions--Registration Rights."

ANTI-TAKEOVER PROVISION

    The Companies Law requires a party who wishes to acquire shares of a
publicly-held company without the approval of its minority shareholders to
acquire 95% of all outstanding shares not held by the acquirer before the
acquisition. Even if the acquirer acquires 95% of the outstanding shares, the
remaining minority shareholders may seek to block the acquisition in court.

MERGERS AND ACQUISITIONS UNDER ISRAELI LAW

    The Companies Law includes provisions that allow a merger transaction and
requires that each company that is party to a merger approve the transaction by
its board of directors and a vote of the majority of its shares, voting on the
proposed merger at a shareholders' meeting called on at least 21 days' prior
notice. In determining whether a majority has approved the merger, shares held
by the other party to the merger or any person holding at least 25% of the other
party to the merger are excluded from the vote. The Companies Law does not
require court approval of a merger other than in specified situations. Upon the
request of a creditor of either party to the proposed merger, the court may
delay or prevent the merger if it concludes that there exists a reasonable
concern that as a result of the merger, the surviving company will be unable to
satisfy the obligations of any of the parties to the merger. In addition, a
merger may not be completed unless at least 70 days have passed from the time
that a proposal for approval of the merger has been filed with the Israeli
Registrar of Companies.

    The Companies Law also provides that an acquisition of shares in a public
company on the open market must be made by means of a tender offer if as a
result of the acquisition the purchaser would become a 25% shareholder of the
company. If there already is another shareholder who holds more than 25% but
less than 50% of the company's outstanding share capital, the Companies Law
provides that an acquisition of shares in a public company on the open market
must be made by means of a tender offer if as a result of the acquisition the
purchaser would become a 45% shareholder of the company. However, under the
Companies Law, if following any acquisition of shares, the acquirer who hold 90%
or more of the company's shares, the acquisition must be made by means of a
tender offer for all of the shares of the class. These rules do not apply if the
acquisition is made by way of a merger.

MODIFICATION OF CLASS RIGHTS

    Under our articles of association, the rights attached to any class, unless
otherwise provided by the terms of the class, including voting, rights to
dividends and the like, may be varied by:

    - written consent of holders of 65% of the issued shares of that class; or

                                       65
<PAGE>
    - adoption of a resolution by the holders of 65% of the shares of that class
      at a special meeting of the holders of that class.

ISRAELI SECURITIES LAW REQUIREMENTS

    We have received from the Israeli Securities Authority an exemption from
Israel's prospectus delivery requirements applicable to the offering. We have
also received from the Israeli Securities Authority an exemption from the
reporting obligations to which Israeli companies whose shares are publicly
traded are subject, provided that a copy of each of the reports filed by us
under applicable United States securities laws shall be available for public
review at our offices.

TRANSFER AGENT AND REGISTRAR

    The transfer agent and registrar for our ordinary shares is American Stock
Transfer & Trust Company, New York, New York.

                              CONDITIONS IN ISRAEL

    We are incorporated under the laws of, and our principal offices and
manufacturing and research and development facilities are located in, the State
of Israel. Therefore, we are directly affected by political, economic and
military conditions in Israel.

POLITICAL CONDITIONS

    Since the establishment of the State of Israel in 1948, a number of armed
conflicts have taken place between Israel and its Arab neighbors and a state of
hostility, varying from time to time in intensity and degree, has led to
security and economic problems for Israel. Israel signed a peace treaty with
Egypt in 1979 and a peace treaty with Jordan in 1994. Since 1993, a joint
Israeli-Palestinian declaration of principles and several other agreements have
been signed between Israel and the Palestinians. As of the date of this
prospectus, Israel has not entered into any peace agreement with Syria and
Lebanon. We cannot assure you whether any peace agreement with Syria and Lebanon
will be signed.

    Despite the progress towards peace between Israel and its Arab neighbors and
the Palestinians, some countries, companies and organizations continue to
participate in a boycott of Israeli firms and others doing business with Israel
or with Israeli companies. Although we are precluded from marketing our products
to these countries, we believe that in the past, the boycott has not had a
material adverse effect on us. However, restrictive laws, policies or practices
directed towards Israel or Israeli businesses could have an adverse impact on
the expansion of our business.

    All male adult citizens and permanent residents of Israel under the age of
48 are, unless exempt, obligated to perform up to 39 days of military reserve
duty annually. Additionally, these residents are subject to being called to
active duty at any time under emergency circumstances. Many of our officers and
employees are currently obligated to perform annual reserve duty. While we have
operated effectively under these requirements since we began operations, we
cannot assess the full impact of these requirements on our workforce or business
if conditions should change, and we cannot predict the effect on us of any
expansion or reduction of these obligations.

ECONOMIC CONDITIONS

    Israel's economy has been subject to numerous destabilizing factors,
including a period of rampant inflation in the early to mid-1980s, low foreign
exchange reserves, fluctuations in world commodity prices, military conflicts
and civil unrest. The Israeli government has intervened in various sectors of
the economy, by utilizing fiscal and monetary policies, import duties, foreign
currency restrictions and

                                       66
<PAGE>
control of wages, prices and foreign currency exchange rates. In 1998, the
Israeli currency control regulations were liberalized significantly to allow
Israeli residents to deal in foreign currency and non-residents of Israel to
purchase and sell Israeli currency and assets. The Israeli government has
periodically changed its policies in all these areas. There are currently no
Israeli currency control restrictions on remittances of dividends on the
ordinary shares or the proceeds from the sale of the shares. However,
legislation remains in effect under which currency controls can be imposed by
administrative action at any time.

    The Israeli government's monetary policy contributed to relative price and
exchange rate stability in recent years, despite fluctuating rates of economic
growth and a high rate of unemployment. We cannot assure you that the Israeli
government will be successful in its attempts to keep prices and exchange rates
stable. Price and exchange rate instability may have a material adverse effect
on us.

TRADE RELATIONS

    Israel is a member of the United Nations, the International Monetary Fund,
the International Bank for Reconstruction and Development and the International
Finance Corporation. Israel is a member of the World Trade Organization and is
signatory to the Global Agreement on Trade in Services. In addition, Israel has
been granted preferences under the Generalized System of Preferences from the
United States, Australia, Canada and Japan. These preferences allow Israel to
export the products covered by these programs either duty-free or at reduced
tariffs.

    Israel and the EEC, known now as the European Union, concluded a free trade
agreement in July 1975 which confers various advantages on Israeli exports to
most European countries and obligates Israel to lower its tariffs on imports
from these countries over a number of years. In 1985, Israel and the United
States entered into an agreement to establish a free trade area. The free trade
area has eliminated all tariff and specified non-tariff barriers on most trade
between the two countries. On January 1, 1993, an agreement between Israel and
the European Free Trade Association, known as the EFTA, established a free-trade
zone between Israel and the EFTA nations. In November 1995, Israel entered into
a new agreement with the European Union, which includes redefinement of rules of
origin and other improvements, including providing for Israel to become a member
of the research and technology programs of the European Union. In recent years,
Israel has established commercial and trade relations with a number of other
nations, including Russia, China, India, Turkey and other nations in Eastern
Europe and Asia.

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<PAGE>
                        TAXATION AND GOVERNMENT PROGRAMS

ISRAELI TAX CONSIDERATIONS AND GOVERNMENT PROGRAMS

    The following is a summary of the current tax structure applicable to
companies in Israel, with special reference to its effect on us. The following
also contains a discussion of the material Israeli and United States tax
consequences to persons purchasing our ordinary shares offered by this
prospectus and Israeli government programs benefiting us. To the extent that the
discussion is based on new tax legislation which has not been subject to
judicial or administrative interpretation, we cannot assure you that the tax
authorities will accept the views expressed in the discussion in question. The
discussion is not intended, and should not be taken, as legal or professional
tax advice and is not exhaustive of all possible tax considerations.

    PROSPECTIVE PURCHASERS OF OUR ORDINARY SHARES SHOULD CONSULT THEIR OWN TAX
ADVISORS CONCERNING THE UNITED STATES, ISRAELI OR OTHER TAX CONSEQUENCES OF THE
PURCHASE, OWNERSHIP AND DISPOSITION OF ORDINARY SHARES, INCLUDING, IN
PARTICULAR, THE EFFECT OF ANY FOREIGN, STATE OR LOCAL TAXES.

    GENERAL CORPORATE TAX STRUCTURE

    Israeli companies are subject to company tax at the rate of 36% of taxable
income. However, the effective tax rate payable by a company, which derives
income from an approved enterprise discussed further below, may be considerably
less.

    TAX BENEFITS UNDER THE LAW FOR THE ENCOURAGEMENT OF CAPITAL INVESTMENTS,
     1959

    The Law for the Encouragement of Capital Investments, 1959, commonly
referred to as the Investment Law, provides that a proposed capital investment
in eligible facilities may, upon application to the Investment Center of the
Ministry of Industry and Trade of the State of Israel, be designated as an
approved enterprise. Each certificate of approval for an approved enterprise
relates to a specific investment program delineated both by its financial scope,
including its capital sources, and by its physical characteristics, for example,
the equipment to be purchased and utilized under the program. The tax benefits
derived from any certificate of approval relate only to taxable income
attributable to the specific approved enterprise. If a company has more than one
approval or only a portion of its capital investments is approved, its effective
tax rate is the result of a weighted average of the applicable rates.

    Taxable income of a company derived from an approved enterprise is subject
to company tax at the maximum rate of 25%, rather than 36%, for the benefit
period. This period is ordinarily seven years, or ten years if the company
qualifies as a foreign investors' company as described below, commencing with
the year in which the approved enterprise first generates taxable income.
However, this period is limited to twelve years from commencement of production
or 14 years from the date of approval, whichever is earlier. The Investment Law
also provides that a company that has an approved enterprise within Israel will
be eligible for a reduced tax rate for the remainder of the benefit period.

    A company owning an approved enterprise may elect to receive an alternative
package of benefits. Under the alternative package of benefits, a company's
undistributed income derived from an approved enterprise will be exempt from
company tax for a period of between two and ten years from the first year of
taxable income, depending on the geographic location of the approved enterprise
within Israel, and the company will be eligible for a reduced tax rate for the
remainder of the benefits period.

    A company that has an approved enterprise program is eligible for further
tax benefits if it qualifies as a foreign investors' company. A foreign
investors' company is a company more than 25% of whose share capital and
combined share and loan capital is owned by non-Israeli residents. A company
which qualifies as a foreign investors' company and has an approved enterprise
program is eligible for tax benefits for a ten year benefit period. Income
derived from the approved enterprise program will be

                                       68
<PAGE>
exempt from tax for a period of two years and will be subject to a reduced tax
for an additional eight years. The tax rate is for the additional eight years is
25% unless the level of foreign investment exceeds 49%, in which case the tax
rate is 20% if the foreign investment is more than 49% and less than 74%; 15% if
more than 74% and less than 90%; and 10% if 90% or more.

    A company that has elected the alternative package of benefits and that
subsequently pays a dividend out of income derived from the approved enterprise
during the tax exemption period will be subject to tax on of the amount
distributed. The rate of the tax will be the rate which would have been
applicable had the company not elected the alternative package of benefits. This
rate is generally 10%-25%, depending on the percentage of the company's shares
held by foreign shareholders. The dividend recipient is taxed at the reduced
rate applicable to dividends from approved enterprises which is 15%, if the
dividend is distributed during the tax exemption period or within 12 years after
the period. The company must withhold this tax at source, regardless of whether
the dividend is converted into foreign currency.

    Subject to applicable provisions concerning income under the alternative
package of benefits, all dividends are considered to be attributable to the
entire enterprise and their effective tax rate is the result of a weighted
average of the various applicable tax rates. Under the Investment Law, a company
that has elected the alternative package of benefits is not obliged to
distribute exempt retained profits, and may generally decide from which year's
profits to declare dividends. We currently intend to reinvest any income derived
from our approved enterprise programs and not to distribute the income as a
dividend.

    The Investment Center bases its decision whether or not to approve an
application on the criteria in the Investment Law and regulations, the then
prevailing policy of the Investment Center and the specific objectives and
financial criteria of the applicant. Therefore, we cannot assure you that any of
our applications will be approved. In addition, the benefits available to an
approved enterprise are conditional upon the fulfillment of conditions
stipulated in the Investment Law and its regulations and the criteria in the
specific certificate of approval, as described above. If a company does not meet
these conditions, it would be required to refund the amount of tax benefits,
with the addition of the consumer price index linkage adjustment and interest.

    The Investment Center of the Ministry of Industry and Trade has granted
several investment programs at our manufacturing facility approved enterprise
status under Israeli law. We have elected the alternative package of benefits
under these approved enterprise programs. The portion of our income derived from
these approved enterprise programs will be exempt from tax for a period of two
years and will be subject to a reduced tax for an additional five to eight years
depending on the percentage of our share capital held by non-Israelis,
commencing when we begin to realize net income from these programs. The benefits
available to an approved enterprise program are dependent upon the fulfillment
of conditions stipulated in applicable law and in the certificate of approval.

    We have derived, and expect to continue to derive, a substantial portion of
our income from our approved enterprise programs. Subject to compliance with
applicable requirements, income derived from our approved enterprise programs
will be tax exempt for a period of two years commencing in the first year in
which there is taxable income and will be subject for the subsequent period of
five years to a reduced company tax of up to 25%, or eight years if the
percentage of non-Israeli investors who hold our ordinary shares exceeds 25%.
The period of tax benefits for our approved enterprise programs has not yet
commenced, because we have yet to realize taxable income.

    GRANTS UNDER THE LAW FOR THE ENCOURAGEMENT OF INDUSTRIAL RESEARCH AND
     DEVELOPMENT, 1984

    Under the Law for the Encouragement of Industrial Research and Development,
1984, commonly referred to as the Research Law, research and development
programs which meet specified criteria and are approved by a governmental
committee of the Office of the Chief Scientist are eligible for grants of up to
50% of the project's expenditure, as determined by the research committee, in
exchange for the

                                       69
<PAGE>
payment of royalties from the sale of products developed under the program.
Regulations under the Research Law generally provide for the payment of
royalties to the Chief Scientist of 3-5% on sales of products and services
derived from our technology developed using these grants until 100%-150% of the
dollar-linked grant is repaid. Following the full repayment of the grant, there
is no further liability for repayment.

    The terms of the Israeli government participation also require that the
manufacture of products developed with government grants be performed in Israel.
However, under the regulations of the Research Law, if any of the manufacturing
is performed outside Israel by any entity other than us, assuming we receive
approval from the Chief Scientist for the foreign manufacturing, we may be
required to pay increased royalties. The increase in royalties depends upon the
manufacturing volume that is performed outside of Israel follows:

<TABLE>
<CAPTION>
        MANUFACTURING VOLUME             ROYALTIES TO THE CHIEF SCIENTIST
          OUTSIDE OF ISRAEL                  AS A PERCENTAGE OF GRANT
- -------------------------------------  -------------------------------------
<S>                                    <C>
            less than 50%                              120%
         between 50% and 90%                           150%
            more than 90%                              300%
</TABLE>

    The technology developed with Chief Scientist grants may not be transferred
to third parties without the prior approval of a governmental committee under
the Research Law. The approval, however, is not required for the export of any
products developed using the grants. Approval of the transfer of technology may
be granted in specific circumstances, only if the recipient abides by the
provisions of the Research Law and related regulations, including the
restrictions on the transfer of know-how and the obligation to pay royalties in
an amount that may be increased. We cannot assure you that any consent, if
requested, will be granted.

    Effective for grants received from the Chief Scientist under programs
approved after January 1, 1999, the outstanding balance of the grants will be
subject to interest equal to the 12 month London interbank offered rate
applicable to dollar deposits that is published on the first business day of
each calendar year.

    The funds generally available for grants from the Chief Scientist were
reduced for 1998, and the Israeli authorities have indicated that the government
may further reduce or abolish grants from the Chief Scientist in the future.
Even if these grants are maintained, we cannot assure you that we will receive
Chief Scientist grants in the future. In addition, each application to the Chief
Scientist is reviewed separately, and grants are based on the program approved
by the research committee. Generally, expenditures supported under other
incentive programs of the State of Israel are not eligible for grants from the
Chief Scientist. We cannot assure you that applications to the Chief Scientist
will be approved and, until approved, the amounts of any grants are not
determinable.

    TAX BENEFITS AND GRANTS FOR RESEARCH AND DEVELOPMENT

    Israeli tax law allows, under specific conditions, a tax deduction in the
year incurred for expenditures, including capital expenditures, relating to
scientific research and development projects, if:

    - the expenditures are approved by the relevant Israeli government ministry,
      determined by the field of research;

    - the research and development is for the promotion of the company; and

    - the research and development is carried out by or on behalf of the company
      seeking the deduction.

    Expenditures not so approved are deductible over a three-year period.
However, expenditures made out of proceeds made available to us through
government grants are not deductible according to Israeli law.

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<PAGE>
    TAX BENEFITS UNDER THE LAW FOR THE ENCOURAGEMENT OF INDUSTRY (TAXES), 1969

    According to the Law for the Encouragement of Industry (Taxes), 1969,
generally referred to as the Industry Encouragement Law, an industrial company
is a company resident in Israel, at least 90% of the income of which, in a given
tax year, determined in Israeli currency exclusive of income from specified
government loans, capital gains, interest and dividends, is derived from an
industrial enterprise owned by it. An industrial enterprise is defined as an
enterprise whose major activity in a given tax year is industrial production
activity. We believe that we currently qualify as an industrial company within
the definition of the Industry Encouragement Law.

    Under the Industry Encouragement Law, industrial companies are entitled to
the following preferred corporate tax benefits:

    - deduction of purchases of know-how and patents over an eight-year period
      for tax purposes;

    - deduction of specified expenses incurred for a public issuance of
      securities over a three-year period for tax purposes;

    - right to elect, under specified conditions, to file a consolidated tax
      return with additional related Israeli industrial companies; and

    - accelerated depreciation rates on equipment and buildings.

    Eligibility for benefits under the Industry Encouragement Law is not subject
to receipt of prior approval from any governmental authority.

    We believe that we currently qualify as an industrial company within the
definition of the Industry Encouragement Law. We cannot assure you that we will
continue to qualify as an industrial company or that the benefits described
above will be available to us in the future.

    SPECIAL PROVISIONS RELATING TO TAXATION UNDER INFLATIONARY CONDITIONS

    The Income Tax Law (Inflationary Adjustments), 1985, generally referred to
as the Inflationary Adjustments Law, represents an attempt to overcome the
problems presented to a traditional tax system by an economy undergoing rapid
inflation. The Inflationary Adjustments Law is highly complex. Its features
which are material to us can be described as follows:

    - There is a special tax adjustment for the preservation of equity as
      follows:

       - Where a company's equity, as calculated under the Inflationary
         Adjustments Law, exceeds the depreciated cost of fixed assets, a
         deduction from taxable income is permitted equal to the excess
         multiplied by the applicable annual rate of inflation. The maximum
         deduction permitted in any single tax year is 70% of taxable income,
         with the unused portion permitted to be carried forward.

       - Where a company's depreciated cost of fixed assets exceeds its equity,
         then the excess multiplied by the applicable annual rate of inflation
         is added to taxable income.

    - Subject to specified limitations, depreciation deductions on fixed assets
      and losses carried forward are adjusted for inflation based on the
      increase in the consumer price index.

    - Gains on traded securities, which are normally exempt from tax, are
      taxable in specified circumstances. However, dealers in securities are
      subject to the regular tax rules applicable to business income in Israel.

    CAPITAL GAINS TAX ON SALES OF OUR ORDINARY SHARES

    Israeli law imposes a capital gains tax on the sale of capital assets. The
law distinguishes between real gain and inflationary surplus. The inflationary
surplus is a portion of the total capital gain that is equivalent to the
increase of the relevant asset's purchase price which is attributable to the
increase in

                                       71
<PAGE>
the Israeli consumer price index between the date of purchase and the date of
sale. The real gain is the excess of the total capital gain over the
inflationary surplus. The inflationary surplus accumulated from and after
December 31, 1993, is exempt from any capital gains tax in Israel while the real
gain is added to ordinary income, which is taxed at ordinary rates of 30% to 50%
for individuals and 36% for corporations.

    Under current law, sales of our ordinary shares offered by this prospectus
are exempt from Israeli capital gains for so long as they are quoted on Nasdaq
or listed on a stock exchange in specified countries and we qualify as an
industrial company. We cannot assure you that we will maintain this
qualification or our status as an industrial company. Moreover, dealers in
securities in Israel are taxed at regular tax rates applicable to business
income.

    Under the convention between the United States and Israel concerning taxes
on income, Israeli capital gains tax will not apply to the sale, exchange or
disposition of ordinary shares by a person:

    - who qualifies as a resident of the United States within the meaning of the
      U.S.-Israel tax treaty; and

    - who is entitled to claim the benefits available to the person by the
      U.S.-Israel tax treaty.

    However, this exemption will not apply if the treaty U.S. resident holds,
directly or indirectly, shares representing 10% or more of our voting power
during any part of the 12-month period preceding the sale, exchange or
disposition, subject to specified conditions. In this case, the sale, exchange
or disposition would be subject to Israeli tax, to the extent applicable.
However, under the U.S.-Israel tax treaty, the treaty U.S. resident would be
permitted to claim a credit for the taxes against the U.S. federal income tax
imposed on the sale, exchange or disposition, subject to the limitations in U.S.
laws applicable to foreign tax credits. The U.S.-Israel tax treaty does not
relate to U.S. state or local taxes.

    TAXATION OF NON-RESIDENT HOLDERS OF SHARES

    Non-residents of Israel are subject to income tax on income accrued or
derived from sources in Israel. These sources of income include passive income,
including dividends, royalties and interest, as well as non-passive income from
services provided in Israel. On distributions of dividends other than bonus
shares or stock dividends, income tax is withheld at source. Unless a different
rate is provided in a treaty between Israel and the shareholder's country of
residence, the withholding rate is as follows:

<TABLE>
<CAPTION>
                                                      DIVIDENDS NOT GENERATED BY AN
                                                           APPROVED ENTERPRISE
                                                 ---------------------------------------
           DIVIDENDS GENERATED BY AN             U.S. COMPANY HOLDING 10%      OTHER
              APPROVED ENTERPRISE                 OR MORE OF OUR SHARES     NON-RESIDENT
           -------------------------             ------------------------   ------------
<S>                                              <C>                        <C>
                      15%                                  12.5%                  25%
</TABLE>

    Under an amendment to the Inflationary Adjustments Law, non-Israeli
corporations might be subject to Israeli taxes on the sale of traded securities
in an Israeli company, subject to the provisions of any applicable double
taxation treaty.

    FOREIGN EXCHANGE REGULATIONS

    We are permitted to pay in Israeli and non-Israeli currency:

    - dividends to holders of our ordinary shares; and

    - any amounts payable to the holders of our ordinary shares upon our
      dissolution, liquidation or winding up.

    If we make any payments in Israeli currency, the payments may be converted
into freely repatriable dollars at the rate of exchange prevailing at the time
of conversion.

                                       72
<PAGE>
UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS

    Subject to the limitations described in the next paragraph, the following
discussion describes the material United States federal income tax consequences
to a holder of our ordinary shares, referred to for purposes of this discussion
as a U.S. holder, that is:

    - a citizen or resident of the United States,

    - a corporation created or organized in the United States or under the laws
      of the United States or of any state,

    - an estate, the income of which is includible in gross income for United
      States federal income tax purposes regardless of its source, or

    - a trust, if a court within the United States is able to exercise primary
      supervision over the administration of the trust and one or more U.S.
      persons have the authority to control all substantial decisions of the
      trust.

    This summary is not a comprehensive description of all of the tax
considerations that may be relevant to each person's decision to purchase
ordinary shares. This summary considers only U.S. holders that will own ordinary
shares as capital assets.

    This discussion is based on current provisions of the Internal Revenue Code
of 1986, current and proposed Treasury regulations, and administrative and
judicial decisions as of the date of this prospectus, all of which are subject
to change, possibly on a retroactive basis. This discussion does not address all
aspects of United States federal income taxation that may be relevant to any
particular shareholder based on the shareholder's individual circumstances. In
particular, this discussion does not address the potential application of the
alternative minimum tax or the United States federal income tax consequences to
U.S. holders that are subject to special treatment, including U.S. holders that:

    - are broker-dealers or insurance companies;

    - have elected mark-to-market accounting;

    - are tax-exempt organizations;

    - are financial institutions or financial services entities;

    - hold ordinary shares as part of a straddle, hedge or conversion
      transaction with other investments;

    - own directly, indirectly or by attribution at least 10% of our voting
      power; and

    - have a functional currency that is not the U.S. dollar.

    In addition, this discussion does not address any aspect of state, local or
non-United States tax laws.

    Additionally, the discussion does not consider the tax treatment of persons
who hold ordinary shares through a partnership or other pass-through entity or
the possible application of United States federal gift or estate tax. Material
aspects of United States federal income tax relevant to a holder other than a
U.S. holder, or a non-U.S. holder, are also discussed below.

    EACH PROSPECTIVE INVESTOR IS ADVISED TO CONSULT HIS OWN TAX ADVISOR FOR THE
SPECIFIC TAX CONSEQUENCES TO HIM OF PURCHASING, HOLDING OR DISPOSING OF OUR
ORDINARY SHARES.

    TAXATION OF DIVIDENDS PAID ON ORDINARY SHARES

    A U.S. holder will be required to include in gross income as ordinary income
the amount of any distribution paid on ordinary shares, including any Israeli
taxes withheld from the amount paid, on the date the distribution is received to
the extent the distribution is paid out of our current or accumulated earnings
and profits as determined for United States federal income tax purposes.
Distributions in

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<PAGE>
excess of earnings and profits will be applied against and will reduce the U.S.
holder's basis in the ordinary shares and, to the extent in excess of the basis,
will be treated as gain from the sale or exchange of ordinary shares.

    Distributions of current or accumulated earnings and profits paid in foreign
currency to a U.S. holder will be includible in the income of a U.S. holder in a
U.S. dollar amount calculated by reference to the exchange rate on the day the
distribution is received. A U.S. holder that receives a foreign currency
distribution and converts the foreign currency into U.S. dollars after receipt
will have foreign exchange gain or loss based on any appreciation or
depreciation in the value of the foreign currency against the U.S. dollar, which
will generally be U.S. source ordinary income or loss.

    U.S. holders will have the option of claiming the amount of any Israeli
income taxes withheld at source either as a deduction from gross income or as a
dollar-for-dollar credit against their United States federal income tax
liability. Individuals who do not claim itemized deductions, but instead utilize
the standard deduction, may not claim a deduction for the amount of the Israeli
income taxes withheld, but the amount may be claimed as a credit against the
individual's United States federal income tax liability. The amount of foreign
income taxes that may be claimed as a credit in any year is subject to complex
limitations and restrictions, which must be determined on an individual basis by
each shareholder. These limitations include rules which limit foreign tax
credits allowable for specific classes of income to the United States federal
income taxes otherwise payable on each class of income. The total amount of
allowable foreign tax credits in any year cannot exceed the pre-credit U.S. tax
liability for the year attributable to foreign source taxable income.

    A U.S. holder will be denied a foreign tax credit for Israeli income tax
withheld from dividends received on the ordinary shares:

    - to the extent the U.S. holder has not held the ordinary shares for at
      least 16 days of the 30 day period beginning on the date which is 15 days
      before the ex-dividend date; or

    - to the extent the U.S. holder is under an obligation to make related
      payments on substantially similar or related property.

    Any days during which a U.S. holder has substantially diminished its risk of
loss on the ordinary shares are not counted toward meeting the 16 day holding
period required by the statute. In addition, distributions of current or
accumulated earnings and profits will be foreign source passive income for
United States foreign tax credit purposes and will not qualify for the dividends
received deduction available to corporations.

    TAXATION OF THE DISPOSITION OF ORDINARY SHARES

    Upon the sale, exchange or other disposition of ordinary shares, a U.S.
holder will recognize capital gain or loss in an amount equal to the difference
between the U.S. holder's basis in the ordinary shares, which is usually the
cost of the shares, and the amount realized on the disposition. If, as
anticipated, the ordinary shares are publicly traded, a disposition of shares
will be considered to occur on the trade date, regardless of the holder's method
of accounting. Capital gain from the sale, exchange or other disposition of
ordinary shares held more than one year is long-term capital gain, and is
eligible for a maximum 20% rate of taxation for individuals. Gain or loss
recognized by a U.S. holder on a sale, exchange or other disposition of ordinary
shares will be treated as United States source income for United States foreign
tax credit purposes. The deductibility of a capital loss recognized on the sale,
exchange or other disposition of ordinary shares is subject to limitations.

    A U.S. holder that uses the cash method of accounting calculates the U.S.
dollar value of the proceeds received on the sale as of the date that the sale
settles. However, a U.S. holder that uses the accrual method of accounting is
required to calculate the value of the proceeds of the sale as of the trade date
and may therefore realize foreign currency gain or loss. The U.S. holder may
avoid realizing foreign currency gain or loss if he has elected to use the
settlement date to determine its proceeds of

                                       74
<PAGE>
sale for purposes of calculating the foreign currency gain or loss. In addition,
a U.S. holder that receives foreign currency upon disposition of ordinary shares
and converts the foreign currency into U.S. dollars after receipt will have
foreign exchange gain or loss based on any appreciation or depreciation in the
value of the foreign currency against the U.S. dollar, which will generally be
U.S. source ordinary income or loss.

    TAX CONSEQUENCES IF WE ARE A PASSIVE FOREIGN INVESTMENT COMPANY

    We will be a passive foreign investment company, or PFIC, if 75% or more of
our gross income in a taxable year, including the pro rata share of the gross
income of any company, U.S. or foreign, in which we are considered to own 25% or
more of the shares by value, is passive income. Alternatively, we will be
considered to be a PFIC if at least 50% of our assets in a taxable year,
averaged over the year and ordinarily determined based on fair market value and
including the pro rata share of the assets of any company in which we are
considered to own 25% or more of the shares by value, are held for the
production of, or produce, passive income. Passive income includes amounts
derived by reason of the temporary investment of funds raised in this offering.

    If we were a PFIC, and a U.S. holder did not make an election to treat us as
a qualified electing fund as described below, excess distributions by us to a
U.S. holder would be taxed in a special way. Excess distributions are amounts
received by a U.S. holder on our stock in any taxable year that exceed 125% of
the average distributions received by the U.S. holder from us in the shorter of:

       - the three previous years; or

       - the U.S. holder's holding period for ordinary shares before the present
         taxable year.

    Excess distributions must be allocated ratably to each day that a U.S.
holder has held our stock. A U.S. holder would then be required to include
amounts allocated to the current taxable year in its gross income as ordinary
income for that year. Further, a U.S. holder would be required to pay tax on
amounts allocated to each prior taxable year at the highest rate in effect for
that year on ordinary income and the tax would be subject to an interest charge
at the rate applicable to deficiencies for income tax.

    The entire amount of gain that is realized by a U.S. holder upon the sale or
other disposition of ordinary shares will also be treated as an excess
distribution and will be subject to tax as described above.

    A U.S. holder's tax basis in our ordinary shares that were inherited from a
deceased person who was a U.S. holder would not receive a step-up to fair market
value as of the date of the deceased's death but would instead be equal to the
deceased's basis, if lower.

    The special PFIC rules described above will not apply to a U.S. holder if
the U.S. holder makes an election to treat us as a qualified electing fund in
the first taxable year in which the U.S. holder owns ordinary shares and if we
comply with specified reporting requirements. Instead, a shareholder of a
qualified electing fund is required for each taxable year to include in income a
pro rata share of the ordinary earnings of the qualified electing fund as
ordinary income and a pro rata share of the net capital gain of the qualified
electing fund as long-term capital gain, subject to a separate election to defer
payment of taxes. If deferred, the taxes will be subject to an interest charge.
We will supply U.S. holders with the information needed to report income and
gain under a QEF election if we are classified as a PFIC.

    The QEF election is made on a shareholder-by-shareholder basis and can be
revoked only with the consent of the Internal Revenue Service, or IRS. A
shareholder makes a QEF election by attaching a completed IRS Form 8621,
including the PFIC annual information statement, to a timely filed United States
federal income tax return and by filing a copy of the form with the IRS Service
Center in

                                       75
<PAGE>
Philadelphia, Pennsylvania. Even if a QEF election is not made, a shareholder in
a PFIC who is a U.S. person must file a completed IRS Form 8621 every year.

    A U.S. holder of PFIC stock which is publicly traded could elect to mark the
stock to market annually, recognizing as ordinary income or loss each year an
amount equal to the difference as of the close of the taxable year between the
fair market value of the PFIC stock and the U.S. holder's adjusted tax basis in
the PFIC stock. Losses would be allowed only to the extent of net mark-to-market
gain previously included by the U.S. holder under the election for prior taxable
years. If the mark-to-market election were made, then the rules presented above
would not apply for periods covered by the election.

    We do not believe that we will be a PFIC in 2000. However, the tests for
determining PFIC status are applied annually and it is difficult to make
accurate predictions of future income and assets, which are relevant to this
determination. Therefore, there can be no assurance that we will not become a
PFIC in 2000 or in a subsequent year. U.S. holders who hold ordinary shares
during a period when we are a PFIC will be subject to these rules, even if we
cease to be a PFIC, subject to specified exceptions for U.S. holders who made a
QEF election. U.S. holders are urged to consult their tax advisors about the
PFIC rules, including QEF and mark-to-market elections.

    TAX CONSEQUENCES FOR NON-U.S. HOLDERS OF ORDINARY SHARES

    Except as described in "Information Reporting and Back-up Withholding"
below, a non-U.S. holder of ordinary shares will not be subject to U.S. federal
income or withholding tax on the payment of dividends on, and the proceeds from
the disposition of, ordinary shares, unless:

    - the item is effectively connected with the conduct by the non-U.S. holder
      of a trade or business in the United States and:

       - in the case of a resident of a country which has a treaty with the
         United States, the item is attributable to a permanent establishment;
         or

       - in the case of an individual, the item is attributable to a fixed place
         of business in the United States;

    - the non-U.S. holder is an individual who holds the ordinary shares as a
      capital asset and is present in the United States for 183 days or more in
      the taxable year of the disposition and does not qualify for an exemption;
      or

    - the non-U.S. holder is subject to tax under the provisions of United
      States tax law applicable to U.S. expatriates.

    INFORMATION REPORTING AND BACK-UP WITHHOLDING

    U.S. holders generally are subject to information reporting requirements for
dividends paid in the United States on ordinary shares. Under existing
regulations, dividends are not subject to back-up withholding. U.S. holders are
subject to information reporting and back-up withholding at a rate of 31% on
proceeds paid from the disposition of ordinary shares unless the U.S. holder
provides IRS Form W-9 or establishes an exemption.

    Non-U.S. holders generally are not subject to information reporting or
back-up withholding for dividends paid on, or upon the disposition of, ordinary
shares, provided that the non-U.S. holder provides a taxpayer identification
number, certifies to its foreign status, or establishes another exemption to the
information reporting or back-up withholding requirements.

    Treasury regulations effective January 1, 2001 impose back-up withholding on
dividends paid in the United States on ordinary shares unless the U.S. holder
provides IRS Form W-9 or establishes an exemption. Prospective investors should
consult their tax advisors concerning the effect, if any, of these Treasury
regulations on an investment in ordinary shares.

    The amount of any back-up withholding will be allowed as a credit against a
U.S. or non-U.S. holder's United States federal income tax liability and may
entitle the holder to a refund, provided that required information is furnished
to the IRS.

                                       76
<PAGE>
                                  UNDERWRITING

GENERAL

    Under the underwriting agreement, which is filed as an exhibit to the
registration statement relating to this prospectus, each of the underwriters
named below, for whom Lehman Brothers Inc., Salomon Smith Barney Inc., U.S.
Bancorp Piper Jaffray Inc. and Fidelity Capital Markets, a division of National
Financial Services Corporation, are acting as representatives, has agreed to
purchase from us the number of ordinary shares shown opposite its name below:

<TABLE>
<CAPTION>
                                                              NUMBER OF
                        UNDERWRITERS                           SHARES
                        ------------                          ---------
<S>                                                           <C>
Lehman Brothers Inc.........................................
Salomon Smith Barney Inc....................................
U.S. Bancorp Piper Jaffray Inc..............................
Fidelity Capital Markets, a division of
  National Financial Services Corporation...................

                                                              ---------
      Total.................................................  3,800,000
                                                              =========
</TABLE>

    The underwriting agreement provides that the underwriters' obligations to
purchase ordinary shares depend on the satisfaction of the conditions contained
in the underwriting agreement, and that if any of the ordinary shares are
purchased by the underwriters under the underwriting agreement, then all of the
ordinary shares which the underwriters have agreed to purchase under the
underwriting agreement must be purchased. The conditions contained in the
underwriting agreement include that:

    - the representations and warranties made by us to the underwriters are
      true;

    - there is no material change in the financial markets; and

    - we deliver customary closing documents to the underwriters.

COMMISSIONS AND EXPENSES

    The representatives had advised us that the underwriters propose to offer
the ordinary shares directly to the public at the public offering price
presented on the cover page of this prospectus, and to selected dealers, who may
include the underwriters, at the public offering price less a selling concession
not in excess of $           per share. The underwriters may allow, and the
selected dealers may reallow, a concession not in excess of $           per
share to brokers and dealers. After the offering, the underwriters may change
the offering price and other selling terms.

    The following table summarizes the underwriting discounts and commissions we
will pay. The underwriting discounts and commissions are equal to the public
offer price per share less the amount paid to us per share. The underwriting
discounts and commissions will equal 7% of the public offering price.

<TABLE>
<CAPTION>
                                                                                  TOTAL
                                                                     -------------------------------
                                                                        WITHOUT            WITH
                                                         PER SHARE   OVER-ALLOTMENT   OVER-ALLOTMENT
                                                         ---------   --------------   --------------
<S>                                                      <C>         <C>              <C>
Underwriting discounts and commissions to be paid by
  us...................................................  $             $               $
</TABLE>

    We estimate that the total expenses of the offering, including registration,
filing and listing fees, printing fees and legal and accounting expenses but
excluding underwriting discounts and commissions, will be approximately
$2,000,000.

                                       77
<PAGE>
OVER-ALLOTMENT OPTION

    We have granted to the underwriters an option to purchase up to an aggregate
of 570,000 additional ordinary shares, exercisable solely to cover
over-allotments, if any, at the public offering price less the underwriting
discounts and commissions shown on the cover page of this prospectus. The
underwriters may exercise this option at any time, and from time to time, until
30 days after the date of the underwriting agreement. To the extent the
underwriters exercise this option, each underwriter will be committed, so long
as the conditions of the underwriting agreement are satisfied, to purchase a
number of additional ordinary shares proportionate to that underwriter's initial
commitment as indicated in the preceding table, and we will be obligated, under
the over-allotment option, to sell the ordinary shares to the underwriters.

LOCK-UP AGREEMENTS

    We have agreed that, without the prior written consent of Lehman
Brothers Inc., we will not, directly or indirectly, offer, sell or dispose of
any ordinary shares or any securities which may be converted into or exchanged
for any ordinary shares for a period of 180 days from the date of this
prospectus. Each of our officers and directors, all of our employees and
substantially all of our existing shareholders have agreed under lock-up
agreements that, without the prior written consent of Lehman Brothers Inc., they
will not, directly or indirectly, offer, sell or otherwise dispose of any
ordinary shares or any securities which may be converted into or exchanged for
any ordinary shares for a period of 180 days from the date of this prospectus.
In addition, as a condition to the private placement, Siemens and Samsung have
agreed not to dispose of the shares they acquire in the private placement for a
period of 270 days from the date of this prospectus.

OFFERING PRICE DETERMINATION

    Before this offering, there has been no public market for the ordinary
shares. The initial public offering price will be negotiated between the
representatives and us. In determining the initial public offering price of the
ordinary shares, the representatives will consider prevailing market conditions,
our historical performance and capital structure, estimates of our business
potential and earnings prospects, an overall assessment of our management and
the consideration of these factors in relation to market valuation of companies
in related businesses.

INDEMNIFICATION

    We have agreed to indemnify the underwriters against liabilities relating to
the offering, including liabilities under the Securities Act and liabilities
arising from breaches of the representations and warranties contained in the
underwriting agreement and to contribute to payments that the underwriters may
be required to make for these liabilities.

STABILIZATION, SHORT POSITIONS AND PENALTY BIDS

    Until the distribution of the ordinary shares is completed, rules of the
Securities and Exchange Commission may limit the ability of the underwriters and
selling group members to bid for and purchase ordinary shares. As an exception
to these rules, the representatives are permitted to engage in transactions that
stabilize the price of the ordinary shares. These transactions may consist of
bids or purchases for the purpose of stabilizing, fixing or maintaining the
price of the ordinary shares.

    The underwriters may create a short position in the ordinary shares in
connection with the offering, which means that they may sell more ordinary
shares than are presented on the cover page of this prospectus. If the
underwriters create a short position, then the representatives may reduce that
short position by purchasing ordinary shares in the open market. The
representatives also may elect to reduce any short position by exercising all or
part of the over-allotment option described in this prospectus.

                                       78
<PAGE>
    The underwriters have informed us that they do not intend to confirm sales
to discretionary accounts that exceed 5% of the total number of ordinary shares
offered by them.

    The representatives also may impose a penalty bid on underwriters and
selling group members. This means that if the representatives purchase ordinary
shares in the open market to reduce the underwriters' short position or to
stabilize the price of the ordinary shares, they may reclaim the amount of the
selling concession from the underwriters and selling group members who sold
those ordinary shares as part of the offering.

    In general, purchases of a security for the purpose of stabilization or to
reduce a syndicate short position could cause the price of the security to be
higher than it might be in the absence of these purchases. The imposition of a
penalty bid could have an effect on the price of a security to the extent that
it were to discourage resales of the security by purchasers in an offering.

    Neither we nor any of the underwriters make any representation or prediction
concerning the direction or magnitude of any effect that the transactions
described above may have on the price of the ordinary shares. In addition,
neither we nor any of the underwriters make any representation that the
representatives will engage in these transactions or that any transaction, once
commenced, will not be discontinued without notice.

STAMP TAXES

    Purchasers of the ordinary shares offered in this prospectus may be required
to pay stamp taxes and other charges under the laws and practices of the country
of purchase, in addition to the offering price listed on the cover page of this
prospectus.

FIDELITY CAPITAL MARKETS

    Fidelity Capital Markets, a division of National Financial Services
Corporation, is acting as an underwriter in this offering and will be
facilitating electronic distribution of information through the Internet,
intranet and other proprietary electronic technology.

OFFERS AND SALES IN ISRAEL

    The underwriters have agreed that:

    - they will not offer or sell the ordinary shares in Israel to more than 35
      potential purchasers in the aggregate;

    - they will deliver to us the names and addresses of these potential
      purchasers within seven days of the consummation of this offering; and

    - they will obtain representations from each of these potential purchasers
      who purchases ordinary shares that he is purchasing ordinary shares for
      investment purposes only, and not for the purposes of resale.

DIRECTED SHARE PROGRAM

    At our request, the underwriters have reserved up to 228,000 ordinary
shares, or 6% of the ordinary shares offered by this prospectus, for sale under
a directed share program to officers, directors, employees, business associates
and persons otherwise connected to us. All of the persons purchasing the
reserved shares must commit to purchase no later than the close of business on
the day following the date of this prospectus. The number of shares available
for sale to the general public will be reduced to the extent these persons
purchase the reserved shares.

