Document:

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                                                                    Exhibit 4.10

                             STOCK OPTION AGREEMENT

         THIS STOCK OPTION AGREEMENT (the "Agreement") is dated as of the 31st
day of October, 1999 (the "Grant Date") by and between FIRSTCOM CORPORATION (the
"Grantor" or the "Company") and PATRICIO E. NORTHLAND (the "Optionee").

                               W I T N E S S E T H

         WHEREAS, pursuant to the Agreement and Plan of Merger, dated as of
November 1, 1999, among AT&T Corp., a New York corporation, Kiri Inc., a
Delaware corporation, Frantis, Inc., a Delaware corporation, and the Company
(the "Merger Agreement"), the parties thereto have agreed to enter into the
business combination transaction described therein; and

         WHEREAS, the Optionee has served as Chairman of the Board of Directors,
Chief Executive Officer and President of the Company pursuant to the Executive
Employment and Severance Agreement, dated as of October 7, 1997, between the
Company and the Executive (the "Employment Agreement"); and

         WHEREAS, the parties to the Merger Agreement desire that, following the
"Effective Time" (as defined in the Merger Agreement) the Optionee serve as the
Chief Executive Officer and the President of Kiri, Inc., and the Optionee
desires to so serve, in each case upon the terms and conditions set forth in the
Employment Agreement, dated as of the date hereof, among the Company, Kiri, Inc,
and the Optionee (the "Successor Employment Agreement"); and

         WHEREAS, in consideration of prior services and services to be rendered
by the Optionee to the Grantor, whether or not the transactions contemplated by
the Merger Agreement are consummated, the Grantor desires to grant the Optionee
an option to purchase TWO MILLION TWO HUNDRED THOUSAND (2,200,000) shares of
Common Stock par value $.001 per ("Common Stock"), of the Grantor, upon the
terms and subject to the conditions hereinafter set forth.

         NOW, THEREFORE, the Grantor hereby agrees, for the benefit of the
Optionee, as follows:

SECTION 1. GRANT OF OPTION. Subject to the provisions of this Agreement, the
Grantor hereby grants to the Optionee a non-qualified stock option (the
"Option") (subject to Section 8 hereof) to purchase from the Grantor TWO MILLION
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TWO HUNDRED THOUSAND (2,200,000) shares of Common Stock (after the exercise of
the option and the acquisition of the shares, the "Options Shares"), at the
price of $10.70 per whole share (the "Option Price"). This Option is being
granted pursuant to the FirstCom Corporation 1999 Stock Option and Restricted
Stock Purchase Plan (the "Plan"). Capitalized terms used herein have the meaning
given in the Plan.

SECTION 2. EXERCISE OF OPTION. The Option shall be exercisable commencing as
follows and, unless sooner terminated, shall remain exercisable until the tenth
anniversary hereof (the "Expiration Date"): one-ninth (1/9) on March 1, 2001,
three-ninths (3/9) on each of the second and third anniversaries thereof, and
one-ninth (1/9) on each of the fourth and fifth anniversaries thereof. The
Option may be exercised by the Optionee's delivering to the Grantor a written
notice specifying the number of the Option Shares that the Optionee wishes to
purchase pursuant to the Option and tendering the Option Price multiplied by the
number of such Option Shares. The Option Price of any Option Shares purchased
shall be paid in cash, by certified or official bank check or money order, or by
the Optionee's delivering shares of Common Stock that the Optionee has held for
not less than six months and having a Fair Market Value at the time of exercise
equal to such amount. The Optionee shall be deemed to be a holder of the Option
Shares immediately upon, and to the extent of, the exercise of this Option as
set forth above.

SECTION 3. NUMBER OF SHARES EXERCISABLE. Each exercise of an Option hereunder
shall reduce the total number of Option Shares that may thereafter be purchased
under this Option.

SECTION 4. SHARE CERTIFICATES. Upon each exercise of the right to purchase
Option Shares pursuant to this Option, the Grantor shall cause one or more stock
certificates evidencing the Optionee's ownership of the Option Shares to be
issued to the Optionee, which certificates shall bear such legend or legends as
the Committee may be determine necessary or appropriate.

SECTION 5. ANTI-DILUTION PROVISIONS.

