[Letterhead of Kirkland & Ellis]
                                        

                               January 16, 1998

Communications Instruments, Inc.
1396 Charlotte Highway
Fairview, NC 28730

     Re:  10% Senior Subordinated Notes due 2004, Series B
          ------------------------------------------------

Ladies and Gentlemen:

     We are acting as special counsel to Communications Instruments, Inc., a
Delaware corporation (the "Company"), in connection with the proposed
registration by the Company of up to $95,000,000 in aggregate principal amount
of the Company's 10% Senior Subordinated Notes due 2004, Series B (the "Exchange
Notes"), pursuant to a Registration Statement on Form S-4 originally filed with
the Securities and Exchange Commission (the "Commission") on October 17, 1997
under the Securities Act of 1933, as amended (the "Securities Act") (such
Registration Statement, as amended or supplemented, is hereinafter referred to
as the "Registration Statement"), for the purpose of effecting an exchange offer
(the "Exchange Offer") for the Company's 10% Senior Subordinated Notes due 2004
(the "Old Notes"). We are also acting as special counsel to Kilovac Corporation
and Kilovac International, Inc. (collectively, the "Guarantors") as issuers of
guarantees (collectively, the "Guarantees") of the obligations of the Company
under the Exchange Notes. The Exchange Notes and the Guarantees are to be issued
pursuant to the Indenture (the "Indenture"), dated as of September 18, 1997,
among the Company, the Guarantors and Norwest Bank Minnesota, National
Association, as Trustee, in exchange for and in replacement of the Company's
outstanding Old Notes, of which $95,000,000 in aggregate principal amount is
outstanding.

     In that connection, we have examined originals, or copies certified or
otherwise identified to our satisfaction, of such documents, corporate records
and other instruments as we have deemed necessary for the purpose of this
opinion, including (i) the corporate and organizational documents of the Company
and each Guarantor, (ii) minutes and records of the corporate proceedings of the
Company and each Guarantor with respect to the issuance of the Exchange Notes
and the Guarantees, respectively, (iii) the Registration Statement and exhibits
thereto and (iv) the Registration Rights Agreement, dated as of September 18,
1997, among the Company, the Guarantors, and BancAmerica Securities Inc. and
Salomon Brothers Inc.

     For purposes of this opinion, we have assumed the authenticity of all
documents submitted to us as originals, the conformity to the originals of all
documents submitted to us as copies and the



 


Communications Instruments, Inc.
January 16, 1998
Page 2

 
authenticity of the originals of all documents submitted to us as copies. We
have also assumed the genuineness of the signatures of persons signing all
documents in connection with which this opinion is rendered, the authority of
such persons signing on behalf of the parties thereto other than the Company and
the Guarantors, and the due authorization, execution and delivery of all
documents by the parties thereto other than the Company and the Guarantors. As
to any facts material to the opinions expressed herein which we have not
independently established or verified, we have relied upon statements and
representations of officers and other representatives of the Company and others.

     Based upon the subject to the foregoing qualifications, assumptions and
limitations and the further limitations set forth below, we are of the opinion
that:

     (1)  The sale and issuance of the Exchange Notes has been validly
authorized by the Company.

     (2)  The Guarantees have been validly authorized by each of the Guarantors.

     (3)  When, as and if (i) the Registration Statement shall have become
effective pursuant to the provisions of the Securities Act, (ii) the Indenture
shall have been qualified pursuant to the provisions of the Trust Indenture Act
of 1939, as amended, (iii) the Old Notes shall have been validly tendered to the
Company and (iv) the Exchange Notes shall have been issued in the form and
containing the terms described in the Registration Statement, the Indenture, the
resolutions of the Company's and each Guarantor's Board of Directors (or
authorized committee thereof) authorizing the foregoing and any legally required
consents, approvals, authorization and other order of the Commission and any
other regulatory authorities to be obtained, the Exchange Notes when issued
pursuant to the Exchange Offer will be legally issued and will constitute valid
and binding obligations of the Company and each Guarantee will constitute the
valid and binding obligation of the respective Guarantor.

     Our opinions expressed above are subject to the qualifications that we
express no opinion as to the applicability of, compliance with, or effect of (i)
any bankruptcy, insolvency, reorganization, fraudulent transfer, fraudulent
conveyance, moratorium or other similar law affecting the enforcement of
creditors' rights generally, (ii) general principles of equity or at law
(regardless of whether enforcement is considered in a proceeding in equity or at
law), and (iii) public policy considerations which may limit the rights of
parties to obtain certain remedies.

 
Communications Instruments, Inc.
January 16, 1998
Page 3


     Our advice on every legal issue addressed in this letter is based
exclusively on the federal law of the United States and the laws of the state of
New York except that certain of the opinions are based on the Delaware General
Corporation Law (in the case of the Company) and on the California General
Corporation Law (in the case of Kilovac Corporation and Kilovac International,
Inc.). We advise you that we are not admitted to practice in California and our
knowledge of the California General Corporation Law for purposes of this opinion
is limited to a reading of a copy of those statutes as reproduced in the
Prentice Hall Law and Business Corporation Statutes; we did not review or
attempt to identify California case law or any other California law which might
be relevant for purposes of our opinions. Issues addressed by this letter may be
governed in whole or in part by other laws, but we express no opinion as to
whether any relevant difference exists between the laws upon which our opinions
are based and any other laws which may actually govern.

     We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement. We also consent to the reference to our firm under the
heading "Legal Matters" in the Registration Statement. In giving this consent,
we do not thereby admit that we are in the category of persons whose consent is
required under Section 7 of the Securities Act or the rules and regulations of
the Commission.

     We do not find it necessary for the purposes of this opinion, and
accordingly we do not purport to cover herein, the application of the securities
or "Blue Sky" laws of the various states to the issuance of the Exchange Notes.

     This opinion is limited to the specific issues addressed herein, and no
opinion may be inferred or implied beyond that expressly stated herein. We
assume no obligation to revise or supplement this opinion should the present
laws of the States of Delaware or New York be changed by legislative action,
judicial decision or otherwise.

     This opinion is furnished to you in connection with the filing of the
Registration Statement, and is not to be used, circulated, quoted or otherwise
relied upon for any other purposes.

                          Very truly yours,



                          Kirkland & Ellis