                                       79
<PAGE>
                                 LEGAL MATTERS

    The validity of the ordinary shares being offered by this prospectus and
other legal matters concerning this offering relating to Israeli law will be
passed upon for us by Goldfarb, Levy, Eran & Co., Tel Aviv, Israel. Some legal
matters concerning this offering relating to United States law will be passed
upon for us by Weil, Gotshal & Manges LLP, New York, New York.

    Some legal matters concerning this offering relating to Israeli law will be
passed upon for the underwriters by Meitar, Liquornik, Geva & Co., Ramat Gan,
Israel. Some legal matters concerning this offering relating to United States
law will be passed upon for the underwriters by Brobeck, Phleger & Harrison LLP,
New York, New York.

                                    EXPERTS

    Our financial statements at December 31, 1998 and 1999 and for the years
ended December 31, 1997, 1998 and 1999 appearing in this prospectus have been
audited by Luboshitz Kasierer, a member firm of Arthur Andersen, independent
auditors, as stated in their report on the financial statements appearing
elsewhere in this prospectus, and are included in reliance upon their report
given upon the authority of this firm as experts in auditing and accounting.

                      ENFORCEABILITY OF CIVIL LIABILITIES

    Service of process upon us and upon our directors and officers and the
Israeli experts named in this prospectus, substantially all of whom reside
outside the United States, may be difficult to obtain within the United States.
Furthermore, because substantially all of our assets and substantially all of
our directors and officers are located outside the United States, any judgment
obtained in the United States against us or any of our directors and officers
may not be collectible within the United States.

    We have been informed by our legal counsel in Israel, Goldfarb, Levy,
Eran & Co., that there is doubt concerning the enforceability of civil
liabilities under the Securities Act and the Exchange Act in original actions
instituted in Israel. However, subject to specified time limitations, Israeli
courts may enforce a United States final executory judgment in a civil matter,
including a monetary or compensatory judgment in a non-civil matter, obtained
after due process before a court of competent jurisdiction according to the laws
of the state in which the judgment is given and the rules of private
international law currently prevailing in Israel. The rules of private
international law currently prevailing in Israel do not prohibit the enforcement
of judgment of Israeli courts, provided that:

    - the judgment is enforceable in the state in which it was given;

    - adequate service of process has been effected and the defendant has had a
      reasonable opportunity to present his arguments and evidence;

    - the judgment and the enforcement of the judgment are not contrary to the
      law, public policy, security or sovereignty of the State of Israel;

    - the judgment was not obtained by fraud and does not conflict with any
      other valid judgment in the same matter between the same parties; and

    - an action between the same parties in the same matter is not pending in
      any Israeli court at the time the lawsuit is instituted in the foreign
      court.

    We have irrevocably appointed RADVision Inc. as our agent to receive service
of process in any action against us in any federal court or court of the State
of New York arising out of this offering or any purchase or sale of securities
in connection with this offering.

    If a foreign judgment is enforced by an Israeli court, it generally will be
payable in Israeli currency, which can then be converted into non-Israeli
currency and transferred out of Israel. The usual practice in an action before
an Israeli court to recover an amount in a non-Israeli currency is for the
Israeli court to issue a judgment for the equivalent amount in Israeli currency
at the rate of exchange in force

                                       80
<PAGE>
on the date of the judgment, but the judgment debtor may make payment in foreign
currency. Pending collection, the amount of the judgment of an Israeli court
stated in Israeli currency ordinarily will be linked to the Israeli consumer
price index plus interest at the annual statutory rate set by Israeli
regulations prevailing at the time. Judgment creditors must bear the risk of
unfavorable exchange rates.

                   WHERE YOU CAN FIND ADDITIONAL INFORMATION

    We have filed with the Securities and Exchange Commission a registration
statement on Form F-1 under the Securities Act relating to this offering of our
ordinary shares. This prospectus does not contain all of the information
contained in the registration statement. The rules and regulations of the
Securities and Exchange Commission allow us to omit various information from
this prospectus that is included in the registration statement. Statements made
in this prospectus concerning the contents of any contract, agreement or other
document are summaries of all material information about the documents
summarized, but are not complete descriptions of all terms of these documents.
If we filed any of these documents as an exhibit to the registration statement,
you may read the document itself for a complete description of its terms.

    You may read and copy the registration statement, including the related
exhibits and schedules, and any document we file with the Securities and
Exchange Commission without charge at the Securities and Exchange Commission's
public reference room at 450 Fifth Street, N.W., Washington, D.C. 20549. Copies
of the material may be obtained by mail from the public reference branch of the
Securities and Exchange Commission at this address at rates specified by the
Securities and Exchange Commission. Please call the Securities and Exchange
Commission at 1-800-SEC-0330 for further information on the public reference
room. In addition, the registration statement is publicly available through the
website maintained by the Securities and Exchange Commission on the Internet's
worldwide web located at http://www.sec.gov.

    We are not currently subject to the informational requirements of the
Securities Exchange Act of 1934. As a result of this offering, we will become
subject to the informational requirements of the Exchange Act applicable to
foreign private issuers and will fulfill the obligations of these requirements
by filing reports with the Securities and Exchange Commission. You may obtain
copies of the documents that we file electronically with the Securities and
Exchange Commission through its website located at http://www.sec.gov.

    As a foreign private issuer, we will be exempt from the rules under the
Exchange Act relating to the furnishing and content of proxy statements, and our
officers, directors and principal shareholders will be exempt from the reporting
and short-swing profit recovery provisions contained in Section 16 of the
Exchange Act.

    In addition, we will not be required under the Exchange Act to file periodic
reports and financial statements with the Securities and Exchange Commission as
frequently or as promptly as United States companies whose securities are
registered under the Exchange Act. However, we intend to file with the
Securities and Exchange Commission, within 180 days after the end of each fiscal
year, an annual report on Form 20-F containing financial statements which will
be examined and reported on, with an opinion expressed, by an independent public
accounting firm. We also intend to file with the Securities and Exchange
Commission reports on Form 6-K containing unaudited financial information for
the first three quarters of each fiscal year, within 60 days after the end of
each quarter.

                                       81
<PAGE>
                                 RADVISION LTD.

                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

<TABLE>
<CAPTION>
                                                                PAGE
                                                              --------
<S>                                                           <C>
Report of Independent Public Accountants....................  F-2

Consolidated Balance Sheets as of December 31, 1998 and
  1999......................................................  F-3

Consolidated Statements of Operations for the years ended
  December 31, 1997, 1998 and 1999..........................  F-4

Consolidated Statements of Changes in Shareholders' Equity
  for the years ended December 31, 1997, 1998 and 1999 .....  F-5

Consolidated Statements of Cash Flows for the years ended
  December 31, 1997, 1998 and 1999..........................  F-6

Notes to the Consolidated Financial Statements..............  F-7
</TABLE>

                                      F-1
<PAGE>

                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS


To the Board of Directors and the Shareholders of
RADVision Ltd.

    We have audited the accompanying consolidated balance sheets of
RADVision Ltd. (an Israeli corporation) as of December 31, 1998 and 1999, and
the related consolidated statements of operations, changes in shareholders'
equity and cash flows for the years ended December 31, 1997, 1998 and 1999.
These financial statements are the responsibility of the Company's management.
Our responsibility is to express an opinion on these financial statements based
on our audits.

    We conducted our audits in accordance with generally accepted auditing
standards in the United States. Those standards require that we plan and perform
the audit to obtain reasonable assurance about whether the financial statements
are free of material misstatement. An audit includes examining, on a test basis,
evidence supporting the amounts and disclosures in the financial statements. An
audit also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provides a reasonable basis
for our opinion.

    In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the consolidated financial position of
the Company as of December 31, 1998 and 1999, and the results of operations,
changes in shareholders' equity and cash flows for the years ended December 31,
1997, 1998 and 1999, in conformity with accounting principles generally accepted
in the United States.


                                                    LUBOSHITZ KASIERER
                                              MEMBER FIRM OF ARTHUR ANDERSEN



Tel Aviv, Israel



March 7, 2000


                                      F-2
<PAGE>
                                 RADVISION LTD.

                          CONSOLIDATED BALANCE SHEETS


<TABLE>
<CAPTION>
                                                                                                       DECEMBER 31, 1999
                                                                               DECEMBER 31,                PRO FORMA
                                                                         -------------------------   SHAREHOLDERS' EQUITY
                                                                NOTE        1998          1999              NOTE 2
                                                              --------   -----------   -----------   ---------------------
<S>                                                           <C>        <C>           <C>           <C>
Current assets
  Cash and cash equivalents.................................    (3)      $ 3,304,738   $ 2,604,735
  Trade receivables, net of allowance for doubtful
    accounts................................................    (4)        2,567,346     3,214,462
  Other receivables and prepaid expenses....................    (4)          886,951     1,516,576
  Inventories...............................................    (5)          872,632     2,433,422
                                                                         -----------   -----------
    Total current assets....................................               7,631,667     9,769,195
                                                                         -----------   -----------
Property and equipment, net of accumulated depreciation.....    (6)        1,444,534     3,021,015
                                                                         -----------   -----------
Deposit with insurance companies............................                 295,001       470,361
                                                                         -----------   -----------
    Total assets............................................             $ 9,371,202   $13,260,571
                                                                         ===========   ===========
Current liabilities
  Current maturities of long-term loans.....................             $    74,602   $    63,901
  Trade payables............................................                 634,083     2,557,978
  Other payables and accrued expenses.......................    (7)        2,604,836     6,333,376
                                                                         -----------   -----------
    Total current liabilities...............................               3,313,521     8,955,255
                                                                         -----------   -----------
Long-term liabilities
  Bank loans................................................    (8)          130,146        67,383
  Accrued severance pay.....................................    (9)          477,836       756,812
                                                                         -----------   -----------
                                                                             607,982       824,195
                                                                         -----------   -----------
  Total liabilities.........................................               3,921,503     9,779,450
                                                                         -----------   -----------

Commitments and contingencies                                   (10)
Shareholders' equity                                            (11)
Preferred shares of NIS 0.1 par value:
  Authorized 5,275,000 shares; issued and outstanding
    2,957,165 shares as of December 31, 1998 and 1999;
    issued and outstanding pro forma as of December 31, 1999
    - none..................................................                   3,825         3,825
Ordinary shares of NIS 0.1 par value:
  Authorized - 12,332,317 shares as of December 31, 1998 and
    1999; issued and outstanding - 10,528,056 and 10,627,859
    shares as of December 31, 1998 and 1999; authorized pro
    forma - 24,984,470 shares; issued and outstanding pro
    forma - 13,585,024 shares as of December 31, 1999.......                  16,641        16,820        $    20,645
Additional paid-in capital..................................              12,088,150    13,788,618         13,788,618
Deferred compensation.......................................                 (78,378)   (1,051,549)        (1,051,549)
Accumulated deficit.........................................              (6,580,539)   (9,276,593)        (9,276,593)
                                                                         -----------   -----------        -----------
    Total shareholders' equity..............................               5,449,699     3,481,121        $ 3,481,121
                                                                         -----------   -----------        -----------
    Total liabilities and shareholders' equity..............             $ 9,371,202   $13,260,571
                                                                         ===========   ===========
</TABLE>


  THE ACCOMPANYING NOTES FORM AN INTEGRAL PART OF THESE CONSOLIDATED FINANCIAL
                                  STATEMENTS.

                                      F-3
<PAGE>
                                 RADVISION LTD.

                     CONSOLIDATED STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                                        FOR THE YEAR ENDED
                                                                           DECEMBER 31,
                                                             ----------------------------------------
                                                    NOTE         1997          1998          1999
                                                  --------   ------------   -----------   -----------
<S>                                               <C>        <C>            <C>           <C>
Revenues........................................   (12)      $  4,899,211   $ 8,894,414   $17,549,903
Cost of revenues................................                1,210,650     1,412,147     2,853,393
                                                             ------------   -----------   -----------
Gross profit....................................                3,688,561     7,482,267    14,696,510
                                                             ------------   -----------   -----------
Operating expenses
  Research and development expenses.............                2,763,786     4,378,829     7,666,583
  Less-participation by the Chief Scientist of
    the Government of Israel....................   (10)           890,326     1,139,749     1,096,722
                                                             ------------   -----------   -----------
  Research and development expenses, net........                1,873,460     3,239,080     6,569,861
  Marketing and selling expenses, net...........   (13)         2,383,704     4,425,231     9,501,682
  General and administrative expenses...........                  493,593       669,578     1,426,154
                                                             ------------   -----------   -----------
    Total operating expenses....................                4,750,757     8,333,889    17,497,697
                                                             ------------   -----------   -----------
Operating loss..................................               (1,062,196)     (851,622)   (2,801,187)
Financing income, net...........................                    6,001        22,447       105,133
                                                             ------------   -----------   -----------
Net loss........................................             $ (1,056,195)  $  (829,175)  $(2,696,054)
                                                             ============   ===========   ===========
Basic and diluted net loss per ordinary share...             $      (0.10)  $     (0.08)  $     (0.26)
                                                             ============   ===========   ===========
Weighted average number of ordinary shares
  outstanding--basic and diluted................               10,233,711    10,491,764    10,538,395
                                                             ============   ===========   ===========
Pro forma basic and diluted net loss per
  ordinary share (unaudited)....................   (2)                                    $     (0.20)
                                                                                          ===========
Weighted average number of ordinary shares
  outstanding--pro forma basic and diluted
  (unaudited)...................................   (2)                                     13,495,560
                                                                                          ===========
</TABLE>

  THE ACCOMPANYING NOTES FORM AN INTEGRAL PART OF THESE CONSOLIDATED FINANCIAL
                                  STATEMENTS.

                                      F-4
<PAGE>
                                 RADVISION LTD.

           CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY
<TABLE>
<CAPTION>
                             PREFERRED SHARES        ORDINARY SHARES
                           --------------------   ---------------------     ADDITIONAL        DEFERRED     ACCUMULATED
                            SHARES      AMOUNT      SHARES      AMOUNT    PAID-IN CAPITAL   COMPENSATION     DEFICIT
                           ---------   --------   ----------   --------   ---------------   ------------   ------------
<S>                        <C>         <C>        <C>          <C>        <C>               <C>            <C>
Balance as of
  January 1, 1997........         --    $   --    10,065,333   $15,893      $ 6,132,408     $        --    $(4,695,169)
Ordinary shares issued...         --        --       373,048       589          888,763 (1)          --             --
Deferred compensation....         --        --            --        --          159,084        (159,084)            --
Amortization of deferred
  compensation...........         --        --            --        --               --          76,591             --
Net loss.................         --        --            --        --               --              --     (1,056,195)
                           ---------    ------    ----------   -------      -----------     -----------    -----------
Balance as of
  December 31, 1997......         --        --    10,438,381    16,482        7,180,255         (82,493)    (5,751,364)
Ordinary shares issued...         --        --        89,675       159               --              --             --
Preferred shares
  issued.................  2,957,165     3,825            --        --        4,795,895 (2)          --             --
Deferred compensation....         --        --            --        --          112,000        (112,000)            --
Amortization of deferred
  compensation...........         --        --            --        --               --         116,115             --
Net loss.................         --        --            --        --               --              --       (829,175)
                           ---------    ------    ----------   -------      -----------     -----------    -----------
Balance as of
  December 31, 1998......  2,957,165     3,825    10,528,056    16,641       12,088,150         (78,378)    (6,580,539)
Ordinary shares issued...         --        --       158,250       179          249,821              --             --
Deferred compensation....         --        --            --        --        1,466,647      (1,466,647)            --
Amortization of deferred
  compensation...........         --        --            --        --          (16,000)        493,476             --
Net loss.................         --        --            --        --               --              --     (2,696,054)
                           ---------    ------    ----------   -------      -----------     -----------    -----------
Balance as of
  December 31, 1999......  2,957,165    $3,825    10,686,306   $16,820      $13,788,618     $(1,051,549)   $(9,276,593)
                           =========    ======    ==========   =======      ===========     ===========    ===========

<CAPTION>

                              TOTAL
                           -----------
<S>                        <C>
Balance as of
  January 1, 1997........  $ 1,453,132
Ordinary shares issued...      889,352
Deferred compensation....           --
Amortization of deferred
  compensation...........       76,591
Net loss.................   (1,056,195)
                           -----------
Balance as of
  December 31, 1997......    1,362,880
Ordinary shares issued...          159
Preferred shares
  issued.................    4,799,720
Deferred compensation....           --
Amortization of deferred
  compensation...........      116,115
Net loss.................     (829,175)
                           -----------
Balance as of
  December 31, 1998......    5,449,699
Ordinary shares issued...      250,000
Deferred compensation....           --
Amortization of deferred
  compensation...........      477,476
Net loss.................   (2,696,054)
                           -----------
Balance as of
  December 31, 1999......  $ 3,481,121
                           ===========
</TABLE>

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

(1) Net of issuance expenses of approximately $9,000.

(2) Net of issuance expenses of approximately $85,000.

  THE ACCOMPANYING NOTES FORM AN INTEGRAL PART OF THESE CONSOLIDATED FINANCIAL
                                  STATEMENTS.

                                      F-5
<PAGE>
                                 RADVISION LTD.

                     CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                          FOR THE YEAR ENDED
                                                                             DECEMBER 31,
                                                              ------------------------------------------
                                                                 1997          1998             1999
                                                              -----------   -----------      -----------
<S>                                                           <C>           <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES
  Net loss..................................................  $(1,056,195)  $  (829,175)     $(2,696,054)
  Adjustments to reconcile net loss to net cash provided by
    (used in) operating activities:
      Income and expenses not affecting operating cash
        flows:
        Depreciation........................................      204,357       360,331          718,444
        Severance pay.......................................       31,741        39,051          103,616
        Amortization of deferred compensation...............       76,591       116,115          477,476
        Other...............................................        1,511        17,159           19,308
      Changes in operating assets and liabilities:
        Increase in trade receivables.......................   (1,391,255)     (724,060)        (647,116)
        Increase in other receivables and prepaid
          expenses..........................................      (32,324)     (625,820)        (429,625)
        Decrease (increase) in inventories..................      101,043      (447,200)      (1,560,790)
        Increase in trade payables..........................       42,826       282,924        1,923,895
        Increase in other payables and accrued expenses.....    1,051,813       963,589        3,528,540
                                                              -----------   -----------      -----------
            Net cash provided by (used in) operating
              activities....................................     (969,892)     (847,086)       1,437,694
                                                              -----------   -----------      -----------

CASH FLOWS FROM INVESTING ACTIVITIES
  Purchase of property and equipment........................     (460,193)   (1,102,164)      (2,388,490)
  Proceeds from sale of property and equipment..............       32,097        19,285           74,257
                                                              -----------   -----------      -----------
            Net cash used in investing activities...........     (428,096)   (1,082,879)      (2,314,233)
                                                              -----------   -----------      -----------

CASH FLOWS FROM FINANCING ACTIVITIES
  Issuance of share capital.................................      889,352     4,799,879          250,000
  Decrease in short-term credit.............................     (524,716)      (54,055)         (10,701)
  Long-term loans received..................................      452,080       100,000               --
  Repayment of long-term loans..............................     (333,336)      (45,734)         (62,763)
                                                              -----------   -----------      -----------
            Net cash provided by financing activities.......      483,380     4,800,090          176,536
                                                              -----------   -----------      -----------

INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS............     (914,608)    2,870,125         (700,003)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD............    1,349,221       434,613        3,304,738
                                                              -----------   -----------      -----------
CASH AND CASH EQUIVALENTS AT END OF PERIOD..................  $   434,613   $ 3,304,738      $ 2,604,735
                                                              ===========   ===========      ===========
CASH PAID DURING THE PERIOD IN RESPECT OF INTEREST..........  $    29,387   $    22,715      $    15,839
NON-CASH ACTIVITY...........................................           --            --      $   200,000
                                                              ===========   ===========      ===========
</TABLE>

  THE ACCOMPANYING NOTES FORM AN INTEGRAL PART OF THESE CONSOLIDATED FINANCIAL
                                  STATEMENTS.

                                      F-6
<PAGE>
                                 RADVISION LTD.

                 NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

NOTE 1--GENERAL

    RADVision Ltd., referred to in these consolidated financial statements as
the Company, an Israeli corporation, designs, develops and supplies products and
technology that enable real-time voice, video and data communications over
packet networks, including the Internet and other networks based on the Internet
protocol.

    The consolidated financial statements include the financial statements of
the Company and its wholly-owned subsidiaries, RADVision Inc., in the United
States and RADVision B.V. in the Netherlands. The subsidiaries are primarily
engaged in the sale and marketing of the Company's products and technology.

    The financial statements of the Company have been prepared in U.S. dollars,
as the currency of the primary economic environment in which the operations of
the Company are conducted is the U.S. dollar. All of the Company's sales are in
U.S. dollars or are dollar-linked. Most purchases of materials and components
and most marketing costs are denominated in U.S. dollars. Therefore, the
functional currency of the Company is the U.S. dollar.

    Transactions and balances originally denominated in U.S. dollars are
presented at their original amounts. Transactions and balances in other
currencies are translated into U.S. dollars in accordance with the principles
set forth in Statement No. 52 of the Financial Accounting Standards Board of the
United States. Items have been translated as follows:

    -- Monetary items--at the exchange rate in effect on balance sheet date.

    -- Non monetary items--at historical exchange rates.

    -- Revenue and expense items--at the exchange rates in effect as of date of
       recognition of those items, excluding depreciation and other items
       deriving from non-monetary items.

    All exchange gains and losses from the translation mentioned above, which
are immaterial for all periods presented, are reflected in the statement of
operations. The representative rate of exchange at December 31, 1999 was
U.S.$1.00 = NIS 4.153; and at December 31, 1998 and 1997 was U.S.$1.00 =
NIS 4.16 and NIS 3.536.

NOTE 2--SIGNIFICANT ACCOUNTING POLICIES

    The financial statements are prepared according to generally accepted
accounting principles in the United States. The significant accounting policies
followed in the preparation of the financial statements, applied on a consistent
basis, are as follows:

    A. PRINCIPLES OF CONSOLIDATION

    The financial statements include the accounts of the Company and its
wholly-owned subsidiaries in the United States and Netherlands. Material
intercompany balances and transactions have been eliminated.

    B. CASH AND CASH EQUIVALENTS

    All highly liquid investments with an original maturity of three months or
less are considered cash equivalents.

                                      F-7
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 2--SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    C. ALLOWANCE FOR DOUBTFUL ACCOUNTS

    Allowance for doubtful accounts is computed for specific debts the
collectibility of which is doubtful based upon the Company's experience.

    D. INVENTORIES

    Inventories are valued at the lower of cost or market. Cost is determined on
the moving average basis.

    E. PROPERTY AND EQUIPMENT

    Property and equipment are stated at cost. Depreciation is computed by the
straight-line method over the estimated useful life of the assets, ranging from
3 to 15 years.

    F. REVENUE RECOGNITION


    Revenues from sales of products and technology are recognized in accordance
with Statement of Position (SOP) 97-2, as amended by SOP 98-4, upon delivery,
when collection is probable, the vendor's fee is fixed or determinable and
persuasive evidence of an arrangement exists. Provided that all other elements
of SOP 97-2 are met, revenues are recognized upon delivery, whether the customer
is a distributor or the final end user. Revenues for maintenance and support
services are deferred and recognized ratably over the service period.


    In accordance with SOP 97-2, revenues for multi-element arrangements, that
is, sales of products or technology in conjunction with post-contract customer
support services, are segregated. Revenues allocated to the delivered elements
are recognized upon delivery, provided that the other elements of SOP 97-2 are
satisified. Revenues allocated to the undelivered elements (post-contract
customer support services) are deferred and recognized ratably over the service
period. The portion of the fee for multi-element arrangements allocated to the
undelivered elements (post-contract customer support services) is based on
vendor-specific object evidence determined, in the case of post-contract
customer support services, based on the annual renewal rate for such services
actually charged to customers for years subsequent to the first year following
sale. The remaining portion of the fee is allocated to the delivered elements
based on the residual value method.

    G. RESEARCH AND DEVELOPMENT COSTS

    Research and development costs, net of participations by the Government of
Israel through the Ministry of Industry and Trade, Office of the Chief
Scientist, are charged to operations as incurred. Software development costs are
considered for capitalization when technological feasibility is established
according to Statement of Financial Accounting Standards No. 86, "Accounting for
the Costs of Computer Software to be Sold, Leased or Otherwise Marketed." Costs
incurred after achievement of technological feasibility in the process of
software production have not been material. Therefore, the Company has not
capitalized any of its research and development expenses and does not anticipate
that its development process will differ materially in the future.

                                      F-8
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 2--SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    H. INCOME TAXES

    The Company accounts for income taxes under the liability method of
accounting. Under the liability method, deferred taxes are determined based on
the differences between the financial statement and tax bases of assets and
liabilities at enacted tax rates in effect in the year in which the differences
are expected to reverse. Valuation allowances are established, when necessary,
to reduce deferred tax assets to amounts expected to be realized.

    I. FAIR VALUE OF FINANCIAL INSTRUMENTS

    Unless otherwise noted, the carrying amount of financial instruments
approximates fair value.

    J. PROVISION FOR WARRANTY COSTS

    The Company warrants its products for a twelve-month period. Provisions for
warranty costs are based on the Company's past experience.

    K. BASIC AND DILUTED NET LOSS PER SHARE

    Basic and diluted net loss per share are presented according to SFAS
No. 128, "Earnings per share", for all periods presented.

    Basic and diluted net loss per share have been computed using the
weighted-average number of ordinary shares outstanding during the period. Basic
and diluted pro forma net loss per share, as presented in the statements of
operations, have been computed using the weighted average number of ordinary
shares outstanding during the period and also give effect to the automatic
conversion of the preferred shares into ordinary shares upon the closing of an
initial public offering, using the as-if converted method from original date of
issuance.

    All preferred shares and outstanding share options have been excluded from
the calculation of diluted net loss per share because all these securities are
antidilutive for all periods presented. The total number of shares related to
the outstanding options excluded from the calculations of diluted net loss per
share were 649,880, 1,430,580 and 2,667,251 for the years ended December 31,
1997, 1998 and 1999.

    L. PRO FORMA SHAREHOLDERS' EQUITY

    Upon the closing of an initial public offering, all of the preferred shares
outstanding will automatically be converted into an identical number of ordinary
shares. Pro forma shareholders' equity at December 31, 1999, as adjusted for the
assumed conversion of the preferred shares outstanding at December 31, 1999, is
disclosed in the balance sheet. Pro forma share and per share data is adjusted
to reflect the conversion and the share split and share dividend effected after
December 31, 1999. See note 17.

    M. SHARE-BASED COMPENSATION

    The Company has adopted the disclosure provisions of SFAS No. 123,
"Accounting for Stock-Based Compensation," and the accounting rules in
Accounting Principles Board Opinion No. 25, "Accounting

                                      F-9
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 2--SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
for Stock Issued to Employees." The Company has provided the necessary pro forma
disclosures as if the fair value method had been applied. See note 11(B).

    N. USE OF ESTIMATES

    The preparation of the financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting period. Actual results could differ from those estimates.

    O. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS

    In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities." SFAS No. 133
established accounting and reporting standards requiring that every derivative
instrument be recorded on the balance sheet at its fair value. SFAS No. 133
requires that changes in the derivative's fair value be recognized currently in
earnings unless specific hedge accounting criteria are met. Special accounting
for qualifying hedges allows a derivative's gains and losses to offset related
results on the hedged item in the statement of operations. SFAS No. 133 is
effective for fiscal years beginning after June 15, 2000. The Company believes
that the adoption of SFAS No. 133 will not have a material effect on its
financial statements.

NOTE 3--CASH AND CASH EQUIVALENTS

<TABLE>
<CAPTION>
                                                            DECEMBER 31,
                                                       -----------------------
                                                          1998         1999
                                                       ----------   ----------
<S>                                                    <C>          <C>
Cash in banks, primarily in U.S. dollars.............  $  955,053   $1,828,335
Bank deposits in U.S. dollars, bearing annual
  interest rate of 4.3%..............................   1,350,000      615,875
Bank deposits in NIS, bearing annual interest rate of
  10.3%..............................................     999,685      160,525
                                                       ----------   ----------
                                                       $3,304,738   $2,604,735
                                                       ==========   ==========
</TABLE>

    The interest rates are as of December 31, 1999.

NOTE 4--TRADE RECEIVABLES, NET

    A. Trade receivables are presented net of allowance for doubtful accounts in
the amount of $72,539 and $224,705 as of December 31, 1998 and 1999. The Company
generally provides customers with a thirty day post-sale acceptance period,
during which customers can return products for a full refund. Historically,
returns during this period have been negligible.

    B. Other receivables and prepaid expenses include grants receivable from the
Government of Israel in the amount of $442,681 and $864,444 as of December 31,
1998 and 1999.

                                      F-10
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 5--INVENTORIES

<TABLE>
<CAPTION>
                                                            DECEMBER 31,
                                                        ---------------------
                                                          1998        1999
                                                        --------   ----------
<S>                                                     <C>        <C>
Materials and components..............................  $393,206   $1,037,633
Work in process.......................................   136,772      634,969
Finished products.....................................   342,654      760,820
                                                        --------   ----------
                                                        $872,632   $2,433,422
                                                        ========   ==========
</TABLE>

NOTE 6--PROPERTY AND EQUIPMENT

<TABLE>
<CAPTION>
                                                                   DECEMBER 31,
                                                              -----------------------
                                                                 1998         1999
                                                              ----------   ----------
<S>                                                           <C>          <C>
COST
  Research and development equipment........................  $  751,565   $1,370,345
  Motor vehicles............................................     513,200    1,039,715
  Manufacturing equipment...................................     114,366      236,208
  Office furniture and equipment and leasehold
    improvements............................................     811,833    1,753,264
                                                              ----------   ----------
                                                               2,190,964    4,399,532
                                                              ----------   ----------
ACCUMULATED DEPRECIATION
  Research and development equipment........................     378,017      669,773
  Motor vehicles............................................     105,704      148,674
  Manufacturing equipment...................................      62,396      109,383
  Office furniture and equipment and leasehold
    improvements............................................     200,313      450,687
                                                              ----------   ----------
                                                                 746,430    1,378,517
                                                              ----------   ----------
NET BOOK VALUE..............................................  $1,444,534   $3,021,015
                                                              ==========   ==========
</TABLE>

    For the years ended December 31, 1997, 1998 and 1999, depreciation expense
was $204,357, $360,331 and $718,444.

    The Company's property and equipment are primarily located in Israel.

                                      F-11
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 7--OTHERS PAYABLES AND ACCRUED EXPENSES

<TABLE>
<CAPTION>
                                                                           DECEMBER 31,
                                                                      -----------------------
                                                                         1998         1999
                                                                      ----------   ----------
        <S>                                                           <C>          <C>
        Deferred income.............................................  $1,521,763   $2,930,587
        Employees and employee institutions(1)......................     705,973    1,493,704
        Accrued royalties...........................................     289,000      476,000
        Tax withholding payable.....................................          --      403,000
        Offering expenses payable...................................          --      200,000
        Accrued expenses............................................      88,100      830,085
                                                                      ----------   ----------
                                                                      $2,604,836   $6,333,376
                                                                      ==========   ==========
</TABLE>

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

(1) Employees and employee institutions include salaries, bonuses and employee
    institutions payable. The employee institutions include amounts deducted
    from employees payroll for December 1998 and 1999, respectively, for
    educational funds and insurance policies funds. For the years ended December
    31, 1997, 1998 and 1999, educational funds expenses were $72,205, $122,239
    and $232,996 and insurance policies funds expenses were $136,060, $208,195
    and $409,598.

NOTE 8--LONG-TERM BANK LOANS

<TABLE>
<CAPTION>
                                                             DECEMBER 31,
                                                          -------------------
                                                            1998       1999
                                                          --------   --------
<S>                                                       <C>        <C>
Loans linked to the U.S. dollar.........................  $204,748   $131,284
Less--current maturities................................    74,602     63,901
                                                          --------   --------
                                                          $130,146   $ 67,383
                                                          ========   ========
</TABLE>

    The loans bear interest at an annual rate of the London interbank offered
rate plus 1%, which was 5.5% at December 31, 1999, and mature in equal quarterly
installments through 2002.

NOTE 9--ACCRUED SEVERANCE PAY

    Under Israeli law and labor agreements, the Company is required to make
severance payments to its dismissed employees and employees leaving its
employment in other circumstances. The Company's severance pay liability to its
employees, which is calculated on the basis of the salary of each employee for
the last month of the reported period multiplied by the years of the employee's
employment, is reflected in the Company's balance sheet on the accrual basis,
and is partially funded by purchase of insurance policies in the name of the
Company. The severance pay expense for the years ended December 31, 1997, 1998
and 1999 amounted to $113,579, $134,248 and $365,076.

NOTE 10--COMMITMENTS AND CONTINGENCIES

    A. In connection with its research and development, the Company received and
       accrued participation payments from the Office of the Chief Scientist of
       the Ministry of Industry and Trade in Israel in the total amount of
       approximately $4.5 million. In return for the Government of Israel's
       participation, the Company is committed to pay royalties at a rate of
       3% - 5% of sales of the developed product, up to 100% - 150% of the
       amount of grants

                                      F-12
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 10--COMMITMENTS AND CONTINGENCIES (CONTINUED)
       received, or for grants received under programs approved after
       January 1, 1999, 100% plus interest at the London interbank offered rate.
       The Company's total commitment for royalties payable with respect to
       future sales, based on Government of Israel participations received or
       accrued, net of royalties paid or accrued, totaled approximately
       $3.7 million as of December 31, 1999. In the event that the development
       program does not result in the sale of products, the Company is not
       obligated to repay any grants. However, if the Company fails to comply
       with any of the conditions imposed by the Chief Scientist, it could be
       required to refund any payments previously received, together with
       interest and penalties.

    B.  In connection with its marketing activities, the Company received and
       accrued participation payments from the Government of Israel--Fund for
       the Encouragement of Marketing Activities, in the total amount of
       approximately $686,000. In return for the participation payments, the
       Company is committed to pay royalties at a rate of 3% of the Company's
       total increase in export sales, from the end of the second year of
       implementation of the marketing plan until the date at which the
       participation has been fully repaid. The Company's total commitment for
       royalties payable with respect to future sales, based on Government of
       Israel participations received or accrued, net of royalties paid or
       accrued, totaled approximately $199,000 as of December 31, 1999.

    C.  In connection with its research and development, the Company received
       and accrued participation payments from the Israel U.S. Binational
       Industrial Research and Development Foundation (BIRDF), in the total
       amount of approximately $188,000. In return for the participation, the
       Company is committed to pay royalties at a rate of 2.5% of proceeds from
       the first year's sales and 5% of the proceeds from the succeeding years'
       sales, up to the amount of the grant. Once the amount of the grant has
       been repaid, royalties will be payable at the rate of 2.5% of proceeds,
       until additional royalties equal to one half of the grant amount have
       been repaid. The Company's total commitment for royalties payable with
       respect to future sales, based on Government participations received or
       accrued, net of royalties paid or accrued, totaled approximately $276,000
       as of December 31, 1999.

    D. The Company and its U.S. subsidiary operate from leased premises in Tel
       Aviv, Israel and in Mahwah, New Jersey and Sunnyvale, California. Lease
       agreements expire in December 1999 through May 2002 (some with renewal
       options). Annual minimum future rental payments due under the above
       agreements, at the exchange rate in effect on December 31, 1999, are
       approximately as follows:

<TABLE>
<S>                                                 <C>
2000..............................................  $510,877
2001..............................................   129,910
2002..............................................    74,514
                                                    --------
                                                    $715,301
                                                    ========
</TABLE>

    E.  The Company is committed to pay royalties to third parties for the
       integration of these third parties' technologies into the Company's
       products. Royalties are payable based on the sales volume of these
       products, for as long as the Company uses these technologies, without
       limit on the amount of royalties payable. The rates of these royalties
       are based on a fixed amount per product sold by the Company in the range
       of $1.00 to $5.00 per unit sold. The agreements

                                      F-13
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 10--COMMITMENTS AND CONTINGENCIES (CONTINUED)

<TABLE>
<S>                                                 <C>
</TABLE>

       pursuant to which the royalties are payable have no expiration date.
       Annual minimum future royalty payments are approximately as follows:

<TABLE>
<S>                                                 <C>
2000..............................................  $ 30,000
2001..............................................    25,000
2002..............................................    25,000
2003..............................................    25,000
                                                    --------
                                                    $105,000
                                                    ========
</TABLE>

    F.  In 1998, a third party sent correspondence to the Company's affiliate
       alleging that some products manufactured by the Company infringe upon
       patents held by the third party and offered to license these patents to
       the Company. In subsequent correspondence, the Company's affiliate
       requested that the third party specifically substantiate each allegation
       of infringement before the Company's affiliate would be prepared to enter
       into any licensing arrangements. The Company does not believe that these
       allegations will have a material adverse effect upon its business,
       financial condition or liquidity. The Company's affiliate has recently
       received further correspondence from the third party, in which the third
       party has, among other things, reiterated its claims. The Company's
       affiliate does not believe the third party has substantiated its claims
       and has communicated this belief to the third party. The Company's
       affiliate has advised the Company that the alleged infringement claims
       are unresolved.

NOTE 11--SHAREHOLDERS' EQUITY


    A. The Company's preferred shares confer the same right as the Company's
       ordinary shares except that the preferred shares have preference over the
       ordinary shares in the event of any voluntary or involuntary liquidation,
       dissolution or winding up of the Company. Each share of preferred shares
       is convertible into ordinary shares at a conversion rate of 1-to-1 at any
       time, at the holder's option, and automatically upon an initial public
       offering of the Company. The preferred shares have anti-dilution rights
       which provide that the conversion ratio pursuant to which the preferred
       shares convert into ordinary shares is to be adjusted upon any share
       dividend, share split or similar event affecting the ordinary shares in
       order to preserve the 1-to-1 preferred shares to ordinary shares
       conversion rate in effect at the time the preferred shares were issued.


    B.  The Company adopted a key employee share incentive plan which provides
       for the grant by the Company of option awards to purchase up to an
       aggregate of 3,163,523 ordinary shares to officers, employees, directors
       and consultants of the Company, its subsidiaries and affiliates. The
       options vest ratably over vesting periods ranging from three to five
       years. The options expire 62 months from the date of issuance. The
       exercise price of options under the plan is at varying prices ranging
       from $0.95 to $1.74.

                                      F-14
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 11--SHAREHOLDERS' EQUITY (CONTINUED)

<TABLE>
<S>                                                 <C>
</TABLE>

       Transactions related to the share incentive plan during the years ended
       December 31, 1997, 1998 and 1999 and the weighted average exercise prices
       per share and weighted average fair value of the options at the date of
       grant are summarized as follows:

<TABLE>
<CAPTION>
                                                                             WEIGHTED
                                                             WEIGHTED      AVERAGE FAIR
                                                             AVERAGE         VALUE OF
                                            OUTSTANDING   EXERCISE PRICE     OPTIONS
                                              OPTIONS       PER SHARE        GRANTED
                                            -----------   --------------   ------------
<S>                                         <C>           <C>              <C>
Outstanding as of January 1, 1997.........     132,930         $1.33
Options granted...........................     516,950          1.43          $0.57
                                             ---------         -----

Outstanding as of December 31, 1997.......     649,880          1.41
Options granted...........................     791,250          1.18          $0.29
Options forfeited.........................     (10,550)         1.64
                                             ---------         -----

Outstanding as of December 31, 1998.......   1,430,580          1.28
Options granted...........................   1,421,296          1.18          $1.14
Options forfeited.........................    (184,625)         1.18
                                             ---------         -----
Outstanding as of December 31, 1999.......   2,667,251         $1.23
                                             =========         =====
</TABLE>

       The following table summarizes information about options outstanding and
       exercisable at December 31, 1999:

<TABLE>
<CAPTION>
                                OPTIONS OUTSTANDING                OPTIONS EXERCISABLE
                       --------------------------------------   -------------------------
                          NUMBER       WEIGHTED-                   NUMBER
                       OUTSTANDING      AVERAGE     WEIGHTED-   OUTSTANDING    WEIGHTED-
                            AT         REMAINING     AVERAGE         AT         AVERAGE
                       DECEMBER 31,   CONTRACTUAL   EXERCISE    DECEMBER 31,    EXERCISE
EXERCISE PRICE             1999          LIFE        PRICES         1999         PRICES
- --------------         ------------   -----------   ---------   ------------   ----------
<S>                    <C>            <C>           <C>         <C>            <C>
$0.95 - $0.98........     860,458        4.38         $0.95        34,182        $0.96
1.18.................   1,023,350(1)     3.43          1.18       349,838         1.18
1.58 - 1.64..........     688,493        4.01          1.59       114,573         1.63
1.74.................      94,950        2.42          1.74        44,310         1.74
                        ---------                                 -------
                        2,667,251                                 542,903
                        =========                                 =======
</TABLE>

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

(1) Includes 63,300 options that were granted in 1998 to two consultants that
    meet the definition of a common law employee for U.S. GAAP purposes because
    the Company has the right to direct and control the work of each consultant,
    that is, both the final results and the details of when, where and how the
    work is to be done. If deferred compensation for the options granted to
    these consultants had been accounted for under SFAS No. 123, deferred
    compensation would have been increased by approximately $10,000.

                                      F-15
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 11--SHAREHOLDERS' EQUITY (CONTINUED)
       The amounts of deferred compensation recognized arising from the
       difference between the exercise price and the fair market value on the
       date of the grant of $112,000 and $1,466,647 for options granted in the
       years ended December 31, 1998 and 1999 are included in shareholders'
       equity and was amortized over the vesting periods of the options
       according to APB 25. Under APB 25, the deferred compensation expense for
       the years ended December 31, 1997, 1998 and 1999, amounted to $76,591,
       $116,115 and $477,476.

       If deferred compensation had been determined under the alternative fair
       value accounting method provided for under SFAS Statement No. 123,
       "Accounting for Stock-Based Compensation," the Company's net loss and net
       loss per share would have been increased to the following pro forma
       amounts:

<TABLE>
<CAPTION>
                                                    FOR THE YEAR ENDED
                                                       DECEMBER 31,
                                          --------------------------------------
                                             1997         1998          1999
                                          -----------   ---------   ------------
<S>                                       <C>           <C>         <C>
Net loss:
  As reported...........................  $(1,056,195)  $(829,175)  $ (2,696,054)
  Pro forma.............................   (1,148,999)   (956,396)    (2,733,876)
Net loss per share:
  As reported...........................  $     (0.10)  $   (0.08)  $      (0.26)
  Pro forma.............................        (0.11)      (0.09)         (0.26)
</TABLE>

       Under SFAS No. 123, the fair value of each option grant is estimated on
       the date of grant using the Black-Scholes option-pricing model with the
       following weighted-average assumptions used for grants in 1997, 1998 and
       1999:

       - expected life of the options of 2.57, 2.72 and 2.84;

       - no dividend yield;

       - expected volatility of 0%; and

       - risk-free interest rate of 5%.

    C.  Authorized share capital includes 12,760 deferred shares of par value
       NIS 0.1 each. The deferred shares confer no rights or privileges on their
       holders except for the right to receive upon dissolution or liquidation
       the par value of the deferred shares.

    D. In 1998, the Company issued 121,114 ordinary shares at NIS 0.1 per share
       as an anti-dilution adjustment to existing shareholders that purchased
       shares in a 1997 private placement. Pursuant to a resolution adopted by
       the board of directors of the Company in connection with the 1997 private
       placement, the shareholders who participated in the private placement
       were granted anti-dilution rights. These anti-dilution rights were
       triggered in 1998 when the Company issued preferred shares at a lower
       price per share than the price per share at which the shares sold in the
       1997 private placement were offered.

