Document:

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                                                                    Exhibit 10.1

                                 AMENDMENT NO. 4
                   TO AMTC CORPORATION STOCK OPTION AGREEMENT

     This Amendment No. 4 is entered into as of March 1, 2002, between David P.
Cook ("Cook") and ZixIt Corporation, a Texas corporation ("ZixIt"). Reference is
made to that certain AMTC Corporation Stock Option Agreement, effective as of
April 29, 1998, as amended, between Cook and ZixIt (the "Cook Option").

1.   Amendments.  The Cook Option is amended to delete "2,375,277" from Section
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1 and substitute in its place "1,308,610." (Note: 1,308,610 shares is the number
of shares covered by the Cook Option after giving effect to all previous
re-allocations of option shares by Mr. Cook. Furthermore, giving effect to the
March 2000 option exercise and all previous re-allocations by Mr. Cook, the
number of option shares remaining under the Cook Option is 1,056,910.)

2.   No Other Changes.  Other than as provided herein, the Cook Option shall
     ----------------
remain in full force and effect.

     Executed on the dates set forth below, to be effective as of the date first
set forth above.

                                         ZIXIT CORPORATION

                                         By:     /s/ Steve M. York
                                                 -------------------------------
                                                  Steve M. York,
                                                  Senior Vice President

                                         Date:     4-1-02
                                                 -------------------------------

                                         /s/ David P. Cook
                                         ---------------------------------------
                                         David P. Cook

                                         Date:      4-1-02
                                                  ------------------------------

                                         /s/ Cheryl G. Cook
                                         ---------------------------------------
                                         Cheryl G. Cook

                                         Date:      4-1-02
                                                  ------------------------------<PAGE>

                                                                    Exhibit 10.2

                               SEVERANCE AGREEMENT
                               -------------------

     THIS SEVERANCE AGREEMENT (this "Agreement"), entered into as of January 31,
2002, is made and entered into between ZixIt Corporation, a Texas corporation
(the "Company"), and _____________________ ("Employee").

     WHEREAS, Employee is currently employed by the Company;

     WHEREAS, Employee is willing to continue working for the Company or an
Affiliate, as applicable, on an "at-will" basis, if applicable;

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

1.   Definitions.
     -----------

     1.1  Acquiring Person. An "Acquiring Person" shall mean any person
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(including any "person" as such term is used in Sections 13(d)(3) or 14(d)(2) of
the Securities Exchange Act of 1934, as amended (the "Exchange Act")) that,
together with all Affiliates and Associates of such person, is the beneficial
owner of 35% or more of the outstanding Common Stock of the Company. The term
"Acquiring Person" shall not include the Company, any subsidiary of the Company,
any employee benefit plan of the Company (or trust with respect thereto) or
subsidiary of the Company, or any person holding Common Stock of the Company for
or pursuant to the terms of any such plan. For purposes of this Agreement, a
person who becomes an Acquiring Person by acquiring beneficial ownership of 35%
of more of the Common Stock at any time after the date of this Agreement shall
continue to be an Acquiring Person whether or not such person continues to be
the beneficial owner of 35% or more of the outstanding Common Stock.

     1.2  Affiliate and Associate. "Affiliate" and "Associate" shall have the
          -----------------------
respective meanings ascribed to such terms in Rule 12b-2 of the General Rules
and Regulations under the Exchange Act in effect on the date of this Agreement.

     1.3  Cause. For "Cause" shall mean any of the following shall have
          -----
occurred:

          (a) The conviction of Employee of any felony;

          (b) The intentional and continued failure by Employee to substantially
     perform Employee's employment duties, such intentional action involving
     willful and deliberate malfeasance or gross negligence in the performance
     of Employee's duties (other than any such failure resulting from Employee's
     incapacity due to physical or mental illness), after written demand for
     substantial performance, such demand not to be unreasonable, is delivered
     by the Company or an Affiliate, as applicable, that specifically identifies
     the manner in which the Company or the Affiliate, as applicable, believes
     Employee has not substantially performed Employee's duties and which
     continues

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     beyond a period of 10 business days immediately after notice thereof by the
     Company to Employee;

          (c) The intentional wrongdoing by Employee that is materially
     injurious to the Company or employing Affiliate, as applicable; or

          (d) Acts by Employee of moral turpitude that are injurious to the
     Company.

     For purposes of this definition, no act, or failure to act, on the part of
Employee shall be deemed to be "intentional" unless done, or omitted to be done,
by Employee not in good faith and without reasonable belief that Employee's
action or omission was in the best interests of the Company or the employing
Affiliate, or both, as applicable.

