1 Exhibit 4.1 NUMBER SHARES BAY NETWORKS, INC. COMMON STOCK INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE THIS CERTIFICATE IS TRANSFERABLE IN BOSTON, MA OR NEW YORK, NY CUSIP 072510 10 0 THIS CERTIFIES THAT IS THE OWNER FULLY-PAID AND NON-ASSESSABLE SHARES OF THE COMMON STOCK, $.01 PAR VALUE, OF CERTIFICATE OF STOCK (herein after called the Corporation) transferable on the books of the Corporation by the holder hereof in person or by duly authorized attorney upon surrender of this Certificate properly endorsed. This Certificate and the shares represented hereby are issued and held subject to the laws of the State of Delaware, the Certificate of Incorporation of the Corporation, as amended, and the By laws of the Corporation, as amended. This Certificate is not valid until countersigned by the Transfer Agent and registered by the Registrar. IN WITNESS WHEREOF, the Corporation has caused this Certificate to be executed by the facsimile signatures of its duly authorized officers and sealed with the facsimile seal of the Corporation. Dated /s/ Paul J. Lewis CHAIRMAN BAY NETWORKS, INC. [Seal] 1986 DELAWARE /s/ Ronald Y. Schmidt /s/ Andrew K. Ludwick EXECUTIVE VICE-PRESIDENT AND PRESIDENT AND ASSISTANT SECRETARY CHIEF EXECUTIVE OFFICER SEE REVERSE FOR TRANSFER AGENT CERTIFICATION BY AND REGISTRAR AUTHORIZED SIGNATURE 2 THE CORPORATION WILL FURNISH WITHOUT CHARGE TO EACH STOCKHOLDER WHO SO REQUESTS A STATEMENT OF THE POWERS, DESIGNATIONS, PREFERENCES AND RELATIVE, PARTICIPATING, OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OR SERIES THEREOF AND THE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND/OR RIGHTS. SUCH REQUEST MAY BE MADE TO THE CORPORATION OR THE TRANSFER AGENT. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full accordingly to applicable laws or regulations: TEN COM -- as tenants in common UNIF GIFT MIN ACT -- _____ Custodian _____ (Cust) (Minor) TEN ENT -- as tenants by the under Uniform Gifts to Minors entireties Act _________________ JT TEN -- as joint tenants with (State) right of survivorship and not as tenants in common Additional abbreviations may also be used though not in the above list. FOR VALUE RECEIVED, ________________ HEREBY SELL, ASSIGN AND TRANSFER UNTO PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE ____________________________ | | |____________________________| ______________________________________________________________________________ (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE OF ASSIGNEE) ______________________________________________________________________________ ______________________________________________________________________________ _______________________________________________________________________ SHARES OF THE COMMON STOCK REPRESENTED BY THE WITHIN CERTIFICATE, AND DO HEREBY IRREVOCABLY CONSTITUTE AND APPOINT _____________________________________________________________________ ATTORNEY TO TRANSFER THE SAID STOCK ON THE BOOKS OF THE WITHIN NAMED CORPORATION WITH FULL POWER OF SUBSTITUTION IN THE PREMISES. DATED: ___________________________ (Signature) __________________________________________________ NOTICE: THE SIGNATURE TO THE ASSIGNMENT MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER. Signature(s) Guaranteed: ____________________________________________________ THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEED MEDALLION PROGRAM), PURSUANT TO SEC RULE 17AG16. This certificate also evidences and entitles the holder hereof to certain Rights as set forth in the Rights Agreement between Bay Networks, Inc., (the "Company") and The First National Bank of Boston (the "Rights Agent") dated as of February 7, 1995, as the same ???? amended from time to time (the "Rights Agreement"), the terms of which are hereby incorporated herein by reference and a copy of which is on file at the principal offices of the Company. Under certain circumstances, as set forth in the Rights Agreement, such Rights will be evidenced by separate certificates and will no longer be evidenced by this certificate. The Company will mail to the holder of this certificate a copy of the Rights Agreement, as in effect on the date of mailing, without charge promptly after receipt of a written request therefor. UNDER CERTAIN CIRCUMSTANCES SET FORTH IN THE RIGHTS AGREEMENT, RIGHTS ISSUED TO OR HELD BY, ANY PERSON WHO IS, WAS OR BECOMES AN ACQUIRING PERSON OR ANY AFFILIATE OR ASSOCIATE THEREOF (AS SUCH TERMS ARE DEFINED IN THE RIGHTS AGREEMENT), WHETHER CURRENTLY HELD BY OR ON BEHALF OF SUCH PERSON OR BY ANY SUBSEQUENT HOLDER, WILL BE NULL AND VOID, AND WILL NO LONGER BE TRANSFERABLE.