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                                                                    Exhibit 5.1

                             SECORE & WALLER, L.L.P.
                            ATTORNEYS AND COUNSELORS

                            ONE GALLERIA TOWER, 2290
                             13355 NOEL ROAD, LB 75
                            DALLAS, TEXAS 75240-6657
                                 (972) 776-0200
                            TELECOPIER (972) 776-0240


                                 August 21, 2000



Board of Directors
Microwave Transmission Systems, Inc.
541 Sterling Drive
Richardson, Texas 75081

         RE:      REGISTRATION STATEMENT ON FORM S-8
                  MICROWAVE TRANSMISSION SYSTEMS, INC. 2000 BONUS PLAN

Gentlemen:

         We have acted as counsel to Microwave Transmission Systems, Inc., a
Texas corporation (the "Company"), in connection with the preparation of the
Registration Statement on Form S-8 (the "Registration Statement") to be filed
with the Securities and Exchange Commission on or about August 18, 2000 under
the Securities Act of 1933, as amended (the "Securities Act"), relating to
100,000 shares of the $.001 par value common stock (the "Common Stock") of the
Company that will be issued on the exercise of stock bonuses (collectively,
the "Stock Bonuses") granted or that may be granted under the "Microwave
Transmission Systems, Inc. 2000 Stock Bonus Plan" (the "Plan").

         You have requested the opinion of this firm with respect to the
legality of the securities being registered. In connection therewith, we have
examined and relied upon the original, or copies identified to our
satisfaction, of (1) the Articles of Incorporation and the Bylaws of the
Company, as both have been amended; (2) minutes and records of the corporate
proceedings of the Company with respect to the Plan and related matters; (3)
the Registration Statement and exhibits hereto, including the Plan listed as
an exhibit to the Registration Statement; and (4) such other documents and
instruments as we have deemed necessary for the expression of the opinions
herein contained. In making the foregoing examinations, we have assumed the
genuineness of all signatures and the authenticity of all documents submitted
to us as originals, and the conformity to original documents of all documents
submitted to us as certified or photostatic copies. As to various questions of
fact material to this opinion, and as to the content and form of the Articles
of Incorporation, the Bylaws, minutes, records, resolutions and other
documents or writings of the Company, we have relied, to

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Board of Directors
August 21, 2000
Page 2


the extent we deem reasonably appropriate, upon representations or
certificates of officers or directors of the Company and upon documents,
records and instruments furnished to us by the Company, without independent
check or verification of their accuracy.

         Based upon our examination, consideration of, and reliance on the
documents and other information described above, and subject to the
assumptions, limitations and exceptions noted below, we are of the opinion
that the shares of Common Stock issued by the Company pursuant to Stock
Bonuses granted under the Plan will be validly issued, fully paid and
nonassessable. In issuing this opinion, we have assumed that (i) the Common
Stock to be granted through Stock Bonuses in the future will be duly granted
in accordance with the terms of the Plan, (ii) the Company maintains an
adequate number of authorized but unissued shares and/or treasury shares of
Common Stock available for issuance to those persons who are granted Stock
Bonuses under the Plan, and (iii) the consideration for the shares of Common
Stock issuable upon the grant of such Stock Bonuses is actually received by
the Company as provided in the Plan or in the applicable Stock Bonus Agreement
and such consideration exceeds the par value of such shares.

         This legal opinion is an expression of professional judgment and not
a guaranty of result. This opinion is rendered as of the date hereof, and we
undertake no, and hereby disclaim any, obligation to advise you of any changes
or new developments that might affect any matters or opinions set forth herein.

         This opinion is limited in all respects to the Texas Business
Corporation Act (the "TBCA") and our knowledge of the TBCA is derived from a
reading of the most recent compilation of that statute available to us without
consideration of any judicial or administrative interpretations thereof.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to references to our firm included in or made a
part of the Registration Statement. In giving this consent, we do not admit
that we come within the category of person whose consent is required under
Section 7 of the Securities Act or the Rules and Regulations of the Securities
and Exchange Commission thereunder. This opinion may not be relied upon by any
person other than the Company

                                                     Respectfully submitted,



                                                     /s/ SECORE & WALLER, L.L.P.