    E.  Amounts due for shares issued, but not yet fully paid, as of
       December 31, 1999 was approximately $300,000.

    F.  In December 1999, the Company issued 158,250 ordinary shares to Intel
       for $250,000, or $1.58 per share, which is $17.42 less than the assumed
       initial public offering price of $19.00 per

                                      F-16
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 11--SHAREHOLDERS' EQUITY (CONTINUED)
       share. The shares were issued under an agreement entered into with Intel
       in 1996 under which Intel agreed to invest $1.0 million in the Company
       through the purchase of ordinary shares in three installments of
       $500,000, $250,000 and $250,000 upon the Company's achieving specified
       milestones or, in the case of the third installment, at Intel's option
       before the Company's initial public offering of its ordinary shares.

    G. Subsequent Events--see notes 17(C) and 17(D).

NOTE 12--REVENUES

    The Company's sales by geographic area are as follows:

<TABLE>
<CAPTION>
                                                                   FOR THE YEAR ENDED
                                                                      DECEMBER 31,
                                                          -------------------------------------
                                                             1997         1998         1999
                                                          ----------   ----------   -----------
<S>                                                       <C>          <C>          <C>
United States...........................................  $3,012,256   $4,569,477   $ 9,062,187
Europe..................................................     632,278    2,248,880     4,045,882
Far East................................................     331,649      942,460     2,662,865
Israel..................................................     616,804      857,552     1,310,208
Other...................................................     306,224      276,045       468,761
                                                          ----------   ----------   -----------
                                                          $4,899,211   $8,894,414   $17,549,903
                                                          ==========   ==========   ===========
</TABLE>

    The Company manages its business on the basis of one reportable segment.

NOTE 13--MARKETING AND SELLING EXPENSES, NET

<TABLE>
<CAPTION>
                                                                    FOR THE YEAR ENDED
                                                                       DECEMBER 31,
                                                           ------------------------------------
                                                              1997         1998         1999
                                                           ----------   ----------   ----------
<S>                                                        <C>          <C>          <C>
Marketing and selling expenses...........................  $2,465,071   $4,603,336   $9,699,745
Participation by the Government of Israel................      81,367      178,105      198,063
                                                           ----------   ----------   ----------
Marketing and selling expenses, net......................  $2,383,704   $4,425,231   $9,501,682
                                                           ==========   ==========   ==========
Marketing and selling expenses include: Royalties to the
  Government of Israel...................................  $  175,236   $  366,736   $  896,249
                                                           ==========   ==========   ==========
</TABLE>

NOTE 14--CONCENTRATION OF CREDIT RISK

    For the periods ended December 31, 1998 and 1999, no single customer
accounted for more than 10% of the Company's sales and no customer represented
more than 10% of trade receivables. The Company does not generally require
collateral to support credit sales. Allowances are maintained for potential
credit losses.

                                      F-17
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 15--RELATED PARTY BALANCES AND TRANSACTIONS

    A. BALANCES WITH RELATED PARTIES

<TABLE>
<CAPTION>
                                                             DECEMBER 31,
                                                          -------------------
                                                            1998       1999
                                                          --------   --------
<S>                                                       <C>        <C>
Receivables.............................................  $ 72,476   $124,264
Trade payables..........................................    88,946    305,325
</TABLE>

    B. TRANSACTIONS WITH RELATED PARTIES

<TABLE>
<CAPTION>
                                                      FOR THE YEAR ENDED
                                                         DECEMBER 31,
                                               ---------------------------------
                                                 1997       1998          1999
                                               --------   --------      --------
<S>                                            <C>        <C>           <C>
Revenues(1)..................................  $285,813   $ 47,429      $166,812
Cost of revenues(3)(4).......................   124,177    252,655       384,951
Research and development
  expenses(2)(3).............................    12,823      3,017       362,573
Marketing, selling, general and
  administrative expenses(2)(3)..............   405,650    201,238       343,873
Purchase of property and
  equipment(5)...............................    37,695     64,225       283,752
</TABLE>

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

       (1) Includes revenues from agreements to license the Company's technology
           to RADCOM Ltd. and RAD Data Communications Ltd., affiliated
           companies. The agreements are based on the Company's standard form
           and include a licensing fee, maintenance and support services for one
           year and minimum royalty payments on sales of products which
           incorporate the technology.

       (2) Includes legal, human resources and administrative services provided
           to the Company by affiliated companies which the Company reimburses
           for the costs incurred in providing these services.

       (3) Includes rental fees based on lease agreements with RIT Technologies
           Ltd., RAD Data Communications Ltd., and several other affiliated
           companies. Under these lease agreements, the Company leases office
           space of approximately 21,830 and 9,000 square feet, in Israel and in
           New Jersey, respectively. The expiration dates of these lease
           agreements range from August 2000 to May 2002.

       (4) Includes the purchase of components from RAD Data Communications
           Ltd., an affiliated company, which the Company integrates into its
           products.

       (5) Includes property and equipment that were purchased mainly from BYNET
           Data Communications Ltd., an affiliated company.

NOTE 16--TAXES ON INCOME

    A. The Company's investment program totaling $122,000 has been granted
       Approved Enterprise status under the Law for Encouragement of Capital
       Investments, 1959. In addition, the Company was granted Approved
       Enterprise status for an expansion of a previous program totaling
       $210,000. The Company is entitled to a benefit period of seven years on
       income derived from these programs, as follows: a full income tax
       exemption for the first two years

                                      F-18
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 16--TAXES ON INCOME (CONTINUED)
       and a reduced income tax rate of 25% (instead of the regular rate of 36%)
       for the remaining five year period. If foreign shareholdings in the
       Company exceed 25%, the period for which the Company is entitled to a
       reduced income tax is extended to eight years.

       If the Company distributes a cash dividend out of retained earnings which
       were tax exempt due to its approved enterprise status, the Company would
       have to pay a 25% corporate tax on the amount distributed, and a further
       15% withholding tax would be deducted from the amounts distributed to the
       recipients.

       Should the Company derive income from sources other than the approved
       enterprise programs during the relevant period of benefits, this income
       will be taxable at the regular corporate tax rate, which is 36%.

       The benefits from the Company's approved enterprise programs are
       dependent upon the Company fulfilling the conditions stipulated by the
       Law for Encouragement of Capital Investments, 1959, and the regulations
       published under this law, as well as the criteria in the approval for the
       specific investment in the Company's approved enterprise programs. If the
       Company does not comply with these conditions, the tax benefits may be
       canceled, and the Company may be required to refund the amount of the
       canceled benefits, with the addition of linkage differences and interest.
       As of the date of these financial statements, the Company believes it has
       complied with these conditions.

    B.  The Company is subject to the Income Tax Law (Inflationary Adjustments),
       1985, measuring income on the basis of changes in the Israeli Consumer
       Price Index.

    C.  The Company is an Industrial Company under the Law for Encouragement of
       Industry (Taxes), 1969 and is therefore entitled to tax benefits, mainly
       accelerated depreciation of machinery and equipment and deduction of
       expenses incurred in connection with a public offering.

    D. Through December 31, 1994, the Company's losses for tax purposes were
       assigned to a shareholder, and are not available to the Company.

    E.  As of December 31, 1999, the Company's net operating loss carryforwards
       for tax purposes amounted to approximately $2.3 million. These net
       operating losses may be carried forward indefinitely and offset against
       future taxable income. The Company expects that during the period in
       which these tax losses are utilized its income would be substantially tax
       exempt. Therefore, the income tax rate of the Company during the
       tax-exempt period will be zero, and there will be no tax benefit
       available from these losses and no deferred income taxes have been
       included in these financial statements. Deferred taxes in respect of
       other temporary differences are immaterial.

    F.  The U.S. subsidiary's carryforward tax losses through December 31, 1999
       amounted to approximately $2.2 million. These losses are available to
       offset any future U.S. taxable income of the U.S. subsidiary and will
       expire in the years 2010 - 2014.

                                      F-19
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 16--TAXES ON INCOME (CONTINUED)
    Details of deferred tax assets are as follows:

<TABLE>
<CAPTION>
                                                    DECEMBER 31,
                                                ---------------------
                                                  1998        1999
                                                ---------   ---------
<S>                                             <C>         <C>
Net operating loss carryforwards..............  $ 560,000   $ 770,000
Less--valuation allowance.....................   (560,000)   (770,000)
                                                =========   =========
                                                $      --   $      --
                                                =========   =========
</TABLE>

    G. The Company has been assessed for tax purposes through the year 1995.

    H. A reconciliation between the theoretical tax benefit, assuming all income
       is taxed at the statutory rate applicable to the income of the Company,
       and the actual tax expense as reported in the statements of operations is
       as follows:

<TABLE>
<CAPTION>
                                               FOR THE YEAR ENDED DECEMBER 31,
                                              ---------------------------------
                                                1997        1998        1999
                                              ---------   ---------   ---------
<S>                                           <C>         <C>         <C>
Theoretical tax benefit computed at the
  statutory rate (36%)......................  $(380,230)  $(298,503)  $(863,264)
Loss and other items for which deferred
  taxes were not provided...................    369,000     277,000     819,000
Non-deductible expenses.....................     11,230      21,503      44,264
                                              ---------   ---------   ---------
Income tax benefit..........................  $      --   $      --   $      --
                                              =========   =========   =========
</TABLE>

NOTE 17--SUBSEQUENT EVENTS

    A. After December 31, 1999, the Company:

       - increased its authorized share capital to 25,000,000 shares;

       - effected a 10-for-1 share split with respect to its ordinary shares and
         deferred shares;

       - converted 2,770 ordinary shares into deferred shares;

       - issued 20.1 shares for each outstanding ordinary share as a share
         dividend; and

       - issued 52,750 ordinary shares upon exercise of outstanding options.

       After the conversion of preferred shares into ordinary shares (see
       note 2(L)), the increase in share capital, the share dividend and the
       share split, the Company's authorized share capital consists of
       24,984,470 ordinary and 15,530 deferred shares of NIS 0.1 par value each,
       of which 13,637,774 ordinary shares and 15,530 deferred shares are issued
       and outstanding. All references to per share amounts and the number of
       shares in these financial statements have been restated to reflect the
       above increase in share capital, share split and share dividend.

    B.  The Board of Directors has authorized the Company to file a registration
       statement with the United States Securities and Exchange Commission for
       an initial public offering of its ordinary shares. Upon the closing of
       the initial public offering, all outstanding preferred shares will be
       converted into an identical number of ordinary shares.

                                      F-20
<PAGE>
                                 RADVISION LTD.

           NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

NOTE 17--SUBSEQUENT EVENTS (CONTINUED)
    C.  Concurrently with the initial public offering, the Company has agreed to
       issue 590,822 ordinary shares at the initial public offering price in a
       private placement to Siemens Aktiengesellschaft, Samsung
       Electro-Mechanics Co. Ltd. and Samsung Venture Investment Corporation for
       aggregate consideration of approximately $10.0 million.

    D. Subsequent to December 31, 1999, the Company granted 480,159 options to
       its employees. The options vest ratably over vesting periods ranging from
       four to five years with exercise prices ranging from $10.20 to $12.00.
       The Company expects to recognize deferred compensation expenses related
       to these grants in the aggregate amount of $218,000, which will be
       amortized to operating expenses over the vesting periods.

                                      F-21
<PAGE>
                                3,800,000 SHARES

                                     [LOGO]

                                Ordinary Shares

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

                                   PROSPECTUS
                                          , 2000

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

                                LEHMAN BROTHERS

                              SALOMON SMITH BARNEY

                           U.S. BANCORP PIPER JAFFRAY

                            FIDELITY CAPITAL MARKETS
             a division of National Financial Services Corporation
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

    The expenses, other than underwriting commissions, expected to be incurred
by RADVision in connection with the issuance and distribution of the securities
being registered under this Registration Statement will be paid by RADVision and
are estimated to be as follows:

<TABLE>
<S>                                                           <C>
Securities and Exchange Commission Registration Fee.........  $   23,074
National Association of Securities Dealers, Inc. Filing
  Fee.......................................................       9,240
Nasdaq National Market Filing Fee...........................      90,000
Israeli Taxes...............................................     786,000
Printing and Engraving......................................     150,000
Legal Fees and Expenses.....................................     400,000
Accounting Fees and Expenses................................     120,000
Indemnification Policy for Directors and Officers...........     400,000
Miscellaneous...............................................      21,686
                                                              ----------
      Total.................................................  $2,000,000
                                                              ==========
</TABLE>

ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

    Under the Companies Law, an Israeli company may not exempt an office holder
from liability with respect to a breach of his duty of loyalty, but may exempt
in advance an office holder from his liability to the company, in whole or in
part, with respect to a breach of his duty of care.

    OFFICE HOLDER INSURANCE

    Our articles of association provide that, subject to the provisions of the
Companies Law, we may enter into a contract for the insurance of the liability
of any of our office holders with respect to:

    - a breach of his duty of care to us or to another person;

    - a breach of his duty of loyalty to us, provided that the office holder
      acted in good faith and had reasonable cause to assume that his act would
      not prejudice our interests; or

    - a financial liability imposed upon him in favor of another person
      concerning an act performed by him in his capacity as an office holder.

    INDEMNIFICATION OF OFFICE HOLDERS

    Our articles of association provide that we may indemnify an office holder
against:

    - a financial liability imposed on him in favor of another person by any
      judgment, including a settlement or an arbitrator's award approved by a
      court concerning an act performed in his capacity as an office holder; and

    - reasonable litigation expenses, including attorneys' fees, expended by the
      office holder or charged to him by a court, in proceedings we institute
      against him or instituted on our behalf or by another person, or in a
      criminal charge from which he was acquitted, or a criminal charge in which
      he was convicted for a criminal offense that does not require proof of
      intent, in each case relating to an act performed in his capacity as an
      office holder.

                                      II-1
<PAGE>
    Our articles of association also include the following:

    - We are authorized to grant in advance an undertaking to indemnify an
      office holder, provided that the undertaking is limited to specified
      events which the board of directors deems to be anticipated and limited in
      amount determined by the board of directors to be reasonable under the
      circumstances.

    - We are authorized to indemnify retroactively an office holder.

    LIMITATIONS ON INSURANCE AND INDEMNIFICATION

    The Companies Law provides that a company may not indemnify an office holder
nor enter into an insurance contract which would provide coverage for any
monetary liability incurred as a result of any of the following:

    - a breach by the office holder of his duty of loyalty unless the office
      holder acted in good faith and had a reasonable basis to believe that the
      act would not prejudice the company;

    - a breach by the office holder of his duty of care if the breach was done
      intentionally or recklessly;

    - any act or omission done with the intent to derive an illegal personal
      benefit; or

    - any fine levied against the office holder.

    In addition, under the Companies Law, indemnification of, and procurement of
insurance coverage for, our office holders must be approved by our audit
committee and our board of directors and, in specified circumstances, by our
shareholders.

    We have agreed to indemnify our office holders to the fullest extent
permitted under the Companies Law. Before this offering, we intend to obtain
directors and officers liability insurance for the benefit of our office
holders.

ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES.

    Described below are unregistered securities sold by RADVision during the
three years preceding the filing of this Registration Statement. The share
figures below reflect the share split and share dividend to be effected prior to
the offering.

    In September 1996, RADVision agreed to issue and sell an aggregate of
1,030,946 ordinary shares in a private placement at an aggregate purchase price
of approximately $1.6 million. Out of the aggregate 1,030,946 shares, the
Company issued an aggregate of 714,235 shares in September 1996 to Clal Venture
Capital Fund LP, ECI Telecom Ltd., Intel Corporation, Madge Network
(Israel) Ltd. and The Trust Company of Maritime Bank of Israel. Pursuant to an
agreement with Intel Corporation, the Company issued an additional 158,461
shares in November 1997 and an additional 158,250 shares in December 1999 in
exchange for an additional aggregate investment in the Company of $500,000.

    From May through July 1997, RADVision issued and sold an aggregate of
269,447 ordinary shares in a private placement to Zohar Zisapel, Michael and
Klil Holdings (93) Ltd., Lomsha Ltd., Madge Network (Israel) Ltd., Zohar Gilon,
Avraham Neuman, Yair Tauman, W.S.P. Capital Investments Ltd., RAD Data
Communications Ltd., The Trust Company of Maritime Bank of Israel, ECI Telecom,
Intel Corporation and Clal Venture Capital Fund LP, at an aggregate purchase
price of approximately $650,000.

    In May 1998, RADVision issued and sold an aggregate of 2,957,165 preferred
shares in a private placement to the Evergreen Group, Dovrat Shrem Founders
Group, Canada Israel Opportunity Fund L.P., The Canada Israel Opportunity Fund
II, Dovrat Shrem & Co. Ltd., Rubin Gruber, C.E.

                                      II-2
<PAGE>
Unterberg, Towbin LLC, C.E. Unterberg, Towbin Private Equity Partners LP, C.E.
Unterberg, Towbin Private Equity Partners CV, C.E. Unterberg, Towbin Profit
Sharing Plan FBO Alex Bernstein, Steimatzsky Ltd., Zohar Zisapel, Michael and
Klil Holdings (93) Ltd., Lomsha Ltd., Zohar Gilon, Avraham Neuman, Yair Tauman,
W.S.P. Capital Investments Ltd. RAD Data Communications Ltd., The Trust Company
of Maritime Bank of Israel and Houston Venture Partners, Ltd., at an aggregate
purchase price of $5 million. The Evergreen Group consists of Evergreen Canada
Israel Management Ltd., IJT Technologies Ltd., Periscope I Fund, L.P., Periscope
I Fund Israeli Partnership. We also issued 121,114 ordinary shares at par value
to Zohar Zisapel, Michael and Klil Holdings (93) Ltd., Lomsha Ltd, Zohar Gilon,
Avraham Neuman, Yair Tauman, W.S.P. Capital Investments Ltd. RAD Data
Communications Ltd., The Trust Company of Maritime Bank of Israel, Madge Network
(Israel) Ltd., ECI Telecom, Intel Corporation and Clal Venture Capital Fund LP
as an anti-dilution adjustment to the shares they purchased in the May 1997
private placement.

    Each of the securities referred to above was sold (i) pursuant to exemptions
from registration under Section 4(2) of the Securities Act and/or (ii) to
persons who were neither nationals nor residents of the United States and no
facilities or instrumentalities of United States interstate commerce were used
in connection with any offer or sale thereof. No underwriter or underwriting
discount or commission was involved in any of such sales. The recipients of
securities in each such transaction represented their intentions to acquire the
securities for investment only and not with a view to or for sale in connection
with any distribution thereof and appropriate legends were affixed to the share
certificates and warrants issued in such transactions. All recipients had
adequate access, through their relationship with us, to information about us.

ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

    (a) EXHIBITS


<TABLE>
<CAPTION>
       EXHIBIT
         NO.                                    DESCRIPTION
- ---------------------   ------------------------------------------------------------
<C>                     <S>
         1              Form of Underwriting Agreement*
         3.1            Memorandum of Association of Registrant (English translation
                        accompanied by Hebrew original)*
         3.2            Articles of Association of Registrant*
         4.1            Form of Ordinary Share Certificate*
         4.2            Agreement, dated as of April 14, 1995, by and among
                        Registrant, RAD Data Communications Ltd. and Yehuda Zisapel
                        and Zohar Zisapel*
         4.3            Agreement, dated as of April 18, 1995, by and among
                        Registrant, Clal Venture Capital Fund LP and Yehuda Zisapel
                        and Zohar Zisapel*
         4.4            Agreement, dated as of April 18, 1995, by and among
                        Registrant, Lannet Data Communications Ltd. and Yehuda
                        Zisapel and Zohar Zisapel*
         4.5            Agreement, dated as of April 19, 1995, by and among
                        Registrant, ECI Telecom Ltd. and Yehuda Zisapel and Zohar
                        Zisapel*
         4.6            Agreement, dated as of April 24, 1995, by and among
                        Registrant, Zohar Gilon, Avraham Neuman, Yair Tauman and
                        W.S.P. Capital Investments Ltd., and Yehuda Zisapel and
                        Zohar Zisapel*
         4.7            Agreement, dated as of April 26, 1995, by and among
                        Registrant, Lerosh Investments Ltd., Gevahim Investments
                        House Limited Ltd., Yoav Chelouche, Permal Emerging Growth V
                        Ltd., Maritime--Julex Investment Ltd., Shraga Blazer and Eli
                        Luz and Yehuda Zisapel and Zohar Zisapel*
         4.8            Agreement, dated as of April 27, 1995, by and among
                        Registrant, Finovelec, Factory Systemes, Houston Venture
                        Partners, Ltd. and Yehuda Zisapel and Zohar Zisapel*
</TABLE>


                                      II-3
<PAGE>


<TABLE>
<CAPTION>
       EXHIBIT
         NO.                                    DESCRIPTION
- ---------------------   ------------------------------------------------------------
<C>                     <S>
         4.9            Agreement, dated September 12, 1996, by and among Registrant
                        and Intel Corporation, as amended*
         4.10           Agreement, dated May 12, 1998, by and among Registrant,
                        Evergreen Canada Israel Management Ltd., IJT Technologies
                        Ltd., Periscope I Fund, L.P., Periscope I Fund Israeli
                        Partnership, Dovrat Shrem Trust Company Ltd., Rubin Gruber,
                        C.E. Unterberg, Towbin LLC, C.E. Unterberg, Towbin Private
                        Equity Partners LP, C.E. Unterberg, Towbin Private Equity
                        Partners CV, C.E. Unterberg, Towbin Profit Sharing Plan FBO
                        Alex Bernstein and Steimatzsky Ltd.*
         4.11           Share Purchase Agreement, dated February 22, 2000, among
                        Registrant, Siemens Aktiengesellschaft and the persons
                        listed on Exhibit I thereto.*
         4.12           Share Purchase Agreement, dated February 22, 2000, among
                        Registrant, Samsung Electro-Mechanics Co. Ltd., Samsung
                        Venture Investment Corp. and the persons listed on
                        Exhibit I thereto.*
         4.13           Amendment Number 1 to Share Purchase Agreement, dated
                        February 22, 2000, among Registrant, Samsung
                        Electro-Mechanics Co. Ltd., Samsung Venture Investment Corp.
                        and the persons listed on Exhibit I thereto.*
         5              Opinion of Goldfarb, Levy, Eran & Co.*
        10.1            Key Employee Share Incentive Plan, as amended*
        10.2            Consultants Option Plan, as amended*
        10.3            License Agreement, dated January 13, 1999, between
                        Registrant and RADCOM Ltd.*
        10.4            Sub-Lease Agreement, dated August 26, 1999, between
                        Registrant and RIT Technologies Ltd.
        10.5            Lease Agreement, dated May 12, 1997, between RADVision Inc.
                        and RAD Data Communications Inc., as amended.
        10.6            Warehouse Lease Agreement, dated May 2, 1999, between
                        Registrant, Zisapel Properties (1992) Ltd. and Klil &
                        Michael Properties (1992) Ltd., as amended.
        10.7            Sub-Lease Agreement, dated March 1999, between Registrant
                        and RAD Data Communications Ltd.
        10.8            Lease Agreement, dated December 31, 1997, between
                        Registrant, Zisapel Properties (1992) and Klil & Michael
                        Properties (1992) Ltd., as amended.
        10.9            Software License Agreement, dated February 23, 2000, between
                        Registrant and Siemens Aktiengesellschaft.
        21              Subsidiaries of the Registrant*
        23.1            Consent of Luboshitz Kasierer
        23.2            Consent of Goldfarb, Levy Eran & Co. (included in Exhibit 5
                        hereto)*
        23.3            Consent of Weil, Gotshal & Manges LLP*
        24              Power of Attorney (included in the signature pages to the
                        Registration Statement)*
        99              Consent of Nominee Director*
</TABLE>


    (b) FINANCIAL STATEMENT SCHEDULES

    Schedule II--Valuation and Quantifying Accounts

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

*     Previously filed.

                                      II-4
<PAGE>
ITEM 17. UNDERTAKINGS.

    (a) The undersigned Registrant hereby undertakes to provide to the
Underwriters at the closing specified in the underwriting agreement,
certificates in such denominations and registered in such names as required by
the Underwriters to permit prompt delivery to each purchaser.

    (b) Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the provisions described under Item 14 above, or
otherwise, the Registrant has been advised that, in the opinion of the
Securities and Exchange Commission, such indemnification is against public
policy as expressed in the Securities Act and is, therefore, unenforceable. In
the event that a claim for indemnification against such liabilities (other than
the payment by the Registrant of expenses incurred or paid by a director,
officer or controlling person of the Registrant in the successful defense of any
action, suit or proceeding) is asserted by such director, officer or controlling
person in connection with the securities being registered, the Registrant will,
unless in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.

    (c) The undersigned Registrant hereby undertakes that:

        (1) For purposes of determining any liability under the Securities Act,
    the information omitted from the form of prospectus filed as part of this
    Registration Statement in reliance upon Rule 430A and contained in a form of
    prospectus filed by the Registrant pursuant to Rule 424(b)(1) or (4) or
    497(h) under the Securities Act shall be deemed to be part of this
    Registration Statement as of the time it was declared effective.

        (2) For the purpose of determining any liability under the Securities
    Act, each post-effective amendment that contains a form of prospectus shall
    be deemed to be a new registration statement relating to the securities
    offered therein, and this offering of such securities at that time shall be
    deemed to be the initial BONA FIDE offering thereof.

                                      II-5
<PAGE>
                                   SIGNATURES


    Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form F-1 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Tel Aviv, Israel, on the 13th day of March, 2000.


<TABLE>
<S>                                                    <C>  <C>
                                                       RADVISION LTD.

                                                       By:  /s/ YEHUDA ZISAPEL
                                                            -----------------------------------------
                                                            Name: Yehuda Zisapel
                                                            Title: Chairman of the Board of Directors
</TABLE>

    Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated:


<TABLE>
<CAPTION>
SIGNATURE                                                          TITLE                    DATE
- ---------                                                          -----                    ----
<C>                                                    <S>                             <C>
/s/ YEHUDA ZISAPEL                                     Chairman of the Board of        March 13, 2000
- -------------------------------------------              Directors
Yehuda Zisapel

                     *                                 Chief Executive Officer         March 13, 2000
- -------------------------------------------              (principal executive
Ami Amir                                                 officer)

                     *                                 Chief Financial Officer         March 13, 2000
- -------------------------------------------              (principal financial and
David Seligman                                           accounting officer)

                     *                                 Director                        March 13, 2000
- -------------------------------------------
Zohar Zisapel

                     *                                 Director                        March 13, 2000
- -------------------------------------------
Adi Gan

                     *                                 Director                        March 13, 2000
- -------------------------------------------
Dan Goldstein

                     *                                 Director                        March 13, 2000
- -------------------------------------------
Hillel E. Milo
</TABLE>


                                      II-6
<PAGE>


<TABLE>
<CAPTION>
SIGNATURE                                                          TITLE                    DATE
- ---------                                                          -----                    ----
<C>                                                    <S>                             <C>
                     *                                 Director                        March 13, 2000
- -------------------------------------------
Efraim Wachtel
</TABLE>



<TABLE>
<S>   <C>                                                    <C>                             <C>
Authorized Representative
  in the United States:

RADVision Inc.

By:   *
      --------------------------------------
      Name: Eugene Wolf                                                                      March 13, 2000
      Title: President

*By:  /s/ YAEL LANGER
      --------------------------------------
      Yael Langer                                                                            March 13, 2000
      (Attorney in fact)
</TABLE>


                                      II-7
<PAGE>
                                  SCHEDULE II
                       VALUATION AND QUANTIFYING ACCOUNTS

<TABLE>
<CAPTION>
                                                                        ADDITIONS
                                                           -----------------------------------
                                       BALANCE AT THE      CHARGED TO BAD       CHARGED TO       BALANCE AT THE
                                     BEGINNING OF PERIOD   DEBT EXPENSES    COST OF GOODS SOLD   END OF PERIOD
                                     -------------------   --------------   ------------------   --------------
<S>                                  <C>                   <C>              <C>                  <C>
YEAR ENDED DECEMBER 31, 1997
Allowance for doubtful accounts....             --
Allowance for warranty reserve.....        $ 5,000                               $ 12,656           $ 17,656

YEAR ENDED DECEMBER 31, 1998
Allowance for doubtful accounts....             --            $ 72,539                              $ 72,539
Allowance for warranty reserve.....        $17,656                               $  3,854           $ 13,802

YEAR ENDED DECEMBER 31, 1999
Allowance for doubtful accounts....        $72,539            $152,166                              $224,705
Allowance for warranty reserve.....        $13,802                               $     23           $ 13,825
Allowance for inventory reserve....             --                               $100,000           $100,000
</TABLE>
<PAGE>

                                 EXHIBIT INDEX



<TABLE>
<CAPTION>
       EXHIBIT
         NO.                                    DESCRIPTION
- ---------------------   ------------------------------------------------------------
<C>                     <S>
         1              Form of Underwriting Agreement*
         3.1            Memorandum of Association of Registrant (English translation
                        accompanied by Hebrew original)*
         3.2            Articles of Association of Registrant*
         4.1            Form of Ordinary Share Certificate*
         4.2            Agreement, dated as of April 14, 1995, by and among
                        Registrant, RAD Data Communications Ltd. and Yehuda Zisapel
                        and Zohar Zisapel*
         4.3            Agreement, dated as of April 18, 1995, by and among
                        Registrant, Clal Venture Capital Fund LP and Yehuda Zisapel
                        and Zohar Zisapel*
         4.4            Agreement, dated as of April 18, 1995, by and among
                        Registrant, Lannet Data Communications Ltd. and Yehuda
                        Zisapel and Zohar Zisapel*
         4.5            Agreement, dated as of April 19, 1995, by and among
                        Registrant, ECI Telecom Ltd. and Yehuda Zisapel and Zohar
                        Zisapel*
         4.6            Agreement, dated as of April 24, 1995, by and among
                        Registrant, Zohar Gilon, Avraham Neuman, Yair Tauman and
                        W.S.P. Capital Investments Ltd., and Yehuda Zisapel and
                        Zohar Zisapel*
         4.7            Agreement, dated as of April 26, 1995, by and among
                        Registrant, Lerosh Investments Ltd., Gevahim Investments
                        House Limited Ltd., Yoav Chelouche, Permal Emerging Growth V
                        Ltd., Maritime--Julex Investment Ltd., Shraga Blazer and Eli
                        Luz and Yehuda Zisapel and Zohar Zisapel*
         4.8            Agreement, dated as of April 27, 1995, by and among
                        Registrant, Finovelec, Factory Systemes, Houston Venture
                        Partners, Ltd. and Yehuda Zisapel and Zohar Zisapel*
         4.9            Agreement, dated September 12, 1996, by and among Registrant
                        and Intel Corporation, as amended*
         4.10           Agreement, dated May 12, 1998, by and among Registrant,
                        Evergreen Canada Israel Management Ltd., IJT Technologies
                        Ltd., Periscope I Fund, L.P., Periscope I Fund Israeli
                        Partnership, Dovrat Shrem Trust Company Ltd., Rubin Gruber,
                        C.E. Unterberg, Towbin LLC, C.E. Unterberg, Towbin Private
                        Equity Partners LP, C.E. Unterberg, Towbin Private Equity
                        Partners CV, C.E. Unterberg, Towbin Profit Sharing Plan FBO
                        Alex Bernstein and Steimatzsky Ltd.*
         4.11           Share Purchase Agreement, dated February 22, 2000, among
                        Registrant, Siemens Aktiengesellschaft and the persons
                        listed on Exhibit I thereto.*
         4.12           Share Purchase Agreement, dated February 22, 2000, among
                        Registrant, Samsung Electro-Mechanics Co. Ltd., Samsung
                        Venture Investment Corp. and the persons listed on
                        Exhibit I thereto.*
         4.13           Amendment Number 1 to Share Purchase Agreement, dated
                        February 22, 2000, among Registrant, Samsung
                        Electro-Mechanics Co. Ltd., Samsung Venture Investment Corp.
                        and the persons listed on Exhibit I thereto.*
         5              Opinion of Goldfarb, Levy, Eran & Co.*
        10.1            Key Employee Share Incentive Plan, as amended*
        10.2            Consultants Option Plan, as amended*
        10.3            License Agreement, dated January 13, 1999, between
                        Registrant and RADCOM Ltd.*
        10.4            Sub-Lease Agreement, dated August 26, 1999, between
                        Registrant and RIT Technologies Ltd.
        10.5            Lease Agreement, dated May 12, 1997, between RADVision Inc.
                        and RAD Data Communications Inc., as amended.
        10.6            Warehouse Lease Agreement, dated May 2, 1999, between
                        Registrant, Zisapel Properties (1992) Ltd. and Klil &
                        Michael Properties (1992) Ltd., as amended.
</TABLE>


<PAGE>


<TABLE>
<CAPTION>
       EXHIBIT
         NO.                                    DESCRIPTION
- ---------------------   ------------------------------------------------------------
<C>                     <S>
        10.7            Sub-Lease Agreement, dated March 1999, between Registrant
                        and RAD Data Communications Ltd.
        10.8            Lease Agreement, dated December 31, 1997, between
                        Registrant, Zisapel Properties (1992) and Klil & Michael
                        Properties (1992) Ltd., as amended.
        10.9            Software License Agreement, dated February 23, 2000, between
                        Registrant and Siemens Aktiengesellschaft.
        21              Subsidiaries of the Registrant*
        23.1            Consent of Luboshitz Kasierer
        23.2            Consent of Goldfarb, Levy Eran & Co. (included in Exhibit 5
                        hereto)*
        23.3            Consent of Weil, Gotshal & Manges LLP*
        24              Power of Attorney (included in the signature pages to the
                        Registration Statement)*
        99              Consent of Nominee Director*
</TABLE>


<PAGE>

                                                                    Exhibit 10.4

                             AGREEMENT OF SUB-LEASE

              Made and entered into at Tel Aviv on 26th August 1999

                                     Between

            RIT Technologies Ltd. Public Company Registration No. 52-004335-7
            of 24 Raoul Wallenberg Street, Tel Aviv 69719

            Hereinafter called - "RIT"

                                                                 OF THE ONE PART

                                       And

            RADVision Ltd., Private Company Registration No. 51-1651812
            of 24 Raoul Wallenberg Street, Tel Aviv 69719

            Hereinafter called - "RADVision"

                                                               OF THE OTHER PART

Whereas              RIT entered into contractual arrangements under an
                     Agreement of Lease dated 2nd November 1998 (hereinafter -
                     "the Principal Lease") with Vitalgo Textile Enterprises
                     Ltd., Zisapel Properties (1992) Ltd. and Klil & Michael
                     Properties (1992) Ltd. (hereinafter - "the Principal
                     Lessor") relating to the lease of a commercial area on the
                     entrance level of the building situate at 24 Raoul
                     Wallenberg Street, Ramat Ha'Hayil (hereinafter - "the
                     Principal Premises").
                     The Principal Lease is attached to this Agreement as
                     ANNEX A.

And Whereas          RADVision wishes to lease from RIT and RIT wishes
                     to let to RADVision under an unrestricted unprotected
                     sub-lease, an area of 215 square metres situate within the
                     area of the Principal Premises, as described in the plan
                     attached to this Agreement as ANNEX B (hereinafter - "the
                     Premises").


<PAGE>
                                       2


NOW THEREFORE IT IS DECLARED, STIPULATED AND AGREED BETWEEN THE PARTIES AS
FOLLOWS :

1.       PREAMBLE

         1.1      The preamble to this Agreement, together with the facts and
                  declarations included therein, and the Annexes to this
                  Agreement, constitute an integral part hereof.

         1.2      Paragraph headings in this Agreement are for convenience only
                  and do not constitute part of the Agreement nor shall they
                  serve for purposes of interpretation.

2.       LEASE

         2.1      RIT hereby lets the Premises to RADVision and RADVision hereby
                  leases the same from RIT for a period of 12 months with effect
                  from 1st September 1999, and terminating on 31st August 2000
                  (hereinafter - "the Lease Period") upon the conditions set
                  forth in this Agreement heretofore and hereunder and subject
                  to the conditions set forth in the Principal Lease.

         2.2      Subject to the faithful fulfilment by RADVision of the
                  provisions of this Agreement, and as long as RIT is still the
                  lessee of the Principal Premises, an option shall be granted
                  to RADVision to extend the Lease Period for a further period
                  until 31st August 2001 (hereinafter : "the Further Lease
                  Period").

         2.3      "The Lease Period", whenever this appears in this Agreement,
                  shall also be deemed to include the Further Lease Period or
                  the Further Lease Periods.

3.       CONSIDERATION

         3.1      RADVision undertakes to pay to RIT for each month of the lease
                  of the Premises a rental in a sum equal to $ 18.50 per square
                  metre, that is, an amount equal to 1,850 United States dollars
                  ($1,850 dollars) ($ 18.50 x 100 square metres).

         3.2      The rental shall be paid to RIT at the representative rate of
                  exchange of the United States dollar as at the date of payment
                  together with value added tax as applicable.


<PAGE>
                                       3


         3.3      The rental shall be paid to the Lessor 3 (three) monthly in
                  advance on the first day of each payment month, or on the
                  first business day next following the first day of the month,
                  should this fall on a Sabbath or Holiday. The rental for the
                  first month of the Lease Period shall be paid at the time of
                  signature of this Agreement.

         3.4      In addition to the foregoing rental, RADVision shall bear its
                  share, pro rata to its share of the Principal Premises, of the
                  management fee as set forth in paragraph 15 hereunder and in
                  Annex B 2 to the Principal Lease, and municipal rates debited.

         3.5      RADVision shall effect the foregoing payments to RIT against a
                  tax invoice.

4.       APPLICABILITY OF THE PRINCIPAL LEASE

         4.1      All the provisions of the Principal Lease, to the extent that
                  these relate to the Premises, shall MUTATIS MUTANDIS apply to
                  the lease pursuant to this Agreement.

         4.2      RADVision hereby agrees to assume all the obligations of the
                  Lessee as set forth in the Principal Lease, MUTATIS MUTANDIS,
                  in relation to the Premises which it hereby leases.

         4.3      For the sake of clarity, RADVision shall obtain the approval
                  of the Lessor with respect to any alterations which it intends
                  to carry out on the Premises and shall furnish such security
                  and/or insurance as shall be required by the Lessor concerning
                  the Premises.

5.       AREA COMMON TO RIT AND RADVISION

         5.1      Apart from the Premises as set forth in Annex B, RADVision
                  shall also be entitled to use the kitchen and toilets situate
                  within the area of the Principal Premises.

         5.2      RADVision shall be entitled to install a separate
                  communications cabinet inside the existing communications room
                  on the Principal Premises. For the sake of clarity, RADVision
                  shall be given no access to RIT's communication cabinet.


<PAGE>
                                       4


         5.3      In the light of the existence of the common area, the parties
                  hereby agree to respect the privacy of each of them and to
                  refrain from any act which may constitute a nuisance in
                  relation to the use by the other to its Premises.

            IN WITNESS WHREEOF. they have affixed their signatures :

RIT Technologies Ltd.                                         RADVision Ltd.

 /s/ OFER BENGAL                                        /s/ ALON MOALEM
- ------------------------------                         -----------------------
Ofer Bengal, Managing Director                         Alon Moalem, Controller

<PAGE>


                                  ANNEX A


Summary of Agreement of Lease, between RIT Technologies Ltd., Vitalgo Textile
Enterprises, Zisapel Properties (1992) Ltd. and Klil and Michael Properties
(1992) Ltd.--translated from Hebrew original

Date of Lease:           November 2, 1998.

Landlord:                Vitalgo Textile Industries Ltd.
                         Zisapel Properties (1992) Ltd.
                         Klil and Michael Properties (1992) Ltd.

Tenant:                  Rit Technologies Ltd.

Premises:                24 Raoul Wallenberg Street, Tel Aviv Israel.

Square Meters:           458 sq meters.

Permitted Use:           General office and manufacturing.

Term:                    40 months.

                         (a) Scheduled commencement date: August 1, 1998.
                         (b) Scheduled expiration date: December 2, 2001.

There is an option to extend the lease upon mutual consent for an additional
two years until December 2, 2003. ("Additional Period")

Basic Rent--(lease months 1-40)--$18.50 per square meter, i.e. $8473.

Additional Period Rent--additional 5.5% i.e. $19.51 per square meter,
i.e. $8935.58

Security Deposit:        approximately $8000 in bank guarantee.

<PAGE>




                                 ANNEX B


[This Exhibit consists of a two dimensional floor plan for the leased
premises at 24 Raoul Wallenberg Street Tel Aviv Israel consisting of
215 square meters. The floor plan shows a cross sectional view of room
divisions within the premises.]




<PAGE>

                                                                    Exhibit 10.5


                                 LEASE AGREEMENT

                                     Between

                          RAD DATA COMMUNICATIONS, INC.

                                   "Landlord"


                                      -and-

                                 RADVISION, INC.

                                    "Tenant"



                               575 Corporate Drive
                            Mahwah, New Jersey 07430



<PAGE>


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
ARTICLE NO.                            DESCRIPTION                                                PAGE
- ----------                             -----------                                                ----
<S>          <C>                                                                                  <C>
                                   Basic Lease Provisions

I            Demised Premises                                                                     7
II           Term                                                                                 7
III          Rent                                                                                 8
IV           Use and Occupancy                                                                    9
V            Alterations or Improvements by Tenant                                                10
VI           Maintenance                                                                          11
VII          Compliance with Laws, Indemnity and Insurance                                        12
VIII         Subordination and Estoppel                                                           13
IX           Destruction - Fire or Other Casualty                                                 14
X            Mutual Waiver of Subrogation                                                         14
XI           Condemnation and Other Proceedings                                                   15
XII          Assignment and Subletting                                                            16
XIII         Surrender                                                                            18
XIV          Holding Over                                                                         18
XV           Landlord's Right of Entry                                                            19
XVI          Default                                                                              19
XVII         Landlord's Rights Upon Tenant's Default                                              20
XVIII        Landlord's Remedies Cumulative: Expenses                                             21
XIX          No Waiver                                                                            22
XX           Landlord's Reserved Rights                                                           23
XXI          Landlord's Liability                                                                 23
XXII         Tenant's Liability                                                                   24
XXIII        Tenant's Insurance                                                                   25
XXIV         Mechanic's Liens                                                                     26
XXV          Quiet Enjoyment                                                                      26
XXVI         Relocation of Tenant                                                                 26
XXVII        Landlord's Services                                                                  27
XXVIII       Additional Rent                                                                      28
XXIX         Personal Property Taxes                                                              29
XXX          Security Deposit                                                                     30
XXXI         Use of Security Deposit                                                              30
XXXII        Definition of Landlord                                                               30
XXXIII       Notices                                                                              31
XXXIV        Signs                                                                                31
XXXV         Notice of Defects and Accidents                                                      31
XXXVI        Rules and Regulations                                                                32
XXXVII       Directory                                                                            32
XXXVIII      Hazardous Materials and Compliance
                          with Environmental Laws                                                 32
XXXIX        Miscellaneous                                                                        34
</TABLE>

                                       2

<PAGE>

<TABLE>
<S>        <C>           <C>                                                                      <C>
EXHIBITS   EXHIBIT A:    The Premises                                                             41
           EXHIBIT B:    Landlord's Work
                         in the Premises                                                          42
           EXHIBIT C:    Rules and Regulations                                                    43
</TABLE>

                                       3

<PAGE>


                             BASIC LEASE PROVISIONS

                                     of the

                                 LEASE AGREEMENT

                                     between

                   RAD DATA COMMUNICATIONS, INC., as Landlord,

                                       and

                           RADVISION, INC., as Tenant.

The following basic terms of the Lease (hereinafter referred to as the "Basic
Lease Provisions") between Landlord and Tenant are an integral part of and are
incorporated by reference into the within Lease:

A. The "Building":          575 Corporate Drive, Mahwah, New Jersey 07430
                            comprising  approximately  144,570 rentable
                            square feet.  The foregoing  land and building
                            shall  sometimes be referred to herein as the
                            "Real Property".