         (a)  ADJUSTMENT FOR RECAPITALIZATION. If the Grantor shall any time
subdivide its outstanding shares of Common Stock by recapitalization,
reclassification or split-up thereof, or if the Grantor shall declare a stock
dividend or distribute shares of Common Stock to its stockholders, the number of
Option Shares then subject to this Option immediately prior to such subdivision
shall be proportionately increased and the exercise price shall be
proportionately decreased, and if the Grantor shall at any time combine the
outstanding shares of Common Stock by

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              recapitalization, reclassification or combination thereof, the
              number of option shares then subject to this Option immediately
              prior to such combination shall be proportionately decreased and
              the exercise price shall be proportionately increased. Any such
              adjustments pursuant to this Section 4(a) shall be effective at
              the close of business on the effective date of such subdivision or
              combination or if any adjustment is the result of a stock dividend
              or distribution then the effective date for such adjustment based
              thereon shall be the record date thereof.

         (b) ADJUSTMENT FOR REORGANIZATION, CONSOLIDATION, MERGER, ETC. In case
of any reorganization of the Grantor or in case the Grantor shall consolidate
with or merge into another corporation or convey all or substantially all of its
assets to another corporation, then, and in each such case, the Optionee upon
the exercise of this Option at any time after the consummation of such
reorganization, consolidation, merger or conveyance, shall be entitled to
receive, in lieu of the Option Shares issuable upon the exercise of this option
prior to such consummation, the securities or properties to which the Optionee
would have been entitled upon such consummation if the Optionee had exercised
this option immediately prior to thereto; in each such case, the terms of this
option shall be applicable to the securities or property receivable upon the
exercise of this Option after such consummation. For the avoidance of doubt,
upon consummation of the transactions contemplated by the Merger Agreement, the
Options will, subject to such adjustments as may be appropriate pursuant to
paragraphs (a) and (b) of this Section, become Options to purchase common stock
of Kiri Inc. and references to the "Company" herein will be deemed to refer to
Kiri Inc.

         (c) NO ADJUSTMENT FOR STOCK ISSUANCES. Except as otherwise expressly
provided herein, the issuance by the Grantor of shares of its capital stock of
any class, or securities convertible into shares of capital stock of any class,
either in connection with the direct sale or upon the exercise of rights or
warrants to subscribe therefore, or upon conversion of shares or obligations of
the Grantor convertible into such shares or other securities, shall not effect
this Option, and no adjustment by reason thereof shall be made with respect to
the number of or exercise price of Option Shares then subject to this Option.

         (d) NO EFFECT ON CORPORATE ACTIONS. Without limiting the generality of
The foregoing, the existence of this Option shall not affect in any manner the
right or power of the Grantor to approve or the Grantor to make, authorize of
consummate (i) any or all adjustments, recapitalizations, reorganizations or
other changes in the Grantor's capital structure or its business; (ii) any
merger or consolidation of the Grantor; (iii) any issuance by the Grantor of
debt securities, or preferred or preference stock that would rank above the
Option Shares subject to outstanding Options; (iv) the dissolution or
liquidation of the Grantor; (v) any sale, transfer or assignment of all or any
part of the assets or business of the Grantor or (vi) any other corporate act or
proceeding, whether of similar character or otherwise.

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SECTION 6. IMMEDIATELY EXERCISE OF OPTION UPON CHANGE IN CONTROL. Except as
otherwise provided herein, each outstanding Option shall become immediately
fully exercisable upon a Change in Control. For these purposes, "CHANGE IN
CONTROL" means the occurrence of any of the following events:

                  (a) the members of the Board at the beginning of any
         consecutive twenty-four calendar month period (the "INCUMBENT
         DIRECTORS") cease for any reason other than due to death to constitute
         at least a majority of the members of the Board, provided that any
         director whose election, or nomination for election by the Company's
         stockholders, was approved by a vote of at least a majority of the
         members of the Board then still in office who were members of the Board
         at the beginning of such twenty-four calendar month period other than
         as a result of a proxy contest, or any agreement arising out of an
         actual or threatened proxy contest, shall be treated as an Incumbent
         Director; or

                  (b) any "person," including a "group" (as such terms are used
         in Sections 13 (d) and 14(d)(2) of the Act), but excluding AT&T Corp.,
         the Company or any of their respective subsidiaries or any employee
         benefit plan thereof, becomes the "beneficial owner" (as defined in
         Rule 13(d)-3 under the Act), directly or indirectly, of securities of
         the Company representing more than 50% of the combined voting power of
         the Company's then outstanding securities, other than pursuant to a
         tender offer or exchange offer initiated by AT&T Corp., the Company or
         any of their respective subsidiaries; or

