EXHIBIT 4.3 CERTIFICATE OF AMENDMENT OF THE BYLAWS OF ACCOM, INC. Accom, Inc., a corporation duly organized and existing under the General Corporation Law of the State of Delaware (the "Corporation"), does hereby certify that: 1. The amendment to the Corporation's Bylaws set forth below was duly adopted by the Board of Directors of the Corporation and consented to by the stockholders of the Corporation in accordance with Section 109 of the General Corporation Law of the State of Delaware. 2. Article III of the Corporation's Bylaws is hereby amended to read in its entirety as follows: "ARTICLE III DIRECTORS Section 1. Unless otherwise provided in the corporation's certificate of incorporation, the total number of directors of the corporation shall be not less than five (5) nor more than nine (9), with the actual total number of directors set from time to time exclusively by resolution of the Board of Directors. The Board of Directors shall consist of six members until changed by such a resolution. There shall be three classes of directors (each, a "Class"), known as Class 1, Class 2 and Class 3. The initial Class 1, Class 2 and Class 3 directors shall serve in office as follows: Class 1 shall retire at the first annual meeting of stockholders following the filing of the Amendment to the corporation's Amended and Restated Certificate of Incorporation (the "Effective Date"), Class 2 shall retire at the second annual meeting of stockholders following the Effective Date, and Class 3 shall retire at the third annual meeting of stockholders following the Effective Date. This annual sequence shall be repeated thereafter. Each director in a Class shall be eligible for re-election if nominated, and such director's seat shall be open for election of a director, at the annual meeting of stockholders of the corporation at which such Class shall retire, to hold office for three years or until his successor is elected or appointed. Any additional directors elected or appointed shall be elected or appointed to such Class as will ensure that the number of directors in each Class remains as nearly equal as possible, and if all Classes have an equal number of directors or if one Class has one director more than the other two Classes, then any additional directors elected or appointed shall be elected or appointed to the Class that does not have more directors than any other Class and is subject to election at an ensuing annual meeting before any other such Class. Section 2. Vacancies due to resignation, death, increases in the number of directors, or any other cause shall be filled only by the Board of Directors (unless there are no directors, in which case vacancies will be filled by the stockholders) in accordance with the rule that each Class of directors shall be as nearly equal in number of directors as possible. Notwithstanding such rule, in the event of any change in the authorized number of directors each director then continuing to serve as such will nevertheless continue as a director of the Class of which he or she is a member, until the expiration of his or her current term or his earlier death, resignation or removal. If any newly created directorship or vacancy on the Board of Directors, consistent with the rule that the three Classes shall be as nearly equal in number of directors as possible, may be allocated to one or two or more Classes, then the Board of Directors shall allocate it to that of the available Classes whose term of office is due to expire at the earliest date following such allocation. When the Board of Directors fills a vacancy, the director chosen to fill that vacancy shall be of the same Class as the director he or she succeeds and shall hold office until such director's successor shall have been elected and qualified or until such director shall resign or shall have been removed. No reduction of the authorized number of directors shall have the effect of removing any director prior to the expiration of such director's term of office. Section 3. The business of the corporation shall be managed by or under the direction of its Board of Directors which may exercise all such powers of the corporation and do all such lawful acts and things as are not by statute or by the certificate of incorporation or by these bylaws directed or required to be exercised or done by the stockholders." 6 IN WITNESS WHEREOF, the Corporation has caused this Certificate of Amendment to be signed by Donald K. McCauley, its Secretary, on this 20th day of July, 1999. Donald K. McCauley -------------------------------------- Donald K. McCauley Secretary 7