Document:

<PAGE>

                                EXHIBIT NO. 4.3

     Amendment to Shareholders Rights Agreement dated as of July 19, 1999
     ---------------------------------------------------------------------

<PAGE>
                  AMENDMENT TO SHAREHOLDERS RIGHTS AGREEMENT
                  ------------------------------------------

THIS AMENDMENT TO SHAREHOLDERS RIGHTS AGREEMENT is made as of the 19/th/ day of
July, 1999.

WHEREAS: The parties hereto are all the parties to that certain Shareholders
Rights Agreement dated as of June 22, 1999 (the "Shareholders Rights
Agreement"); and

WHEREAS: the parties hereto desire to amend the terms of the Shareholders Rights
Agreements as provided below.

NOW THEREFORE, the parties hereto hereby agree as follows:

1.   All terms used herein shall have the meaning ascribed to them in the
     Shareholders Rights Agreement unless the context otherwise requires.

2.   The provisions of Section 6.1 of the Shareholders Rights Agreement limiting
     the obligation of the Company to provide reports to competitors and
     associates of competitors of the Company shall not apply to VTEL
     Corporation.

3.   For the avoidance of doubt, it is hereby expressly provided that the other
     terms and conditions of Section 6 of the Shareholders Rights Agreement will
     continue to apply to VTEL Corporation and the provisions of Section 7 of
     the Shareholders Rights Agreement will apply to all reports provided to
     VTEL Corporation.

4.   Except as expressly amended hereby, the provisions of the Shareholders
     Rights Agreement shall remain in full force and effect.

IN WITNESS WHEREOF the parties have signed this Agreement as of the date first
hereinabove set forth.

ACCORD TELECOMMUNICATIONS LTD.                    GILDE IT FUND B.V.

By: /s/ [ILLEGIBLE]                               By: /s/ [ILLEGIBLE]
   -------------------------                         --------------------------
Name: [ILLEGIBLE]                                 Name: [ILLEGIBLE]
     -----------------------                           ------------------------
Title:______________________                      Title: Investment Manager
                                                        -----------------------

<PAGE>

ONE LIBERTY FUND III LIMITED             NITZANIM FUND (1993) LTD.
PARTNERSHIP

By: /s/ [ILLEGIBLE]                      By: /s/ [ILLEGIBLE]
   ------------------------------           ---------------------------
Name: [ILLEGIBLE]                        Name:_________________________
     ----------------------------
Title: [ILLEGIBLE]                       Title:________________________
      ---------------------------

ADVANCED TECHNOLOGY VENTURES IV,         SVE STAR VENTURES
L.P.                                     ENTERPRISES NO. II GbR, a
                                         German Civil Law Partnership
                                         (with limitation of liability)

By: /s/ [ILLEGIBLE]                      By: /s/ [ILLEGIBLE]
   ------------------------------           ---------------------------
Name: [ILLEGIBLE]                        Name:_________________________
     ----------------------------
Title: General Partner                   Title:________________________
      ---------------------------

SVE STAR VENTURES ENTERPRISES NO.        SVE STAR VENTURES
III GbR, a German Civil Law              ENTERPRISES NO. IIIA GbR, a
Partnership (with limitaiton of          German Civil Law Partnership
liability)                               (with limitation of liability)

By: /s/ [ILLEGIBLE]                      By: /s/ [ILLEGIBLE]
   ------------------------------           ---------------------------
Name:____________________________        Name:_________________________
Title:___________________________        Title:________________________

STAR MANAGEMENT OF INVESTMENTS           SVM STAR VENTURES
(1993) LIMITED PARTNERSHIP               MANAGEMENT GmbH NR. 3
                                         & CO. BETEILIGUNGS KG

By: /s/ [ILLEGIBLE]                      By: /s/ [ILLEGIBLE]
   ------------------------------           ---------------------------
Name:____________________________        Name:_________________________
Title:___________________________        Title:________________________

UNICYCLE TRADING COMPANY L.P.            MANAKIN INVESTMENTS LTD.