B. The "Premises":          (1) The Premises is known as Suite 420 in Lobby 4
                            and is depicted on the Floor Plan attached hereto
                            as Exhibit "A" and consists of approximately
                            2,148 rentable square feet.

C. The "Term":              (1) The Term of this Lease shall be five (5) years
                            beginning on May 12, 1997 (the Commencement Date")
                            and ending May 11, 2002 (the "Expiration Date").

D. The "Basic Rent":        (1) Annual Base Rent: $21,480 Net
                            (2) Monthly  Installments of Base Rent: $1,790 Net
                            plus Tenant  utilities and other pass throughs,
                            as set f'orth in the Lease.

E. Tenant's Proportionate Share:        1.49%

F. The Security Deposit:                NONE

G.  Broker(s):                          NONE


                                       4

<PAGE>


H.  Addresses for Notice
    and Payments:            (1) Landlord:

                             RAD Data Communications, Inc.
                             900 Corporate Drive
                             Mahwah, New Jersey 07430
                             ATTN: Comptroller
                             cc: Real Estate Management Co.
                             155 North Dean Street
                             Englewood, NJ 07631

                             Donald N. Render, Esq.
                             10 S. Franklin Turnpike
                             Suite 205, P.O. Box 630
                             Ramsey, NJ 01446

                             (2) Tenant:

                             RADVISION, INC.
                             575 Corporate Drive
                             Mahwah, New Jersey 07430

                             (3) Checks Payable to:

                             R.E. Mgt Co. - 575 Special

                             Mail Payments to:

                             Real Estate Management Company
                             155 North Dean Street
                             Englewood, NJ 07631

I. Use:

                SIC Number:  ________

J. Landlord's Work:           As set forth on Exhibit "B" attached hereto. The
                              work shall specifically  including the following:

                                       5

<PAGE>


                                As Delivered.

                              All of Landlord's Work shall commence upon the
                              execution of this Lease and shall diligently
                              proceed to completion. Said Landlord's Work shall
                              be performed in accordance with all applicable
                              local, state and Federal building laws,
                              regulations and standards. Landlord shall procure
                              at its sole cost and expense all necessary permits
                              to commence and to complete the Landlord's Work.

K. Cleaning:                  Tenant shall be responsible for  cleaning its own
                              premises

L. Parking:                   Seven (7) Parking Spaces

M. Net Lease
   Additional Rent:           The Base Rent shown above shall be net-net; the
                              Tenant will be required to pay 1.49% of all Real
                              Estate Taxes (as defined in Article 28.2 herein),
                              together with 1.49% of the Landlord's Operating
                              Costs (as defined in Article 28.4 herein). Such
                              payments shall be made monthly by Tenant with the
                              Base Rent, as billed by the Landlord and as more
                              particularly set forth in the Lease. In addition,
                              the Tenant will be required to pay its Tenant
                              Electric and Gas at a rate of $1.25 per rentable
                              square foot, which is $2,685 per annum, subject to
                              revisions based on a survey of usage or gross
                              amount negotiated by Landlord and Tenant.


Approved by Landlord:                       Approved by Tenant:

RAD Data Communications, Inc.               RADVISION, Inc.



By:                                          By:
   -----------------------------                -------------------------------

                                       6

<PAGE>


 THIS AGREEMENT OF LEASE (this "Lease") dated as of May 12, 1997, between RAD
Data Communications, Inc., a New Jersey Corporation, (hereinafter referred to as
"Landlord"), and RADVISION, Inc. (hereinafter referred to as "Tenant").

                              W I T N E S S E T H:

Landlord and Tenant hereby covenant and agree as follows:

                                    ARTICLE I
                                Demised Premises

      1.1 Landlord hereby leases to Tenant and Tenant hereby leases from
Landlord for the term and upon the terms, conditions, covenants and agreements
hereinafter provided, the Premises. The Premises consist of space which: (i) is
located on the floor or floors of the Building as is specified in Item B(1) of
the Basic Lease Provisions, (ii) is located in one or more areas or parts of
each such floor, and (iii) is bounded by the proposed or existing demising walls
therefor, the approximate locations of such demising walls and space being
marked in color or crosshatched and shown on the diagram(s) of the floor plan
for each such floor, such diagram(s) being attached to this Lease as Exhibit A
and made a part hereof. The Premises is to be known and called by the Suite
Number or Numbers specified in Item B(1) of the Basic Lease Provisions. The
appropriate number of rentable square feet contained in the Premises, as
determined by Landlord, for identification purposes only, is specified in Item
B(1) of the Basic Lease Provisions (the "Rentable Area"). The lease of the
Premises includes the right, together with other tenants of the Building and
members of the public, to use the common public areas of the Building, but
includes no other rights not specifically set forth herein. Landlord shall
finish the Premises as set forth in Exhibit B attached hereto and made a part
hereof. It is understood and agreed that Landlord will not make and is under no
obligation to make, any alterations, decorations, additions or improvements in
or to the Premises, structural or otherwise, except as set forth in Exhibit B.
Landlord agrees to deliver possession of the Premises to Tenant and Tenant
agrees to accept the same from Landlord, upon written notice from Landlord to
Tenant, that Landlord's work in the Premises described in Exhibit B has been
substantially completed.


                                   ARTICLE II
                                      Term

      2.1 The Premises are leased for the period of years and months as
specified in Item C of the Basic Lease Provisions to commence at 12:01 A.M. on
the Commencement Date and to end at 11:59 P.M. on the Expiration Date unless the
Term

                                       7

<PAGE>


shall sooner terminate pursuant to any of the terms, covenants or conditions of
this Lease or pursuant to law.

      2.2 Notwithstanding anything in 2.1 to the contrary, if, on or prior to
the Commencement Date of the Term, the premises are not ready for occupancy,
this Lease shall nevertheless continue in full force and effect and Tenant shall
have no right to rescind, cancel or terminate same nor shall Landlord be liable
for damages, if any, sustained by Tenant by reason of inability to obtain
possession thereof on such date. In such event, Landlord shall give to Tenant,
written notice at least fifteen (15) days in advance of the date when Landlord
expects the Premises to be ready for occupancy by Tenant which date shall then
become the revised Commencement Date. The Term shall end on the revised
Expiration Date, which date shall be the same number of days after the revised
Commencement Date as it was after the original Commencement Date, unless sooner
terminated pursuant to any of the terms, covenants or conditions of this Lease
or pursuant to law.

      2.3 Then Tenant takes possession of the premises, Tenant shall be deemed
to have accepted the premises as being satisfactory and in good condition as of
the date of such possession.

                                   ARTICLE III
                                      Rent

      3.1 Tenant covenants and agrees to pay to Landlord as rent for and during
the Term hereof the annual sum as specified in Item D(1) of the Basic Lease
Provisions as Basic Rent.

      3.2 Basic Rent and any Additional Rent payable pursuant to the provisions
of this Lease shall be payable by Tenant to Landlord with payment made to Real
Estate Management Company and sent to 155 Dean Street, Englewood, NJ 07631 (or
at such other place as Landlord may designate in a notice to Tenant) in lawful
money of the United States without prior demand therefor and without any offset
or deduction whatsoever except as otherwise specifically provided in this Lease
for the convenience of Tenant. Basic Rent shall be payable in equal monthly
installments in the amount of $1,790.00, in advance, on the first (1st) day of
each month during the Term. The installment of Basic Rent for the first (1st)
full calendar month of the Term, is due and payable by Tenant to Landlord at the
time of the execution and delivery of this Lease. In the event that the
Commencement Date shall occur on a date other than the first (1st) day of any
calendar month, Tenant shall pay to Landlord on the first (1st) day of the month
next succeeding the month during which the Commencement Date shall occur, a sum
equal to $1,790.00, divided by thirty (30) then multiplied by the number of
calendar days in the period from the commencement Date to the last day of the


                                       8

<PAGE>


month in which the Commencement Date shall occur, both inclusive. Such payment,
together with the sum paid by Tenant upon execution of this Lease, shall
constitute payment of the Basic Rent for the period from the Commencement Date
to and including the last day of the next succeeding calendar month.

      3.3. Tenant covenants to pay Basic Rent and any Additional Rent payable
pursuant to the provisions of this Lease and to observe and perform and to
permit no violation of the terms, covenants and conditions of this Lease on
Tenant's part.

                                   ARTICLE IV
                                Use and Occupancy

      4.1 Tenant shall use and occupy the Premises solely for general office use
and only in accordance with the uses permitted under applicable zoning and other
municipal regulations. Without the prior written consent of Landlord, the
Premises shall not be used for any other purpose, or for any purpose that will
constitute a nuisance or unreasonable annoyance to Landlord or other tenants of
the Building and shall comply with all present and future laws, ordinances,
regulations, and orders of the United States of America, the jurisdiction in
which the Building is located, and any other public or quasi-public authority
having jurisdiction over the Premises. It is expressly understood that if any
law, ordinance, regulation or order requires an occupancy permit for the
Premises, Landlord shall obtain such permit at Landlord's own expense (that is
to say, Landlord will pay the cost of the application for the issuance of the
Certificate of Occupancy).

      4.2 Landlord has adopted a policy prohibiting smoking within the Entire
Premises. Tenant hereby acknowledges that Tenant, Tenant's employees, agents and
invitees are not permitted to smoke anywhere within the Premises or Entire
Premises.

      4.3 In addition to the parking spaces provided to Tenant under paragraph L
as set forth in the Basic Lease Provisions, supra, Tenant shall have the right
to the non-exclusive use of the parking lot on the Real Property (as defined in
paragraph 5.1) for all employees and visitors. The same right has been or will
be given to all other tenants in the Building, and to their respective
employees, agents, customers and invitees and to other persons, and it does not
entitle Tenant or other tenants to any particular assigned spaces in the parking
lot. Tenant covenants and agrees to comply with all reasonable rules and
regulations which Landlord may hereafter from time to time or at any time make
pursuant to the terms of Article XXXVI to assure exclusive use of designated
parking spaces on the Real Property by permitted users. Landlord's remedies
under such rules and regulations may include, but shall not be limited to, the
right to tow away at owner's expense any vehicles not parked in compliance with
these rules and regulations. Landlord shall not be responsible to Tenant for the
non-


                                       9

<PAGE>



compliance or breach by any other tenant of said rules and regulations,
provided, however, Landlord agrees to use reasonable efforts to enforce such
rules and regulations uniformly.

                                    ARTICLE V
                      Alterations or Improvements by Tenant

      5.1 Tenant shall make no changes in or to the Premises of any nature
without Landlord's prior written consent not to be unreasonably withheld or
delayed, except that Tenant may make immaterial and decorative changes to the
Premises without the Landlord's prior written consent. Subject to the prior
written consent of Landlord, Tenant, at Tenant's sole expense, may hire
contractors approved by Landlord to make alterations, installations, additions
or improvements in or to the Premises (collectively hereinafter referred to as
the "Alterations") which are non-structural and which do not affect utility
services, plumbing or electrical lines in or to the Premises or the Building.
The Alterations shall, upon installation, become the property of Landlord and
shall remain upon and be surrendered with the Premises, unless Tenant by written
notice to Landlord no later than thirty (30) days prior to the Expiration Date
requests Landlord's consent to remove same. If Landlord so consents the
Alterations shall be removed from the Premises by Tenant prior to the Expiration
Date at Tenant's sole expense. Nothing in this Article V shall be construed to
give Landlord title to or to prevent Tenant's removal of trade fixtures,
moveable office furniture and equipment, but upon removal of any such from the
Premises or upon removal of any other installation as may be permitted by
Landlord, Tenant shall immediately and at its expense, repair and restore the
Premises to the condition existing prior to the Alterations. Tenant shall repair
any damage to the Premises, the Building, or the real property on which the
Building is located (hereinafter collectively referred to as the "Real
Property") incurred during such removal. All property permitted or required to
be removed by Tenant at the Expiration Date or sooner termination of the Term
which remains on the Premises after the Expiration Date or sooner termination of
the Term shall be deemed abandoned and may, at the election of Landlord, either
be retained as Landlord's property or may be removed from the Premises by
Landlord at Tenant's expense. If Tenant does not repair or restore said damage
Landlord is entitled to deduct said cost and expense from Tenant's security
deposit.

      5.2 Prior to the commencement of the Alterations, Tenant shall at its sole
expense, obtain all required permits, approvals and certificates required by all
Governmental Authorities and upon completion of the Alterations, certificates of
final approval thereof. Tenant shall deliver duplicates of same to Landlord
promptly upon their receipt. Tenant shall carry and will cause Tenant's
contractors and subcontractors to carry such worker's compensation, general
liability, personal and property damage


                                       10

<PAGE>


insurance as required by law and in amounts no less than the amounts set forth
in Article XXIII hereof.

      5.3 As a condition precedent to the written consent of Landlord, Tenant
agrees to obtain and deliver to Landlord written and unconditional waivers of
mechanics' and materialmen's liens upon the Real Property or a part, for all
work, labor and services to be performed, and materials to be furnished, by them
in connection with such work, signed by all contractors, subcontractors,
materialmen and laborers to be involved in such work. If, notwithstanding the
foregoing, any mechanic's or materialmen's lien is filed against the Real
Property, for work claimed to have been done for, or materials claimed to have
been furnished to, Tenant, such lien shall be discharged by Tenant within ten
(10) days thereafter, at Tenant's sole cost and expense, by the payment thereof
or by filing any bond required by law. If Tenant shall fail to discharge any
such mechanic's or materialmen's lien, Landlord may, at its option, discharge
the same and treat the cost thereof as Additional Rent payable with the monthly
installment of rent next becoming due; it being hereby expressly covenanted and
agreed that such discharge by Landlord shall not be deemed to waive or release
the default of Tenant in not discharging the same. It is understood and agreed
by Landlord and Tenant that any alterations, decorations, additions or
improvements shall be constructed on behalf of Tenant and that in the event
Landlord gives its written consent to Tenant's making any such alterations,
decorations, additions or improvements, such written consent shall not be deemed
to be an agreement or consent by Landlord to subject Landlord's interest in the
Premises, the Building or the Real Property to any mechanic's or materialmen's
liens which may be filed in respect to any such work done by or on behalf of
Tenant.

      5.4 Tenant shall indemnify and hold Landlord harmless from and against any
and all expenses, liens, claims or damages to person or property which arise
directly or indirectly by reason of the Alterations, structural or otherwise,
made by Tenant without the prior written consent of Landlord. Landlord shall
have the right to remove same and Tenant shall be liable for any and all
expenses incurred by Landlord in said removal and subsequent restoration of the
Premises to the original condition.

      5.5 In any case where Landlord's consent is required pursuant to this
Article V, such consent shall not be unreasonably withheld or delayed.

                                   ARTICLE VI
                                   Maintenance

      6.1 Tenant shall take good care of the Premises throughout the Term and
preserve same in the condition delivered to Tenant on the Commencement Date,
normal wear and tear and damage by fire or other casualty not caused by Tenant,
excepted. Tenant


                                       11

<PAGE>


further agrees not to injure, overload, deface or commit waste of the Premises.
Tenant shall be responsible for all injury or damage of any kind or character to
the Real Property, including the windows, floors, walls, ceilings, lights,
electrical equipment and HVAC equipment, caused by Tenant or by anyone using or
occupying the Premises by, through or under Tenant. Landlord shall repair the
same and Tenant shall pay the costs incurred therefor to Landlord immediately
upon demand plus a ten (10%) management fee. If the Premises become infested
with vermin, Tenant shall, at Tenant's expense, cause the same to be
exterminated from time to time to the satisfaction of Landlord and shall employ
such exterminators as shall be approved by Landlord (except if resulting from
Landlord or other tenants, in which case Landlord shall be liable for the cost
thereof).

      6.2 Landlord will operate, maintain and repair the "Common Facilities"
which may be provided pursuant to this Article.

      6.3 For the purposes of this Lease, "Common Facilities" shall mean
facilities which may be provided by the Landlord in the Building or Real
Property for the general common use or benefit to Tenant or other tenants,
including, without limitation, all parking areas, access roads, employee parking
areas, driveways, pedestrian sidewalks, hallways for some or all Tenants,
reception areas for some or all Tenants and ramps, landscaped and planted areas,
walls, retaining walls, foundation, roof, stairways, fire escapes, lighting
facilities, comfort stations and other similar areas and improvements. The
Common Facilities shall at all times be subject to the exclusive control and
management of Landlord. Landlord shall have the right to establish, modify and
enforce reasonable rules and regulations with respect to the Common Facilities;
to change the areas, locations and arrangements of parking areas and other
Common Facilities; to enter into, modify and terminate easement and other
agreements pertaining to the use and maintenance of the parking areas and other
Common Facilities.

      6.4 Landlord reserves the right in its sole discretion, to change,
rearrange, alter, modify, reduce or supplement any or all of the Common
Facilities so long as adequate facilities are made available to the Tenant.

                                   ARTICLE VII
                  Compliance with Laws, Indemnity and Insurance

      7.1 Tenant shall not do, or permit anything to be done in or to the
Premises, or bring or keep anything therein which will, in any way, increase the
cost o f fire or public liability insurance on the Real Property, or invalidate
or conflict with the fire insurance or public liability insurance policies
covering the Real Property, the Building, fixtures or any personal property kept
therein, or obstruct or interfere with

                                       12

<PAGE>


the rights of Landlord or of other tenants, or in any other way injure or annoy
Landlord or other tenants, or subject Landlord to any liability for injury to
persons or damage to property, or interfere with the good order of the Building,
or conflict with the present or future laws, rules or regulations of any
Governmental Authority. Tenant hereby indemnifies and shall hold Landlord
harmless of and from all liability for injury to persons or damage occurring on
the Premises or in the Building or on the Real Property occasioned by any act or
omission of Tenant, or Tenant's agents, servants, employees, invitees or
licensees excluding Landlord's gross negligence or willful misconduct. Tenant
agrees that any increase in fire and casualty insurance premiums on the Building
or contents caused by the occupancy of Tenant and any expense or cost incurred
in consequence of negligence, carelessness or willful action of Tenant, Tenant's
agents, servants, employees, invitees or licensees, shall be reimbursed to
Landlord with ten (10) days of demand therefor. Landlord shall have all the
rights and remedies for the collection of same as are conferred upon Landlord
for the collection of Basic Rent provided to be paid pursuant to the terms
hereof,

                                  ARTICLE VIII
                           Subordination and Estoppel

      8.1 Tenant agrees that this Lease is subject and subordinate to all ground
or underlying leases and to the lien of any mortgages or deeds of trust now on
or which at any time in the future that may be made a lien upon the Real
Property, and to all advances made or hereafter to be made upon the security
thereof. This subordination provision shall be self-operative and no further
instrument of subordination shall be required, provided, however, that Tenant
agrees to execute and deliver within five (5) business days, upon request, such
further instrument or instruments confirming this subordination as shall be
desired by Landlord or by any mortgagee or proposed mortgagee of the Real
Property; and Tenant hereby constitutes and appoints Landlord as Tenant's
attorney-in-fact to execute any such instrument or instruments. Tenant further
agrees that at the option of the holder of any mortgage or of the trustee under
any deed of trust securing the Real Property, this Lease may be made superior to
said mortgage or deed of trust by the insertion therein of a declaration that
this Lease is superior. Landlord shall make its best efforts to procure from any
future Mortgagee, a Non-Disturbance Agreement which shall comprise the
Mortgagee's recognition of Tenant's peaceful possession of the subject premises
pursuant to the terms of this Lease, so long as the Tenant is not in default
under the Lease provisions.

      8.2 Tenant agrees at any time and from time to time upon not less than
five (5) business days' prior written request by Landlord, to execute,
acknowledge and deliver to Landlord a statement in writing certifying that this
Lease is unmodified and in full force and effect (or, if there have been
modifications, that the same are in full force and effect as modified) and
stating the modifications, that there are no offsets,


                                       13

<PAGE>


defenses, defaults, or counterclaims under this Lease or against Landlord, the
dates to which the Basic Rent and Additional Rent have been paid in advance, if
any, it being intended that any such statement delivered pursuant to this
paragraph 8.2 may be relied upon by a prospective purchaser of Landlord's
interest or a mortgagee of Landlord's interest or assignee of any mortgage upon
Landlord's interest in the Real Property.

                                   ARTICLE IX
                      Destruction - Fire or Other Casualty

      9.1 If the Premises or the Building shall be damaged by fire or other
casualty; (i) except as otherwise provided in subsection (ii) hereof, the damage
shall be repaired by and at the expense of Landlord and until such repairs shall
be made the Basic Rent and Additional Rent shall be equitably abated according
to the part of the Premises which is usable by Tenant. Landlord agrees, at its
expense, to repair promptly any damage to the Premises, except that Tenant
agrees to repair or replace its own furniture, furnishings and equipment. No
penalty shall accrue due to a delay caused by strike, lockout, act of God,
inability to obtain labor or materials, governmental restrictions, enemy
actions, civil commotion, fire, unawardable casualty or any other cause similar
or dissimilar beyond the reasonable control of either Landlord or Tenant or due
to the passing of time while waiting for an adjustment of insurance proceeds
(hereinafter referred to as an "Excusable Delay"); (ii) If the Premises are
totally damaged or are rendered wholly untenantable by fire or other casualty,
or if Landlord's architect certifies that it cannot be repaired within ninety
(90) days of the casualty or if Landlord shall decide not to restore or repair
the same, or shall decide to demolish the Building, or not to rebuild the
Building or the Premises, then Landlord shall, within ninety (90) days after
such fire or other casualty, give Tenant a notice of such decision, and
thereupon the Term shall expire ten (10) days after such notice is given, and
Tenant shall vacate the Premises and surrender the same to Landlord; (iii) If
Landlord fails to complete the repair and restoration of the Premises within one
hundred twenty (120) days from the date of the casualty (subject to Excusable
Delays) then Tenant shall have the right to cancel and terminate this Lease upon
the delivery of a notice to Landlord delivered within fifteen (15) days after
the expiration of the aforesaid one hundred twenty (120) days period; (iv)
Landlord agrees that it shall diligently pursue all repair and restoration work
required on its part to be completed hereunder.

                                    ARTICLE X
                          Mutual Waiver of Subrogation

      10.1 Landlord hereby waives any and all rights of recovery against Tenant
for or arising out of damage to or destruction of the Premises, the Building, or
the Real


                                       14

<PAGE>


Property and any other property of Landlord from causes then insured under
standard fire and extended coverage insurance policies or endorsements to the
extent that its insurance policies then in effect permit such waiver, and Tenant
hereby waives any and all rights of recovery against Landlord for or arising out
of damage to or destruction of the Premises, the Building or the Real Property
and any property of Tenant from causes then insured under standard fire and
extended coverage insurance policies to the extent that its insurance policies
then in effect permit such waiver. If at any time during the Term any insurance
carrier which shall have issued a policy to either of the parties covering the
Real Property, the Premises, the Building or any of the property of Tenant,
shall refuse to consent to the waiver of the right of recovery with respect to
any loss payable under such policy, or if such carrier shall consent to such
waiver only upon the payment of an additional premium (unless such additional
premium is voluntarily paid by one of the parties hereto) or shall cancel a
consent previously given, or shall cancel or threaten to cancel any policy
previously issued and then in full force and effect, then in any such event, the
waiver in this paragraph 10.1 shall thereupon be of no further force and effect
as to the loss, damage or destruction covered by such Policy except as
hereinafter provided. If, however, at any time thereafter such consent shall be
obtained therefor from any existing or any substitute insurance carrier, the
waiver hereinabove provided for shall again become effective.

                                   ARTICLE XI
                       Condemnation and Other Proceedings

      11.1 If substantially all of the Premises shall be acquired or condemned
by eminent domain proceedings, or by giving of a deed in lieu thereof, or shall
be ordered demolished or unfit for present use by any governmental body, then
and in that event, the Term shall cease and terminate from the date of
title-vesting or final order pursuant to such proceeding or agreement. If a
partial taking of the Premises or the Building shall be so ordered, acquired or
condemned but Tenant is able to reasonably conduct its business at the Premises
consistent with its Permitted Use as set forth in Article IV hereinabove, this
Lease shall cease and terminate Landlord's option, and if such option is not
exercised by Landlord, an equitable adjustment of the Basic Rent and Additional
Rent payable by Tenant for the remaining useable portion of the Premises shall
be made. In the event of a termination under this Article Xl, Tenant shall have
no claim against Landlord for the value of any unexpired Term and Tenant shall
have no claim against Landlord, other than for the adjustment of the Basic Rent
and Additional Rent as hereinbefore mentioned, or be entitled to any portion of
any amount that may be awarded as damages or paid as a result of such
proceedings or as the result of any agreement made by any governmental authority
with Landlord.

      11.2 Tenant may, if allowed by statute, seek such awards or damages for
moving expenses, loss of profits and fixtures and other equipment installed by
it (if any) which


                                       15


<PAGE>


do not, under the terms of this Lease, become the property of Landlord at the
termination hereof. Such awards or damages must be made by a condemnation court
or other authority and must be separate and distinct from any award to Landlord
for the Real Property and Building and shall not diminish any award of Landlord.
For purposes of this paragraph 11.2, a substantial part of the Premises shall be
considered to have been taken if Tenant is not reasonably able to conduct its
business at the Premises consistent with its permitted use as set forth in
Article IV hereinabove or more than thirty percent (30%) of the Premises are
unusable by Tenant as a direct result of such taking.

                                   ARTICLE XII
                            Assignment and Subletting

      12.1 Tenant for itself, its heirs, distributees, successors and assigns,
expressly covenants that it shall not by operation of law or otherwise assign,
mortgage or encumber this Lease, or any part thereof, or permit the premises to
be used by others without the prior written consent of Landlord in each
instance. Any attempt to do so by Tenant shall be void. The consent by Landlord
to any assignment, mortgage, encumbrance, subletting or use of the Premises by
others, shall not constitute a waiver of Landlord's right to withhold its
consent to any other assignment, mortgage, encumbrance or use of the Premises by
others. Without the prior written consent of Landlord, this Lease and the
interest of Tenant therein or any assignee of Tenant therein, shall not pass by
operation of law, and shall not be subject to garnishment or sale under
execution in any suit or proceeding which nay be brought against or by Tenant or
any assignee of Tenant.

      12.2 Landlord covenants and agrees that it will not unreasonably withhold
its consent to Tenant's assigning or subletting all or a part of the Premises;
provided, however, that Tenant shall not be in default under any of the terms,
covenants, conditions, provisions and agreements of this Lease at the time of
any notice or request for consent under the terms of this Article XII or at the
effective date of such subletting or assigning.

      12.3 (a) If Tenant requests Landlord's consent to an assignment of this
Lease or a subletting of all or any part of the Premises, Tenant shall submit to
Landlord:

       (1)  the sum of one thousand dollars ($1,000.00) as a non refundable fee
            to process each such request;

       (2)  the name of the proposed assignee or subtenant;

       (3)  the terms of the proposed assignment or subletting;


                                       16

<PAGE>


       (4)  the nature of the proposed subtenant's or assignee's business; and

       (5)  such information as to the proposed subtenant's or assignee's
            financial responsibility and general reputation as Landlord may
            reasonably require.

       (b) Upon the receipt of such request and information from Tenant,
Landlord shall have the option, to be exercised in writing within thirty (30)
days after such receipt, to either (1) cancel and terminate this Lease as of the
date of the notice if the request is to assign this Lease or to sublet all of
the Premises or, (2) if the request is to sublet a portion of the Premises only,
to cancel and terminate this Lease with respect to such portion, as of the date
set forth in Landlord's notice of exercise of such option; or (3) to grant said
request.

       (c) In the event Landlord shall cancel this Lease, Tenant shall surrender
possession of the Premises, or the portion of the Premises which is subject of
the request, as the case may be, on the date set forth in such notice in
accordance with the provisions of this Lease relating to surrender of the
Premises. If the Lease shall be canceled as to a portion of the Premises only,
the Basic Rent and Additional Rent payable by Tenant hereunder shall be reduced
proportionately according to the ratio that the number of rentable square feet
in the portion of space surrendered bears to the rentable square feet in the
Premises.

       (d) In the event that Landlord shall consent to a sublease or assignment
pursuant to the request from Tenant, Tenant shall cause to be executed by its
assignee or subtenant an agreement to perform faithfully and to assume and be
bound by all of the terms, covenants, conditions, provisions and agreements of
this Lease for the period covered by the assignment or sublease and to the
extent of the space sublet or assigned. An executed copy of each sublease or
assignment and assumption of performance by the sublessee or assignee, on
Landlord's standard form, shall be delivered to Landlord within five (5) days
prior to the commencement of occupancy set forth in such assignment or sublease.
No such assignment or sublease shall be binding on Landlord until Landlord has
received such copies as required herein.

       (e) In the event that Landlord shall consent to a sublease or assignment
pursuant to the request from Tenant, and such agreement shall be executed and go
into effect, and Tenant realizes a profit from such agreement, Tenant agrees to
pay to Landlord 100% of said profit. Profit is defined as any amount in excess
of amount that Tenant pays to Landlord as defined in Article III and Article
XXVIII of this Lease, less the reasonable cost of subletting the space; i.e.,
brokerage, advertisement, etc.

                                       17

<PAGE>


      12.4 In no event shall any assignment or subletting to which Landlord may
consent, release or relieve Tenant from its obligations to fully perform all of
the terms, covenants and conditions of this Lease on its part to be performed.

                                  ARTICLE XIII
                                    Surrender

      13.1 Upon the Expiration Date or sooner termination of the Term, Tenant
shall peaceably and quietly quit and surrender to Landlord the Premises, broom
clean, in as good condition as they were on the Commencement Date ordinary wear
and tear, repairs and replacements by Landlord, loss by fire, casualty and other
causes beyond Tenant's control, and alterations, additions and improvements
permitted hereunder, excepted. Tenant's obligation to observe or perform this
covenant shall survive the Expiration Date or prior expiration of the Term. If
the Expiration Date falls on a Sunday or a legal holiday, this Lease shall
expire at 12 noon on the business day first preceding said date.

                                   ARTICLE XIV
                                  Holding Over

         14.1 If Tenant holds possession of the Premises beyond the Expiration
date or prior expiration of the Term, Tenant shall become a tenant from
month-to-month at DOUBLE the Basic rent and Additional Rent payable hereunder
and upon all other terms and conditions of this lease, and shall continue to be
such month-to-month tenant until such tenancy shall be terminated by Landlord or
Tenant and such possession shall cease. Nothing contained in this Lease shall be
construed as a consent by Landlord to the occupancy or possession by Tenant of
the premises beyond the Expiration Date or prior expiration of the Term, and
Landlord, upon such Expiration date or prior expiration of the Term shall be
entitled to the benefit of all legal remedies that now may be in force or may be
hereafter enacted relating to the speedy repossession of the Premises and to all
damages to which Landlord is entitled.

                                   ARTICLE XV
                            Landlord's Right of Entry

      15.1 Landlord and Landlord's agents and representatives upon reasonable
prior notice to tenant shall have the right to enter into or upon the Premises,
or any part thereof, at all reasonable hours for the following purposes:

       (1)  examining the Premises;

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<PAGE>


       (2)  making such repairs or alterations therein as may be necessary in
            landlord's sole judgment for the safety and preservation thereof;

       (3)  erecting, maintaining, repairing or replacing wires, cables,
            conduits, vents or plumbing equipment running in, to or through the
            Premises; or

       (4)  showing the Premises to prospective new tenants (only during the
            last year of the Term), purchasers or mortgagees.

      15.2 Landlord may enter upon the Premises at any time in case of emergency
without prior notice to Tenant.

      15.3 Landlord, in exercising any of its rights under this Article XV,
shall not be deemed guilty of an eviction, partial eviction or disturbance of
Tenant's use or possession of the Premises and shall not be liable to Tenant for
same.

      15.4 All work performed by or on behalf of Landlord in or on the Premises
pursuant to this Article XV shall be performed with as little inconvenience to
Tenant's business as possible, and in such manner as not reasonably to interfere
therewith.

                                   ARTICLE XVI
                                     Default

      16.1 Each of the following, whether occurring before or after the
Commencement Date, shall be deemed a Default by Tenant and a breach of this
Lease:

     (a)   the filing of a petition by or against Tenant for adjudication as a
           bankrupt, or for reorganization, or for arrangement under any
           bankruptcy act;

     (b)   the commencement of any action or proceeding for the dissolution or
           liquidation of Tenant, whether instituted by or against tenant, or
           for the appointment of a receiver or trustee of the property of
           Tenant under any state or federal statute for relief of debtors;

     (c)   the making by Tenant of an assignment for the benefit of creditors;

     (d)   the filing of a tax lien or a mechanics' lien against any property of
           Tenant;

     (e)   Tenant's causing or permitting the Premises to be abandoned for a
           period in excess of ten (10) days;

                                       19


<PAGE>


     (f)   failure by Tenant to pay Landlord when due Basic Rent, Additional
           Rent herein reserved, or any other sum by the time required by the
           terms of this Lease;

     (g)   a failure by Tenant in the performance of any other term, covenant,
           agreement or condition of this Lease on the part of Tenant to be
           performed;

     (h)   a default by Tenant under any other lease or sublease with Landlord.

                                  ARTICLE XVII
                     Landlord's Rights Upon Tenant's Default

      17.1 Upon a Default by Tenant or any subtenant or assignee: (a) Landlord,
upon failure of Tenant to cure a default within ten (10) days of the due date in
the payment of Basic Rent, Additional Rent or any other sum of money due to
Landlord hereunder on the day same was due (without notice thereof from
Landlord) or to cure or diligently commence to cure any other Default within
thirty (30) days after notice thereof from Landlord (provided same is cured
within a reasonable time thereafter and without any delay), may immediately or
at any time thereafter, without further notice to Tenant (i) enter upon the
Premises as agent for Tenant, by legal entry, without terminating this Lease and
do any and all acts as Landlord may deem necessary, proper or convenient to
curing such Default, for the account of and at the expense of Tenant, and Tenant
agrees to pay Landlord, upon demand, all damages and/or expenses incurred by
Landlord in so doing: or (ii) terminate this Lease and Tenant's right to
possession of the Premises and, with or without legal process, take possession
of the Premises and remove Tenant, any occupant and any property therefrom,
using such legal means, without being guilty of trespass and without
relinquishing any rights of Landlord against Tenant.

      (b) Landlord shall be entitled to recover damages foam Tenant in an amount
equal to the amount herein covenanted to be paid as Basic Rent and Additional
Rent, together with: (i) all expenses of any proceedings (including but not
limited to, Legal expenses and attorney's fees) which may be necessary in order
for Landlord to recover possession of the Premises: and (ii) the expenses of
re-renting the Premises including, but not limited to, any commissions paid to
any real estate broker, advertising expenses and the costs of such alterations,
repairs, replacements and decoration or redecoration as Landlord in ins sole
judgement considers advisable and necessary for the purpose or re-renting the
Premises; provided, however, that there shall be credited against the amount of
such damages all amounts received by Landlord from such re-renting of the
Premises. Landlord shall in no event be liable in any way whatsoever for failure
to collect the rent thereof under such re-renting. However, Landlord shall be
under no obligation to re-rent the Premises.

                                       20

<PAGE>


      17.2 No act or thing done by Landlord shall be deemed to be an acceptance
of Tenant's surrender of the Premises, unless Landlord should execute a written
agreement of surrender with Tenant. Tenant's liability hereunder shall not be
terminated by the execution of a new lease of the Premises by Landlord. Tenant
agrees to Pay to Landlord, upon demand, the amount of damages herein provided
after the amount of such damages for any month shall have been ascertained;
provided however, that any expenses incurred by Landlord shall be deemed to be a
part of the damages for the month in which they were incurred. Separate actions
may be maintained each month by Landlord against Tenant to recover the damages
then due, without waiting until the end of the Term to determine the aggregate
amount of such damages or Landlord, at its option, if the Premises have been
re-let for a term extending at least as long as the remainder of the Term
hereof, may hold Tenant in advance for the entire deficiency to be realized
during the term of the re-letting. Tenant hereby expressly waives any and all
rights of redemption granted by or under any present or future laws in the event
of the eviction of Tenant or Tenant being dispossessed for any cause, or in the
event of Landlord obtaining possession of the Premises by reason of the
violation by Tenant of any of the covenants or conditions of this Lease.

      17.3 Landlord may retain, as partial liquidated damages, any Basic Rent,
Additional Rent, Security Deposit or monies received from Tenant or others on
behalf of Tenant.

      17.4 Landlord shall have the right, as agent for Tenant, to take
possession of any furniture or fixtures of tenant found upon the Premises after
taking possession of same pursuant to this Article XVII and sell the same at any
private or public sale and apply the proceeds to any amount due Landlord. Tenant
waives any notice of execution or levy in connection therewith.

                                  ARTICLE XVIII
                    Landlord's Remedies Cumulative: Expenses

      18.1 All rights and remedies of Landlord herein enumerated shall be
cumulative, and none shall exclude any other right or remedy allowed by law. For
the purposes of any suit brought or based herein, this Lease shall be construed
to be a divisible contract, to the end that successive actions may be maintained
on this Lease as successive periodic sums which mature hereunder.

      18.2 Tenant shall pay, upon demand, all of the Landlord's costs, charges
and expenses, including the fees of counsel, agents and others retained by
Landlord, incurred in enforcing Tenant's obligations hereunder.


                                       21

<PAGE>


      18.3 If Tenant fails to pay an installment of Basic Rent, Additional Rent
or any other sum due and payable to Landlord on or before the fifth day of the
calendar month following the date when such installment becomes due and payable,
Tenant shall pay to Landlord a late charge (to cover Landlord's administrative
and overhead expenses of processing late payments) equal to six percent (6%) of
the amount of such installment and, in addition, if the payment is not received
within thirty (30) days of the due date than, such unpaid installment shall bear
interest at the rate per annum which is two percent (2%) greater than the "prime
rate" then in effect (or if such prime rate is not available, a replacement rate
designated by Landlord) from the date such installment became due and payable to
the date of payment thereof by Tenant; provided, however, that nothing herein
contained shall be construed or implemented in such a manner as to allow
Landlord to charge or receive interest in excess of the maximum legal rate then
allowed by law. Such late charge and interest shall constitute Additional Rent
hereunder due and payable with the next monthly installment of Basic Rent.

                                   ARTICLE XIX
                                    No Waiver

      19.1 No waiver by Landlord of any breach by Tenant of any of the terms,
covenants, agreements, or conditions of this Lease shall be deemed to constitute
a waiver of any succeeding breach thereof, or a waiver of any breach of any of
the terms, covenants, agreements and conditions herein contained.

      19.2 No employee of Landlord or of Landlord's representatives or agents
shall have any authority to accept the keys of the Premises prior to the
Expiration date and the delivery of keys to any employees of Landlord or
Landlord's representatives or agents shall not operate as an acceptance of a
termination of this Lease or an acceptance of a surrender of the Premises.

      19.3 The receipt by Landlord of the Basic Rent and Additional Rent with
knowledge of the breach of any covenant of this Lease shall not be deemed a
waiver of such breach. No payment by Tenant or receipt by Landlord of a lesser
amount than the monthly Basic Rent or a lesser amount of the Additional Rent
then due shall be deemed to be other than on account of the earliest stipulated
amount then due, nor shall any endorsement or statement on any check or any
letter or other instrument accompanying any check or payment as Basic rent or
Additional Rent be deemed an accord and satisfaction and Landlord may accept
such check or payment without prejudice to Landlord's right to recover the
balance of such Basic Rent or Additional Rent or pursue any other remedy
provided in this Lease.

                                       22

<PAGE>


      19.4 The failure of Landlord to enforce any of the Rules or Regulations as
may be set by Landlord from time to time against Tenant or against any other
tenant in the Building shall not be deemed a waiver of any such Rule or
Regulation.

                                   ARTICLE XX
                           Landlord's Reserved Rights

      20.1 (a) Landlord reserves the following rights: (i) If during the last
ninety (90) days of the Term, Tenant vacates the Premises, to decorate, remodel,
repair, alter or otherwise prepare the Premises for reoccupancy and, (ii) To
have pass keys to the Premises.

         (b) Landlord may exercise either of the foregoing rights hereby
reserved without being deemed to have caused an eviction or disturbance of
Tenant's use and possession of the Premises and without being liable in any
manner to Tenant.

                                   ARTICLE XXI
                              Landlord's Liability

      21.1 Except for Landlord's gross negligence or willful misconduct,
Landlord or its agents or representatives shall not be liable for any injury or
damage to persons or property resulting from fire, explosion, falling plaster,
steam, gas, electricity, water, rain, snow or leaks from any part of the
Building or from the pipes, appliances, plumbing, or the roof, street,
subsurface or from any other place or by dampness or by any other cause of
nature whatsoever; or resulting from the carelessness, negligence or improper
conduct on the part of any other tenant or of Landlord's contractors or its or
any other tenant's agents, employees, guests, licensees, invitees, subtenant's
assignees or successors.

      21.2 Anything contained in this Lease to the contrary notwithstanding,
Tenant agrees that it shall look solely to the estate and property of Landlord
in the Real Property and the Building of which the Premises form a part for the
collection of any judgement (or other judicial process) requiring the payment of
money by Landlord for any default or breach by Landlord of any of its
obligations under this Lease, subject, however, to the prior rights of any
ground or underlying landlord or the holder of any mortgage covering the Real
Property or the Building or of Landlord's interest therein. No other assets of
Landlord shall be subject to levy, execution or other judicial process for the
satisfaction of Tenant's claim. This provision shall not be deemed, construed or
interpreted to be or constitute an agreement, express or implied, between
Landlord and Tenant that Landlord's interest hereunder and in the Real Property
or the Building shall be subject to impressment of an equitable lien otherwise.
Nothing herein contained shall be construed to limit any right of injunction
against Landlord, where appropriate.

                                       23

<PAGE>


      21.3 Landlord shall not be deemed in default with respect to the failure
to perform any of the terms, covenants and conditions of this Lease on
Landlord's part to be performed, if such failure is due in whole or in part to
any strike, lockout, labor dispute (whether legal or illegal), civil disorder,
inability to procure materials, failure of power, restrictive governmental laws
and regulations, riots, insurrections, war, fuel shortages, accidents,
casualties, Acts of God, acts caused directly or indirectly by Tenant (or
Tenant's agents, employees, guests or invitees), acts of other tenants or
occupants of the Building or any other cause beyond the reasonable control of
Landlord. In such event, the time for performance by Landlord shall be extended
by an amount of time equal to the period of the delay so caused. Landlord shall
use best efforts to restore as quickly as possible.

                                  ARTICLE XXII
                               Tenant's Liability

      22.1 Tenant shall reimburse Landlord for all expenses, damages or fines,
incurred or suffered by Landlord by reason of any breach, violation or
non-performance by Tenant, its agents, servants, employees, invitees or
licensees of any covenant or provision of this Lease, or by reason of damage to
persons or property caused by moving property of or for Tenant in or out of the
Building, or by the installation or removal of furniture or other property of or
for Tenant or by reason of or arising out of the carelessness, negligence or
improper conduct of Tenant, or its agents, servants, employees, invitees and
licensees in the use or occupancy of the Premises. Any such expense shall be
deemed Additional Rent, due in the next calendar month after it is incurred.

