<PAGE>   1
                                                                   EXHIBIT 10.19

                          AGREEMENT AND PLAN OF MERGER

         This Agreement and Plan of Merger, dated as of December 20, 1995, is
by and between Ultrak, Inc., a Colorado corporation ("Parent"), and Exxis
Technologies, Inc., a Texas corporation ("Exxis").

                                  WITNESSETH:

         WHEREAS, the authorized capital stock of Exxis consists of 1,000,000
shares of Common Stock, $0.01 par value ("Exxis Common Stock"), of which
100,000 shares of Exxis Common Stock are issued and outstanding and owned by
Parent; and

         WHEREAS, the respective boards of directors of Parent and Exxis deem
it to be desirable and in the best interest of the respective corporations that
the corporations merge into a single corporation (the "Merger"), and, pursuant
to resolutions duly adopted, such boards of directors have approved and adopted
this Agreement;

         NOW, THEREFORE, in consideration of the foregoing and of the mutual
agreements and covenants contained herein, the parties hereto agree as follows:

                                   ARTICLE I

         Section 1.1. In accordance with the provisions of the Colorado
Business Corporation Act and the Texas Business Corporation Act at the
Effective Time (as defined below) of the Merger, Exxis shall be merged into
Parent, which shall be the surviving corporation (in its capacity as such
surviving corporation Parent is hereinafter sometimes referred to as the
"Surviving Corporation", and Parent and Exxis are hereinafter sometimes
referred to collectively as the "Constituent Corporations"), and as such the
Surviving Corporation shall continue to be governed by the laws of the State of
Colorado.

         Section 1.2. The Merger shall become effective on the date that
Articles of Merger, executed, adopted and approved in accordance with the
Colorado Business Corporation Act, shall have been filed with the Secretary of
State of Colorado. The time when the Merger shall become effective is herein
called the "Effective Time." The actions described above shall be conclusive
evidence, for all purposes of this Agreement, of compliance with all conditions
precedent.

         Section 1.3. Except as may otherwise be set forth herein, at the
Effective Time, the corporate existence and identity of Parent, with all its
purposes, powers, franchises, privileges, rights and immunities shall continue
under the laws of the State of Colorado, unaffected and unimpaired by the
Merger, and the corporate existence and identity of Exxis with all its
purposes, powers, franchises, privileges, rights and immunities, shall be
merged with and into Parent and the Surviving Corporation shall be vested fully
therewith, and the separate corporate existence and identity of Exxis shall
thereafter cease, except to the extent continued by applicable law. At the
Effective Time, the Surviving Corporation shall have the following rights and
obligations:

                 (a)      The Surviving Corporation shall have all the rights,
         privileges, immunities and powers, and shall be subject to all of the
         duties and liabilities, of a corporation organized under the laws of
         the State of Colorado.
<PAGE>   2
                 (b)      The Surviving Corporation shall succeed to, without
         other transfer, and shall possess and enjoy, all of the rights,
         privileges, immunities, powers, purposes and franchises, of both a
         public and private nature, of the Constituent Corporations and all
         property, real, personal and mixed, and all debts due to either of the
         Constituent Corporations on whatever account and all other choses in
         action, and every other interest of or belonging to either of the
         Constituent Corporations shall be deemed to be transferred to and
         vested in the Surviving Corporation without further act or deed, and
         shall thereafter be the property of the Surviving Corporation as they
         were of the respective Constituent Corporations, and the title to any
         real estate vested by deed or otherwise in either of said Constituent
         Corporations shall not revert or be in any way impaired by reason of
         the Merger.

                 (c)      The Surviving Corporation shall thenceforth be
         responsible and liable for all debts, liabilities, obligations and
         duties of either of the Constituent Corporations, and any claim
         existing or action or proceeding pending by or against either
         Constituent Corporation may be prosecuted as if the Merger had not
         occurred, or the Surviving Corporation may be substituted in its
         place. Neither the rights of creditors nor any liens upon the property
         of either Constituent Corporation shall be impaired by the Merger.

         Section 1.4. If at any time the Surviving Corporation shall deem or be
advised that any further transfers, assignments, conveyances, assurances in law
or other acts or things are necessary or desirable to vest or confirm in the
Surviving Corporation the title to any property or assets of either of the
Constituent Corporations, each Constituent Corporation and its proper officers
and directors shall execute and deliver any and all such proper transfers,
assignments, conveyances and assurances in law, and shall do all other acts and
things as are necessary or proper to vest or confirm title to such property and
assets in the Surviving Corporation and to otherwise carry out the purposes and
intent of this Agreement.

                                   ARTICLE II

         Section 2.1. The Articles of Incorporation of Parent in effect at the
Effective Time shall constitute the Articles of Incorporation of the Surviving
Corporation until amended, altered or repealed in the manner provided by law.

         Section 2.2. The By-Laws of Parent in effect at the Effective Time
shall be the By-Laws of the Surviving Corporation, until amended, altered or
repealed.

         Section 2.3. The directors of Parent at the Effective Time shall be
the directors of the Surviving Corporation and shall hold office in accordance
with the By-Laws of the Surviving Corporation until the next annual meeting of
shareholders of the Surviving Corporation or until their respective successors
are elected and qualified.

         Section 2.4. The officers of Parent at the Effective Time shall be the
officers of the Surviving Corporation and shall hold office subject to the
By-Laws of the Surviving Corporation.

                                   ARTICLE III

         Section 3.1. At the Effective Time, each share of Exxis Common Stock
outstanding immediately prior to the Effective Time shall by virtue of the
Merger and without any action on the part of the holder thereof be canceled.




                                      2
<PAGE>   3
                                   ARTICLE IV

         Section 4.1. This Agreement may be executed by the parties hereto in
counterparts, each of which when so executed and delivered shall be an
original, but all of which shall constitute one instrument.

         Section 4.2. Subject to applicable law, this Agreement may be amended,
modified or supplemented only by written agreement of Parent and Exxis at any
time prior to the Effective Time.

         Section 4.3. This Agreement may be terminated at any time prior to the
Effective Time by mutual agreement of the parties hereto.

         IN WITNESS WHEREOF, each of the Constituent Corporations has caused
this Agreement to be executed on its behalf by its respective officers hereunto
duly authorized as of the date first above written.



                                        ULTRAK, INC.,
                                        a Colorado corporation



                                        By: /s/ GEORGE K. BROADY
                                            ------------------------------------
                                            George K. Broady, President



                                        EXXIS TECHNOLOGIES, INC.
                                        a Texas corporation



                                        By: /s/ GEORGE K. BROADY
                                            ------------------------------------
                                            George K. Broady, President




                                      3