By: /s/ Mark Chris                       By: /s/ Gideon Talkowsky
   ------------------------------           ---------------------------
Name: Mark Chris                         Name: Gideon Talkowsky
     ----------------------------             -------------------------
Title: President                         Title:________________________
      ---------------------------

VTEL CORPORATION                         COURSES INVESTMENTS IN
                                         TECHNOLOGY L.P.

By: /s/ R.S. Bond, V.P.                  By: /s/ [ILLEGIBLE]
   ------------------------------           ---------------------------
Name: R.S. Bond                          Name: [ILLEGIBLE]
     ----------------------------             -------------------------
Title: V.P.                              Title: [ILLEGIBLE]
      ---------------------------              ------------------------
                                       2

<PAGE>

K.T. CONCORD VENTURE                            K.T. CONCORD VENTURE
FUND (ISRAEL), L.P.                             FUND (CAYMAN) L.P.

By: ____________________________                By: ________________________

Name: [ILLEGIBLE]                               Name: [ILLEGIBLE]
      --------------------------                      ----------------------

Title: _________________________                Title: _____________________

/s/ Sigi Gavish                                 /s/ Gil Rosenfeld
--------------------------------                ____________________________
SIGI GAVISH                                     GIL ROSENFELD

/s/ Amnon Shoham                                /s/ Michal Rosenfeld
--------------------------------                ----------------------------
AMNON SHOHAM                                    MICHAL ROSENFELD

                                                /s/ Eduardo Shoval
                                                ----------------------------
                                                EDUARDO SHOVAL/VAMOS LTD.

NORWEST EQUITY CAPITAL L.L.C.                   KEVIN G. HALL FAMILY TRUST

By: Itasca NEC. L.L.C., Managing Member         /s/ Kevin G. Hall
---------------------------------------         -------------------------
                                                Kevin G. Hall, Trustee
    /s/ Kevin G. Hall
    -----------------------------------
    Kevin G. Hall, Member

                                       3<PAGE>

                                  EXHIBIT 4.4
                                  -----------

                              SECOND AMENDMENT TO
                              -------------------
                         SHAREHOLDERS RIGHTS AGREEMENT
                         -----------------------------

THIS AMENDMENT TO SHAREHOLDERS RIGHTS AGREEMENT is made as of the 25th day of
May, 2000.

WHEREAS:  The parties hereto are all the parties to that certain Shareholders
Rights Agreement dated as of June 22, 1999 (the "SRA") and;

WHEREAS:  The parties hereto desire to amend the terms of the SRA as provided
below.

NOW THEREFORE, the parties hereto hereby agree as follows:

1.  All terms used herein shall have the meaning ascribed to them in the SRA
    unless the context otherwise requires.

2.  Effective immediately upon the closing of the initial public offering of
    Ordinary Shares of Accord Networks Ltd. pursuant to a registration statement
    under the U.S. Securities Act of 1933, as amended, or pursuant to a
    prospectus or similar document under the Israeli Securities Law, 1968, or
    the securities laws of another jurisdiction, Section 3 of the SRA regarding
    Pre-Emptive Rights and Section 4 of the SRA regarding the Right of First
    Refusal will be canceled and will become null and void, and no such rights
    shall thereafter exist.

3.  Except as expressly amended hereby, the provisions of the SRA shall remain
    in full force and effect.

IN WITNESS WHEREOF the parties have signed this Agreement as of the date first
hereinabove set forth.

ACCORD NETWORKS LTD.                    GILDE IT FUND B.V.