                                  ARTICLE XXIII
                               Tenant's Insurance

      23.1 (a) Notwithstanding Article XXII, Tenant covenants to provide on or
before the Commencement Date for the benefit of Landlord, Landlord's mortgagee,
Landlord's Managing Agent and Tenant a comprehensive policy of liability
insurance and/or Certificate of Insurance protecting Landlord, Landlord's
mortgagee, and Landlord's Managing Agent and Tenant against any liability
whatsoever occasioned by accident on the Premises or in the common areas of the
Building, including the parking areas or any appurtenances thereto. Such policy
is to be written by insurance companies qualified to do business in the State of
New Jersey, which shall be rated grade A or better in Best's with a rating
therein of 12 or better and the limits of liability thereunder shall be in at
least the following minimum amounts:

A.    Workmen's Compensation                            Statutory.

                                       24


<PAGE>


B.    Employers Liability                               Not less than $100,000
C.    Broad Form Comprehensive                          Not less than $2,000,000
      General Liability Insurance                       combined single limit
      including Contractual                             for both bodily injury
      Liability, Broad Form                             and property damage
      Property Damage, Personal
      Injury, Completed Operations,
      Products Liability, Fire Damage

Such insurance may be carried under a blanket policy covering the Premises and
other locations of Tenant, if any.

      (b) Fire and Extended Coverage, Vandalism, Malicious Mischief and Special
Extended Coverage Insurance in an amount adequate to cover the cost of
replacement of all personal property, decoration, trade fixtures, furnishings,
equipment in the Premises and all contents therein. Landlord shall not be liable
for any damage to such property of Tenant by fire or other peril includable in
the coverage afforded by the standard form of fire insurance policy with
extended coverage endorsement attached (whether or not such Coverage is in
effect), no matter how caused, it being understood that the Tenant will look
solely to its insurer for reimbursement.

      23.2 Prior to the time such insurance is first required by this Article
XXIII to be carried by Tenant, and thereafter, at least thirty (30) days prior
to the expiration of any such policy, Tenant agrees to deliver to Landlord
either a duplicate original of the aforesaid policy or a certificate evidencing
such insurance, provided said certificate contains an endorsement that such
insurance may not be canceled except upon thirty (30) days' notice to Landlord,
together with evidence of payment for the policy.

      23.3 Upon failure at any time on the part of Tenant to procure and deliver
to Landlord the policy or certificate of insurance, as hereinabove provided,
stamped "Premium Paid" by the issuing company at least thirty (30) days before
the expiration of the prior insurance policy or certificate, if any, or to pay
the premiums therefor, Landlord shall be at liberty, from time to time, as often
as such failure shall occur, to procure such insurance and to pay the premium
therefor, and any sums paid for insurance by Landlord shall be and become, and
are hereby declared, to be Additional Rent hereunder due immediately for the
collection of which Landlord shall have all the remedies provided for in this
Lease or by law for the collection of rent. Payment by Landlord of such premium
or the carrying by Landlord of any such policy shall not be deemed to waive or
release the default of Tenant with respect thereto. Tenant's failure to provide
and keep in force the aforementioned insurance shall be regarded as a Default
hereunder entitling Landlord to exercise any or all of the remedies as provided
in this Lease in the event of Default.


                                       25

<PAGE>


      23.4 Landlord shall maintain fire and extended coverage on the Building
and improvements at the property in amounts reasonably satisfactory to Landlord.

                                  ARTICLE XXIV
                                Mechanics' Liens

      24.1 Any mechanics' liens filed against the Real Property for work claimed
to have been done for, or materials claimed to have been furnished to, Tenant
shall be bonded by Tenant within thirty (30) days after notice of filing at
Tenant's expense.

                                   ARTICLE XXV
                                 Quiet Enjoyment

      25.1 Landlord covenants and agrees that, upon the performance by Tenant of
all of the covenants, agreements and provisions hereof on Tenant's part to be
kept and performed, Tenant shall have, hold and enjoy the Premises, subject and
subordinate to the rights set forth in Article VIII, free from any interference
whatsoever by, from or through Landlord, provided, however, that no diminution
or abatement of Basic Rent, Additional Rent or other payment to Landlord shall
be claimed by or allowed to Tenant for inconvenience or discomfort arising from
the making of any repairs or improvements to the Premises or the Real Property,
nor for any space taken to comply with any law, ordinance or order of any
Governmental Authority, except as provided for herein.

                                  Article XXVI
                              Relocation of Tenant

      26.1 Landlord shall have the right, upon giving to Tenant thirty (30)
days' prior written notice, to relocate Tenant by substituting for the Premises
described herein other space in the Building containing approximately as much
area as that contained in the Premises and by paying Tenant's reasonable moving
and relocation expenses. Such substituted space shall be improved by Landlord,
at its expense, with Tenant finished improvements comparable in quantity and
quality to those made in the Premises. Landlord shall pay all reasonable
expenses incurred by Tenant in connection with such relocation, including the
moving, door lettering and telephone relocation. In connection with such
relocation, Landlord and Tenant shall amend this Lease to change the description
of the Premises and any other matter which may pertain thereto.

                                       26

<PAGE>


                                  ARTICLE XXVII
                               Landlord's Services

      27.1 Landlord shall furnish to Tenant the services set forth in this Lease
and the Rules and Regulations as services which are covered by the Basic Rent.

      27.2 Air heating and air cooling shall be furnished for the common areas
only between the hours of 8:00 a.m. and 6:00 p.m., Mondays through Fridays
(hereinafter referred to as the "Business Hours"), with Saturdays, Sundays and
Building Holidays excluded, and then only when weather conditions, in the
opinion of Landlord, require. As used herein, the term "Building Holidays" shall
mean all holidays including, but not limited to: President's Day, Memorial Day,
Independence Day, Labor Day, Columbus Day, Veteran's Day, Thanksgiving Day and
the day after, Christmas Day and New Year's Day, as each of said holidays are
celebrated in the State of New Jersey.

      27.3 (a) Throughout the Term, Landlord agrees that electrical energy to
the Premises (not exceeding the present electrical capacity at the Premises),
will be provided in the manner specified in Item M of the Basic Lease
Provisions. Landlord shall not be liable in any way to Tenant for any loss,
damage or expense which Tenant may sustain or incur as a result of any failure,
defect or change in the quantity or character of electricity furnished to the
Premises or if such quantity or character of electricity furnished to the
Premises is no longer available or suitable for Tenant's requirements or due to
any cessation, diminution or interruption of the supply thereof. Tenant shall be
responsible for the cost and expense of replacing all light bulbs, fluorescent
bulbs, fluorescent lamps, non-building standard lamps and bulbs, and all
ballasts used by Tenant in the Premises, plus a ten (10%) percent management
fee.

         (b) Tenant covenants that its use of electricity in the Premises shall
be limited to and for the operation of (1) the Building standard lighting, and
(2) personal computers, electric typewriters, calculators, copying machines and
other small office machines.

         (c) Tenant shall make no alteration to the existing electrical and gas
equipment or connect any fixtures, appliances or equipment in addition to the
equipment permitted in Article 21.3(b) above without the prior written consent
of Landlord in each instance. Should landlord grant such consent, all additional
risers or other equipment required therefor shall be provided by Landlord and
the cost thereof shall be paid by Tenant upon Landlord's demand.

         (d) Landlord shall not be liable in the event of any interruption in
the supply of electricity and gas, and Tenant agrees that such supply may be
interrupted for inspection, repairs, replacement and in emergencies.

                                       27

<PAGE>


       27.4 The failure of Landlord to furnish any service hereunder shall not
be construed as a constructive eviction of Tenant and shall not excuse Tenant
from performing any of its obligations hereunder and shall not give Tenant any
claim against Landlord for damages for failure to furnish such service .

                                 ARTICLE XXVIII
                                 Additional Rent

      28.1 Tenant hereby covenants and agrees to pay as additional rent the
amounts as set forth hereinbelow.

      28.2 Tenant's Proportionate Share of the total annual real estate taxes,
assessments, (including special assessment), personal property tax, sewer rents,
rates and charges (hereinafter referred to as the "Real Estate Taxes") which
shall be levied, imposed or assessed upon the Real Property. Taxes are paid
quarterly by the Landlord and appropriate billing will be submitted to the
Tenant quarterly, setting forth the amount of the taxes paid or to be paid, at
which time the Tenant will be required to pay said amount to the Landlord as
additional rent hereunder.

      28.3 During the Term of this Lease, Tenant shall pay to Landlord its
Proportionate Share of the Landlord's Operating Expenses.

      28.4 The "Landlord's Operating Costs" shall be the cost and expense of
operating and maintaining the Building and the Real Property, including the
Common Facilities, in a manner deemed by Landlord to be reasonable and
appropriate and for the best interests of the Entire Premises, including,
without limitation, all reasonable costs and reasonable expenses of operating,
maintaining, managing, repairing, replacement, lighting, cleaning, painting,
stripping, insuring, policing and securing (including the cost of uniforms,
equipment and all employmant taxes), heating, ventilating and air-conditioning
the Common Facilities or the Entire Premises as a whole; each and every expense
incurred in connection with the ownership, administration, management, operation
and maintenance of the Entire Premises, including, but not limited to, wages,
salaries and fees paid to persons either employed by Landlord or engaged as
independent contractors in the operation of the Entire Premises and such other
typical items of expense as indicated below; operating and maintaining any
sprinkler system serving the Entire Premises, as a whole or the Common
Facilities; any electrical, gas, water and sewer costs and charges relating to
the Common Facilities or the Entire Premises as a whole (except to the extent
separately charged to Tenants); taxes, insurance, including liability insurance
for personal injury, death and property damage, flood insurance (if required by
mortgagee), insurance against fire, extended coverage and such other casualty
insurance as Landlord shall deem appropriate, rental


                                       28


<PAGE>


insurance, boiler and machinery insurance, insurance against liability for
defamation (except to the extent separately charged to Tenants); plate glass
insurance for glass exclusively serving the area in which the Common facilities
are from time to time located or the Entire Premises as a whole: cleaning costs,
including, but not limited to, window cleaning, general office cleaning,
cleaning of common areas; service contracts, including but not limited to;
contracts for elevator service, HVAC service, rubbish removal, carting,
janitorial and watchman services and snow removal; costs of landscaping; cost of
insurances fees and/or salaries of superintendents, engineers, custodians; towel
service for common lavatories; removal of snow, ice and debris; regulation of
traffic; costs and expenses of inspection and personal property taxes and other
charges incurred in connection with such equipment; costs and expenses of
replacement of paving, curbs, walkways, landscaping, drainage, pipes, ducts,
conduits, lighting facilities and similar items; costs and expenses of repairing
and other structural repairs relating to the Entire Premises; or if reimbursed
to Landlord within the scope of fire or other casualty insurance coverage; costs
and expense of planting, replanting and replacing flowers, shrubbery and
planters; services, if any, furnished by Landlord for non-exclusive use of all
Lessees on a non-profit basis, including parcel pick-up and delivery services
and shuttle bus services. Provided, however, to the extent that any common areas
such as waiting or reception areas are limited to some but not all Tenants, then
only those Tenants to whom the common facility is limited shall share pro rata
in accordance with the aforementioned formula. Landlord shall, in writing,
designate those limited Common Facilities.

      28.5 The charges required hereunder shall be paid by Tenant in monthly
installments with monthly installments of Annual Basic Rent in such amounts as
are estimated by Landlord, together with such additional amounts and credits
invoiced by Landlord as and when Landlord's Operating Costs for any accounting
year of Landlord have been determined, within thirty (30) days of Landlord's
statement therefor. Upon Tenant's reasonable notice, Landlord shall make
available for Tenant's inspection, during normal business hours, Landlord's
records relating to Landlord's Operating Costs for the period covered by any
invoice. Failure of Landlord to provide the statement called for hereunder,
within the time prescribed, shall not discharge Tenant from its obligation
hereunder. In the event of any overpayment, such overpayment shall be refunded
to Tenant. In the event Landlord or any mortgagee should require any particular
Operating Cost to be escrowed, such escrow items shall be paid by Tenant.

                                  ARTICLE XXIX
                             Personal Property Taxes

      29.1 Tenant agrees to pay all taxes imposed on the personal property of
Tenant, the conduct of its business and its use and occupancy of the Premises.


                                       29

<PAGE>


                                   ARTICLE XXX
                                Security Deposit

      30.1 Simultaneously with the execution hereof, Tenant has deposited with
Landlord the sum as specified in Item F of the Basic Lease Provisions.

                                  ARTICLE XXXI
                             Use of Security Deposit

      31.1 In the event of a Default by Tenant in respect of any of the terms,
covenants or conditions of this Lease, Landlord may use, apply or retain the
whole or any part of the Security Deposit to the extent required for the payment
of any Basic Rent, Additional Rent or any other sum as to which Tenant is in
Default or for any sum which Landlord may expend or may be required to expand by
reason of Tenant's Default in respect of any of the terms, covenants or
conditions of this Lease, including but not limited to, any damages or
deficiency accrued before or after summary proceedings or other re-entry by
Landlord. In the event that Tenant shall fully and faithfully comply with all of
the terms, covenants and conditions of this Lease, the Security Deposit shall be
returned to Tenant within thirty (30) days after the Expiration Date and after
delivery of possession of the Premises to Landlord. For all purposes hereunder,
the security deposit shall be deemed additional rent.

      31.2 In the event of a sale of the Real Property or a leasing thereof,
Landlord shall have the right to transfer the Security Deposit to the vendee or
Tenant, as the case may be, and Landlord shall thereupon be released by Tenant
from all liability for the return of such Security Deposits and Tenant agrees to
look to the new landlord solely for the return of the Security Deposit; and it
is agreed that the provisions hereof shall apply to every transfer or assignment
made of the Security Deposit to a new landlord. Tenant further covenants that it
will not assign or encumber or attempt to assign or encumber the Security
Deposit and that neither Landlord nor its successors or assigns shall be bound
by any such assignment, encumbrance, attempted assignment or attempted
encumbrance.

                                  ARTXCLE XXXII
                             Definition of Landlord

      32.1 The Term "Landlord" as used in this Lease means only the owner for
the time being of the Real Property and/or the Building or the owner of a lease
of the Real Property. In the event of any transfer of title to or lease of the
Real Property, Landlord

                                       30

<PAGE>


shall be and hereby is entirely freed and relieved of all covenants and
obligations of Landlord hereunder and this Lease shall be deemed and construed
as a covenant running with the land without further agreement between the
parties or their successors in interest.

      32.2 Landlord shall be under no personal liability with respect to any of
the provisions of this Lease, and if Landlord is in breach or default with
respect to its obligations or otherwise, Tenant shall look solely to the equity
of Landlord in Real Property for the satisfaction of Tenant's remedies. It is
expressly understood and agreed that Landlord's liability under the terms,
covenants, conditions, and obligations of this Lease shall in no event exceed
the loss of its equity in the Real Property.

                                 ARTICLE XXXIII
                                     Notices

      33.1 Notices by either party to the other shall be in writing, sent via
registered or certified mail, return receipt requested, postage prepaid and
addressed to Landlord or Tenant at their respective addresses as specified in
Items H(1) and H(2) of the Basic Lease Provisions, or to such other address as
either party shall hereafter designate by notice as aforesaid. All notices
properly addressed shall be deemed served three (3) business days after the date
of mailing.

                                  ARTICLE XXXIV
                                      Signs

      34.1 No sign advertisement or notice shall be affixed to or placed upon
any part of the Premises, the Building or the Real Property by the Tenant,
except Tenant's entry door and the directory in the respective lobby. The size,
design and color shall be as approved in advance in writing by Landlord, which
approval shall not be unreasonably withheld or delayed.

                                  ARTICLE XXXV
                         Notice of Defects and Accidents

      35.1 Tenant shall give Landlord prompt notice in case of accident on the
Premises involving Tenant, its servants, agents, employees, invitees or
licensees in the Building or on the Real Property or of any defects in the
Building.

                                       31

<PAGE>


                                  ARTICLE XXXVI
                              Rules and Regulations

      36.1 Tenant, on behalf of itself and its employees, agents, servants,
invitees and licensees, agrees to comply with the Rules and Regulations attached
hereto and incorporated by reference as Exhibit C with respect to the Real
Property. Landlord shall have the right to make reasonable amendments thereto
from time to time for the safety, care and cleanliness of the Real Property and
the Building, the preservation of good order therein and the general convenience
of all the tenants and Tenant agrees to comply with such amended Rules and
Regulations, after twenty (20) days' written notice thereof from Landlord.

                                 ARTICLE XXXVII
                                    Directory

      37.1 Landlord shall furnish and service in the lobby of the Building a
tenant directory. Tenant, at its expense, may request from Landlord and pay for
such reasonable and customary number of names that Tenant may from time to time
request to be listed in such directory.

                                 ARTICLE XXXVIII
           Hazardous Materials and Compliance with Environmental Laws

      38.1 Tenant shall not cause or permit any hazardous or toxic substance,
except as otherwise provided in this paragraph, material or waste which is or
becomes regulated by any local governmental authority, of the United States
Government ("Hazardous Material") to be brought upon, kept, or used in or about
the Premises by Tenant, its agents, employees, contractors or invitees, without
the prior written consent of Landlord (which demonstrates to Landlord's
reasonable satisfaction that such Hazardous Material is necessary or useful to
Tenant's business and will be used, kept in or about the Premises). If Tenant
breaches the obligations stated in the preceding sentence, or if the presence of
Hazardous Material on the Premises, the Building or the Real Property caused or
permitted by Tenant results in contamination of the Premises, the Building, or
the Real Property by Hazardous Material or otherwise occurs, for which Tenant is
legally liable to Landlord for damage resulting therefrom, then Tenant shall
indemnify, defend and hold Landlord harmless from any and all claims, judgments,
damages, penalties, fines, costs, liabilities or losses (including, without
limitation, diminution in value of the Premises, the Building, or the Real
Property, damages for the loss or restriction on use of rentable or usable space
or of any amenity of the Premises, the Building, or the Real Property, damages
arising from any adverse impact on marketing of space, and sums paid in
settlement of claims, attorney's fees,

                                       32


<PAGE>


consultant fees and expert fees] which arise during or after the Term as a
result of such contamination. This indemnification of Landlord by Tenant
includes, without limitation, costs incurred in connection with any
investigation of site conditions or any cleanup, remedial, removal, or
restoration work required by any federal, state or local governmental agency or
political subdivision because of Hazardous Material present including in the
soil or ground water on or under the Building. Without limiting the foregoing,
if the presence of any Hazardous Material on the Premises, the Building, or the
Real Property, caused or permitted by Tenant results in any contamination of the
Premises, the Building, or the Real Property, Tenant shall promptly take all
actions at its sole expense as are necessary to return the Premises and/or the
Building, and/or the Real Property to the condition existing prior to the
introduction of any such Hazardous Material to the Premises and/or the Building
and/or the Real Property; provided that Landlord's approval of such actions
shall first be obtained, which approval shall not be unreasonably withheld so
long as such actions would not potentially have any material adverse long-term
or short-term effect on the Premises, the Building or the Real Property.
Notwithstanding anything to the contrary provided herein, Landlord's approval
shall not be required for the lawful storage of materials regularly used in the
ordinary course of Tenant's business; provided, however, upon request of the
Landlord, Tenant shall provide Landlord with a list of materials being stored.

      38.2 Tenant shall, at Tenant's sole cost and expense, comply with the
requirements of any Federal, state, county, municipal or other governmental law,
ordinance, rule, regulation, requirement and/or directive pertaining to the
environment (an "Environmental Law" or "Environmental Laws") including, but not
limited to, the New Jersey Spill Compensation and Control Act (N.J.S.A.
58:10-23.11 ET SEQ.); the New Jersey Water Pollution Control Act (N.J.S.A. 58:
10A-1 ET SEQ.); the Worker and Community Right to Know Act (N.J.S.A. 34:5A-1 ET
SEQ.); the Resource Conservation and Recovery Act of 1976 (42 U.S.C. Section
6901 ET SEQ.); the comprehensive Environmental Response Compensation and
Liability Act of 1980 (42 U.S.C- Section 9601 ET SEQ.); and the industrial Site
Recovery Act and the regulations promulgated thereunder ("ISRA"). ln this
regard, Tenant shall, at Tenant's sole cost and expense, make all submissions
to, provide all information to and comply with all requirements of any
governmental authority. Should said governmental authority determine that action
is necessary to clean up, remove and/or eliminate any spills or discharges by
Tenant or dangerous or hazardous substances or wastes in and upon the Premises,
the Building and/or the Real Property caused by Tenant or its agents, servants,
employees, licensees, invitees and contractors and/or that a cleanup plan must
be prepared and submitted, then and in that event, Tenant shall, at Tenant's
sole cost and expense, take any and all action required and carry out any and
all approved plans. Tenant's obligations pursuant to this section shall arise
whenever required by any appropriate governmental agency, including, but not
limited to, any closing, terminating or transferring of operations at the
Premises.

                                       33

<PAGE>


      38.3 Tenant shall, at Tenant's sole cost and expense, comply with ISRA.
Tenant shall, at Tenant's sole cost and expense, make all submissions to,
provide any information to, and comply with all requirements of, the Bureau of
Industrial Site Evaluation ("the Bureau") of the New Jersey Department of
Environmental Protection ("NJDEP") applicable to its use of the Premises. Should
the Bureau or any other division of NJDEP determine that a cleanup plan be
prepared and that a cleanup be undertaken because of any spills or discharges of
hazardous substances or wastes at the Premises caused by Tenant or its agents,
servants, employees, licensees, invitees and contractors which occur during the
Term or any renewal thereof, as the case may be, then Tenant shall, at Tenant's
sole cost and expense, prepare and submit the required plans and financial
assurances, and carry out the approved plans. Tenant's obligations under this
Article XXXVIII shall also arise if there is any closing, terminating or
transferring of Tenant's operations at the Premises subject to ISRA, including
without limitation, a sale, transfer or conveyance of the Premises by Tenant, an
assignment or subletting by Tenant, or the vacation of the Premises by Tenant
for any reason whatsoever. At no expense to Landlord, Tenant shall promptly
provide all information within its personal knowledge requested by Landlord for
preparation of non-applicability affidavits and shall promptly sign such
affidavits when requested by Landlord. Tenant shall indemnify, defend and hold
harmless Landlord from all fines, suits, procedures, claims and actions of any
kind arising out of or in any way connected with any spills or discharges of
hazardous substances or wastes at the Premises which occur during the Term or
any renewal thereof, as the case may be and which are caused by Tenant or its
agents, servants, employees, licensees, invitees and contractors; and from all
fines, suits, procedures, claims and actions of any kind arising out of tenant's
failure to provide all information, make all submissions and take all actions
required by the ISRA Bureau or any other division of NJDSP. Tenant's failure to
abide by the terms of this Article XXXVIII shall be enforceable in a court of
law and subject to all equitable remedies. Tenant's obligations hereunder shall
survive the Expiration Date of this Lease.

                                  ARTICLE XXXIX
                                  Miscellaneous

      39.1 ENTIRE AGREEMENT. This Lease contains the entire agreement between
the parties, and any attempt hereafter made to change, modify, discharge or
effect an abandonment of it in whole or in part shall be void and ineffective
unless in writing and signed by the party against whom enforcement of the
change, modification, discharge or abandonment is sought.

      39.2 JURY TRIAL WAIVER. Landlord and Tenant do hereby waive trial by jury
in action, proceeding or counterclaim brought by either of the parties hereto
against the other on any matter arising out of or in any connection with this
Lease, the relationship

                                       34

<PAGE>


of Landlord and Tenant, Tenant's use or occupancy of the Premises, and/or any
claim, injury or damage, or any emergency or statutory remedy.

      39.3 FORCE MAJEURE. If, by reason of strike, labor troubles or other cause
beyond Landlord's control, including, but not limited to, governmental
preemption in connection with a national emergency or any rule, order or
regulation of any Governmental Authority, or conditions of supply and demand
which are affected by war or other emergency, Landlord shall be unable to
fulfill its obligations under this Lease or shall be unable to supply any
service which Landlord is obligated to supply, this Lease and Tenant's
obligation to pay Basic Rent and Additional Rent hereunder shall except as
otherwise provided herein, in no way be affected, impaired or excused.

      39.4 BROKER. Landlord and Tenant represents that they have not dealt with
any real estate brokers in connection with this Lease, other than as specified
in Item G of the Basic Lease Provisions. Landlord and Tenant indemnify and hold
each other harmless of and from any and all claims, liabilities, costs or
damages Landlord may incur as a result of a breach of this representation.

      39.5 SEPARABILITY. If any term or provision of this Lease or the
application thereof to any person or circumstance shall, to any extent, be
invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those to which it
is held invalid or unenforceable, shall not be effected thereby and all other
terms and provisions of this Lease shall be valid and enforced to the fullest
extend permitted by law.

      39.6 (a) INTERPRETATION. Whenever in this Lease any words of obligation or
duty are used, such words or expressions shall have the same force and effect as
though made in the form of covenants.

      (b) Words of any gender used in this Lease shall be held to include any
other gender, and words in the singular number shall be held to include the
plural, when the sense requires.

      (c) All pronouns and any variations thereof shall be deemed to refer to
the neuter, masculine, feminine, singular or plural as the identity of Tenant
requires.

      (d) This Lease shall be strictly construed neither against Landlord nor
Tenant. No remedy or election given by any provision in this Lease shall be
deemed exclusive unless so indicated, but each shall, wherever possible, be
cumulative with all other remedies in law or equity as otherwise specifically
provided. Each provision hereof shall be deemed both a covenant and a condition
and shall run with the land.

                                       35

<PAGE>


      (e) If, and to the extent that, any of the provisions of any rider,
addendum or amendment to this Lease conflict or are otherwise inconsistent with
any of the preceding provisions of this Lease, or of the Rules and Regulations
appended to this Lease, whether or not such inconsistency is expressly noted in
the rider, addendum or amendment, the provisions of the rider, addendum or
amendment shall prevail, and in case of inconsistency with said Rules and
Regulations, shall be deemed a waiver of such Rules and Regulations with respect
to Tenant to the extent of such inconsistency.

      (f) Tenant agrees that all of Tenant's covenants and agreements herein
contained providing for the payment of money and Tenant's covenant to remove
mechanics' liens shall be deemed conditions as well as covenants, and that if
default be made in any such covenants, Landlord shall have all of the rights
provided for herein.

      (g) The parties mutually agree that the headings and captions contained in
this Lease are inserted for convenience of reference only, and are not to be
deemed part of or to be used in construing this Lease.

      (h) The covenants and agreements herein contained shall, subject to the
provisions of this Lease, bind and inure to the benefit of Landlord, its
successors and assigns, Tenant, its successors and assigns except as otherwise
provided herein.

      (i) This Lease shall be construed in accordance with the laws of the State
of New Jersey, and Landlord and Tenant acknowledge that all of the applicable
statutes of the State of New Jersey are superimposed on the rights, duties and
obligations of Landlord and Tenant hereunder and this Lease shall not otherwise
provide that which said statutes prohibit.

      (j) Landlord has made no representations or provisos with respect to the
Premises or the Real property, except as expressly contained herein. Tenant has
inspected the Premises and agrees to take the same in an "as is" condition,
except as otherwise expressly set forth in Exhibit B, attached hereto and
incorporated by reference herein. Landlord shall have no obligation, except as
set forth in Exhibit B, to do any work in and to the Premises to render the
Premises ready for occupancy and use by Tenant.

      39.7 NO RECORDATION. Tenant shall not record this Lease or a memorandum
hereof.

      39.8 NO PARTNERSHIP. Nothing contained in this Lease shall be deemed or
construed to create a partnership or joint venture of or between Landlord and
Tenant, or to create any other relationship between the parties hereto other
than that of landlord and tenant.

      39.9 AUTHORITY. Landlord and Tenant hereby covenant each for itself, that
each has full right, power and authority to enter into this Lease upon the terms
and conditions

                                       36

<PAGE>


set forth. If Tenant signs as a corporation, each of the persons executing this
Lease on behalf of Tenant does hereby covenant and warrant that Tenant is a duly
authorized and existing corporation, qualified to do business in the
jurisdiction in which the Building is located, that the corporation has full
right and authority to enter this Lease, and that each of the persons signing on
behalf of the corporation was authorized to do so.

      39.10 EXAMINATION OF LEASE. Submission of this Lease to Tenant to
examination or signature by Tenant shall not constitute reservation of or option
to lease, and the same shall not be effective as a lease or otherwise until
execution and delivery by both Landlord and Tenant.

                                       37

<PAGE>


         IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease under
seal on the day and year first hereinabove written.

WITNESS OR ATTEST:                       LANDLORD:
                                             RAD Data Communications,  Inc.

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

WITNESS OR ATTEST:                       TENANT:
                                              RADVISION,  Inc.

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



                                       38

<PAGE>


                         CORPORATE TENANT ACKNOWLEDGMENT

STATE OF NEW JERSEY

                         SS.______________________

COUNTY OF BERGEN

On this ______, day of ______, 19___, before me personally came _________, to me
known, who, being by me duly sworn, did depose and say that she/he resides in
_______ City of__________ State of__________ that she/he is the__________ of
____________, the corporation ______________________________ described in and
which executed the foregoing Lease, as Tenant; that she/he knows the seal of
said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by order of the Board of Directors of said
corporation, and that she/he signed her/his name thereto by like order.


                                        Notary Public


                        PARTNERSHIP TENANT ACKNOWLEDGMENT

STATE OF

                         SS.____________________

COUNTY OF

         On this _____day of _________19____, before me personally came _______,
to me known, and known to me to be the individuals described in and who executed
the foregoing Lease, as Tenant, and to me acknowledged that each is a partner in
the firm of and that they each executed the same individually and as co-partners
of said firm.


                                        Notary Public


                                       39

<PAGE>


                        INDIVIDUAL TENANT ACKNOWLEDGMENT

STATE OF

                         SS.

COUNTY OF

         On this day of ____, 19__, before me personally came ________ to me
known, and known to me to be the individual described in and who executed the
foregoing Lease, as Tenant, and she/he duly acknowledged to me that she/he
executed the same.


                                           Notary Public




                                       40


<PAGE>


                                    EXHIBIT A


[This exhibit consists of a two dimensional floor plan for the leased
premises (Suite 420 in Lobby 4) at 575 Corporate Drive Mahwah New Jersey,
consisting of approximately 2,148 square feet. The floor plan shows a cross
sectional view of room divisions within the premises.]


<PAGE>


                                    EXHIBIT B

                         LANDLORD'S WORK IN THE PREMISES





                                     [None]










                                       42


<PAGE>


                                    EXHIBIT C

                              RULES AND REGULATIONS

         1. Tenant shall not (a) obstruct or permit its employees, agents,
servants, invitees or licensees to obstruct, in any way, the sidewalks, entry
passages, corridors, exit doorways, halls, stairways or elevators of the
Building, or use the same in any way other than as a means of passage to and
from the offices of Tenant; (b) bring in, store, test or use any materials in
the Building which could cause a fire or an explosion or produce any fumes or
vapor; (c) make or permit any improper noises in the Building; (d) smoke in any
elevator; throw substances of any kind out of windows or doors, or down the
passages of the Building, or in the halls t or passageways, sit on or place
anything upon the window sills; or (e) clean the windows.

         2. Water closets and urinals shall not be used for any purpose other
than those for which they were constructed, and no sweepings, rubbish, ashes,
newspaper or any other substances of any kind shall be thrown into them. Waste
and excessive or unusual use of electricity or water is prohibited.

         3. The windows, doors, partitions and lights that reflect or admit
light into the halls or other places of the Building shall not be obstructed. NO
SIGNS, ADVERTISEMENT OR NOTICES SHALL BE INSCRIBED, PAINTED, AFFIXED OR
DISPLAYED IN, ON, UPON, OR BEHIND ANY WINDOWS.

         4. No contract of any kind with any supplier of towels, water, ice,
toilet articles, waxing, rug shampooing, Venetian blind washing, furniture
polishing, lamp servicing, cleaning or repair of electrical fixtures, removal of
waste paper, rubbish or garbage, or other like service shall be entered into by
Tenant, nor shall any vending machine of any kind be installed in the Building
without the prior written consent of Landlord.

         5. Tenant shall not employ any person or persons for the purpose of
cleaning the Premises, without the prior written consent of Landlord and
obtaining a Certificate of Insurance protecting Landlord and Landlord's Managing
Agent, which shall not be unreasonably withheld or delayed, Landlord shall not
be responsible to Tenant for any loss of property from the Premises however
occurring, or for any damage done to the effects of Tenant by janitors or any of
its employees, or by any other person or any other cause.

         6. When electric wiring of any kind is introduced, it must be connected
as directed by Landlord, and no stringing or cutting of wires will be allowed,
except with the prior written consent of Landlord, and shall be done only by
contractors approved by Landlord. The number and location of telephones,
telegraph instruments, electric appliances, call boxes, etc., shall be approved
by Landlord. No tenant shall lay floor


                                       43

<PAGE>


covering so that the same shall be in direct contact with the floor of the
Premises; and if floor covering is desired to be used, an interlining of
builder's deadening felt shall be first affixed to the floor by a paste or other
material, the use of cement or other similar adhesive material being expressly
prohibited.

         7. Tenant must submit to Landlord in writing a description of the
weight, size and position of all safes and other bulky or heavy equipment and
all freight which Tenant proposes to bring into the Building; and including the
time of moving the same in and out of the Building. Tenant shall not bring such
items into the Building until receiving Landlord's written consent. Once such
Landlord consent is received, all such moving shall be done under the strict
supervision of Landlord or Landlord' s property manager. Landlord will not be
responsible for loss or damage to any such equipment or freight from any cause;
but all damage done to the Building by moving or maintaining any such equipment
or freight shall be repaired at the expense of Tenant. All safes shall stand on
a base of such size as shall be designated by Landlord. Landlord reserves the
right to inspect all freight to be brought into the Building and to exclude from
the Building all freight which violates any of these Rules and Regulations of
the Lease of which these Rules and Regulations are a part.

         8. No machinery of any kind or articles of unusual weight or size will
be allowed in the Building, without the prior written consent of Landlord.
Business machines and mechanical equipment shall be placed and maintained by
Tenant at Tenant's expense, in settings sufficient (including proper floor
load), in Landlord's judgement, to absorb and prevent vibration, noise and
annoyance to other tenants.

         9. No additional lock or locks shall be placed by Tenant on any door in
the Building, without the prior written consent of Landlord. Two keys will
initially be furnished to Tenant by Landlord; two additional keys will be
supplied to Tenant by Landlord, upon request, without charge; any additional
keys requested by Tenant shall be paid for by Tenant. Tenant, its agents and
employees, shall not have any duplicate key made and shall not change any lock.
All keys to doors and washrooms shall be returned to Landlord on or before the
Expiration Date or earlier termination of this Lease, and, in the event of a
loss of any keys furnished, Tenant shall pay Landlord the cost thereof.

         10. No bicycles, vehicles (except wheelchairs) or animals of any kind
shall be brought into or kept in or about the Premises.

         11. The requirements of Tenant will be attended to only upon
application at the office of Landlord or Landlord's property manager. Employees
of Landlord or Landlord's property manager shall not perform any work for Tenant
or do anything outside of their regular duties, unless under special
instructions from Landlord.


                                       44

<PAGE>


         12. The Premises shall not be used for lodging or sleeping purposes,
and cooking therein is prohibited.

         13. Tenant shall not conduct, or permit any other person to conduct,
any auction upon the Premises; manufacture or store goods, wares or merchandise
upon the Premises, without the prior written approval of Landlord, except the
storage of usual supplies and inventory to be used by Tenant in the conduct of
its business; permit the Premises to be used for gambling; make any unusual
noises in the Building; permit to be played any musical instrument in the
Premises; permit to be played any radio, television, recorded or wired music in
such a loud manner as to disturb or annoy other tenants; or permit any unusual
odors to be produced upon the Premises.

         14. Tenant will be entitled to access to the Building by master key
during non-business or overtime hours; it shall be Tenant's responsibility to
secure the Premises at the nonbusiness hours when Tenant enters or leaves the
Building.

         15. No awnings or other projections shall be attached to the outside
walls of the Building. No curtains, shades or screens shall be attached to or
hung in, or used in connection with, any window or door of the Premises, without
the prior written consent of Landlord. All blinds must be of a quality, type,
design, and color, and attached in a manner approved by Landlord.

         16. Canvassing, soliciting and peddling on the Real Property or in the
Building are prohibited, and Tenant shall cooperate to prevent the same.

         17. There shall not be used in the Premises or in the Building either
by Tenant or by others in the delivery or receipt of merchandise, supplies or
equipment, any hand trucks except those equipped with rubber tires and side
guards.

         18. Each tenant, before closing and leaving the Premises, shall ensure
that all windows are closed and all entrance doors closed and locked.

         19. No animals of any kind shall be allowed in the Building except for
lead dogs.

         20. Landlord shall have the right to prohibit any advertising by Tenant
which in Landlord's opinion tends to impair the reputation of the Building or
its desirability for offices, and upon written notice from Landlord, Tenant
shall refrain from or discontinue such advertising.

         21. Landlord hereby reserves to itself any and all rights not granted
to Tenant hereunder, including, but not limited to, the following rights which
are reserved for Landlord's purposes in operating the Building: (a) the
exclusive right to the use of the


                                       45

<PAGE>


name of the Building for all purposes, for Landlord or anyone Landlord might
designate, except that Tenant may use the name as its business address and for
no other purpose; (b) the right to change the name or address of the Building,
without incurring any liability to Tenant for so doing; (c) the right to install
and maintain a sign or signs on the exterior of the Building; (d) the exclusive
right to use or dispose of the use of the roof of the Building; (e) the right to
limit the space on the directory of the Building allotted to Tenant; (f) the
right to grant to anyone the right to conduct any particular business or
undertaking in the Building.

         22. Tenant shall have the non-exclusive right to use in common with
Landlord and other tenants of the Building and their employees and invitees the
unassigned parking areas provided by Landlord for the parking of passenger
automobiles. Landlord may issue parking permits, install a gate system, and
impose any other system as Landlord deems necessary for the use of the parking
area. Tenant agrees that it and its employees and invitees shall not park their
automobiles in parking spaces allocated to others by Landlord and shall comply
with such rules and regulations for use of the perking area as Landlord may from
time to time prescribe. Landlord shall not be responsible for any damage to or
theft of any vehicle in the parking area and shall not be required to keep
parking spaces clear of unauthorized vehicles or to otherwise supervise the use
of the parking area. Landlord reserves the right to change any existing or
future parking area, roads or driveways, and may make any repairs or alterations
it deems necessary to the parking area, roads and driveways end to temporarily
revoke or modify the parking rights granted to Tenant hereunder. The persistent
or frequent violation of this right by Tenant, its employees and invitees, which
continues after written notice from the Landlord shall be deemed a default by
Tenant under the terms of this Lease and shall also subject Tenant to a
revocation by Landlord of Tenant's right to use any parking spaces.

         23. Tenant shall not use the Premises or permit the Premises to be used
for the sale of food or beverages.

         24. Tenant, its employees and agents, hereby agree to abide by
reasonable rules and regulations of which Tenant shall be notified in writing
pertaining to the use of the Building as may be hereafter promulgated from time
to time by Landlord.


                                       46

<PAGE>


May 12, 1997

RADVision, Inc.
575 Corporate Drive
Mahwah, NJ 07430

RE:    575 Corporate Drive
       Mahwah, NJ 07430


Dear Sirs:

As of this date, RAD Data Communications, Inc. ("Landlord") and RADVision, Inc.
("Tenant") have entered into a Lease Agreement, relating to space in the
premises known as 575 Corporate Drive, Mahwah, New Jersey, (the "Property").
Notwithstanding the specific terms of said Lease Agreement, as a further
consideration for each of us entering into said Lease Agreement, it is agreed
that for such period of time as Landlord owns the premises, the basic rent
payable by Tenant shall be $8.50 per square foot per annum. In the event at any
time the Property should be sold by Landlord, it is agreed that the basic rent
shall revert to the rental set forth in the Lease Agreement, which is initially
$10.00 per square foot.

Please indicate your acceptance of the above by signing this letter agreement in
the space indicated.

Very truly yours,

/s/PAUL L. SWEENEY
Paul L. Sweeney
Controller
RAD Data Communications, Inc.

Agreed to and accepted this 30th day of May, 1997.

RADVision, Inc.


By:
   ------------------------------

<PAGE>


                          SECOND MODIFICATION OF LEASE

THIS AGREEMENT, made this 16th day of March, 1998, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

        WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

        WHEREAS, the Landlord and Tenant heretofore entered in a Modification of
Lease dated September 10, 1997 (the "Modification of Lease"), by which Tenant
agreed to lease an additional 688.5 square feet in the Building (as defined in
the Lease Agreement) on the terms and conditions set forth therein; and

        WHEREAS, the term of the Lease Agreement commenced on May 12, 1997 and
will expire on May 11, 2002; and

        WHEREAS, the parties desire that Tenant shall rent from Landlord an
additional 506 square feet in the Building (as defined in the Lease Agreement),
which space is adjacent to the Premises (as defined in the Lease Agreement),
under the terms and conditions hereinafter set forth.

        NOW, THEREFORE, the parties hereto agree as follows:

       1.    All defined terms in the Lease Agreement shall have the same
             meaning in this Modification of Lease as though set forth herein in
             full.

       2.    The Premises shall be amended to consist of approximately 3,342.5
             rentable square feet, as shown on the Floor Plan attached to this
             Second Modification of Lease as Exhibit "A".

       3.    The Annual Base Rent shall be $33,425.00 Net, which shall be made
             in Monthly Installments of Base Rent of $2,785.42 Net plus Tenant
             Utilities and other pass throughs as set forth in the Lease
             Agreement.

       4.    Tenant's Proportionate Share, as set forth in paragraph E of the
             Lease Agreement, shall be amended to be 2.312%.

       5.    The number of parking spaces set forth in paragraph "L" of the
             Lease Agreement shall be amended to be Fourteen (14) Parking
             Spaces.

<PAGE>


       6.    The percentage as set forth in paragraph "M" of the Lease Agreement
             shall be amended to read 2.312% in all places.

       7.    The per annum figure for Tenant Electric and Gas set forth in
             paragraph "M" of the Lease Agreement shall be amended to be
             $4,178.13.

       8.    The Effective Date of all changes set forth in this Second
             Modification of Lease shall be as of March 16, 1998. The Expiration
             Date of May 11, 2002 set forth in the Lease Agreement shall remain
             unchanged.

       9.    Except for the foregoing terms, conditions and amendments, this
             Second Modification of Lease shall be on the same terms, covenants
             and provisions of the Lease Agreement and the Modification of Lease
             which are now in effect and which are incorporated herein by
             reference thereof as if set forth herein at length.


       IN WITNESS WHEREOF, said parties have hereunto set their hands and seals
this 16th day of March, 1998.


WITNESS:                                  RAD DATA Communications, Inc.
                                            Landlord


                                          By:
- --------------------------                   ----------------------------------

WITNESS:                                  RADVISION, Inc.
                                               Tenant


                                          By:
- --------------------------                   ----------------------------------


                                       2

<PAGE>


March 16, 1998


RADVision, Inc.
575 Corporate Drive
Mahwah, NJ 07430

RE:    575 Corporate Drive
       Mahwah, NJ 07430

Dear Sirs:

As of this date, RAD Data Communications, Inc. ("Landlord") and
RADVision, Inc. ("Tenant") have entered into a Second Lease
Modification, relating to space in the premises known as 575 Corporate
Drive, Mahwah, New Jersey, (the "Property"). Notwithstanding the
specific terms of said Lease Modification, as a further consideration
for each of us entering into said Lease Modification, it is agreed that
for such period of time as Landlord owns the premises, the basic rent
payable by Tenant shall be $8.50 per square foot per annum
($28,411.25/year, $2,367.61/month) plus an additional monthly charge of
$180.46 which commenced on November 16, 1997. The latter charge
represents the $9,925 cost of renovations amortized over the remaining
55 months of the lease. In the event at any time the Property should be
sold by Landlord, it is agreed that the basic rent shall revert to the
rental set forth in the Lease Modification, which is initially $10.00
per square foot.

