Exhibit 4.4

                             SUPPLEMENTAL INDENTURE

         SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as of
June 19, 1998 between Corcom, Inc. (the "New Subsidiary Guarantor"), a
subsidiary of Communications Instruments, Inc., a North Carolina corporation
(the "Company"), and Norwest Bank Minnesota, National Association, as trustee
under the indenture referred to below (the "Trustee"). Capitalized terms used
herein and not defined herein shall have the meaning ascribed to them in the
Indenture (as defined below).

                               W I T N E S S E T H

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an indenture (the "Indenture"), dated as of September 18, 1997,
providing for the issuance of an aggregate principal amount of $95,000,000 of
10% Senior Subordinated Notes due 2004 (the "Senior Subordinated Notes");

         WHEREAS, Sections 4.18 and 11.03 of the Indenture provide that under
certain circumstances the Company is required to cause certain of its
Subsidiaries to execute and deliver to the Trustee a supplemental indenture
pursuant to which such Subsidiaries shall unconditionally guarantee all of the
Company's Obligations under the Senior Subordinated Notes pursuant to a
Subsidiary Guarantee on the terms and conditions set forth herein; and

         WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the New
Subsidiary Guarantor and the Trustee mutually covenant and agree for the equal
and ratable benefit of the Holders of the Senior Subordinated Notes as follows:

         1. CAPITALIZED TERMS.  Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

         2. AGREEMENT TO SUBSIDIARY GUARANTEE. The New Subsidiary Guarantor
hereby agrees, jointly and severally with all other Subsidiary Guarantors, to
guarantee the Company's Obligations under the Senior Subordinated Notes and the
Indenture on the terms and subject to the conditions set forth in Article 11 of
the Indenture and to be bound by all other applicable provisions of the
Indenture.

         3. NO RECOURSE AGAINST OTHERS. No past, present or future director,
officer, employee, incorporator, shareholder or agent of any Subsidiary
Guarantor, as such, shall have any liability for any obligations of the Company
or any Subsidiary Guarantor under the Senior Subordinated Notes, any Subsidiary
Guarantees, the Indenture or this Supplemental Indenture or for any claim based
on, in respect of, or by reason of, such obligations or their creation. Each
Holder by accepting a Senior Subordinated Note waives and releases all such
liability. The waiver and release are part of the consideration for issuance of
the Senior Subordinated Notes.

         4. NEW YORK LAW TO GOVERN. The internal law of the State of New York
shall govern and be used to construe this Supplemental Indenture.


<PAGE>

         5. COUNTERPARTS The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

         6. EFFECT OF HEADINGS. The Section headings herein are for convenience
only and shall not affect the construction hereof.

         7. THE TRUSTEE. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the correctness of the recitals of fact
contained herein, all of which recitals are made solely by the New Subsidiary
Guarantor.

                            *          *          *


<PAGE>


IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture
to be duly executed, all as of the date first above written.


Dated: June 19, 1998

                                              CORCOM, INC.


                                              By: /s/ David Henning
                                                 ----------------------------
                                                   Name: David Henning
                                                        ---------------------
                                                   Title: Vice President &
                                                          Secretary
                                                         --------------------


Dated: June 19, 1998                          NORWEST BANK MINNESOTA,
                                              NATIONAL ASSOCIATION,
                                              as Trustee



                                              By: /s/ Jane Y. Schweiger
                                                 ----------------------------
                                                   Name: Jane Y. Schweiger
                                                        ---------------------
                                                   Title: Corporate Trust
                                                          Officer
                                                         --------------------