     1.4  Change in Control. A "Change in Control" of the Company shall have
          -----------------
occurred if at any time during the term of this Agreement any of the following
events shall occur:

          (a) The Company is merged, consolidated or reorganized into or with
     another corporation or other legal person, other than an Affiliate, and as
     a result of such merger, consolidation or reorganization less than 50.1% of
     the combined voting power to elect directors of the then-outstanding
     securities of the remaining corporation or legal person or its ultimate
     parent immediately after such transaction is owned, directly or indirectly,
     in the aggregate by persons who were shareholders, directly or indirectly,
     of the Company immediately prior to such merger, consolidation, or
     reorganization;

          (b) The Company sells all or substantially all of its assets to any
     other corporation or other legal person, other than an Affiliate, and as a
     result of such sale, less than 50.1% of the combined voting power to elect
     directors of the then-outstanding securities of such corporation or legal
     person or its ultimate parent immediately after such transaction is owned,
     directly or indirectly, in the aggregate by persons who were shareholders,
     directly or indirectly, of the Company immediately prior to such sale;

          (c) Any Acquiring Person has become the beneficial owner (as the term
     "beneficial owner" is defined under Rule 13d-3 or any successor rule or
     regulation promulgated under the Exchange Act) of securities which when
     added to any securities already owned by such person would represent in the
     aggregate 35% or more of the then-outstanding securities of the Company
     which are entitled to vote to elect directors;

          (d) If, at any time, the Continuing Directors then serving on the
     Board of Directors of the Company ("Board") cease for any reason to
     constitute at least a majority thereof;

          (e) Any occurrence that would be required to be reported in response
     to Item 6(e) of Schedule 14A of Regulation 14A or any successor rule or
     regulation promulgated under the Exchange Act; or

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          (f) Such other events that cause a change in control of the Company,
     as determined by the Board in its sole discretion.

     1.5  Change in Control Payments. "Change in Control Payments" shall mean
          --------------------------
six (6) months of base salary utilizing the higher of (i) Employee's annual base
salary in effect on the date of the Change in Control or (ii) Employee's highest
annual base salary during the term of Employee's employment with the Company.

     1.6  Continuing Director. A "Continuing Director" shall mean a director of
          -------------------
the Company who (i) is not an Acquiring Person, an Affiliate or Associate, a
representative of an Acquiring Person or nominated for election by an Acquiring
Person, and (ii) was either a member of the Board on the date of this Agreement
or subsequently became a director of the Company and whose initial election or
initial nomination for election by the Company's shareholders was approved by a
majority of the Continuing Directors then on the Board.

     1.7  Good Reason. "Good Reason" shall mean the occurrence of the following
          -----------
event:

          (a) a cumulative reduction of more than 10% based on Employee's
     highest annual base salary during the term of Employee's employment with
     the Company.

     EXAMPLE: Assume Employee's base salary is $100,000. The Company or
     -------
     Affiliate, as applicable, is permitted to reduce Employee's base salary by
     up to 10% ($10,000) without giving Employee "Good Reason" to terminate
     employment. Any further salary reductions would constitute "Good Reason" to
     terminate employment. Assume that in the example, that the Company or
     Affiliate had reduced the $100,000 salary to $92,000. Later, the Employee
     is given a new salary of $120,000. The Company or Affiliate is then
     entitled to reduce the $120,000 salary by up to $12,000 without entitling
     Employee to "Good Reason", even though the earlier lower salary had been
     reduced by $8,000.

     1.8  Person. A "Person" shall mean an individual, a corporation, a
          ------
partnership, an association, a joint-stock company, a trust, an incorporated
organization or a government or political subdivision thereof.

     1.9  Severance Payment. The "Severance Payment" shall be an amount equal to
          -----------------
six (6) months of base salary utilizing Employee's highest annual base salary
during the term of Employee's employment with the Company; provided that, if the
                                                           -------------
event giving rise to the Severance Payment occurs on or before the 180th day
following a Change in Control (with the day immediately following the day of the
occurrence of the Change in Control being day "1"), then the amount of the
Severance Payment shall be the amount provided for in Sections 1.5 and 3 (as if
Employee had resigned from employment pursuant to Section 3).