Please indicate your acceptance of the above by signing this letter
agreement in the space indicated.

Very truly yours,


Controller
RAD Data Communications, Inc.

Agreed to and accepted this 16th day of March, 1998.

RADVision, Inc.


By:
   ------------------------------

                                       3


<PAGE>


                                  EXHIBIT A


[This exhibit consists of a two dimensional floor plan for the leased premises
(Suite 420 in Lobby 4) at 575 Corporate Drive Mahwah New Jersey, as reflected
in the Second Modification of Lease and consisting of approximately 3,342.5
square feet. The floor plan shows a cross sectional view of room divisions
within the premises, with the additional premises marked in green outline.]

<PAGE>




                           THIRD MODIFICATION OF LEASE

THIS AGREEMENT, made this 25th day of January, 1999, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

         WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

         WHEREAS, the Landlord and Tenant heretofore entered into a Modification
of Lease dated September 10, 1997, (the "Modification of Lease"), by which
Tenant agreed to lease an additional 688.5 square feet in the Building (as
defined in the Lease Agreement) on the terms and conditions set forth therein;
and

         WHEREAS, the Landlord and Tenant heretofore entered into a Second
Modification of Lease dated March 16, 1998, (the "Second Modification of
Lease"), by which Tenant agreed to lease an additional 506 square feet in the
Building (as defined in the Lease Agreement) on the terms and conditions set
forth therein; and

         WHEREAS,  the term of the Lease  Agreement  commenced on May 12, 1997
and will expire on May 11, 2002; and

         WHEREAS, the parties desire that Tenant shall be released from renting
the 506 square feet in the Building covered by the Second Modification of Lease
and desire that Tenant shall rent from Landlord an additional 5,630 square feet
in the Building, which space is adjacent to the Premises (as defined in the
Lease Agreement), under the terms and conditions hereinafter set forth.

         NOW, THEREFORE, the parties hereto agree as follows:

         1.       All defined terms in the Lease Agreement shall have the same
                  meaning in this Third Modification of Lease as though set
                  forth herein in full.

         2.       All of the terms and conditions of the Second Modification of
                  Lease relating to the additional 506 square feet in the
                  Building referred to therein are hereby deemed terminated and
                  of no further force and effect. The parties understand that
                  the Tenant will no longer be renting from Landlord the said
                  additional 506 square feet referred to in the Second
                  Modification of Lease. This termination shall be effective as
                  of February 23, 1999.

         3.       The Premises shall be amended to comprise the approximately
                  2,836.5 rentable square feet referred to in the Modification
                  of Lease (hereinafter

<PAGE>


                  referred to as the "Existing Leased Space") plus the
                  approximately 5,630 rentable square feet, as shown on the
                  floor plan attached to this Third Modification of Lease as
                  Exhibit "A," (hereinafter referred to as the "New Leased
                  Space).

         4.       The Annual Base Rent for the Existing Leased Space shall
                  remain $28,365.00 Net, which shall be made in Monthly
                  Installments of Base Rent of $2,363.75 Net plus Tenant
                  Utilities and other pass throughs as set forth in the Lease
                  Agreement. In addition, Tenant shall continue to pay to
                  Landlord as Additional Rent the amount of $180.46 per month
                  for the Term, which represents reimbursement to Landlord for
                  construction costs toward the preparation of the Existing
                  Leased Space in the total amount of $9,925.00.

         5.       The Base Rent for the New Leased Space shall be a total of
                  $195,565.19 payable as follows:

                  a.    Monthly payments in the amount of $2,345.84 covering the
                        period from February 1, 1999 through July 31, 1999;

                  b.    Monthly payments in the amount of $4,691.68 covering the
                        period from August 1, 1999 through December 31, 1999;

                  c.    Monthly payments in the amount of $5,568.87 covering the
                        period from January 1, 2000 through April 30, 2002, with
                        a payment of $2,103.39 on May 1, 2002.

         6.       Tenant's Proportionate Share, as set forth in paragraph E of
                  the Lease Agreement, shall be amended to be 5.86%.

         7.       The number of parking spaces set forth in paragraph "L" of the
                  Lease Agreement shall be amended to be Thirty-Three (33)
                  Parking Spaces.

         8.       The percentage as set forth in paragraph "M" of the Lease
                  Agreement shall be amended to read 5.86% in all places.

         9.       The per annum figure for Tenant Electric and Gas for the
                  Existing Leased Space set forth in paragraph "M" of the Lease
                  Agreement shall be amended to be $3,545.63. Tenant Electric
                  and Gas expense for the New Leased Space is metered separately
                  and shall be paid directly by Tenant.

         10.      The Effective Date of all changes set forth in this Third
                  Modification of Lease shall be as of February 1, 1999. The
                  Expiration Date of May 11, 2002 set forth in the Lease
                  Agreement shall remain unchanged.

                                       2

<PAGE>


         11.      As to the New Leased Space, Landlord agrees to construct a
                  doorway connection between the Existing Leased Space and the
                  New Leased Space and to paint and clean the carpets in the New
                  Leased Space.

         12.      Except for the foregoing terms, conditions and amendments,
                  this Third Modification of Lease shall be on the same terms,
                  covenants and provisions of the Lease Agreement and the
                  Modification of Lease which are now in effect and which are
                  incorporated herein by reference thereto as if set forth
                  herein at length.

         IN WITNESS WHEREOF, said parties have hereunto set their hands and
seals this 25th day of January, 1999.



WITNESS:                                 RAD Data Communications, Inc.
                                                   Landlord


                                         By:
- -------------------------                   ----------------------------------


WITNESS:                                 RADVISION, Inc.
                                                  Tenant


                                         By:
- -------------------------                   ----------------------------------


                                       3

<PAGE>



                                  EXHIBIT A

[This exhibit consists of a two dimensional floor plan for the leased
premises (Suite 420 in Lobby 4) at 575 Corporate Drive Mahwah New Jersey, as
reflected in the Third Modification of Lease and consisting of approximately
2,836.5 square feet. The floor plan shows a cross sectional view of room
divisions within the premises.]





<PAGE>


                          FOURTH MODIFICATION OF LEASE

THIS AGREEMENT, made this 1st day of August, 1999, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

         WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

         WHEREAS, the Landlord and Tenant heretofore entered in a Modification
of Lease dated September 10, 1997, (the "Modification of Lease"), by which
Tenant agreed to lease an additional 688.5 square feet in the Building (as
defined in the Lease Agreement) on the terms and conditions set forth therein;
and

         WHEREAS, the Landlord and Tenant heretofore entered into a Second
Modification of Lease dated March 16, 1998, (the "Second Modification of
Lease"), by which Tenant agreed to lease an additional 506 square feet in the
Building (as defined in the Lease Agreement) on the terms and conditions set
forth therein; and

         WHEREAS, the Landlord and Tenant heretofore entered into a Third
Modification of Lease dated January 25, 1999, (the "Third Modification of
Lease"), by which Tenant agreed to terminate the Second Modification of Lease,
such that Tenant would no longer be renting from Landlord the additional 506
square feet referred to in the Second Modification of Lease, on the terms and
conditions set forth therein; and

         WHEREAS,  the term of the Lease  Agreement  commenced  on May 12, 1997
and will expire on May 11, 2002; and

         WHEREAS, the parties desire that Tenant shall rent from Landlord an
additional 506 square feet in the Building (as defined in the Lease Agreement),
which space is adjacent to the Premises (as defined in the Lease Agreement),
under the terms and conditions hereinafter set forth.

         NOW, THEREFORE, the parties hereto agree as follows:

         1.       All defined terms in the Lease Agreement shall have the same
                  meaning in this Fourth Modification of Lease as though set
                  forth herein in full.

<PAGE>




         2.       The Premises shall be amended to include an additional
                  approximately 506 rentable square feet, as shown on the Floor
                  Plan attached to this Fourth Modification of Lease as Exhibit
                  "A" (hereinafter referred to as the "Additional Leased
                  Space").

         3.       The Annual Base Rent for the Additional Leased Space shall be
                  $5,060.00 Net which shall be made in monthly installments of
                  $421.67 Net plus Tenant Utilities and other pass through as
                  set forth in the Lease Agreement.

         4.       Tenant's Proportionate Share as set forth in paragraph "E" of
                  the Lease Agreement shall be amended to read 6.21%, which
                  reflects the addition of .35% as a result of the Additional
                  Leased Space.

         5.       The percentage as set forth in paragraph "M" of the Lease
                  Agreement shall be amended to read 6.21% in all places, which
                  reflects the addition of .35% as a result of the Additional
                  Leased Space.

         6.       The per annum figure for Tenant Electric and Gas set forth in
                  paragraph "M" of the Lease Agreement shall be amended to be
                  $4,178.13. Tenant Electric and Gas expense for the New Leased
                  Space (as referred to in the Third Modification of Lease) is
                  metered separately and shall be paid directly by Tenant.

         7.       The Effective Date of all changes set forth in this Fourth
                  Modification of Lease shall be as of August 1, 1999. The
                  Expiration Date of May 11, 2002 set forth in the Lease
                  Agreement shall remain unchanged.

         8.       Except for the foregoing terms, conditions and amendments,
                  this Fourth Modification of Lease shall be on the same terms,
                  covenants and provisions of the Lease Agreement and the
                  Modification of Lease which are now in effect and which are
                  incorporated herein by reference thereto as if set forth
                  herein at length.

                                       2

<PAGE>


         IN WITNESS WHEREOF, said parties have hereunto set their hands and
seals this 1st day of August, 1999.

WITNESS:                                   RAD Data Communications, Inc.
                                           Landlord


                                           By:
- ------------------------                      ----------------------------------


WITNESS:                                   RADVISION, Inc.
                                           Tenant


                                           By:
- ------------------------                      ----------------------------------


                                       3

<PAGE>



                                  EXHIBIT A

[This exhibit consists of a two dimensional floor plan for the leased
premises (Suite 420 in Lobby 4) at 575 Corporate Drive Mahwah New Jersey, as
reflected in the Fourth Modification of Lease. The floor plan shows a cross
sectional view of room divisions within the premises, with the additional 506
square feet marked in green outline.]



<PAGE>

                                                                  EXHIBIT 10.6


                            WAREHOUSE LEASE AGREEMENT

Concluded on 2nd May 1999 between the company Zisapel Properties (1992) Ltd. and
the company Klil & Michael Properties (1992) Ltd. (hereinafter : "the Lessor"),
and RADVision (hereinafter : "the Lessee") herein represented by ______________.

1.       "The Premises" - an area of 23 square metres on the 2ND basement level
         of the building situate at 24 Raoul Wallenberg Street, Tel Aviv, as
         marked on the diagram in ANNEX A together with     covered parking bays
         and     open parking bays.

2.       The Lessee leases the Premises from the Lessor with effect from 2nd
         May 1999 (hereinafter : "the Date of Commencement of the Lease")
         until 31st December 1999 (hereinafter : "the Initial Lease Period").
         The Lessee shall have an option to extend the lease until 31st
         December 2000, thereafter until and      and thereafter until and
           (each of the above periods of extension shall hereunder be called :
         "the Option Period", the Initial Lease Period and each of the
         Option Periods may also hereunder sometimes be called "the Lease
         Period"). The Lessor shall give 60 days prior written notice to the
         Lessee as to the exercise of the Option. During the Option Periods
         all the conditions of this Agreement shall, MUTATIS MUTANDIS, apply.
         Notwithstanding the foregoing provisions, the Lessee shall be
         entitled to terminate the Lease Period prior to the expiration of
         the Lease Period or any Option Period, if a substitute lessee is
         found from within the RAD-Bynet Group and upon 90 days prior written
         notice. Notwithstanding the foregoing, the Lessor shall have the
         right to give notice to the Lessee as to termination of the lease at
         any time and for any reason, upon 90 days prior written notice. In
         any event the aggregate Lease Periods shall not exceed nine years
         and eleven months.

3.       The Lessee accepts the Premises in clean and good condition, meeting
         its needs, including air conditioning, standard telephone extensions,
              parallel telephone extensions,      smart telephone extensions and
         speakers (hereinafter : "the Basic Condition of the Premises").

4.       Should the Lessee request that alterations be effected to the Premises
         in a departure from the Basic Condition of the Premises, the Lessor
         shall effect the same as set forth in ANNEX B. Should the Lessee leave
         the property prior to the expiration of 4 years from the Date of
         Commencement of the Lease, the Lessee shall refund to the Lessor the
         cost of such alterations to the Premises as set forth in ANNEX B,
         together with interest at 5% per annum reckoned from the date on which
         such alterations were effected to date of actual payment. After
         effecting


<PAGE>
                                       7


         such alterations as set out above, the Lessee shall not effect any
         further alteration to the Premises (hereinafter : "Further
         Alterations"), without the prior written consent of the Lessor. Should
         the Lessee effect any Further Alterations as aforesaid - the Lessee
         alone shall bear all the costs involved therein.

5.       The monthly rental shall be as follows :

         5.1      A sum in new Israeli shekels equal to US $ 10 per square metre
                  during the Initial Lease Period.

                  The rental shall be paid at such representative rate of
                  exchange of the dollar as shall be known on the date of actual
                  payment, together with value added tax.

         5.2      In addition, in the first year the Lessee shall pay an amount
                  in new Israeli shekels equals to US $  per month for the
                  installation of an infrastructure for computers on the
                  Premises. Such payment shall be made in conjunction with the
                  rental as set forth in paragraph 6 hereunder.

         5.3      In addition to the rental and to the payments set forth above,
                  the Lessee shall be responsible for all the amounts as set
                  forth in paragraphs 7 and 8 hereunder.

6.       The rental shall be paid quarterly for three (3) months in advance on
         the first day of each calendar month, or on the first business day next
         following the first day of the month, should this day fall on a Sabbath
         or Holiday. The first payment shall be on 1st July 1999 for the months
         of May to September 1999, and with effect from the second payment, on
         the first day of the month commencing on each annual quarter.

7.       The Lessee shall be responsible for all the on-going payments
         associated with the use of the Premises during the Lease Period,
         including municipal assessment rates, accounts for water, electricity,
         gas, telephone (including the cost of the extensions and the
         installation thereof), maintenance and air conditioning. Debiting shall
         be effected in the manner ordinarily applied by the RAD-Bynet Group
         from time to time.

8.       The Lessor shall provide management and maintenance services to the
         structure in which the Premises are situate, subject to and as set
         forth in the Management Agreement attached to this Agreement as ANNEX
         C.


<PAGE>
                                       8


         When required to do so, the Lessee undertakes to enter into an
         agreement with the Management Company for the entire Lease Period in
         such form as shall be prescribed by the Lessor from time to time, and
         to sign any revision or addendum thereto, and it shall be obliged to
         comply with all its obligations in accordance with that agreement.
         Failure to sign an agreement with the Management Company or any breach
         of the agreement between the Lessee and the Management Company shall be
         regarded as a breach of this Agreement on the part of the Lessee, and
         it is expressly recorded that non payment of the management and
         maintenance fee to the Lessor or to the Management Company as required
         and on the due date thereof shall be deemed to be a fundamental breach
         of this Agreement on the part of the Lessee. Furthermore, it is
         recorded that the cleaning of the interior of the Premises is optional
         and is not comprised within the services which the Lessee shall receive
         from the Lessor or from the Management Company.

9.       A delay of 3 or more months in any payment due by the Lessee under this
         Agreement shall constitute a fundamental breach of this Agreement by
         the Lessee and shall confer upon the Lessor the right to evict the
         Lessee forthwith. Without prejudice to the Lessor's right to evict the
         Lessee as aforesaid - this shall accord to the Lessor the right to
         enforce such payment against the Lessee and inasmuch that the Lessee
         may have failed to effect such payment on due date thereof, the Lessee
         shall also be liable to pay to the Lessor arrears interest on the
         amount in arrears at the Libor rate applicable at such time plus 3% per
         month to date of actual payment. The receipt of the interest by the
         Lessor shall be in addition to its rights under this Agreement and
         under any law and the receipt thereof shall not be and shall not be
         considered as any waiver of any rights accorded to it in pursuance of
         this Agreement or under any law.

10.      Upon the expiration of the Lease or Option Period or termination
         thereof as defined in paragraph 2 above, as the case may be, the Lessee
         undertakes to restore the Premises and the appurtenances therein to the
         same condition as they had been received after effecting the
         alterations to the Basic Condition of the Premises and prior to
         carrying out any Further Alterations (if any), including re-painting
         and cleaning as set forth in paragraph 3 above, save for normal wear
         and tear resulting from ordinary and reasonable use or deterioration
         caused to the Premises during the Lease Period, notwithstanding
         ordinary and reasonable use by the Lessee or by a person on its behalf
         or under its authority, or as a result of VIS MAJOR.


<PAGE>


11.      The Lessee shall be liable for damage caused as a result of the lease
         and use of the Premises by it and/or by its agents and/or by its
         invitees and/or by any person on its behalf. The Lessee shall repair
         any damage as aforesaid in accordance with the Lessor's requirements.

12.      The Lessee is an insured within the framework of the insurance held by
         the RAD-Bynet Group and shall remain such an insured for the entire
         Lease Period in such manner as is the Group's practice from time to
         time.

13.      The Lessee shall be entitled to transfer any part of its rights in and
         to the Premises only to a sub-lessee within the RAD-Bynet Group
         (hereinafter : "the Sub-Lessee"). In any event the Lessee shall
         continue to be responsible for all its obligations under this Agreement
         with respect to the whole area of the Premises as a guarantor for the
         fulfilment by the Sub-Lessee of all the provisions of this Agreement.

14.      [deleted]

15.      Remarks :

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

RADVISION LTD.    ZISAPEL PROPERTIES (1992)          KLIL & MICHAEL PROPERTIES
                  LTD.                               (1992) LTD.


   ----------              ----------                        ----------
   The Lessee       Zisapel Properties (1992) Ltd.     Klil & Michael Properties
                                                       (1992) Ltd.


<PAGE>


                                      ANNEX A

[This Exhibit consists of a two dimensional floor plan for the leased premises
(an area of 23 square meters on the 2nd basement level) at 24 Raoul Wallenberg
Street Tel Aviv Israel.]


<PAGE>



                                     ANNEX B

Schedule of the Works Required  AN ESTIMATE OF THE COST (IT IS NECESSARY TO
to be Undertaken                ATTACH PLANS AS REQUIRED BY THE LESSOR) OF THE
                                WORKS IN NEW ISRAELI SHEKELS / DOLLARS


Total amount of the Works ___________ new Israeli shekels / dollars

I confirm the Works and the cost thereof, as set forth in this Annex.

- ---------------------------       -------------------------          ----------
Zisapel Properties(1992)Ltd.      Klil & Michael Properties          The Lessee


<PAGE>

                                     ANNEX C


        Summary of Management Agreement--translated from Hebrew original


Management Company:   Ariel Properties--ZIV Towers Management Ltd.

Building-    24 Raoul Wallenberg Street Tel Aviv Israel.

Services:    Providing maintenance services to the shared area in the building.

Fees:        Each tenant will pay the pro rata cost of its share in the shared
             areas, according to actual costs paid by the management company
             plus 10% (provided such costs are reasonable and as customary in
             similar buildings). Such fees will be paid quarterly.


<PAGE>

          AMENDMENT TO THE WAREHOUSE LEASE AGREEMENT DATED 2ND MAY 1999

             Made and entered into at Tel Aviv on 1st December 1999

On 2nd May 1999 a lease agreement was entered into between Zisapel Properties
(1992) and the company Klil & Michael Properties (1992) Ltd., and the company
RADVision Ltd for the lease of an area of 23 square metres ("the Lease
Agreement").

It is hereby agreed between the parties that the Lease Agreement be extended
until 31st August 2000.

None of the other provisions of the Agreement have been amended.

Zisapel Properties (1992)Ltd.            RADVision Ltd.


- ------------------------------           ---------------------------------------
Zisapel Properties (1992) Ltd.           Klil and Michael Properties (1992) Ltd.



<PAGE>


                           SUB-LEASE - RAD-BYNET GROUP
                                   March 1999

Concluded on March___1999 between the Company RAD Data Communications Ltd.
(hereinafter : "the Lessor") and the Company RADVision Ltd. (hereinafter : "the
Lessee"), as follows :

1.       "The Premises" - an area of 292 square metres on Level A in Stage B in
         the building situate at 24 Raoul Wallenberg Road Tel Aviv, as marked on
         the diagram in ANNEX A together with 32 parking bays.

2.       The Lessor leases the Premises under a sub-lease from the Company Bay
         Networks (Israel) Ltd. (hereinafter : "Bay") which leases the Premises
         from Vitalgo Textile Enterprises Ltd. (hereinafter : "the Owner").

3.       Bay and the Owner have given approval to the Lessor for the lease of
         the Premises to the Lessee, subject to the agreements between Bay and
         the Owner and between Bay and the Lessor (hereinafter : "the Principal
         Lease Agreements"). The Principle Lease Agreements are attached hereto
         as ANNEX C.

4.       Subject to the provisions of the Principal Lease Agreements and of this
         Agreement, the Lessee leases the Premises from the Lessor under a
         sub-lease with effect from 18th March 1999 (hereinafter : "the Date of
         Commencement of the Lease") until 30th September 2000 (hereinafter :
         "the Lease Period"). Notwithstanding all the foregoing, should this be
         required by the Owner and/or by Bay, the Lessor shall have the right to
         give notice of termination of the lease to the Lessee prior to the
         expiration of the Lease Period at such time as it shall be required so
         to do by the Owner and/or by Bay. The Lessee shall not be entitled to
         any consideration and/or compensation of any kind arising from the
         termination of the Agreement for any reason. The provisions of this
         paragraph are fundamental provisions and constitute the basis for the
         entering into of contractual arrangements under this Agreement.

         Should the Lessor also continue to lease the Premises from Bay and/or
         from the Owner after 30th September 2000, an option shall be granted to
         the Lessee to extend the Lease Period and for the lease of the Premises
         by the Lessor for the entire duration of the Lessee's further Lease
         Period from Bay and/or the Owner (hereinafter : "the Further Lease
         Period"), subject however to all the provisions of this Agreement, to
         the Principal Lease Agreements, including the amendments thereto, if
         any, and such agreements for the renewal of the lease relating to the


<PAGE>


         Premises as shall, if at all, be entered into between the Lessor and
         Bay and/or the Owner.

5.       The Lessee accepts the Premises in their present condition, "As Is", in
         clean and good condition, meeting its needs (hereinafter : "the Basic
         Condition of the Premises").

6.       Should the Lessee request alterations to be effected to the Premises in
         a departure from the Basic Condition of the Premises, the Lessor shall
         effect the same in accordance with such specification and plans as
         shall be approved in advance and in writing by the Lessor and which
         shall be attached as ANNEX B to this Agreement. Upon the termination of
         this Agreement for any reason, should the Owner and/or Bay require
         this, the Lessee shall be obliged to restore the Premises to the Basic
         Condition of the Premises. For the sake of clarity, the Lessee shall
         not be required to reinstate the former condition and to remove those
         alterations which had been made as set forth in the diagram attached to
         letter from Mr. Yehuda Kashti dated 17th March 1999, attached to this
         Agreement as ANNEX E. After the alterations have been effected, as set
         out above, the Lessee shall not effect any further alteration to the
         premises (hereinafter : "the Further Changes") without the prior
         written consent of the Lessor.

7.       The monthly rental shall be as follows :

         7.1      A sum in new Israeli shekels equal to US $ 18.5 per square
                  metre. A sum in new Israeli shekels equal to US $ 120 for each
                  covered parking bay.

                  Should during the Further Lease Period the rental which the
                  Lessor pays to Bay and/or to the Owner increase, the rental
                  payable by the Lessee to the Lessor as set forth above shall
                  be increased in the same proportion.

                  The aforesaid rental shall be translated into new Israeli
                  shekels at the representative rate of exchange of the dollar
                  as at 18th March 1999, from which date it shall be linked to
                  the Consumer Price Index as is know on the date of each and
                  every actual payment.

         7.2      In addition to the rental and to the payments set forth above,
                  the Lessee shall be responsible for the payments set forth in
                  paragraphs 9 and 10 hereunder.


<PAGE>


8.       The rental, including value added tax, shall be paid quarterly for
         three (3) months in advance, on the first day of each calendar month,
         or on the first business day next following the first day of the month
         if this day is a Sabbath or Holiday. The first payment shall be on 15th
         April 1999 for the months 18th March - to June 30 1999, and with effect
         from the second payment on the first day of the month commencing on
         each annual quarter.

9.       The Lessee shall be responsible for all the on-going payments
         associated with the use of the Premises during the Lease Period,
         including municipal assessment rates, accounts for water, electricity,
         gas, telephone (including the cost of the extensions and the
         installation thereof), maintenance and air conditioning. Debiting shall
         be effected in the manner ordinarily applied by the RAD-Bynet Group
         from time to time (as the Lessor shall determine).

10.      The Lessee undertakes to enter into a management agreement with the
         Management Company of the building in the form attached to this
         Agreement as ANNEX D, and to sign any revision or addendum thereto, and
         it shall be obliged to comply with all its obligations in accordance
         with that agreement. Failure to sign an agreement with the Management
         Company or any breach of the agreement between the Lessee and the
         Management Company shall be regarded as a breach of this Agreement on
         the part of the Lessee, and it is expressly recorded that non payment
         of the management and maintenance fee to the Lessor or to the
         Management Company as required and on the due date thereof shall be
         deemed to be a fundamental breach of this Agreement on the part of the
         Lessee. Furthermore, it is recorded that the cleaning of the interior
         of the Premises is optional and is not comprised within the services
         which the Lessee shall receive from the Lessor or from the Management
         Company.

11.      A delay of 3 or more months in any payment due by the Lessee under this
         Agreement shall constitute a fundamental breach of this Agreement by
         the Lessee and shall confer upon the Lessor the right to evict the
         Lessee forthwith. Without prejudice to the Lessor's right to evict the
         Lessee as aforesaid - this shall accord the Lessor the right to enforce
         such payment against the Lessee and inasmuch that the Lessee may have
         failed to effect such payment on due date thereof, the Lessee shall
         also be liable to pay the Lessor arrears interest on the amount so in
         arrears at the Libor rate applicable at such time plus 3% per month to
         date of actual payment. The receipt of the interest by the Lessor shall
         be in addition to its rights under this Agreement and under any law and
         the receipt thereof shall not be and shall not be considered as a
         waiver of any rights accorded to it in pursuance of this Agreement or
         under any law.


<PAGE>


12.      Upon the expiration of the Lease Period or termination thereof as
         defined in paragraph 2 above, as the case may be, the Lessee undertakes
         to restore the Premises and the appurtenances therein to the same
         condition as they had been received after effecting the alterations to
         the Basic Condition of the Premises and prior to carrying out any
         Further Alterations (if any), including re-painting and cleaning as set
         forth in paragraph 3 above, save for normal wear and tear resulting
         from ordinary and reasonable use or deterioration caused to the
         Premises during the Lease Period, notwithstanding ordinary and
         reasonable use by the Lessee or by a person on its behalf or under its
         authority, or as a result of VIS MAJOR.

13.      The Lessee shall be liable for damage caused as a result of the lease
         and the use of the Premises by it and/or by its agents and/or by its
         invitees and/or any person on its behalf. The Lessee shall repair any
         damage as aforesaid in accordance with the Lessor's requirements.

14.      The Lessee is an insured within the framework of the insurance held by
         the RAD-Bynet Group and shall remain such an insured for the entire
         Lease Period as shall be customarily applied by the Group from time to
         time.

15.      The Lessee shall not be entitled to transfer any part of its rights in
         and to the Premises.

16.      Should the level of the holdings of Yehuda Zisapel and Zohar Zisapel
         decline, directly or indirectly below 25% of the issued share capital
         of the Lessee, and this as a guarantee for the fulfilment of all the
         obligations of the Lessee under this Agreement, the Lessee shall
         deposit with the Lessor, immediately upon receipt of the Lessor's
         initial request, and to its order, an autonomous unconditional,
         transferable bank guarantee, capable of foreclosure in its entirely or
         in stages at any time without attributing any reason therefor; in an
         amount in new Israeli shekels equal to 6 months rental, including
         management fees, calculated at the rate applicable at the time of the
         issue of such bank guarantee. The guarantee shall be linked to the
         Consumer Price Index. The guarantee shall be valid for the entire Lease
         Period then remaining at the time of receipt of the Lessor's initial
         request, plus 3 months, and the validity thereof shall be renewed from
         time to time, one month prior to the date on which such validity is due
         to lapse, up to the expiration of the Option Period plus 3 months after
         the expiration of such Option Period. The guarantee shall be duly
         stamped and all costs involved in the issue thereof shall be due solely
         be the Lessee.


<PAGE>


17.      Remarks :

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

                 RAD                                     RADVISION LTD.

      --------------------------------                   ------------------
      RAD Data Communications Ltd.                       RADVision Ltd.


<PAGE>


                                    ANNEX A

[This Exhibit consists of a two dimensional floor plan for the leased
premises (an area of 292 square meters on Level A in Stage B, together with
32 parking bays) at 24 Raoul Wallenberg Street Tel Aviv Israel. The floor
plan shows a cross sectional view of room divisions within the premises.]

<PAGE>


                                   ANNEX B

Works to be performed at the leased premises at 24 Raoul Walenberg Street Tel
Aviv Israel--

                                     [NONE]


<PAGE>


                                     ANNEX C

1) Summary of lease agreement between Bay Networks (Israel ) 1996 Ltd. and
Vitalgo Textile Industries Ltd. - translated from Hebrew original

<TABLE>
<S>               <C>

Date of Lease:    June 11, 1996

Landlord:         Vitalgo Textile Industries Ltd.

Tenant:           Bay Networks (Israel) 1996 Ltd..

Premises:         24 Raoul Wallenberg Street, Tel Aviv Israel.

Square Meters:    2112 sq meters and 76 parking spaces.

Permitted Use:    Industry and data communications.

Term:             2 initial years and option to extend the lease to additional
                  3 years, (each extension one year )

                  (a) Scheduled commencement date: October 6, 1996.
                  (b) Scheduled expiration date:   October 5, 1998.

Security Deposit:          $132,000 in bank guarantee.
</TABLE>

2) Summary of lease agreement between Bay Networks Ltd. and RAD Data
Communications Ltd, - translated from Hebrew original

<TABLE>
<S>               <C>

Date of Lease:    March 10, 1999

Landlord:         Bay Networks (Israel) 1996 Ltd.

Tenant:           RAD Data Communications Ltd...

Premises:         24 Raoul Wallenberg Street, Tel Aviv Israel.

Square Meters:    1056 sq meters and 32 parking spaces.

Permitted Use:    development, marketing and manufacturing of data
                  communications products.

Term:             18.5 months.

                  (a) Scheduled commencement date: March 18, 1999
                  (b) Scheduled expiration date:   September 30, 2000.
</TABLE>

Rent - $18.50 per square meter, i.e. $19,536 per month. and $120 per parking
space, i.e. $3840.

Security Deposit:          $61,000 in bank guarantee.


<PAGE>


                                     ANNEX D

           Summary of Management Agreement--translated from Hebrew original

Management Company:   Ariel Properties--ZIV towers Management Ltd.

Building-  24 Raoul Wallenberg Street Tel Aviv Israel.

Services:  Providing maintenance services to the shared area in the building.

Fees:      Each tenant will pay the pro rata of its share in the shared areas,
           according to actual costs paid by the management company plus 10%
           (provided such costs are reasonable and as customary in similar
           buildings). Such fees will be paid quarterly.


<PAGE>


                                   ANNEX E

Summary of letter from Landlord addressed to the Registrant - translated from
Hebrew original

         After performing the changes as detailed in the two dimensional floor
plan attached to the landlord's letter, Registrant will not be required to
restore the premises to their previous condition.



<PAGE>
                                                                   Exhibit 10.8

                                 LEASE AGREEMENT

Concluded on 31st December 1997 between the companies Zisapel Properties (1992)
Ltd. and Klil & Michael Properties (1992) Ltd. (hereinafter : "the Lessor"), and
the company RADVision (hereinafter : "the Lessee") herein represented by
__________ .

1.       "The Premises" - an area of 880 square metres on level B , ___ square
         metres on the ___ level and ___ square metres on the ___ basement level
         of the building situate at 24 Raoul Wallenberg Street, Tel Aviv, as
         marked on the diagram in ANNEX A together with 21 covered parking bays
         and ___ open parking bays.

2.       The Lessee leases the Premises from the Lessor with effect from 15th
         January 1998 (hereinafter : "the Date of Commencement of the Lease")
         until 31st December 1998 (hereinafter : "the Initial Lease Period").
         The Lessee shall have an option to extend the lease until 31st December
         1999, thereafter until and ___ and thereafter until and ___ (each of
         the above periods of extension shall hereunder be called : "the Option
         Period", the Initial Lease Period and each of the Option Periods may
         also hereunder sometimes be called "the Lease Period"). The Lessor
         shall give 60 days prior written notice to the Lessee as to the
         exercise of the Option. During the Option Periods all the conditions of
         this Agreement shall, MUTATIS MUTANDIS, apply. Notwithstanding the
         foregoing provisions, the Lessee shall be entitled to terminate the
         Lease Period prior to the expiration of the Lease Period or any Option
         Period, if a substitute lessee is found from within the RAD-Bynet Group
         and upon 90 days prior written notice. Notwithstanding the foregoing,
         the Lessor shall have the right to give notice to the Lessee as to the
         termination of the lease at any time and for any reason, upon 90 days
         prior written notice. In any event the inclusive Lease Periods shall
         not exceed nine years and eleven months.

3.       The Lessee accepts the Premises in clean and good condition, meeting
         its needs, including air conditioning, kitchenette, toilets, on a
         marble, ceramic, granite, porcelain floor, gypsum partitioning,
         acoustic ceilings, PVC carpets, ___ standard telephone extensions, ___
         parallel telephone extensions, ___ smart telephone extensions and ___
         speakers (hereinafter : "the Basic Condition of the Premises").

4.       Should the Lessee request that alterations be effected to the Premises
         in a departure from the Basic Condition of the Premises, the Lessor
         shall effect the same as set forth in ANNEX B. Should the Lessee leave
         the property prior to the expiration of 4 years from the Date of
         Commencement of the Lease, the Lessee shall refund to the Lessor the
         cost of such alterations to the Premises as set forth


<PAGE>


         in ANNEX B, together with interest at 5% per annum reckoned from the
         date on which such alterations were effected to date of actual payment.
         After effecting such alterations as set out above, the Lessee shall not
         effect any further alteration to the Premises (hereinafter : "Further
         Alterations"), without the prior written consent of the Lessor. Should
         the Lessee so effect any Further Alterations as aforesaid - the Lessee
         alone shall bear all the costs involved therein.

5.       The monthly rental shall be as follows :

         5.1      A sum in new Israeli shekels equal to US $ 16 per square
                  metre. A sum in new Israeli shekels equal to US $ 90 for each
                  covered parking bay. A sum in new Israeli shekels equal to US
                  $ 60 for each open parking bay.

                  The rental shall be paid at the representative rate of
                  exchange of the dollar as shall be known on the date of actual
                  payment, together with value added tax.

         5.2      In addition, in the first year the Lessee shall pay an amount
                  in new Israeli shekels equals to US $ _____ per month for the
                  installation of an infrastructure for computers on the
                  Premises. Such payment shall be made in conjunction with the
                  rental as set forth in paragraph 6 hereunder.

         5.3      In addition to the rental and to the payments set forth above,
                  the Lessee shall be responsible for all the amounts set forth
                  in paragraphs 7 and 8 hereunder.

6.       The rental shall be paid quarterly for three (3) months in advance on
         the first day of each calendar month, or on the first business day next
         following the first day of the month, should this day fall on a Sabbath
         or Holiday. The first payment shall be on __________ for the months of
         __________ , and with effect from the second payment, on the first day
         of the month commencing on each annual quarter.

7.       The Lessee shall be responsible for all the on-going payments
         associated with the use of the Premises during the Lease Period,
         including municipal assessment rates, accounts for water, electricity,
         gas, telephone (including the cost of the extensions and the
         installation thereof), maintenance and air conditioning. Debiting shall
         be effected in the manner ordinarily applied by the RAD-Bynet Group
         from time to time.


<PAGE>


8.       The Lessor shall provide management and maintenance services to the
         structure in which the Premises are situate, subject to and as set
         forth in the management agreement attached to this Agreement as ANNEX
         C.

         When required to do so, the Lessee undertakes to enter into an
         agreement with the Management Company for the entire Lease Period in
         such form as shall be prescribed by the Lessor from time to time, and
         to sign any revision or addendum thereto and it shall be obliged to
         comply with all its obligations in accordance with that agreement.
         Failure to sign an agreement with the Management Company or any breach
         of the agreement between the Lessee and the Management Company shall be
         regarded as a breach of this Agreement on the part of the Lessee, and
         it is expressly recorded that non payment of the management and
         maintenance fee to the Lessor or to the Management Company as required
         and on the due date thereof shall be deemed to be a fundamental breach
         of this Agreement on the part of the Lessee. Furthermore, it is
         recorded that the cleaning of the interior of the Premises is optional
         and is not comprised within the services which the Lessee shall receive
         from the Lessor or from the Management Company.

9.       A delay of 3 or more months in any payment due by the Lessee under this
         Agreement shall constitute a fundamental breach of this Agreement by
         the Lessee and shall confer upon the Lessor the right to evict the
         Lessee forthwith. Without prejudice to the Lessor's right to evict the
         Lessee as aforesaid - this shall accord to the Lessor the right to
         enforce such payment against the Lessee and inasmuch that the Lessee
         may have failed to effect such payment on due date thereof, the Lessee
         shall also be liable to pay the Lessor arrears interest on the amount
         so in arrears at the Libor rate applicable at such time plus 3% per
         month to date of actual payment. The receipt of the interest by the
         Lessor shall be in addition to its rights under this Agreement and
         under any law and the receipt thereof shall not be and shall not be
         considered as any waiver of any rights accorded to it in pursuance of
         this Agreement or under any law.

10.      Upon the expiration of the Lease or Option Period or termination
         thereof as defined in paragraph 2 above, as the case may be, the Lessee
         undertakes to restore the Premises and the appurtenances therein to the
         same condition as they had been received after effecting the
         alterations to the Basic Condition of the Premises and prior to
         carrying out any Further Alterations (if any), including re-painting
         and cleaning as set forth in paragraph 3 above, save for normal wear
         and tear resulting from ordinary and reasonable use or deterioration
         caused to the Premises during


<PAGE>


         the Lease Period, notwithstanding ordinary and reasonable use by the
         Lessee or by a person on its behalf or under its authority, or as a
         result of VIS MAJOR.

11.      The Lessee shall be liable for damage caused as a result of the lease
         and the use of the Premises by it and/or by its agents and/or by its
         invitees and/or any person on its behalf. The Lessee shall repair any
         damage as aforesaid in accordance with the Lessor's requirements.

12.      The Lessee is an insured within the framework of the insurance held by
         the RAD-Bynet Group and shall remain such an insured for the entire
         Lease Period as shall be customarily applied by the Group from time to
         time.

13.      The Lessee shall be entitled to transfer any part of its rights in and
         to the Premises only to a sub-lessee within the RAD-Bynet Group
         (hereinafter : "the Sub-Lessee"). In any event the Lessee shall
         continue to be responsible for all its obligations under this Agreement
         with respect to the whole area of the Premises as a guarantor for the
         fulfilment by the Sub-Lessee of all the provisions of this Agreement.

14.      Should the level of the holdings of Yehuda Zisapel and Zohar Zisapel
         decline, directly or indirectly below 25% of the issued share capital
         of the Lessee, and this as a guarantee for the fulfilment of all the
         obligations of the Lessee under this Agreement, the Lessee shall
         deposit with the Lessor, immediately upon receipt of the Lessor's
         initial request, and to its order, an autonomous unconditional,
         transferable bank guarantee, capable of foreclosure in its entirely or
         in instalments at any time without furnishing reasons therefor; in an
         amount in new Israeli shekels equal to 3 months rental, calculated at
         the rate applicable at the time of the issue of such bank guarantee.
         The guarantee shall be linked to the Consumer Price Index. The
         guarantee shall be valid for the entire Lease Period then remaining at
         the time of receipt of the Lessor's initial request, plus 3 months, and
         the validity thereof shall be renewed from time to time, one month
         prior to the date on which such validity is due to lapse, until the
         expiration of the Option Period plus 3 months after the expiration of
         such Option Period. The guarantee shall be duly stamped and all costs
         involved in the issue thereof shall be due solely be the Lessee.

15. Remarks :

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


<PAGE>



RADVISION LTD.       ZISAPEL PROPERTIES           KLIL & MICHAEL PROPERTIES
                     (1992) LTD.                 (1992) LTD.


- ------------------   ----------------------       -----------------------------
The Lessee           Zisapel Properties           Klil & Michael Properties
                     (1992) Ltd.                  (1992) Ltd.


<PAGE>


                                    ANNEX A

[This exhibit consists of a two dimensional floor plan for the leased premises
(an area of 880 square meters on Level B) at 24 Raoul Wallenberg Street
Tel Aviv Israel. The floor plan shows a cross sectional view of room divisions
within the premises.]

<PAGE>



                                     ANNEX B

Schedule of the Works Required         AN ESTIMATE OF THE COST (IT IS NECESSARY
to be Undertaken                       TO ATTACH PLANS AS REQUIRED BY THE
                                       LESSOR) OF THE WORKS IN NEW ISRAELI
                                       SHEKELS / DOLLARS

Total amount of the Works ___________ new Israeli shekels / dollars

I approve the Works and the cost thereof, as set forth in this Annex.


- -----------------------------       -------------------------      ----------
Zisapel Properties (1992) Ltd.      Klil & Michael Properties      The Lessee
                                    (1992) Ltd.








<PAGE>


                                 ANNEX C

Summary of agreement with the management company--translated from Hebrew
original

Management Company: Ariel Properties--ZIV Towers Management Ltd.

Building:    24 Raoul Wallenberg Street Tel Aviv Israel.

Services:    Providing maintenance services to the shared area in the building.

Fees:    Each tenant will pay the pro rata cost of its share in the shared
areas, according to actual costs paid by the management company plus 10%,
(provided such costs are reasonable and as customary in similar buildings).
Such fees will be paid quarterly.

<PAGE>



                                    AMENDMENT

To the Lease Agreement between the companies Zisapel Properties (1992) Ltd. and
Klil & Michael Properties (1992) Ltd., and the company RADVision dated 15th
January 1998 (hereinafter : "the Agreement"), made and entered into on 31st
December 1997.

The parties agree that with effect from 1st September 1998, an area of 206
square metres shall be added to the Premises (hereinafter : "the First
Additional Area of the Premises") marked in yellow on the diagram attached
hereto, and with effect from   a further area of   square metres shall be
added to the Premises (hereinafter : "the Second Additional Area") marked in
green on the diagram attached to this Amendment, with effect from 1st September
1998 the area of the Premises set forth in paragraph 1 of the Agreement shall be
changed and shall be 1086 square metres and not as it appears in the Agreement.

There are no other changes to the provisions of the Agreement.

For the sake of clarity the amount of the rental under paragraph 5.1 of the
Agreement shall be calculated as if the further area of the Premises had been
leased with effect from signature of the Agreement.

______________    ______________________________     _________________________
  The Lessee      Zisapel Properties (1992) Ltd.     Klil & Michael Properties
RADVision Ltd.                                       (1992) Ltd.