By: /s/ Jules DeVigne                   By: /s/ [ILLEGIBLE]
   -----------------------                 ---------------------
Name:  Jules DeVigne                    Name:  [ILLEGIBLE]
Title: Chairman & CEO                   Title: Executive Director

<PAGE>

ONE LIBERTY FUND III LIMITED             NITZANIM FUND (1993) LTD.
PARTNERSHIP

By: /s/ [ILLEGIBLE]                      By: /s/ Matty Karp
   ------------------------------           ---------------------------
Name: [ILLEGIBLE]                        Name: Matty Karp
     ----------------------------
Title: Executive Director                Title: Managing Partner

ADVANCED TECHNOLOGY VENTURES IV,         SVE STAR VENTURES
L.P.                                     ENTERPRISES NO. II GbR

By: /s/ Jos Henkins                      By: /s/ Meir Barel
   ------------------------------           ---------------------------
Name: Jos Henkins                        Name:  SVM Star Ventures Management
Title: General Partner                          GmbH No. 3--Managing Partner
                                         Title: Meir Barel--Managing Director

SVE STAR VENTURES ENTERPRISES NO.        SVE STAR VENTURES
III GbR                                  ENTERPRISES NO. IIIA GbR

By: /s/ Meir Barel                       By: /s/ Meir Barel
   ------------------------------           ---------------------------
Name:  SVM Star Ventures Management      Name:  SVM Star Ventures Management
       GmbH No. 3--Managing Partner             GmbH No. 3--Managing Partner
Title: Meir Barel--Managing Director     Title: Meir Barel--Managing Director

STAR MANAGEMENT OF INVESTMENTS           SVM STAR VENTURES
(1993) LIMITED PARTNERSHIP               MANAGEMENT GmbH NR. 3
                                         & CO. BETEILIGUNGS KG

By: /s/ Meir Barel                       By: /s/ Meir Barel
   ------------------------------           ---------------------------
Name:  SVM Star Ventures Management      Name:  SVM Star Ventures Management
       GmbH No. 3--Managing Partner             GmbH No. 3--Managing Partner
Title: Meir Barel--Managing Director     Title: Meir Barel--Managing Director

UNICYCLE TRADING COMPANY L.P.            MANAKIN INVESTMENTS LTD.

By: /s/ Mark Chris                       By: /s/ Gideon Talkowsky
   ------------------------------           ---------------------------
Name:  Mark Chris                        Name:  Gideon Talkowsky
Title: President                         Title: Manager

VTEL CORPORATION                         COURSES INVESTMENTS IN
                                         TECHNOLOGY L.P.

By: /s/                                  By: /s/ Meir Kfir
   ------------------------------           ---------------------------
Name:                                    Name:  Meir Kfir
     ----------------------------
Title:                                   Title: CFO
      ---------------------------

<PAGE>

                                      -3-
<TABLE>
<CAPTION>

<S>                                             <C>
K.T. CONCORD VENTURE                            K.T. CONCORD VENTURE
FUND (ISRAEL), L.P.                             FUND (CAYMAN) L.P.

By: /s/ Matty Karp/Yair Safrai                  By: /s/ Matty Karp/Yair Safrai
   ------------------------------------            ------------------------------------
Name:  Matty Karp/Yair Safrai                   Name:  Matty Karp/Yair Safrai
Title: Managing Partner/General Partner         Title: Managing Partner/General Partner

/s/ Sigi Gavish                                 /s/ Gil Rosenfeld
---------------------------------------         ---------------------------------------
SIGI GAVISH                                     GIL ROSENFELD

/s/ Amnon Shoham                                /s/ Michal Rosenfeld
---------------------------------------         ---------------------------------------
AMNON SHOHAM                                    MICHAL ROSENFELD

                                                /s/ [ILLEGIBLE]
                                                ---------------------------------------
                                                EDUARDO SHOVAL/VAMOS LTD.

NORWEST EQUITY CAPITAL L.L.C.                   KEVIN G. HALL FAMILY TRUST

By: /s/ [ILLEGIBLE]                             By: /s/ Kevin G. Hall
   ------------------------------------            ------------------------------------
    Itasca NEC, L.L.C., Managing Member             Kevin G. Hall, Trustee

    /s/ Kevin G. Hall
    -----------------------------------
    Kevin G. Hall, Member

</TABLE>

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00010-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00010-of-00352.parquet"}]]