2.   Severance Payment.
     -----------------

     2.1  From and after the date hereof, upon the occurrence of either of the
following events, and subject to receiving a release reasonably satisfactory to
the Company relating to

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employment matters, the Company will pay to Employee the Severance Payment (in
accordance with Section 4):

          (a) Employee's employment with the Company or an Affiliate, as
     applicable, is terminated by the Company or the employing Affiliate other
     than for Cause; or

          (b) Employee has Good Reason to terminate employment and actually does
     so within 30 days of the event in question.

     2.2  To terminate Employee's employment other than for Cause pursuant to
Subsection 2.1(a), the Company or the employing Affiliate, as applicable, shall
give Employee a written notice of termination setting forth in reasonable detail
the facts and circumstances claimed to provide a basis for termination of
Employee's employment. Such notice shall be effective 30 days following the
Employee's receipt thereof.

3.   Change in Control Payment. If Employee resigns from employment with the
     -------------------------
Company or its Affiliates on or before the 180th day following a Change in
Control (with the day immediately following the day of the occurrence of the
Change in Control being day "1"), the Company shall pay to Employee the Change
in Control Payment (in accordance with Section 4).

4.   Mode of Payment; Acceptance. The Severance Payment and the Change in
     ---------------------------
Control Payment shall be paid in a lump sum (less applicable withholdings for
taxes and other withholdings required by applicable law) within 30 days of the
occurrence of the applicable event. The Company's obligation to pay the
Severance Payment and the Change in Control Payment is absolute, and such
payments shall not be mitigated or offset by virtue of Employee obtaining new
employment or failing to seek new employment. Acceptance by Employee of the
Severance Payment shall constitute a release by Employee of the Company and its
Affiliates, shareholders, officers, employees, directors and other agents from
all claims arising out of, relating to, or in connection with Employee's
employment with the Company.

5.   Miscellaneous.
     -------------

     5.1  Dispute Resolution. Employee and the Company acknowledge that Employee
          ------------------
has, or may have, previously executed a Mutual Alternate Dispute Resolution
Agreement. The provisions of such Mutual Alternate Dispute Resolution Agreement
shall govern any disputes arising under this Agreement.

     5.2  Confidential Information. Employee and the Company acknowledge that
          ------------------------
Employee has previously executed a Confidentiality and Invention Agreement which
is incorporated herein by reference and shall survive Employee's separation from
employment in accordance with its terms.

     5.3  Notice. All notices and other communications provided for in this
          ------
Agreement shall be in writing and shall be deemed to have been received on the
date delivered, if personally delivered, or the date received after being mailed
by United States registered or certified mail, return receipt requested, postage
prepaid, addressed to the applicable party at the address for such party set
forth below or at such other address as such party may designate by like notice:

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     Employee:

     ---------------------------

     ---------------------------

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     The Company:

          ZixIt Corporation
          2711 North Haskell Avenue, Suite 2850, LB 36
          Dallas, Texas 75204-2911
          Attn:    CEO

     5.4  Successors; Binding Agreement. This Agreement will be binding upon and
          -----------------------------
inure to the benefit of the parties hereto and any successors in interest to the
Company following a Change in Control. This Agreement and all rights of
Employees hereunder shall inure to the benefit of and be enforceable by
Employee's personal or legal representatives, executors, administrators,
successors, heirs, distributes, devisees and legatees.

     5.5. Entire Agreement; Modifications. This Agreement does not supersede any
          -------------------------------
employment agreement, stock option agreement or other employment-related
agreement that may be in effect at the time this Agreement is executed. Only an
instrument in writing executed by both parties may amend this Agreement. No
waiver by either party hereto of, or compliance with, any condition or provision
of this Agreement to be performed by such other party shall be deemed a waiver
of similar or dissimilar provisions or conditions at the same or at any prior or
subsequent time.

     5.6  Validity. The invalidity or unenforceability of any provision or
          --------
provisions of this Agreement shall not affect the validity or enforceability of
any other provision of this Agreement, which shall remain in full force and
effect.

     5.7  Enforcement Fees. In the event of a dispute arising under this
          ----------------
Agreement, unless otherwise agreed by the parties in writing, each party shall
pay its own costs and expenses in resolving the dispute.

     5.8  Governing Law. This Agreement shall be governed by and construed in
          -------------
accordance with the laws of the State of Texas (excluding its conflict of laws
rules).

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     IN WITNESS WHEREOF, the parties have executed this Agreement effective on
the date and year first above written.

                                ZIXIT CORPORATION

                                By:_______________________________________
                                             John A. Ryan,
                                           Chairman and CEO

                                EMPLOYEE

                                __________________________________________

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