<PAGE>


                                     DIAGRAM



  [Diagram of an area of 206 square meters (the First Additional Area) marked
  in yellow and further area marked in green (the Second Additional Area),
  totaling 1,086 square meters]

















<PAGE>



                                    AMENDMENT

To the Lease Agreement between the companies Zisapel Properties (1992) Ltd. and
Klil & Michael Properties (1992) Ltd., and the company RADVision dated 15th
January 1998 (hereinafter : "the Agreement"), made and entered into on 31st
December 1997.

The parties agree that with effect from 2nd May 1999, an area of 412 square
metres shall be added to the Premises (hereinafter : "the First Additional Area
of the Premises") marked in yellow on the diagram attached hereto and with
effect from a further area of   square metres shall be added to the
Premises (hereinafter : "the Second Additional Area") marked in green on the
diagram attached to this Amendment, with effect from 2nd May 1999 the area of
the Premises set forth in paragraph 1 of the Agreement shall be changed and
shall be 1498 square metres and not as it appears in the Agreement. Furthermore,
with effect from 2nd May 1999, 10 covered parking bays shall be added.
Accordingly the number of parking bays leased shall be 33, of which 33 shall be
charged at $ 90 and of which   shall be charged at $     .

There are no other changes to the provisions of the Agreement.

For the sake of clarity the amount of the rental under paragraph 5.1 of the
Agreement shall be calculated as if the further area of the Premises had been
leased with effect from signature of the Agreement.

RADVISION LTD.       ZISAPEL PROPERTIES           KLIL & MICHAEL PROPERTIES
                     (1992) LTD.                 (1992) LTD.


- ------------------   ----------------------       -----------------------------
The Lessee           Zisapel Properties           Klil & Michael Properties
                     (1992) Ltd.                  (1992) Ltd.






<PAGE>


                                     DIAGRAM



  [Diagram of an area of 412 square meters (the First Additional Area) marked
  in yellow and further area (the Second Additional Area) marked in green,
  totaling 1,498 square meters]









<PAGE>


                          AMENDMENT TO LEASE AGREEMENT

             Made and entered into at Tel Aviv on 1st December 1999

On 31st December 1997 a lease agreement was entered into between Zisapel
Properties (1992) and the company Klil & Michael Properties (1992) Ltd., and the
company RADVision Ltd for the lease of an area of 880 square metres, for the
lease of a further area of 206 square metres with effect from 1st September
1998, and for the lease of a further area of 412 square metres with effect from
2nd May 1999, and in the aggregate for the lease of an inclusive area of 1498
square metres, and for the lease of 33 parking bays ("the Lease Agreement").

The parties hereby agree to extend the Lease Agreement until 31st August 2000.

Paragraph 5.1 of the Lease Agreement shall be changed as follows :

An amount in new Israeli shekels equal to US $ 16.50 per square metre. An amount
in new Israeli shekels equal to US $ 110 per parking bay. The rest of the
provisions of this paragraph shall remain unchanged.

No change in the rest of the provisions of the Agreement.


- ----------------------     -----------------------------     ------------------
Zisapel Properties         Klil & Michael Properties         RADVision Ltd.
(1992) Ltd.                (1992) Ltd.







<PAGE>

                                                                    Exhibit 10.9

                           Software License Agreement

                                 by and between

                                 RADVISION LTD.
                  24 Raoul Wallenberg Street, Tel Aviv, Israel

                           - henceforth "RADVISION" -

                                       and

                           SIEMENS AKTIENGESELLSCHAFT
                    Hofmannstrasse 51, 81359 Munchen, Germany

                            - henceforth "SIEMENS" -

                       - RADVISION and SIEMENS henceforth
       individually referred to as "Party" and jointly as the "Parties" -


<PAGE>

TABLE OF CONTENTS

<TABLE>

<S>                                                                                               <C>
1    DEFINITIONS...................................................................................4

2    RIGHTS OF SIEMENS.............................................................................7

3    TRADENAMES, TRADEMARK NOTICES.................................................................8

4    INTELLECTUAL PROPERTY RIGHTS..................................................................8

5    DELIVERABLES..................................................................................9

6    ACCEPTANCE...................................................................................10

7    WARRANTY.....................................................................................11

8    PAYMENT, RECORD KEEPING, REPORTS, AUDIT......................................................13

9    INDEMNIFICATION..............................................................................15

10   PRODUCT LIABILITY AND FORCE MAJEURE..........................................................16

11   MAINTENANCE..................................................................................17

12   TECHNICAL SUPPORT; TRAINING..................................................................19

13   CONFIDENTIALITY, MEDIA RELEASES..............................................................20

14   EXPORT CONTROL...............................................................................20

15   NOTICES......................................................................................21

16   ARBITRATION, GOVERNING LAW...................................................................21

17   TERM AND TERMINATION.........................................................................22

18   ISO STANDARDS................................................................................24

19   MISCELLANEOUS................................................................................24

</TABLE>


<PAGE>

ANNEXES:

Annex 1:   Specifications and criteria of the SOFTWARE PRODUCTS
Annex 2:   SYSTEM DOCUMENTATION
Annex 3:   [intentionally deleted]
Annex 4:   REFERENCE ENVIRONMENT
Annex 5:   License and maintenance fees and technical support and training rates
Annex 6:   Maintenance Provisions
Annex 7:   Export Control Data
Annex 8:   List of Sub-Contractors


<PAGE>

PREAMBLE

This Agreement is made and entered into as of February 23, 2000 by and between
RADVision Ltd. ("RADVISION"), with its offices at 24 Raoul Wallenberg Street,
Tel Aviv, Israel and Siemens Aktiengesellschaft ("SIEMENS") with its offices at
Hofmannstr. 51, D-81359 Muenchen, Germany.

WHEREAS, RADVISION holds any and all rights, title and interest in and to the
SOFTWARE PRODUCTS (as hereinafter defined), especially the right to use, copy,
market, distribute, sublicense, modify and/or otherwise dispose of the SOFTWARE
PRODUCTS; the same applying mutatis mutandis to SYSTEM DOCUMENTATION (as
hereinafter defined);

WHEREAS, SIEMENS intends, under the terms and conditions specified herein, to
combine the SOFTWARE PRODUCTS unmodified and/or modified and/or portions thereof
- - with equipment and/or other computer software programs distributed and
marketed by SIEMENS, its RELATED COMPANIES and/or its DISTRIBUTORS( both as
hereinafter defined). It is understood by both Parties that the SOFTWARE
PRODUCTS may be sold and/or licensed only as EMBEDDED PRODUCTS ( as hereinafter
defined).

WHEREAS, SIEMENS is interested in acquiring license rights for the SOFTWARE
PRODUCTS, as set forth in this AGREEMENT;

WHEREAS, RADVISION is willing to grant SIEMENS such license rights on the terms
and conditions set out in this AGREEMENT;

NOW, THEREFORE, RADVISION and SIEMENS, in consideration of the premises and
covenants as stated herein, hereby agree as follows:

1      DEFINITIONS

       For the purposes of this AGREEMENT, the definitions set forth in this
       Clause shall apply to the respective capitalized terms:

1.1    "SOFTWARE PRODUCTS" shall mean the computer software programs in SOURCE
       CODE and OBJECT CODE form, as described in Annex 1, including
       MODIFICATIONS, UPGRADES, UPDATES and BUG FIXES, originating from
       RADVISION.

1.2    "EMBEDDED PRODUCT" shall mean a SOFTWARE PRODUCT either in modified or
       unmodified form physically integrated into hardware and/or software
       developed, manufactured and/or marketed/distributed by SIEMENS, its
       RELATED COMPANIES and/or its DISTRIBUTORS.

1.3    "NEW SOFTWARE PRODUCT" shall mean a computer software program, the
       functionality of which is comparable to the functionality of the most
       recent UPGRADE of the respective SOFTWARE PRODUCT but whose functionality
       as generated by the SOURCE CODE differs from the previous UPGRADE of the
       respective SOFTWARE PRODUCT by more than 50 per cent. Translations shall
       not be deemed to constitute NEW SOFTWARE PRODUCT. Each NEW SOFTWARE
       PRODUCT shall - upon written request of SIEMENS - be incorporated into
       this AGREEMENT by written amendments, whereupon the Parties shall agree
       in good faith on reasonable charges for such NEW SOFTWARE PRODUCT.

1.4    "SOURCE CODE" shall mean a copy of the SOFTWARE PRODUCTS written in
       higher-level programming languages in a form convenient for reading and
       review by a trained individual, such as a printed or written listing of
       programs, containing specific algorithms, instructions, plans,


<PAGE>

       routines and the like, for controlling the operation of a computer
       workstation and/or a central processing unit, but which is not in a form
       that it would be suitable for execution directly on computer hardware.
       SOURCE CODE may be translated into OBJECT CODE for operation on computer
       equipment through the process of compiling, assembling or interpreting.

1.5    "OBJECT CODE" shall mean the machine-readable form of the SOFTWARE
       PRODUCTS resulting from the translation or processing of SOURCE CODE by
       computer equipment into machine language or intermediate code, and which
       is in that form of computer software programs which is not convenient to
       human understanding of the program logic, but which is appropriate for
       execution or interpretation by computer.

1.6    "SYSTEM DOCUMENTATION" shall mean the SOFTWARE PRODUCTS' specifications
       necessary for the technical, programming, maintenance and support manuals
       including program listings as defined in Annex 2. RADVISION shall deliver
       and for the term of this AGREEMENT shall continue to provide the most
       recent version of SYSTEM DOCUMENTATION.

1.7    "REFERENCE ENVIRONMENT" shall mean communication technology and
       information technology systems, whether hardware or software, as defined
       in Annex 4, on which the SOFTWARE PRODUCTS shall fully operate, and their
       future successor products, versions and releases.

1.8    "DISTRIBUTOR" shall mean any third party which has been granted the right
       by SIEMENS or any of its RELATED COMPANIES to distribute the EMBEDDED
       PRODUCT, subject to the terms and conditions herein.

1.9    "END-USER" shall mean a customer of SIEMENS or of a RELATED COMPANY or a
       DISTRIBUTOR, by whom EMBEDDED PRODUCTS are used in the regular course of
       such customers' business and not for resale.

1.10   "RELATED COMPANIES" shall mean any company directly or indirectly owned
       or controlled by SIEMENS. Ownership or control shall exist through the
       direct or indirect ownership of fifty (50) % or more of the nominal value
       of the issued equity share capital or other voting ownership or equity
       interest or of 50 % or more of the participation giving entitlement to
       vote at the election of directors or persons performing similar
       functions, or the right by any other means to elect or appoint directors
       or persons performing similar functions. In countries where equal or
       majority share holding or control by SIEMENS is legally impossible
       minority shareholding shall be sufficient, provided SIEMENS holds the
       maximum share holding as possible at such country, and for the purposes
       of this AGREEMENT be deemed to constitute RELATED COMPANIES.

1.11   "AGREEMENT" shall mean the present Software License Agreement, all
       attached annexes and documents referenced and all amendments hereto, if
       any, agreed by the Parties at a future date.

1.12   "EFFECTIVE DATE" shall mean the last date of signing of this AGREEMENT by
       any of the Parties.

1.13   "IP RIGHTS" shall mean any and all intellectual and industrial property
       rights, including copyrights, patents, patent applications and
       trademarks, and other proprietary rights such as trade secrets and
       know-how contained in SOFTWARE PRODUCTS and/or SYSTEM DOCUMENTATION.

1.14   "MODIFICATION" shall mean any change, modification, enhancement,
       addition, correction done by or on behalf of RADVISION (but not any
       translation in another language other than English) to or of the SOFTWARE
       PRODUCTS, or any derivative work created by or on behalf of RADVISION
       based on the SOFTWARE PRODUCT.

1.15   "UPDATES" - shall mean an update of any SOFTWARE PRODUCT made available
       by RADVISION to its existing customers of the SOFTWARE PRODUCT that
       contain BUG FIXES


<PAGE>

       and/or minor enhancements or improvements, but do not contain significant
       new features, according to RADVISION's reasonable discretion. Each
       function or feature which operated properly in the immediately preceding
       SOFTWARE PRODUCT release must operate properly and consistently in any
       subsequent UPDATE, except when explicitly approved otherwise in writing
       by SIEMENS with respect to a specific UPDATE.

1.16   "UPGRADE" - shall mean an upgrade of any SOFTWARE PRODUCT made available
       by RADVISION to its existing customers of the SOFTWARE PRODUCT that
       contain major enhancements and new features according to RADVISION's
       reasonable discretion.

1.17   "BUG FIXES" - shall mean a fix of an error in any SOFTWARE PRODUCT and /
       or the SYSTEM DOCUMENTATION. BUG FIXES shall apply to all deliverables
       from RADVISION such as SOURCE CODE and/or OBJECT CODE and SYSTEM
       DOCUMENTATION.

1.18   "CLIENT APPLICATION" shall mean end station applications whose
       functionality makes use of the H.323 stack. In contrast to SERVER
       APPLICATIONS, CLIENT APPLICATIONS do not provide a centralized service.

1.19   "SERVER APPLICATION" shall mean an application providing a centralized
       service that is based on the H.323 stack and terminate the voice, video
       and/or data stream. Examples for such services are Messaging Services,
       Telephony Feature Services, Proxy Services for powered down clients, ACD,
       etc.

1.20   "NETWORK APPLICATION" shall mean applications using the H.323 stack and
       that do not terminate the voice, video, and/or data streams, but forward
       them to another entity. Examples for NETWORK APPLICATIONS are H.323
       Gateways, Firewalls with H.323 stack or call control on UNIX or NT
       Servers.

1.21   "H.323 STANDARD" or "H.323" shall mean the issued recommendation of the
       International Telecommunications Union ("ITU"), and any revisions,
       updates or enhancements to such recommendation duly approved by the ITU
       from time to time. Such standard generally relates to transmission of
       audio and visual data over packet networks such as intranets and the
       internet.

1.22   "CONFIDENTIAL INFORMATION" shall mean any information indicated as
       confidential at the time of disclosure (including but not limited to all
       or any part of written and/or oral and/or computer information disclosed
       by RADVISION to SIEMENS relating to RADVISION's business, past, present
       and future, financial information, and commercial information, as well as
       technical, technological and other proprietary information, including but
       not limited to the following: computer programs in any form - object code
       and source code, documentation, installation programs, software code,
       actual products, prototypes, samples, designs, schematics,
       configurations, specifications, techniques, drawings, kits, concepts,
       ideas and all other information, written or oral, relating to the
       SOFTWARE PRODUCT.) Confidential Information includes as well corrections,
       updates, new releases and new versions of the above.

       Oral disclosures shall be deemed confidential only if in addition to the
       indication summarized in writing by the disclosing Party within 30 days.
       Without prejudice to any other information and for the purposes of this
       AGREEMENT, SOURCE CODE, SYSTEM DOCUMENTATION and license accounts shall
       always be considered "Confidential".

1.23   COMPETITIVE PRODUCTS shall mean products that support substantially the
       same functionality as the SOFTWARE PRODUCTS.


<PAGE>

2      RIGHTS OF SIEMENS

2.1    RADVISION hereby grants to SIEMENS solely the following world-wide,
       non-exclusive, non-transferable, royalty-bearing licenses, which are
       perpetual and irrevocable subject to the terms and conditions of this
       AGREEMENT:

(i)    a license to use, copy and modify and have used, copied and modified the
       SOFTWARE PRODUCTS for the sole purpose of developing, creating and
       maintaining EMBEDDED PRODUCTS .

(ii)   a license to copy or have copied the EMBEDDED PRODUCTS to the extent
       necessary to fully utilize the rights granted herein.

(iii)  a license to distribute the EMBEDDED PRODUCTS only in OBJECT CODE form
       world-wide and sub-license (i) the right to use the EMBEDDED PRODUCTS in
       OBJECT CODE form and (ii) the right to create limited copies of the
       EMBEDDED PRODUCTS for archival purposes, both to END-USERS for the
       purpose of the END-USER's utilization of hardware and/or software
       developed, manufactured and/or marketed/distributed by SIEMENS, its
       RELATED COMPANIES and/or its DISTRIBUTORS.

(iv)   a license to sublicense to RELATED COMPANIES and DISTRIBUTORS (a) the
       rights as stated in Clause 2.1 (iii) (b) the right to copy the EMBEDDED
       PRODUCT only in OBJECT CODE form to the extent necessary to fully utilize
       their rights granted to them by SIEMENS according to this AGREEMENT, and
       (c) the right to sublicense the right to create limited copies of the
       EMBEDDED PRODUCT for archival purposes only to the END-USER.

       In no event shall SIEMENS have the right to market or sublicense the
       SOFTWARE PRODUCT, whether with modifications or without modifications, or
       the EMBEDDED PRODUCT in SOURCE CODE form whatsoever.

2.2    On request of RELATED COMPANIES, RADVISION shall enter into a separate
       written license agreement with those RELATED COMPANIES in order to grant
       them the same rights SIEMENS has under Clause 2.1. Such agreement shall
       contain provisions substantially similar to this AGREEMENT except for the
       lump sum, the royalties and the maintenance fees which may differ from
       those set forth herein. Subject to RADVISION's awareness that a company
       is a RELATED COMPANY, RADVISION will immediately inform SIEMENS in
       writing if RADVISION receives such a request of a RELATED COMPANY. In
       case of the RELATED COMPANIES Infineon Technologies AG, SBS GmbH & Co
       OHG, the agreement shall provide only royalties and maintenance fees, but
       no lump sum additional to the sum paid by SIEMENS under this AGREEMENT.

2.3    On request of a Minority Company, as defined below, RADVISION shall enter
       into a separate written license agreement as described in paragraph 2.2
       with such companies provided that the business interests of RADVISION are
       not adversely affected by such an agreement. "Minority Company" shall
       mean any company directly or indirectly owned or controlled by SIEMENS by
       a percentage of 40 to less than 50 % through the direct or indirect
       ownership of 40 % to less than 50 % of the nominal value of the issued
       equity share capital or other voting ownership or equity interest or of
       40 to less than 50 % of the participation giving entitlement to vote at
       the election of directors or persons performing similar functions, or the
       right by any other means to elect or appoint directors or persons
       performing similar functions, provided such company is not a RELATED
       COMPANY. RADVISION will immediately inform SIEMENS in writing if
       RADVISION receives such a request of a Minority Company.


<PAGE>

2.4    SIEMENS may at its discretion engage subcontractors and have them perform
       work for and on behalf of SIEMENS including but not limited by
       authorizing them for the sole purpose of performing such work to use, to
       copy, to modify and/ or to otherwise work with the SOFTWARE PRODUCT in
       its SOURCE CODE form and RADVISION's CONFIDENTIAL INFORMATION, provided
       that such subcontractor shall (1) not be listed in Annex 8 attached
       hereto, and (2) have signed an agreement with SIEMENS that shall bind
       this subcontractor in writing to observe confidentiality obligations
       concerning the non-disclosure of the SOURCE CODE of the SOFTWARE PRODUCTS
       being not less stringent than the confidentiality obligations of SIEMENS
       under this AGREEMENT, and (3) warrant not to be engaged in producing
       COMPETITIVE PRODUCTS.

2.5    RADVISION hereby grants to SIEMENS the world-wide, non-exclusive,
       non-transferable, and subject to the terms and conditions of this
       AGREEMENT perpetual and irrevocable right to use, copy, translate and
       modify and/or to have used, copied, translated, modified any SYSTEM
       DOCUMENTATION in unmodified or modified form, for the purposes of
       utilizing the rights granted in Clause 2.1.

2.6    RADVISION hereby grants to SIEMENS the right to sublicense its rights
       regarding the SYSTEM DOCUMENTATION as set forth in 2.4 in connection with
       the sublicensing of EMBEDDED PRODUCTS, provided that the rights regarding
       the SYSTEM DOCUMENTATION are not sublicensed to END-USERs.

2.7    If migration to communication technology and information technology
       systems other than the REFERENCE ENVIRONMENT is requested by SIEMENS,
       RADVISION shall provide to SIEMENS the necessary MODIFICATIONS of the
       SOFTWARE PRODUCT, subject to the payment by SIEMENS of charges not higher
       than those usually charged by RADVISION to customers comparable to
       SIEMENS.

3      TRADENAMES, TRADEMARK NOTICES

3.1    RADVISION hereby grants and agrees to grant to SIEMENS, its RELATED
       COMPANIES and DISTRIBUTORS, the right to use and reproduce all present
       and future pertinent tradenames, and trademarks, with regard to the
       SOFTWARE PRODUCTS and EMBEDDED PRODUCTS in its original or duly
       abbreviated version. RADVISION shall grant respective rights to future
       trademarks, with regard to the SOFTWARE PRODUCT in its original or
       modified form whenever they come into existence.

3.2    SIEMENS and its RELATED COMPANIES may add and use its own name, trade
       name, logo, trademark(s) and intellectual property rights notices with
       regard to EMBEDDED PRODUCTS, in particular for the purposes of
       distribution and marketing.

3.3    Each of the Parties agrees, covenants and warrants that it shall not use,
       make reference to or otherwise designate in writing any of the other
       Party's trademarks, tradenames or other proprietary notices, except as
       specifically authorized in this AGREEMENT or any other legally binding
       agreement between the Parties, without the prior written consent of such
       other Party.

4      INTELLECTUAL PROPERTY RIGHTS

4.1.   Sublicensing Terms. An END-USER may be authorized only to use the
       EMBEDDED PRODUCT pursuant to a written agreement between Siemens, a
       RELATED COMPANY or a DISTRIBUTOR, as the case may be, and the END-USER.
       The terms and conditions of all such agreements shall provide
       substantially the same protection for the EMBEDDED PRODUCT as the terms
       and


<PAGE>

       conditions SIEMENS uses for its other software products, or the terms set
       forth herein this AGREEMENT.

4.2    Legends and Notices. SIEMENS agrees to reproduce, on all copies of the
       SOFTWARE PRODUCTS and EMBEDDED PRODUCTS and the SYSTEM DOCUMENTATION in
       unmodified or modified form, a RADVISION copyright notice in a form
       approved in advance by RADVISION. The copyright notice shall be the same
       or similar to the following: "Portions of this software are (C) 1996-20__
       RADVision Ltd. All IP Rights in such portions of the software products
       and documentation are owned by RADVision and are protected by United
       States copyright laws, other applicable copyright laws and international
       treaty provisions. RADVision and its suppliers retain all rights not
       expressly granted." If copyright is originated in more than one year,
       mentioning of the first and last year shall be sufficient. In the case of
       a new copyright (e.g. in UPGRADES), the respective notification shall be
       included in the UPGRADE whenever the latter is printed after written
       notification by RADVISION of such new copyright.

4.3.   Title. Notwithstanding, anything contained in this AGREEMENT to the
       contrary, title in and to the SOFTWARE PRODUCTS and SYSTEM DOCUMENTATION,
       additions and MODIFICATIONS to the SOFTWARE PRODUCTS created by
       RADVISION, including but not limited to, all copyright, patent, trade
       secret rights, and intellectual property rights shall remain in and with
       RADVISION.

4.4    SIEMENS shall sufficiently ensure the IP RIGHTS of RADVISION in the
       SOFTWARE PRODUCT when granting software sub-licenses to subcontractors by
       using similar terms and conditions SIEMENS regularly uses vis-a-vis
       comparable subcontractors when licensing its own computer software
       programs. SIEMENS shall reproduce on the EMBEDDED PRODUCT all notices
       regarding said RADVISION's rights.

4.5    If a subcontractor of SIEMENS is using the SOFTWARE PRODUCT it has got
       from SIEMENS in violation of such subcontractor's right as set forth
       herein this AGREEMENT, SIEMENS shall adequately pursue RADVISION's rights
       regarding the SOFTWARE PRODUCT and furnish all available and
       non-confidential information concerning such improper use of the SOFTWARE
       PRODUCT.

4.6    Without undue delay SIEMENS shall notify RADVISION if it comes to
       SIEMENS' knowledge that a specific subcontractor of the SOFTWARE PRODUCT
       is infringing RADVISION's proprietary rights. This Clause 4.6 shall not
       be construed to constitute an obligation on the part of SIEMENS, its
       RELATED COMPANIES or DISTRIBUTORS to grant RADVISION access to SIEMENS'
       customer list.

5      DELIVERABLES

5.1    For the purposes of this AGREEMENT and at no cost to SIEMENS, within five
       (5) business days of the EFFECTIVE DATE RADVISION shall deliver to
       SIEMENS the SOFTWARE PRODUCTS in SOURCE and OBJECT CODE form and the
       SYSTEM DOCUMENTATION on CD media. The SYSTEM DOCUMENTATION on CD will be
       delivered as detailed in Annex 2.

5.2    At any time during the term of this AGREEMENT, RADVISION shall render to
       SIEMENS at the earliest possible advance written notification of any
       MODIFICATION, UPDATES, UPGRADES, and of new features, functionality
       and/or interfaces of the SOFTWARE PRODUCTS.

5.3    Immediately after the respective release, subject to the maintenance
       provisions contained in this AGREEMENT, RADVISION shall deliver to
       SIEMENS the MODIFICATION, UPDATE and / or BUG FIX together with the
       latest version of the SOFTWARE PRODUCTS in SOURCE CODE and


<PAGE>

       OBJECT CODE form and the latest version of the SYSTEM DOCUMENTATION at no
       cost to SIEMENS on appropriate media.

6      ACCEPTANCE

6.1    SIEMENS shall be entitled to evaluate the SOFTWARE PRODUCTS and the
       SYSTEM DOCUMENTATION delivered by RADVISION within 30 (thirty) days (the
       "Evaluation Period") after the delivery of the SOFTWARE PRODUCTS and the
       SYSTEM DOCUMENTATION according to Clause 5.1.

6.2    Within 20 (twenty) working days of the expiry of the Evaluation Period,
       SIEMENS shall submit a written acceptance or rejection notice to
       RADVISION. A rejection notice shall be accompanied by a report on each
       failure of the SOFTWARE PRODUCTS to meet the specifications and criteria
       stated in Annex 1, 2, 3 and 4 and the functionality described in all
       related SYSTEM DOCUMENTATION, and a failure of the SYSTEM DOCUMENTATION
       to meet the requirements of Annexes 2 and 3 respectively, provided that
       SIEMENS has noticed such failure during the Evaluation Period. If
       RADVISION does not receive any written notice within the above time
       period the SOFTWARE PRODUCT and the SYSTEM DOCUMENTATION shall be deemed
       to be accepted by SIEMENS.

6.3    Acceptance shall be determined by SIEMENS and has to be demonstrated by
       RADVISION by conformance to the specifications and criteria stated in
       Annex 1, 2, 3 and 4, which may be amended from time to time by mutual
       written agreement of the Parties, and the functionality described in all
       related SYSTEM DOCUMENTATION. In case of any divergences the agreed
       specifications and criteria (including written amendment(s), if any) as
       per Annexes 1, 2, 3 and 4 shall prevail over the SYSTEM DOCUMENTATION.

6.4    Within 1 (one) month of receipt of any rejection notice (henceforth "the
       Correction Period"), RADVISION shall at no cost to SIEMENS make best
       efforts to correct and deliver corrected and tested SOFTWARE PRODUCTS and
       / or SYSTEM DOCUMENTATION to SIEMENS together with a statement of the
       corrections made by RADVISION.

6.5    After receipt of the corrected SOFTWARE PRODUCTS and / or SYSTEM
       DOCUMENTATION and the statement of corrections as per Clause 6.4, SIEMENS
       is entitled to re-evaluate such corrected and tested SOFTWARE PRODUCTS
       and / or SYSTEM DOCUMENTATION . One half of the costs of re-evaluation
       shall be borne by RADVISION if and when the costs per incident exceed US
       $ 5000, provided that the costs to be borne by RADVision shall in no
       event exceed the amount of US $ 15,000. This procedure will be repeated
       until SIEMENS accepts the deliverables in writing. However, if sixty (60)
       days after SIEMENS has received the corrected SOFTWARE PRODUCTS and / or
       SYSTEM DOCUMENTATION, RADVISION does not receive any written notice, the
       SOFTWARE PRODUCTS and the SYSTEM DOCUMENTATION shall be deemed to be
       accepted by SIEMENS.

6.6    If corrections provided by RADVISION in compliance with the Correction
       Period are repeatedly insufficient to achieve full compliance with Clause
       6.2 obligations, or if RADVISION fails to provide necessary corrections
       and tests in due time, or if SIEMENS' interest in the SOFTWARE PRODUCTS
       and / or SYSTEM DOCUMENTATION becomes frustrated due to the delay in
       submitting SOFTWARE PRODUCTS and / or SYSTEM DOCUMENTATION complying with
       Clause 6.2 obligations, SIEMENS may at its option and notwithstanding any
       other right it may have under applicable law:

       6.6.1      either propose a re-scheduled correction period. Rejection of
                  any SOFTWARE PRODUCTS and / or SYSTEM DOCUMENTATION shall be
                  cured by delivery to SIEMENS within said re-scheduled
                  correction period of a SOFTWARE PRODUCT and /


<PAGE>

                  or SYSTEM DOCUMENTATION which complies with Clause 6.2
                  obligations and accompanied by a statement of correction from
                  RADVISION; or

       6.6.2      elect to accept the non-acceptable Software Product and / or
                  SYSTEM DOCUMENTATION in its then-current condition, or

       6.6.3      finally reject the non-acceptable SOFTWARE PRODUCT and / or
                  SYSTEM DOCUMENTATION and terminate this AGREEMENT with regard
                  to such non-acceptable SOFTWARE PRODUCT or with regard to all
                  SOFTWARE PRODUCTS. If SIEMENS elects to terminate the
                  AGREEMENT pursuant to this Clause 6.6.3, RADVISION shall
                  immediately return to SIEMENS the lump sum payments made to
                  RADVISION regarding the SOFTWARE PRODUCT to which the
                  termination of the AGREEMENT relates. Performance of RADVISION
                  of this obligation shall take place upon SIEMENS' return of
                  the non-acceptable SOFTWARE PRODUCT to which the termination
                  of the AGREEMENT relates and any copies and accompanying
                  SYSTEM DOCUMENTATION thereof to RADVISION. In case of
                  termination with respect to some but not all SOFTWARE
                  PRODUCTS, any rights granted to END-USERS shall not terminate
                  and the AGREEMENT shall remain in full force and effect with
                  respect to the other SOFTWARE PRODUCTS, if any. The right of
                  SIEMENS to terminate the entire AGREEMENT under Clause 17
                  remains unaffected.


7      WARRANTY

7.1    RADVISION warrants that the SOFTWARE PRODUCTS and the SYSTEM
       DOCUMENTATION will meet and comply with all specifications and criteria
       as set forth in Annexes 1, 2, 3 and 4. The same applies with regard to
       MODIFICATIONS, UPGRADES, and UPDATES to the then applicable specification
       and criteria. SIEMENS acknowledges that the SOFTWARE PRODUCTS may have
       errors or may not perform uninterrupted. Additionally, RADVISION does not
       warrant that the SOFTWARE PRODUCTS shall meet SIEMENS' requirements nor
       that it shall perform or operate in combination with other products.

7.2    If any SOFTWARE PRODUCT or SYSTEM DOCUMENTATION supplied by RADVISION
       fails to comply with this warranty within 12 (twelve) months of
       acceptance as per Clause 6, RADVISION shall make best efforts to correct
       all faults at no cost to SIEMENS in accordance with the detailed
       provisions set forth in Annex 6. The above obligation and the following
       procedure in this Clause 7 shall be SIEMENS' sole and final remedy for
       any claim regarding RADVISION's warranty set forth in Clause 7.1.

7.3    Should RADVISION be unable to provide a solution for errors within the
       time periods specified in Annex 6, then, on 10 (ten) days' notice being
       given by SIEMENS to RADVISION (unless the solution is provided within
       said 10 (ten) days notice period), no royalties or proportional
       maintenance fees due under this AGREEMENT shall be owed by SIEMENS with
       regard to the defective SOFTWARE PRODUCT portion for the period starting
       after the 10 days notice period has elapsed until a code correction or a
       circumvention for the error is made available to SIEMENS. SIEMENS is
       entitled to recover from RADVISION the respective payments, if they were
       already made prior to the expiry of the notice period.

7.4    If RADVISION fails more than 2 (two) times to correct the same error,
       SIEMENS may, notwithstanding any other remedies under this AGREEMENT or
       applicable law, terminate this AGREEMENT with regard to such defective
       SOFTWARE PRODUCT, without prejudice to the other provisions of the
       AGREEMENT. Particularly the right of SIEMENS to terminate the entire
       AGREEMENT under Clause 17 shall remain unaffected. In case of
       termination, SIEMENS may disclaim any right to such defective SOFTWARE
       PRODUCT and any copies made thereof to


<PAGE>

       RADVISION, and SIEMENS shall be entitled (i) if the error is to be
       classified as "Fatal" or "Severe Impact" as set out in Annex 6, to a
       refund of any payments made to RADVISION under this AGREEMENT with regard
       to the defective SOFTWARE PRODUCT, or (ii) if the error is to be
       classified as "Degraded Operations" or "Minimal Impact" as set out in
       Annex 6, to a refund of any royalty fees paid under this AGREEMENT with
       regard to such defective SOFTWARE PRODUCT. Clause 17.4 shall apply
       accordingly to such termination.

7.5    NO WARRANTY SHALL APPLY TO DEFECTS, FAILURES, DAMAGES, OR LOSSES
       RESULTING FROM CORRECTIONS, REPAIRS OR SERVICE WHICH CAN BE DEMONSTRATED
       THAT IS NECESSITATED BY:

       (1st) SIEMENS' OR THE ULTIMATE USER'S SYSTEM, OTHER EQUIPMENT OR ITS USE;

       (2nd) ANY ACT OR OMISSION BY ANYONE OTHER THAN RADVISION;

       (3rd) POWER SHORTAGES OR IRREGULARITIES;

       (4th) MODIFICATION OF THE SOFTWARE PRODUCT BY ANYONE OTHER THAN
       RADVISION;

       (5th) OR ANY OTHER CAUSE BEYOND RADVISION'S CONTROL.

       In any such case, RADVISION shall nevertheless on request of SIEMENS
       eliminate any defect of the SOFTWARE PRODUCT or EMBEDDED PRODUCT,
       provided that SIEMENS shall be charged for such work according to the
       fees for technical support as set out in Annex 5.

7.6    RADVISION hereby warrants and represents that the SOFTWARE Product is
       "Year2000 Conform".

       "Year2000 Conform" or "Year2000 Conformity" shall mean that neither
       performance nor functionality is affected by dates prior to, during and
       after the year2000.
       In particular:
       Rule 1. - No value for current date will cause any interruption in
       operation.
       Rule 2. - Date-based functionality must behave consistently for dates
       prior to, during and after year2000.
       Rule 3. - In all interfaces and data storage, the century in any date
       must be specified either explicitly or by unambiguous algorithms or
       inferencing rules.
       Rule 4. - Year 2000 must be recognized as a leap year.
       [THE FOREGOING DEFINITION IS MADE IN ACCORDANCE WITH THE YEAR2000
       CONFORMITY DEFINITION ISSUED BY THE BRITISH STANDARDS INSTITUTION]

       A.     If RADVISION gets knowledge of information which might cause
              doubts regarding the Year2000 Conformity of the PRODUCTS,
              RADVISION shall promptly inform SIEMENS in writing about such
              information under the following address:

       B.     In case the SOFTWARE PRODUCT does not comply with the warranty and
              representation set out above, RADVISION shall assume liability for
              any and all damages resulting therefrom, including any and all
              related damages to SIEMENS' customers. In the event, RADVISION
              shall,, without any cost for SIEMENS, and without any undue delay
              perform best efforts to establish "Year2000 Conformity" regarding
              any and all of the SOFTWARE PRODUCTS concerned. Except in cases of
              product liability or willful or gross negligent actions and/or
              omissions, the total liability assumed by RADVISION for damages
              resulting from non-compliance of the SOFTWARE PRODUCTS with this
              warranty and representation, however, shall be limited to an
              overall maximum amount which is equivalent to 20 % (twenty
              percent) of the accumulated value of SOFTWARE PRODUCTS purchased
              by SIEMENS from RADVISION until expiry of this warranty and
              representation but shall not be less than the equivalent of
              $150,000 (hundred and fifty thousand). The term "value of SOFTWARE
              PRODUCTS" shall include any lump sum and royalty fees to be paid
              by SIEMENS for the SOFTWARE PRODUCT, whereby value added tax on
              such amounts shall not be taken into


<PAGE>

              account. RADVISION is not entitled to retain any payments for
              damages before August 31, 2001 with reference to the above
              described limitation of liability. If it is evident after August
              31, 2001 that the amount of payment for damages by RADVISION
              exceeds the above described limitation of liability, SIEMENS shall
              promptly balance the difference.

              If RADVISION does not, within a reasonable period of time, not to
              exceed thirty (30) working days, establish "Year2000 Conformity"
              nor bypasses any deficiencies with regard to "Year2000 Conformity"
              in a manner reasonably acceptable to SIEMENS and its customers,
              the regulations of Clause 7.4 shall apply.

       C.     The warranty and representation contained in this Clause 7.8
              herein shall be valid until the end of August 31, 2001.


       D.     The foregoing paragraphs A up to and including D shall remain
              unaffected by any contractual provisions to the contrary contained
              in this AGREEMENT.

7.9    ALL THE WARRANTIES ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHER
       WARRANTIES, WHETHER EXPRESS OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES
       OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

8      PAYMENT, RECORD KEEPING, REPORTS, AUDIT

8.1    In consideration of the license granted hereunder and all other rights
       granted in this AGREEMENT, SIEMENS shall pay the lump sum and royalty
       fees according to Annex 5.

       SIEMENS shall pay to RADVISION

       -      a lump sum as set out in Annex 5 (the "Lump Sum") as aggregate one
              time payment for all the SOFTWARE PRODUCTS,
       -      a royalty fee as set out in Annex 5,
       -      an annual maintenance fee as set out in Annex 5.

8.2    Lump Sum - SIEMENS shall issue a purchase order within 10 days after
       signing of the AGREEMENT for the amount of 75% of the total Lump Sum,
       this amount shall be paid within 30 days from the date of receipt of
       respective invoice. SIEMENS shall issue another purchase order
       immediately upon the acceptance of the SOFTWARE PRODUCTS as per Clause 6
       for the remaining balance of 25% of the total Lump Sum, this amount shall
       be paid within 30 days from the date of receipt of respective invoice.

8.3    Royalty fees - Following the signing of this AGREEMENT by both Parties,
       SIEMENS shall prepare a statement in respect of each calendar quarter
       (ending on March 31st, June 30th, September 30th and December 31st) or
       part thereof, detailing the number of copies of the EMBEDDED PRODUCT
       sold/distributed and the number of ports (concurrent calls) per EMBEDDED
       PRODUCT, and the amount of royalties due to RADVISION, according to the
       per unit royalty fees in Annex 5. Such a statement shall be submitted to
       RADVISION within thirty (30) days of the end of the calendar quarter or
       part thereof to which it relates. Upon receipt by RADVISION of the
       preceding statement, RADVISION shall invoice SIEMENS via proper written
       invoice, for the royalty fees due and payable. SIEMENS agrees to pay to
       RADVISION, no later than thirty (30) days from receipt of the invoice,
       payment for the royalty fees due and payable.

8.4    The annual maintenance fee required pursuant to Clause 11 shall be
       invoiced yearly by RADVISION at the beginning of each 12 months period
       starting with delivery of the SOFTWARE PRODUCTS and the SYSTEM
       DOCUMENTATION and paid within thirty (30) days thereafter by


<PAGE>

       SIEMENS. The invoice shall be accompanied by a statement and reference
       number to the invoice issued.

8.5    Each report by SIEMENS shall be accompanied by a statement explaining the
       computation of the royalties and number of copies made.

8.6    Not more than once a year, RADVISION may designate an independent
       certified public auditor who executes upon request by SIEMENS an
       appropriate confidentiality AGREEMENT, to inspect the records of SIEMENS
       directly relevant to the computation of the royalties due under this
       AGREEMENT during SIEMENS' regular business hours to determine the
       accuracy of all payments so far made by SIEMENS hereunder.

       Any and all expenses of such audit shall be borne by RADVISION unless
       audit discloses an underpayment of more than 5 (five) percent in which
       case SIEMENS shall bear the reasonable expenses incurred by RADVISION.

       Any payments made shall be conclusively presumed accurate after 3 (three)
       years from date of delivery to RADVISION by SIEMENS of the respective
       report and shall be excluded from auditing. RADVISION undertakes to
       provide that any and all statements or records or notes disclosed to the
       auditor shall be held in confidence by the auditor and RADVISION as
       CONFIDENTIAL INFORMATION of SIEMENS.

8.7    Any and all payments, including maintenance fees hereunder shall be in
       US-$, and shall be considered as properly given or made if by electronic
       funds transfer to a RADVISION designated U.S. $ bank account.

8.8    Any and all taxes, charges and/or other duties (henceforth "Taxes")
       imposed on RADVISION with respect to any payments to be made by SIEMENS
       to RADVISION under or in connection with this AGREEMENT, shall be borne
       and paid by RADVISION. If required by the laws of Germany, SIEMENS may
       deduct Taxes imposed in Germany on RADVISION with respect to such
       payments from the payments due hereunder and pay such Taxes on behalf of
       RADVISION. To the extent SIEMENS has so deducted and paid Taxes on behalf
       of RADVISION, SIEMENS shall, if so requested by RADVISION, submit to
       RADVISION official tax receipts issued by the German tax authorities and
       evidencing the payment by SIEMENS of Taxes in Germany on behalf of
       RADVISION.

       To the extent the Double Taxation Convention between Germany and Israel
       entitles RADVISION to claim a reduction of or an exemption from Taxes
       imposed on and to be paid by RADVISION according to the laws of Germany,
       SIEMENS shall use reasonable efforts to support RADVISION in obtaining a
       tax reduction/exemption certificate (or the like) from the German tax
       authorities, if so required by the aforementioned Double Taxation
       Convention and/or German tax law to validate the aforementioned claim for
       tax reduction/exemption. As long as SIEMENS has not received copy of such
       tax reduction/exemption certificate from RADVISION, the regulations of
       the foregoing clause shall apply.

8.9    The AGREEMENT may be amended to include further software products and new
       categories of products as set forth in Annex 5.

8.10   SIEMENS has the option to pay a fixed annual royalty fee (hereafter
       called "Buy-Out Fee") for each fiscal year (from October 1st through
       September 30th) instead of paying RADVISION royalty fees. The Parties
       negotiate such Buy-Out -Fee at a later stage in good faith.

8.11   Late Payment Charges. RADVISION reserves the right to levy an interest
       charge for outstanding accrued moneys, duly to be paid hereunder, not
       received in accordance with payment terms as described above. This charge
       will take the form of base interest at a monthly compound rate as


<PAGE>

       published by the European Central Bank on all amounts outstanding for
       more than 60 (sixty) days from the due date of payment. Interest will be
       due on the 61st (sixty first) day for the preceding 60 (sixty) days and
       thereafter levied monthly or part-monthly until arrears plus interest
       have been cleared. This charge applies to amounts of lump sum, and/or
       royalty fee, and/or Buy-Out Fees and/or maintenance fees payments.

9      INDEMNIFICATION

9.1    RADVISION represents and warrants that RADVISION holds any and all
       rights, title and interest in and to the SOFTWARE PRODUCTS and the SYSTEM
       DOCUMENTATION and that RADVISION is entitled to grant the rights and
       licenses herein, and that as of the EFFECTIVE DATE there are - to the
       best of RADVISION's knowledge - no claims, disputes, suits, arbitral or
       other proceedings pending or anticipated which may affect either the
       rights and licenses granted hereunder or the warranties and
       representations made hereunder by RADVISION.

       In particular, RADVISION represents and warrants that the SOFTWARE
       PRODUCTS and SYSTEM DOCUMENTATION do not infringe upon any copyright,
       patent or any other proprietary right of any third party and do not
       violate the trade secret rights of any third party.

