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                                                                     EXHIBIT 5.1
[COOLEY GODWARD LLP LETTERHEAD]



November 22, 1996


Coral Systems, Inc.
1500 Kansas Avenue
Suite 2E
Longmont, Colorado 80501

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by Coral Systems, Inc. (the "Company") of a Registration
Statement on Form S-1 (the "Registration Statement") with the Securities and
Exchange Commission (the "Commission"), including a prospectus to be filed with
the Commission pursuant to Rule 424(b) of Regulation C promulgated under the
Securities Act of 1933, as amended, and the underwritten public offering of up
to 3,105,000 shares of the Company's Common Stock (the "Shares"), which amount
includes 405,000 shares for which the underwriters have been granted an
over-allotment option (of which up to 115,000 shares of Common Stock may be sold
by certain stockholders of the Company in the event that the underwriters
exercise their over-allotment option).

In connection with this opinion, we have (i) examined and relied upon the
Registration Statement, (ii) reviewed the Company's Certificate of
Incorporation and Bylaws, as amended and as proposed to be amended prior to the
closing of the public offering, and the originals or copies certified to our
satisfaction of such records, documents, certificates, memoranda and other
instruments as in our judgment were necessary or appropriate to enable us to
render the opinion expressed below, and (iii) assumed that the Shares to be
sold to the underwriters by the Company will be sold at a price established by
the Board of Directors of the Company or the Pricing Committee thereof in
accordance with Section 153 of the Delaware General Corporation Law.

On the basis of the foregoing and in reliance thereon, we are of the opinion
that the Shares, when issued and sold in accordance with the Registration
Statement, will be validly issued, fully paid and nonassessable.
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Coral Systems, Inc.
November 22, 1996
Page Two


We consent to the reference to our firm under the caption "Legal Matters" in
the prospectus included in the Registration Statement and to the filing of this
opinion as an exhibit to the Registration Statement.

Very truly yours,



/s/JAMES C. T. LINFIELD
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James C. T. Linfield

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