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Filed pursuant to Rule 424(b)(3)
Registration No. 333-33938
NATURAL MICROSYSTEMS CORPORATION
Supplement dated August 28, 2000
to Prospectus dated April 14, 2000
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SELLING STOCKHOLDERS AND PLAN OF DISTRIBUTION
The following text and table are inserted at the end of the above-captioned
section:
The table below lists the stockholders selling shares of common stock with
this prospectus, and the number of shares of common stock they are offering,
after giving effect to our two-for-one stock split on August 7, 2000. The table
also reflects sales and other transfers of common stock by these stockholders as
of that date, to our knowledge.
Name Shares Offered
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Calvary Church Santa Ana 300
Clarent Corporation 9,528
Eileen Coe 2,286
Michael H. Collender 0
Ronald Crawford and Hyong Crawford 4,170
Patrick J. Croswell 5,102
Roger C. Davisson 966
Davisson Family Trust 4,516
Anthony Dominicis 2
Clifford L. Farrar 686
Daniel E. Finley and Mary H. Finley 1,172
Focus on the Family 2,000
Glenn Fountain 23,600
David Allen Garrett 2,286
Chris Hawkinson 4,572
Steven Hoffman 25,866
Jesse M. James 2,744
Judith Kelman 3,056
Stanley M. Lee and Esther J. Lee 8,056
I-Shyh Lin 6,868
Ernest Louie 21,680
Louie Family Trust A 7,668
Kent Lowell 18,592
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Name Shares Offered
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MacDonald Revocable Inter Vivos Trust 94,666
Saul Moreno 1,600
Shawn Nguyen 2,744
Richard Orr 686
Ruby Orr 90
Steve Qu 4,572
Vito Rocco 8,056
Forrest Rose 101,082
Robert Ivan Rose, Jr. 0
K. C. Schaaf 0
Joan Taylor 5,568
Townsend Trust 80,238
Trinity Unity Presbyterian Church 1,000
Diane M. Volden 1,828
Thomas A. Volden 105,198
Brian J. Walker 548
Charles J. Walker 125,566
C. Alan Williams 39,936
Joan Williams 39,936
Gerald Willoughby and Pauline Willoughby 9,266
Winton Family Trust 4,836
Ivan L. Wolff 2,908
Ekrem Yilmaz 548
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TOTAL 786,288
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This Supplement must be read together with our Prospectus dated April 14, 2000.
You may request a copy of the Prospectus dated April 14, 2000 at no cost by
writing or telephoning Natural MicroSystems Corporation, 100 Crossing Boulevard,
Framingham, Massachusetts 01702, Attention: Investor Relations, Telephone: (508)
620-9300.
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