       This warranty applies mutatis mutandis to any alteration of the SYSTEM
       DOCUMENTATION.

9.2    RADVISION shall, at its sole cost, defend, indemnify and hold harmless
       SIEMENS

       -      if no RELATED COMPANY is involved from any and all claims,
              disputes, proceedings, suits, actions, costs, expenses, damages,
              penalties (henceforth collectively referred to as "claim") finally
              awarded resulting from any breach of any warranty in Clause 9.1
              and

       -      If a RELATED COMPANY is involved from any and all claims,
              disputes, proceedings, suits, actions, costs, expenses, damages,
              penalties (henceforth collectively referred to as "claim")
              resulting from any breach of any warranty in Clause 9.1 and,

       provided that

       -      SIEMENS notifies RADVISION in writing without undue delay after
              becoming aware of such claim;

       -      SIEMENS provides RADVISION with the sole control and authority -
              as far as legally possible and always provided that such procedure
              does not adversely affect material business interests of SIEMENS
              to defend and settle such claim; SIEMENS may participate in any
              such settlement negotiation;

       -      SIEMENS at RADVISION's expense cooperates to a reasonable extent
              in the defense and settlement as requested by RADVISION; and

       -      SIEMENS does not of its own accord acknowledge or accept such
              claim from any third party.

       -      SIEMENS does not reach to any settlement or agreement of any kind
              with respect to said claim without RADVISION's prior written
              consent.

9.3    Should RADVISION be in breach of any warranties in Clause 9.1 including
       but not limited if a temporary or final injunction is obtained against
       the use of the SOFTWARE PRODUCT or the SYSTEM DOCUMENTATION or any
       portion thereof, RADVISION will at its sole cost and at its option,


<PAGE>

       -      procure to SIEMENS the right to continue to exercise the rights
              stated in Clauses 2 and 3 of this AGREEMENT;

       -      replace or modify the SOFTWARE PRODUCT and SYSTEM DOCUMENTATION or
              the infringing portion thereof without undue delay such that they
              no longer infringe any right of any third party, as long as the
              performance and functionality of the SOFTWARE PRODUCT and SYSTEM
              DOCUMENTATION is not adversely affected by such replacement or
              modification and the SOFTWARE PRODUCT and SYSTEM DOCUMENTATION
              continue to materially conform with the specifications and
              criteria as set forth in Annexes 1, 2, 3 and 4; or

       -      refund any payments hereunder.

9.4    The indemnity in this Clause 9 shall not apply to

       -      infringements caused by any use of the SOFTWARE PRODUCT in
              combination, operation, or use with any machine, program or other
              material not designated for use with the SOFTWARE PRODUCT or
              otherwise as agreed by the Parties;

       -      modifications of the SOFTWARE PRODUCT and / or the SYSTEM
              DOCUMENTATION made by SIEMENS and/or its RELATED COMPANIES if
              these modifications have obviously caused the relevant
              infringement. ,Said modifications shall also include modifications
              which were performed by RADVISION for and on behalf of SIEMENS
              according to SIEMENS' specifications as detailed in a written
              agreement.

9.5        All RADVISION's obligations set forth in Clauses 9.1-9.4 above are
           SIEMENS' sole and final remedy for any claim regarding infringement
           under Clause 9.1.

10     PRODUCT LIABILITY AND FORCE MAJEURE

10.1   If the use of the SOFTWARE PRODUCT should result in third party claims
       resulting from product liability, against SIEMENS, RADVISION shall
       indemnify, defend and hold harmless SIEMENS

       -      if no RELATED COMPANY is involved against the damages finally
              awarded, except in case RADVISION can demonstrate that such
              liability results from a material breach of this AGREEMENT,
              willful misconduct or from gross negligence of SIEMENS and

       -      If a RELATED COMPANY is involved against the damages, except in
              case RADVISION can demonstrate that such liability results from a
              material breach of this AGREEMENT, willful misconduct or from
              gross negligence of SIEMENS,

       provided that

       -      SIEMENS notifies RADVISION in writing without undue delay after
              becoming aware of such claim;

       -      SIEMENS provides RADVISION with the sole control and authority -
              as far as legally possible and always provided that such procedure
              does not adversely affect material business interests of SIEMENS
              to defend and settle such claim; SIEMENS may participate in any
              such settlement negotiation;

       -      SIEMENS at RADVISION's expense cooperates to a reasonable extent
              in the defense and settlement as requested by RADVISION; and

       -      SIEMENS does not of its own accord acknowledge or accept such
              claim from any third party.


<PAGE>

       -      SIEMENS does not reach to any settlement or agreement of any kind
              with respect to said claim without RADVISION's prior written
              consent.

10.2   Neither Party shall be liable for inability to perform its obligations
       under this AGREEMENT, excluding any payment obligation, to the extent
       such inability is due to Force Majeure, including but not limited to Acts
       of God, general labor disputes, riots, unforeseeable circumstances beyond
       the reasonable control of a Party.

       Each Party shall give the other Party prompt written notice of the
       occurrence of any event of Force Majeure that may cause delay hereunder,
       and the date of performance by any Party that gives such notice shall be
       extended for a period not exceeding the period of delay caused by the
       event of Force Majeure thus identified and the facts of which are
       demonstrated by the Party giving such notice.

       If a Force Majeure event shall continue for more than 6 (six) consecutive
       months rendering either Party unable to perform its obligations under
       this AGREEMENT, each Party may terminate this AGREEMENT pursuant to
       Clause 17.2 below.

11     MAINTENANCE

11.1   RADVISION shall maintain the SOFTWARE PRODUCTS as delivered by RADVISION
       in accordance with the detailed provisions of Annex 6. RADVISION shall
       help diagnose any error raised in modified SOFTWARE PRODUCTS and EMBEDDED
       PRODUCTS. In case RADVISION demonstrates to SIEMENS' reasonable
       satisfaction that the error is not in the part delivered by RADVISION it
       shall be SIEMENS' responsibility to maintain and fix the error. RADVISION
       will provide the maintenance service by appropriately skilled employees
       who are familiar with the SOFTWARE PRODUCTS.

       Regarding errors which can be demonstrated by RADVISION are in those
       parts of the SOFTWARE PRODUCTS that were modified by SIEMENS, RADVISION
       may charge SIEMENS for the elimination of such errors according to the
       rates for technical support as set out in Annex 5.

       RADVISION shall be responsible for quality assurance of the further
       development of the SOFTWARE PRODUCTS.

11.2   The software maintenance service comprises in particular

       -      the submission of service reports upon reporting of a problem or
              question
       -      telephone consulting with a view to identifying the error for the
              generation of diagnostic documentation via hot line;
       -      support via teleservice;
       -      elimination of errors;
       -      use of the web and email service to RADVISION's service center,
       -      supply of UPDATES free of additional charge; and
       -      supply of UPGRADES at additional charge on SIEMENS' request.

11.3   In particular, RADVISION shall provide SIEMENS with MODIFICATIONS, BUG
       FIXES, UPGRADES (subject to additional payment) and UPDATES which contain
       developments and MODIFICATIONS pursuant to fault correction and
       functional enhancement. Such MODIFICATIONS, BUG FIXES, UPGRADES and
       UPDATES shall not adversely affect the functionality or performance of
       the SOFTWARE PRODUCTS.


<PAGE>

       RADVISION intends to discuss with SIEMENS its SOFTWARE PRODUCTS road maps
       which may adversely affect SIEMENS' business. RADVISION may upon its sole
       discretion consider SIEMENS' proposals.

11.4   RADVISION's maintenance service shall as well apply in relation to all
       MODIFICATIONS , BUG FIXES, UPDATES and UPGRADES delivered.

11.5   SIEMENS and its RELATED COMPANIES will communicate any requests for
       support through one of the support centers. SIEMENS will name three
       contact persons for each support center who are responsible for
       communicating the requests of this support center. SIEMENS will notify
       RADVISION of any change regarding those contact persons.

11.6   Only the contact persons from the support centers shall be entitled to
       communicate to RADVISION suspected errors in the SOFTWARE PRODUCTS along
       with all information available in order to reproduce the errors on a
       REFERENCE ENVIRONMENT or the EMBEDDED PRODUCT. Depending on the error
       category, RADVISION agrees to respond and to perform best efforts to
       correct such errors in the manner and within the time periods given in
       Annex 6.

11.7   Should RADVISION be unable to provide a solution for errors within the
       time periods specified in Annex 6, then, on 10 (ten) days' notice being
       given by SIEMENS to RADVISION (unless the solution is provided within
       said 10 (ten) days notice period), no maintenance fees due under this
       AGREEMENT shall be owed by SIEMENS for the period starting after the 10
       days notice period has elapsed until a code correction or a circumvention
       for the error is made available to SIEMENS. SIEMENS is entitled to
       recover from RADVISION the respective payments, if they were already made
       prior to the expiry of the notice period.

11.8   If RADVISION fails more than 3 (three) times to correct the same error,
       SIEMENS with regard to the defective SOFTWARE PRODUCT portion may, at its
       option and notwithstanding any other remedies in this Clause 11 or any
       other right it may have under applicable law:

       -      recover from RADVISION (i) if the error is to be classified as
              "Fatal" or "Severe Impact" as set out in Annex 6 any royalty and
              proportional maintenance fee payments made to RADVISION under this
              AGREEMENT in the last 12 months (ii) if the error is to be
              classified as "Degraded Operations" or "Minimal Impact" as set out
              in Annex 6, any proportional maintenance fees paid under this
              AGREEMENT in the last 12 months, or

       -      if the error is classified as "Fatal" or "Severe Impact" as set
              out in Annex 6 terminate this AGREEMENT with regard to the
              maintenance of such defective SOFTWARE PRODUCT or with regard to
              all SOFTWARE PRODUCTS without prejudice to the other provisions of
              the AGREEMENT. Particularly the right of SIEMENS to terminate the
              entire AGREEMENT under Clause 17 shall remain unaffected. In case
              of termination, SIEMENS may disclaim any right to such defective
              SOFTWARE PRODUCT and any copies made thereof to RADVISION, and
              SIEMENS may reclaim any royalty and maintenance fee payments made
              to RADVISION under this AGREEMENT in the last 12 months. Clause
              17.4 shall apply accordingly to such termination.

11.9   Upon becoming aware thereof, RADVISION will promptly notify SIEMENS of
       any bugs and errors in the serviced SOFTWARE PRODUCTS. RADVISION has
       established a single support center for the placing of bug and error
       reports and for other requests to RADVISION's support center for
       maintenance services for the serviced SOFTWARE PRODUCTS.

11.10  The maintenance services for the SOFTWARE PRODUCTS, set forth in this
       AGREEMENT, are subject to the payment of the maintenance fees set out in
       Annex 5 and will be provided by RADVISION for a period of 1 (one) year
       following the last payment of maintenance fees for a support center,
       unless such maintenance is terminated pursuant to this AGREEMENT.


<PAGE>

       Maintenance services will be provided to the SOFTWARE PRODUCTS for a
       release that is current within eighteen (18) months on request of one of
       the designated support centers.

12     TECHNICAL SUPPORT; TRAINING

12.1   RADVISION agrees to provide on request of SIEMENS technical support and
       training to SIEMENS' software support and development personnel for the
       SOFTWARE PRODUCT.

12.2   RADVISION shall, on request of SIEMENS, provide training of SIEMENS' and
       / or RELATED COMPANIES' and / or DISTRIBUTORS personnel in all matters
       relating to the SOFTWARE PRODUCTS, including but not limited to product
       features and use, at reasonable rates not to exceed the training rates
       set out in Annex 5.

       RADVISION shall provide 5 days training a year for a group of 25 persons
       for each SIEMENS' support center at no charge to SIEMENS and RELATED
       COMPANIES and / or DISTRIBUTORS, provided that SIEMENS shall bear
       travel-related expenses of its own personnel in this regard.

       All such training shall be conducted at facilities of SIEMENS or RELATED
       COMPANIES at SIEMENS' discretion.

12.3   RADVISION is prepared to provide pre- and post-sales technical support to
       SIEMENS for the SOFTWARE PRODUCTS, included but not limited to the
       development of country specific versions of the SOFTWARE PRODUCTS. This
       service shall be provided by RADVISION at SIEMENS' request to SIEMENS and
       RELATED COMPANIES according to the terms agreed on a case by case basis.
       RADVISION will provide SIEMENS with primary and secondary points of
       contact for such pre- and post-sales technical support during RADVISIONs'
       normal business hours. All such technical support will take the form of
       telephone calls, correspondence, remote log-in by RADVISION into SIEMENS'
       computer systems, or visits by RADVISION's technical staff to SIEMENS'
       technical staff. SIEMENS shall pay for such services according to the
       rates for additional technical support as set out in Annex 5.

12.4   For larger systems or for END-USERS purchasing on a large scale, SIEMENS
       and/or RELATED COMPANIES may want to secure RADVISION's assistance to
       make additional changes to the configuration of the SOFTWARE PRODUCT.
       RADVISION is willing to assist SIEMENS and/or its RELATED COMPANIES.

       If RADVISION and SIEMENS are unable to reach agreement on the terms of
       any projects, including responsibility for payment of costs of the
       modification of the SOFTWARE PRODUCT, or if the performance of the
       project is expected to interfere with projects already in progress or
       planned by either Party, then either SIEMENS or RADVISION may refer such
       project for review by a committee consisting of one senior technical
       manager designated by each Party. The committee shall review the scope
       and objectives of existing projects, determine the minimum necessary
       changes to the proposed scope of a project in order to avert or reduce
       prejudice to either Party's interests, and the relative priority of
       performance and completion of such project in the light of each Party's
       critical needs.

12.5   For at least eighteen (18) months after a SOFTWARE PRODUCT's UPDATE or
       UPGRADE has been accepted by SIEMENS, RADVISION shall provide software
       support to SIEMENS for the immediately preceding UPDATE and UPGRADE, if
       any, of such SOFTWARE PRODUCT.

12.6   RADVISION shall inform SIEMENS of RADVISION's engineering contact who
       shall serve as liaison with SIEMENS for software engineering support.


<PAGE>

13     CONFIDENTIALITY, MEDIA RELEASES

13.1   Subject to the provisions set out in this AGREEMENT, the Parties agree to
       maintain in confidence any and all CONFIDENTIAL INFORMATION with the same
       degree of care with which they treat and protect their own proprietary
       information (but not less than reasonable care as applied by a prudent
       businessman).

13.2   Neither Party will use the CONFIDENTIAL INFORMATION except in the course
       of exercising its rights or fulfilling its obligations hereunder, nor
       will it disclose such information to third parties. SIEMENS is prohibited
       from, and shall not, develop, market or sell any COMPETITIVE PRODUCT by
       using CONFIDENTIAL INFORMATION of RADVISION. As third parties under this
       AGREEMENT shall not be deemed RELATED COMPANIES and DISTRIBUTORS who are
       bound by confidentiality obligations at least as strict as the
       confidentiality obligations of this Clause 13. The receiving Party may
       disclose confidential Information to such END-USER and parties
       contracting with the receiving Party as may be necessary for the
       fulfillment of its obligations/using of its rights under this AGREEMENT
       but only if they are bound by confidentiality obligations at least as
       strict as the confidentiality obligations of this Clause 13.

13.3   The confidentiality obligations hereunder shall not extend to any items
       of information which the receiving Party demonstrates that (1) now or
       hereafter may be in the public domain by acts not attributable to the
       receiving Party, (2) were in the possession of or known to the receiving
       Party prior to receipt from the furnishing Party, (3) have been lawfully
       received from other sources, provided such other source did not receive
       it as a result of a breach of confidentiality obligations towards the
       Party whose information is concerned, or (4) have been independently
       developed by the receiving Party and not as a result of a breach of this
       AGREEMENT, or (5) have to be disclosed to a public authority due to
       mandatory law, provided that the furnishing Party is given prompt notice
       before such disclosure.

13.4   The confidentiality obligations shall - irrespective of the term of this
       AGREEMENT - expire 5 (five) years after the date on which the respective
       information was furnished.

13.5   Both Parties acknowledge that the unauthorized disclosure of such
       CONFIDENTIAL INFORMATION could cause irreparable harm and significant
       injury to the other Party which may be difficult to ascertain.
       Accordingly, both Parties shall indemnify each other against any loss and
       expense arising due to such unauthorized disclosure. Furthermore, both
       Parties agree that they shall have the right to obtain an immediate
       injuction enjoining any such unauthorized disclosure.

13.6   Media releases or other information on the conclusion and the content of
       this AGREEMENT shall only be made available to third parties,
       particularly the media, with the prior approval of the other Party.

13.7   SIEMENS shall not copy, in whole or in part, the SOURCE CODE of the
       SOFTWARE PRODUCTS and the SYSTEM DOCUMENTATION except as explicitly
       permitted herein and furthermore for internal backup or archival purposes
       only.

14     EXPORT CONTROL

SOFTWARE PRODUCTS and SYSTEM DOCUMENTATION may be subject to special permits in
accordance with the export regulations of the United States of America, Germany,
the European Union (EU) or any other state, in particular when re-exported to
third countries.


<PAGE>

Both Parties therefore undertake to comply with such export control regulations
per delivery product, as defined in Annex 7. RADVISION shall advise and help
SIEMENS to comply with said export control regulations at SIEMENS` expense.

15     NOTICES

15.1   Any notices, authorizations and requests in connection with this
       AGREEMENT shall be in writing and delivered personally or sent by telefax
       or postal mail. Any notices given pursuant to this AGREEMENT shall be in
       English.

15.2   Any notices to be sent to RADVISION shall be addressed as follows:

       RADVISION Ltd.
       24 Raoul Wallenberg Street, Tel Aviv,
       Israel
       Attn: Adit Tevel
       Cc: Legal Department
        Fax: +972-3 648 9973
        Phone: +972-3 765 9820

15.3   Any notices to be sent to SIEMENS shall be addressed as follows:

       Siemens Aktiengesellschaft
       Hofmannstr. 51,
       D-81359 Muenchen
       Germany

       For Technical issues :
       Attn: Mr. Bitzinger
       Fax: +49-89 722 23847
       Phone: +49-89 722 23846

       For any other issue:
       Attn: Mr. Sentuerk
       Fax: +49-89 722 47018
       Phone: +49-89 722 49251

15.4   The names given above are for convenience purposes only and shall not
       delay the effectiveness of notices in the event of this person's absence.

16     ARBITRATION, GOVERNING LAW

16.1   All disputes arising out of or in connection with this AGREEMENT
       including any question regarding its existence, validity or termination,
       shall be settled by an amicable effort on the part of both Parties. An
       attempt to arrive at a settlement shall be deemed to have failed as soon
       as one of the Parties so notifies the other Party in writing.

       If such an attempt has failed, all disputes arising out of or in
       connection with this AGREEMENT, including any question regarding its
       existence, validity or termination, shall be finally settled under


<PAGE>

       the Rules of Arbitration of the International Chamber of Commerce, Paris
       (ICC) by 3 (three) arbitrators appointed in accordance with said Rules.
       Each Party shall nominate one arbitrator to be confirmed by the competent
       authority under the applicable Rules (Appointing Authority). Both
       arbitrators shall agree on the third arbitrator within thirty days.
       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. If there are two or more defendants, any nomination
       of an arbitrator by or on behalf of such defendants must be by joint
       agreement between them. If defendants fails within the time-limit fixed
       by the Appointing Authority to agree on such joint nomination, the
       proceedings against each of them must be separate. The seat of
       arbitration shall be Zurich, Switzerland. The procedural law of this
       place shall apply where the Rules are silent.

       The language to be used in the arbitration proceeding shall be English.

16.2   All disputes shall be settled in accordance with the provisions of this
       AGREEMENT and all other agreement regarding its performance, otherwise in
       accordance with the substantive law in force in France without reference
       to other laws, with regard to the validity and scope of IP RIGHTS in
       accordance with the mandatory law of the country where such IP RIGHTS
       have been originated and/or registered. The application of the United
       Nations Convention on Contracts for the International Sale of Goods of
       April 11, 1980 shall be excluded.

16.3   The award of the arbitration shall be final and non-appealable.

17     TERM AND TERMINATION

17.1   The term of this AGREEMENT shall commence on the EFFECTIVE DATE and
       continue thereafter for a period of 5 (five) years. Thereafter, the term
       shall automatically be extended by consecutive one year periods unless
       the AGREEMENT is terminated by one of the Parties giving not less than 3
       (three) months prior written notice to the other Party.

17.2   Notwithstanding any other rights such Party may have, either Party may
       elect to terminate this AGREEMENT for a severe breach of contract by the
       other Party by giving at least 30 (thirty) days prior written notice to
       the other Party specifying the nature of such breach; provided that,
       however, should such severe breach of contract be cured by the other
       Party within said 30 (thirty)days period such notice shall be of no
       further force and effect and this AGREEMENT shall not be terminated
       thereby.

       Without any limitation hereto, the following events shall be deemed to
       constitute a severe breach of contract:

       -      a Party has failed substantially in the performance of any
              material obligation;

       -      any declaration of bankruptcy, any commencement of proceedings to
              put substantially all business assets into the hands of a trustee
              or receiver, or any direct or indirect seizure of substantially
              all business assets.

17.3   MAILTO:In the event RADVISION merges with another company or at least 50%
       of RADVISION is acquired by a third party which is a competitor of
       SIEMENS in the field of telecommunication and information technology
       systems, if substantial rights to the SOFTWARE PRODUCT are transferred to
       a competitor of SIEMENS in the field of telecommunication and information
       technology systems or if RADVISION otherwise comes under the direct or
       indirect influence or control of a competitor active in the field of
       telecommunication and information technology systems, RADVISION will


<PAGE>

       promptly notify SIEMENS thereof in writing and SIEMENS shall have the
       right, within 2 (two) months after having knowledge of the above
       mentioned circumstances to terminate this AGREEMENT entirely or only
       parts thereof with immediate effect or with effect from the end of a
       period specified by SIEMENS in its termination notice, however not later
       than six months after giving notice of the termination.

17.4   Following any termination except termination by RADVISION due to material
       breach of this AGREEMENT by SIEMENS

       17.4.1     Subject to SIEMENS' compliance with its payment obligations
                  under Annex 5, SIEMENS, its RELATED COMPANIES and DISTRIBUTORS
                  are nevertheless entitled to continue to exercise the rights
                  described in Clause 2 in order to maintain, sell, distribute
                  and/ or otherwise trade EMBEDDED PRODUCTS, if the integration
                  of the SOFTWARE PRODUCT is effected prior to the date of
                  termination or, even after the date of termination, if the
                  sale, distribution or trade of the respective products falls
                  within the ordinary course of business of SIEMENS, its RELATED
                  COMPANIES and DISTRIBUTORS, in particular constitutes the
                  fulfillment of orders arising from existing business dealings
                  before the date of termination. However, these above stated
                  rights shall cease six months after the date of termination at
                  latest. Therefore, the termination of this AGREEMENT shall
                  under no circumstances affect any rights of an END-USER to the
                  EMBEDDED PRODUCT granted to him in accordance with Clause 2
                  and this Clause 17.4 of this AGREEMENT nor hinder an END-USER
                  from utilizing EMBEDDED PRODUCTS, if these products are traded
                  by SIEMENS, its RELATED COMPANIES and/ or DISTRIBUTORS
                  according to the terms of this AGREEMENT.

       17.4.2     RADVISION shall be obliged for a period of 24 (twenty four )
                  months after the termination of this AGREEMENT to provide on
                  the request of SIEMENS maintenance and support services at
                  such prices these services are usually provided by RADVISION
                  to customers comparable to SIEMENS at the date of termination.

       17.4.3     In the event of a material breach by SIEMENS which is not
                  remedied within 30 days after receipt by SIEMENS of a written
                  notice specifying the nature of such breach, RADVISION shall
                  have the right to immediately terminate all SIEMENS' rights
                  under Clause 17.4 by written notice.

17.5   In case of a termination for default by RADVISION including but not
       limited to breach of contract as described in Clause 17.2 and in case of
       a termination as described in Clause 17.3, RADVISION hereby grants
       SIEMENS in addition to the rights and entitlements described in Clause
       17.4 above subject to all other terms of this AGREEMENT the world-wide,
       perpetual, non-exclusive, non-transferable, irrevocable right to use,
       copy, port and modify and/or to have used, copied, modified the SOFTWARE
       PRODUCTS exclusively for the purposes of remedying of operating defects
       and/ or otherwise servicing and maintaining the SOFTWARE PRODUCTS and the
       EMBEDDED PRODUCTS, if the SOFTWARE PRODUCT is shipped to the END-USER
       according to the terms of this AGREEMENT.

17.6   SIEMENS may elect to terminate this AGREEMENT with regard to all or part
       of the maintenance and technical support and training services, or the
       respective services for one UPDATE/UPGRADE of the SOFTWARE PRODUCT at the
       end of each calendar year giving at least 30 (thirty) days prior written
       notice to RADVISION. In such case, the remainder of the AGREEMENT shall
       remain in full force and effect with respect to the other SOFTWARE
       PRODUCTS.

       Any and all obligations of the Parties with respect to CONFIDENTIAL
       INFORMATION, liability, warranty, indemnification for violation of IP
       RIGHTS, arbitration, governing law, payment due and owed at the date of
       termination shall survive expiration or termination of this AGREEMENT.


<PAGE>

       Termination of this AGREEMENT which is not due to SIEMENS' breach of
       obligations under this AGREEMENT, shall not affect any rights granted
       hereunder to SIEMENS and its RELATED COMPANIES as per Clause 2.1 to use
       the SOURCE CODE for maintaining the EMBEDDED PRODUCTS.

18     ISO STANDARDS

18.1   RADVISION is certified according to ISO 9002 and has implemented such
       standards for the performance of its obligations hereunder. Nevertheless
       SIEMENS may request alterations to quality procedures, development or
       workmanship standards in order to improve the overall SOFTWARE PRODUCT
       quality and RADVISON shall use best efforts to comply with such request.

       18.1.1     General Inspection System

       If SIEMENS so request it shall be entitled once a year to review, at
       RADVISION's premises, RADVISON's quality and inspection system.

       18.1.2     Development Site/Factory Inspection Test of SOFTWARE PRODUCTS

       If SIEMENS requests it shall be entitled once a year to perform a
       development site/factory inspection, such inspection will be performed at
       RADVISION's premises. The time, place and procedure of the development
       site/factory inspections will be agreed upon between the Parties
       reasonably in advance. All expenses accruing in connection with the
       development site/factory inspection shall be borne by RADVISON, except
       for the travel, lodging and living expenses incurred by the participants
       of SIEMENS.

19     MISCELLANEOUS

19.1   Neither Party may delegate its obligations or assign its rights hereunder
       without the prior written consent and approval of the other Party, which
       consent will not be unreasonably withheld; SIEMENS however, subject to
       prior written notice to RADVISION, may assign, delegate or transfer its
       obligations and rights hereunder to any of its RELATED COMPANIES without
       the prior written consent of RADVISION as long as such RELATED COMPANY is
       not a direct competitor of RADVISION in the field of the H 323 stack.
       SIEMENS shall notify RADVISION of the names and addresses of any such
       RELATED COMPANY to which this AGREEMENT has been assigned, delegated or
       transferred , 30 days in advance in writing. Notwithstanding the above,
       RADVISION may assign its rights and obligations hereunder to RADVISION
       Inc. or to RADVISION B.V. Notwithstanding the above, subject to Article
       17.3 above, RADVISION may assign its rights and obligations hereunder to
       a third party as a result of a M&A transaction.

19.2   This AGREEMENT may not be modified or amended except by written
       instrument, executed by the duly authorized officers of the Parties. This
       requirement may only be waived in writing.

19.3   Any provision of this AGREEMENT which may be deemed unenforceable or
       contrary to applicable mandatory law shall be disregarded in the
       performance or interpretation of this AGREEMENT, and shall not operate to
       invalidate any other portion or provision of this AGREEMENT. The Parties
       undertake to substitute such provision by a provision that to the extent
       legally possible approximates the intent and economic effect of the
       unenforceable or invalid provision.


<PAGE>

19.4   No failure or delay by either Party in exercising any right, power or
       remedy under this AGREEMENT, except as specifically provided herein, will
       operate as a waiver of any such right, power or remedy.

19.5   Each of the Parties hereby represents and warrants that it has full
       corporate power and authority to enter into this AGREEMENT without the
       consent of any other person, organization or entity, that this AGREEMENT
       represents the valid and binding AGREEMENT of the Parties enforceable in
       accordance with its terms, and that the execution of this AGREEMENT and
       the consummation of the transactions contemplated herein will not violate
       a term or condition of any AGREEMENT, contract or commitment to which
       either of them is a Party, or any order, judgment or decree by which
       either Party is bound.

       The relationship established between the Parties by this AGREEMENT is
       that of RADVISION and SIEMENS and each Party will be and act as an
       independent contractor and not as agent or partner of the other Party for
       any purpose. Nothing contained herein will in any way make a arty, or
       that Party's employees or agents into employees or agents of the other
       Party, and neither Party by virtue of this AGREEMENT shall have any
       right, power or authority to act or create any obligation, express or
       implied, on behalf of the other Party. Neither this AGREEMENT, nor any
       terms and conditions contained herein shall be construed as creating a
       partnership, a joint venture or an agency or franchising relationship.

19.6   In no event will RADVISION's total liability under this AGREEMENT
       exceed twice the amounts actually paid to RADVISION by SIEMENS under
       this AGREEMENT provided that this sum will in no event be higher than
       US $10,000,000, and except as otherwise specifically stated to the
       contrary herein in no event shall either Party be liable for indirect,
       incidental, or consequential damages. The limitations of liability in
       this AGREEMENT shall not apply if damages are caused by willful
       misconduct or gross negligence of a party hereto.

19.7   The terms and conditions set forth in this AGREEMENT constitute the
       entire agreement between RADVISION and SIEMENS concerning the subject of
       this AGREEMENT, provided that the agreements dated March 18, 1997
       (PN-agreement), May 6, 1999 (ICN WN CS agreement) and any agreements
       relating to business units other than Information and Communication
       Networks are not affected.

IN WITNESS WHEREOF, the Parties hereto have caused this AGREEMENT to be executed
in duplicate by their respective duly authorized representatives as set forth
below:

Signed for and on behalf of                 Signed for and on behalf of

RADVision Ltd.                              Siemens Aktiengesellschaft

- ---------------------      ---------------------          ---------------------
Signature                  Signature                      Signature

Name (print)               Name (print)                   Name (print)

Title                      Title                          Title

Date                       Date                           Date


<PAGE>

ANNEX 1

specification and criteria of the SOFTWARE PRODUCTS

SOFTWARE PRODUCTS:

1.     H.323 Protocol Stack, in a SOURCE CODE form for operating systems as
       defined in Annex 4:

       H.323 Conference Manager: Layer of abstraction that hides details of
       implementation of H.245 and H.225 from application. It also provides
       inter-protocol procedures as described in the ITU-T H.323 recommendation.

       H.225 (Q.931, RAS and RTP/RTCP): Media Stream Packetization and
       Synchronization for Visual Telephone Systems on Non Guaranteed Quality of
       Service LANs

       H.245: Control of communications between Visual Telephone Systems and
       Terminal Equipment.

       H.235: Security Framework for Signaling and Authentication, in SOURCE
       CODE form for Win 32 and Solaris.

       The SOURCE CODE version for Windows NT will be upgraded to Windows 2000
       (and all following versions) when available at no cost.

2.     H.323 Software Development Kit, in an OBJECT CODE form for the operating
       systems Windows NT (including all following versions) and Solaris for
       Sparc (Version 2.6) (including all following versions if available) and -
       if and when available - for the other operating systems as defined in
       Annex 4.

       The SDK includes two compilers: ASN.1 and PDL.

       The ASN.1 compiler compiles a sub-set of the ASN.1 syntax that is defined
       by the following ITU-T recommendations:

       X.680, X.681, X.682, X.683 which are required to support H.245, H.225 and
       H.450 must be supported.

       The PDL compiler compiles the Protocol Description Language that was
       developed by RADVISION and defines State Machines that use data
       structures defined by ASN.1.

3.     H.323 Gatekeeper, in a SOURCE CODE and OBJECT CODE form for operating
       systems Win 32 (Windows 98 and Windows NT), Solaris for Spark as of
       (12/99) Linux and VXWorks as of Q1 2000

       Gatekeeper Software Toolkit, in a SOURCE CODE form for operating systems
       Win 32 (Windows 98 and Windows NT), Solaris for Spark as of Q1 2000 Linux
       and VXWorks as of Q1 2000.

4.     H.450 /1/2/3 add-on modul to the H.323 Stack, in a SOURCE CODE form for
       Win32 and Solaris.


<PAGE>

ANNEX 2

SYSTEM DOCUMENTATION

1      STACK AND SDK DOCUMENTS

1.1    H.323 Stack - Programmer's Guide and Reference WORD
1.2    H.323 Protocol Stack - Source Documentation WORD
1.3    H.323 Stack - Porting Functions and Programmer's Guide and Reference WORD
1.4    H.323 Stack - PDK - Protocol Description Kit and Function Reference Guide
       WORD
1.5    Special Unix Guide - WORD

2      GATEKEEPER DOCUMENTS

2.1    Programmer and Reference Manual Framemaker

2.2    Sample Application Document Framemaker
2.3.   H.235 Proxy Plug-in -  Framemaker
2.4    H.450 Plug-In     Framemaker

3        H.450 DOCUMENTS

3.1    H.450 - Programmer's Guide and Reference WORD

<PAGE>


ANNEX 4

REFERENCE ENVIRONMENT

Win32 (e.g. Windows 98, Windows NT, and all following versions)
Solaris for Sparc (Version 2.6),
VxWorks,
Linux PC ( Version 2.0.3.)5

The support for following versions of the REFERENCE ENVIRONMENT shall be
provided to SIEMENS free of charge if available for the RADVISIONS' SOFTWARE
PRODUCTS, otherwise the provisions of Clause 2.7 will apply.

<PAGE>


ANNEX 5

LICENSE, MAINTENANCE FEES AND TECHNICAL SUPPORT AND TRAINING RATES

       LUMP SUM, ROYALTY AND MAINTENANCE FEES AND TECHNICAL SUPPORT AND TRAINING
       RATES

1.     LUMP SUM (AGGREGATE ONE-TIME PAYMENT FOR ALL SOFTWARE PRODUCTS) One time
Lump Sum for all SOFTWARE PRODUCTS, as defined in Annex 1, of $1,100,000.
License fee payments for the SOFTWARE PRODUCTS made prior to the EFFECTIVE DATE
will not be refunded to SIEMENS.

2.     ROYALTY FEES PER CATEGORIES

The royalty fees shall be per sold / distributed copy of the EMBEDDED PRODUCT
and dependent on the Application Category as detailed in the following table:

- -------------------------------------------------------------------------------
APPLICATION            ROYALTY                            ROYALTIES:
CATEGORY:              FEE PARAMETER:

- -------------------------------------------------------------------------------
CLIENT HW              Per Client                         1 US-$ per client

- -------------------------------------------------------------------------------
CLIENT SW              Per Client                         0,25 US-$ per client

- -------------------------------------------------------------------------------
NETWORK                Per Port                           LESS THAN 10K $6/port
                                                          10K-25K $5/port
                                                          >25K $3.5/port

- -------------------------------------------------------------------------------
SERVER                 Per client                         $0.30
                       Per concurrent user                LESS THAN 25K $3/C.U.
                                                          > 25K $2.75/C.U.

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

- -------------------------------------------------------------------------------
GATEKEEPER (OTHER      Per registered endpoints/clients   $ 0.4 per registered
THAN CARRIER GRADE                                        endpoint / client
GATEKEEPER)

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

CARRIER GRADE GATEKEEPER

                                                                UNITS

<TABLE>
<CAPTION>

CONCURRENT CALLS [CC]     1 - 500 OR 3 YEARS    501 - 1000 OR 4TH AND 5TH YEAR       > 1000 OR ABOVE 5 YEARS
<S>                       <C>                   <C>                                  <C>
   < 96                   1,056                 720                                  576
     97 -    256          2,816                 1,920                                1,536
    257 -    512          5,120                 3,584                                2,816
    513 -  1,024          9,216                 6,656                                5,120
  1,025 -  2,000          16,000                12,000                               9,000
  2,001 -  5,000          US $ 7/CC             US$ 5.5/CC                           US$4.25/CC
 5001-10000               US $ 6/CC             US$ 5/CC                             US$ 4/CC
 >10000                   US$ 5/CC              US$ 4/CC                             US$ 4/CC

</TABLE>

The royalty fees shall be dependent on the # of units and the # of concurrent
calls that a unit can handle.
Unit shall be defined as the applicable HW/SW - End User configuration where the
Gatekeeper functionality is Installed.
The # of units shall be counted for the duration of the AGREEMENT.
Starting with 4th year after the EFFECTIVE DATE, the royalties in column
(501 - 1,000 Units) shall apply


<PAGE>

regardless of the number of units sold/distributed in the first three years.
Starting with 6th year after the EFFECTIVE DATE, the royalties in column
(>1,000 Units) shall apply regardless of the number of units sold/distributed in
the first five years.
The # of units shall be counted for the duration of the AGREEMENT.

 .


3.       MAINTENANCE FEES (ANNUAL FEES PER SIEMENS SUPPORT CENTER)
SIEMENS agrees to pay to RADVISION, each year during the maintenance term, the
following nonrefundable (subject to the provisions of the AGREEMENT) SOFTWARE
PRODUCT annual maintenance and support fees:

Annual Maintenance Fee per support enter: $100,000

Minimal Annual amount  $ 300,000  (for minimum  3 supported support centers)

SIEMENS is free how to organize its support centers. Without limitation there
are no restrictions regarding locations or products.

4.       RATES FOR ADDITIONAL TECHNICAL SUPPORT

Additional technical support fee provided at RADVISION premises $100 per hour.

Additional technical support fee for On Site $1,000 per day not inclusive of
travelling and accommodation expenses to be covered by SIEMENS

5.       RATES FOR ADDITIONAL TRAINING

Additional training fee: $2,000 per day for a group of up to twenty-five persons
not inclusive of travelling and accommodation expenses to be covered by SIEMENS

<PAGE>


ANNEX 6

MAINTENANCE PROVISIONS

             Maintenance services for the SOFTWARE PRODUCTS include:

* Maintenance releases including BUG FIXES, UPDATES, and certain UPGRADES which
RADVISION has expressly agreed to provide as part of the SOFTWARE PRODUCTS
maintenance and support services.
* Telephone support. during working hours (Sunday- Thursday , 9:00-18:00; Israel
Time); RADVISION's services hereunder shall not extend to any SOFTWARE PRODUCT
or components thereof which have been subject to misuse, accident or improper
installation or maintenance.

The guidelines for handling bug reports and fixing of SOFTWARE PRODUCTS errors
shall be handled as follows:

Upon RADVISION's receipt of an error report and verification of the error in the
form of the unmodified SOURCE CODE form of the SOFTWARE PRODUCT from SIEMENS,
the source code of the SIEMENS software that caused the problem, and detailed
log file generated by the SOFTWARE PRODUCT, and provided that the error can be
reproduced at RADVISION's premises in Israel, RADVISION shall promptly do best
efforts to take the corrective action so as to remedy the reported problems
within the following time schedule:

<TABLE>
<CAPTION>

CLASSIFICATION                 REMEDY LEVEL 1                   REMEDY LEVEL 2                REMEDY LEVEL 3
- --------------                 --------------                   --------------                --------------
<S>                            <C>                              <C>                           <C>
Fatal                          6 business hours (in Israel)     7 business days (in Israel)   Within 60 days**
Severe Impact                  12 business hours (in Israel)    14 business days (in Israel)  70 days**
Degraded Operations            24 business hours(in Israel)     30 days**                     100 days**
Minimal Impact                 24 business hours (in Israel)    60 days**                     150 days**

</TABLE>

The bugs/errors are classified by RADVISION and are as follows:

CLASSIFICATION:

Fatal:                Errors preventing all useful work from being done
Severe Impact:        Errors which disable major functions from being performed.
Degraded Operations:  Errors disabling only certain nonessential functions.
Minimal Impact:       All other errors.

REMEDY LEVEL:

First Level Acknowledgment of receipt of error report with written confirmation
delivered to "SIEMENS" during the next business day.
Second Level Patch or work around, temporary fix, or update or major release,
including applicable SYSTEM DOCUMENTATION changes.
Third Level Official fix, update or major release, including applicable SYSTEM
DOCUMENTATION changes.

* If received on a business day during the hours of Monday-Friday, 8:00 AM -
5:00 PM; Israel Time


<PAGE>

** A day is defined as a 24 hour period, regardless of whether work is scheduled
during that period. It is intended that RADVISION and SIEMENS will work within
the framework of these guidelines. In the event that an exceptional circumstance
arises, the Parties will discuss the circumstances and mutually agree on the
correct course of action to take. Exceptions may include but are not limited to
the impossibility of SIEMENS to perform, the severity of the error, or the
availability of a more efficient approach.

MAINTENANCE AND SUPPORT SERVICES. Maintenance and support services to be
provided by RADVISION to SIEMENS during the maintenance term are as follows:

SOURCE CODE UPDATES, including OBJECT CODE, solely as follows:

UPDATES, as, when, and if available within the maintenance term, to the Call
Control program (which includes functionality defined in H.225 and H.245) and
the Gatekeeper SOFTWARE PRODUCT to reflect changes in the ITU Recommendation for
H.323.

OBJECT CODE UPDATES for those SOFTWARE PRODUCT, initially delivered by RADVISION
(per Annex 1), in OBJECT CODE form;

SOURCE CODE UPDATES for those SOFTWARE PRODUCTS, initially delivered by
RADVISION (per Annex 1), in SOURCE CODE and OBJECT CODE form; and telephone
support. Support may also be provided via facsimile, electronic mail, and/or
RADVISION's Worldwide Web site.

Note: Unless otherwise indicated, RADVISION shall provide to SIEMENS only three
(3) copies per release of an UPDATE.

SIEMENS will appoint a technical program manager or technical liaison who will
be responsible for coordinating technical interaction between the Parties.


<PAGE>

ANNEX 7

EXPORT CONTROL DATA

Product number:
Short description:

1.       Is the product subject to US export control regulations?

         YES: / /   NO:   / /

         If yes: Please give Export Control Classification Number (ECCN):

         ____________________

         Is it a "classified product" or does it contain parts which are on the
         US Munitions List of the "US Department of State (Office of Defense
         Trade Controls)"?

         YES: / /   NO: / /

2.       Is the product subject to your national export control regulations?

         YES: / /   NO: / /

         If yes: Please give Export Control Classification Number (ECCN):

         ___________________

3.       Please supply the Harmonized Tariff System Number (HTS) or standard
         international trade classification

         NUMBER: ______________

4.       Does the product originate from the European Union according to EU
         Council Directive 3351/83?

         YES: / /   NO: / /

5.       Please give weight of the product without packaging and shipping crate
         in gram:

         WEIGHT IN GRAM:

         ______________

6.       Please name country of origin :

         ________________________________
         (If there are various countries of origin, please list each single part
         no. and its country of origin.)

RADVISION LTD.

DATE:    _________________________

BY:      _________________________

TITLE:   _________________________


<PAGE>

ANNEX 8:          LIST OF SUB-CONTRACTORS




                                   [None]


<PAGE>

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the use of our report
dated March 7, 2000 (and to all references to our Firm) included in or
made a part of this registration statement filed on Form F-1 registering
3,800,000 Ordinary Shares.

                            LUBOSHITZ KASIERER
                       MEMBER FIRM OF ARTHUR ANDERSEN



Tel Aviv, March 13, 2000




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