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                                                                    EXHIBIT 10.3


                  FOURTH SUPPLEMENT TO CENTIGRAM COMMUNICATIONS
                  CORPORATION PREFERRED SHARES RIGHTS AGREEMENT

         This Fourth Supplement to the Centigram Communications Corporation
Preferred Shares Rights Agreement (the "Supplement") amends the Centigram
Communications Corporation Preferred Shares Rights Agreement dated as of October
20, 1992, as previously amended by the Supplement to Centigram Communications
Corporation Preferred Shares Rights Agreement dated as of October 20, 1992, the
Second Supplement to Centigram Communications Corporation Preferred Shares
Rights Agreement dated as of January 1995 and the Third Supplement to Centigram
Communications Corporation Preferred Shares Rights Agreement dated as of October
22, 1999 (as amended, the "Agreement"). This Supplement is entered into by and
between Centigram Communications Corporation, a Delaware corporation
("Centigram"), and American Stock Transfer and Trust Company, as Rights Agent
(the "Agent"), pursuant to Section 27 of the Agreement.

         Section 1(a) of the Agreement is hereby amended to read in its entirety
as follows:

         (a)   "Acquiring Person" shall mean any Person who or which, together
               with all Affiliates and Associates of such Person, shall be the
               Beneficial Owner of 15% or more of the Common Shares then
               outstanding, but shall not include the Company, any Subsidiary of
               the Company or any employee benefit plan of the Company or of any
               Subsidiary of the Company, any entity holding Common Shares for
               or pursuant to the terms of any such plan. In addition,
               "Acquiring Person" shall not include:

                    (1)  Kopp Investment Advisors, Inc. ("KIA"), LeRoy C. Kopp
                         ("LCK"), the Kopp Emerging Growth Fund ("KEGF") or the
                         Kopp Holding Company ("KHC" and, collectively with KIA,
                         LCK and KEGF, the "Kopp Entities" and each a "Kopp
                         Entity") provided and only for so long as (i) on or
                         prior to May 30, 2000, no Kopp Entity beneficially owns
                         in excess of 28.3% of the Common Shares of the Company
                         then outstanding, (ii) after May 30, 2000, no Kopp
                         Entity beneficially owns in excess of 25% of the Common
                         Shares of the Company then outstanding; (iii) KIA and
                         KECG continue to be entitled to file reports of
                         beneficial ownership of the Common Shares of the
                         Company on Schedule 13G pursuant to Section 13(d) and
                         Section 13(g) of the Securities Exchange Act; (iv)
                         except as otherwise required by Rule 13d-1(b)(1)(ii)(G)
                         promulgated under the Exchange Act, LCK and KHC
                         continue to be entitled to file reports of beneficial
                         ownership of the Common Shares of the Company on
                         Schedule 13G pursuant to Section 13(d) and Section
                         13(g) of the Securities Exchange Act; (v) LCK and KHC
                         do not own in the aggregate (directly or indirectly
                         through IRAs and trusts) in excess of 1.7% of the
                         Common Shares of the Company then outstanding; and (vi)
                         the Kopp Entities continue to



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                         be in compliance with all other terms of the letter
                         agreement dated as of October 8, 1999 among the Kopp
                         Entities and the Company (a copy of which is
                         attached to the Third Supplement to Centigram
                         Communications Corporation Preferred Shares Rights
                         Agreement dated as of October 22, 1999), as determined
                         by a majority of the Continuing Directors in their sole
                         discretion; and

                  (2)    ADC Telecommunications, Inc. ("ADC"), but only in
                         connection with an acquisition effected pursuant to the
                         terms of the Agreement and Plan of Merger by and among
                         ADC, Poundstone Acquisition Corp. and the Company dated
                         June 8, 2000.

                  Notwithstanding the foregoing, no Person shall be deemed to be
                  an Acquiring Person either (i) as the result of an acquisition
                  of Common Shares by the Company which, by reducing the number
                  of shares outstanding, increases the proportionate number of
                  shares beneficially owned by such Person to 15% or more of the
                  Common Shares of the Company then outstanding; provided,
                  however, that if a Person, other than those entities described
                  in the foregoing two sentences, shall become the Beneficial
                  Owner of 15% or more of the Common Shares of the Company then
                  outstanding by reason of share purchases by the Company and
                  shall, after such share purchases by the Company, become the
                  Beneficial Owner of any additional Common Shares of the
                  Company, then such Person shall be deemed to be an Acquiring
                  Person, or (ii) if within eight days after such Person would
                  otherwise become an Acquiring Person (but for the operation of
                  this clause (ii)), such Person notifies the Board of Directors
                  that such Person did so inadvertently and within two days
                  after such notification, such Person is the Beneficial Owner
                  of less than 15% of the outstanding Common Shares.

         Except as amended hereby, the Agreement shall remain in full force and
effect.

         IN WITNESS WHEREOF, the parties hereto have caused this Supplement to
be executed effective as of June 8, 2000.

                         CENTIGRAM COMMUNICATIONS CORPORATION

                         By:  /s/ Thomas E. Brunton
                              -------------------------------------------------
                              Thomas E. Brunton
                              Senior Vice President and Chief Financial Officer


                         AMERICAN STOCK TRANSFER AND TRUST COMPANY

                         By:  /s/ Herbert J. Lemmer
                              -------------------------------------------------
                              Herbert J. Lemmer
                              Vice President




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