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Exhibit 5.1
CHOATE, HALL & STEWART
A PARTNERSHIP INCLUDING PROFESSIONAL CORPORATIONS
EXCHANGE PLACE
53 STATE STREET
BOSTON, MASSACHUSETTS 02109-2891
TELEPHONE (617)248-5000
FACSIMILE (617) 248-4000
TELEX 49615860
July 7, 2000
Natural MicroSystems Corporation
100 Crossing Boulevard
Framingham, Massachusetts 01702-5406
Gentlemen:
This opinion is delivered to you in connection with the registration
statement on Form S-8 (the "Registration Statement") to be filed on or about
July 7, 2000 by Natural MicroSystems Corporation (the "Company") under the
Securities Act of 1933, as amended, for registration under said Act of 3,820,000
shares of common stock, $.01 par value (the "Common Stock"), of the Company.
We are familiar with the Company's Certificate of Incorporation, as
restated, its By-Laws, as amended, and the records of its corporate proceedings.
We have also examined such other documents, records and certificates and made
such further investigation as we have deemed necessary for the purposes of this
opinion.
Based upon and subject to the foregoing, we are of the opinion that the
3,820,000 shares of Common Stock to be sold by the Company under its 2000 Equity
Incentive Plan, 1993 Non-Employee Directors Stock Option Plan, its 1993 Employee
Stock Purchase Plan and its 1995 Non-Statutory Stock Option Plan, each as in
effect on the date hereof, when issued against receipt of the agreed purchase
price therefor, will be legally issued, fully paid and nonassessable.
We understand that this opinion is to be used in connection with the
Registration Statement and consent to the filing of this opinion as an exhibit
to the Registration Statement. We further consent to the reference to this firm
in the section entitled "Interests of Named Experts and Counsel" in the
Registration Statement.
Very truly yours,
/s/ CHOATE, HALL & STEWART