                  (c) stockholders of the Company shall approve a definitive
         agreement for the merger or other business combination of the Company
         with or into, or the sale or other disposition of all or substantially
         all of the assets of the Company to, another corporation a majority of
         the directors of which were not directors of the Company immediately
         prior to the merger and in which the stockholders of the Company
         immediately prior to the effective date of such merger own a percentage
         of the voting power in such corporation that is less than one-half of
         the percentage of the voting power they owned in the Company
         immediately prior to such a transaction, in each case other than
         pursuant to a tender offer or exchange offer initiated by AT&T Corp.,
         the Company or any of their respective subsidiaries, and provided that
         such transaction shall have been consummated.

For the avoidance of doubt, the consummation of the transactions contemplated by
the Merger Agreement shall not be a Change in Control.

SECTION 7. TERMINATION OF EMPLOYMENT. In the event the Optionee's employment
terminates as a result of his death or "Disability", or the Company terminates
the Optionee's employment without "Cause," or the Executive terminates his
employment for "Good Reason", the Options shall immediately and fully vest. For
purposes of this Agreement, the terms "Disability", "Cause" and "Good Reason"
shall have the meanings given in the Employment Agreement prior to the
consummation of the Merger (as defined in the Merger Agreement), and shall have
the meanings given in the Successor Employment Agreement thereafter.

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SECTION 8. NON-TRANSFERABILITY OF OPTION. Unless otherwise permitted by the
Committee, this Option may not be transferred in any manner other than by will
or by the laws of descent or distribution and may be exercised during the
lifetime of the Optionee only by the Optionee. The terms of this Option
Agreement shall be binding upon the executors, administrators, heirs, successors
and assigns of the Optionee.

SECTION 9.  TERMINATION OF OPTION.  The Option shall terminate under the
following circumstances:

                  (a) The Option shall terminate on the Expiration Date;

                  (b) The Option shall terminate three months after the
         Optionee's termination of employment or ceases to be a director of the
         Company

                  (c) The Option shall terminate immediately if the Executive's
         employment terminates for "Cause"

                  (d) If the Optionee dies or his employment is terminated by
         reason of his Disability before the Option terminates pursuant to
         Section 9(a), 9(b) or 9(c), above, the option shall terminate on the
         earlier of (i) the date on which the Option would have lapsed had the
         Optionee lived (or not become disabled) and had his employment status
         (i.e. whether the Optionee was an employed on the date of his death or
         disability or had previously terminated employment) remained unchanged;
         or (ii) 15 months after the date of the Optionee's death or Disability.
         Upon the Optionee's death, any exercisable Options may be exercised by
         the Optionee's legal representative or representatives, by the person
         or persons entitled to do so under the Optionee's last will and
         testament, or, if the Optionee shall fail to make testamentary
         disposition of the Option or shall die intestate, by the person or
         persons entitled to receive said Option under the applicable laws of
         descent and distribution.

SECTION 10. NO RIGHTS AS SHAREHOLDER. The Optionee shall have no rights as a
shareholder in respect to the Option Shares as to which the Option shall not
have been exercised and payment made as herein provided.

SECTION 11. ISSUANCE OF SHARES. As a condition of any sale or issuance of Option
Shares upon exercise of this option, the Grantor may require such agreements or
undertakings, if any, as the Grantor may deem necessary or advisable to assure
compliance with any such applicable securities or other law or regulation
including, but not limited to, the following:

                  (a) a representation and warranty by the Optionee to the
         Grantor, at the time this Option is exercised, that he is acquiring the
         Option Shares to be issued to him for investment and not with a view

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         to, or for sale in connection with, the distribution of any such Option
         Shares; and

                  (b) a representation, warranty and/or agreement to be bound by
         any legends that are, in the opinion of the Grantor, necessary or
         appropriate to comply with the provisions of any securities law deemed
         by the grantor to be applicable to the issuance of the Option Shares
         and are endorsed upon the Option Share certificates.

SECTION 12.  MISCELLANEOUS PROVISIONS.

                  (a) NOTICES. Unless otherwise specifically provided herein,
all notices to be given hereunder shall be in writing and sent to the parties by
certified mail, return receipt requested, to each party's respective address as
set forth in the books and records of the Grantor, or to such other address as
such party shall give to the other party hereto by a notice given in accordance
with this Section. Except as otherwise provided in this Agreement, notice shall
be effective when deposited in the United States mails properly addressed and
postage prepaid. If such notice is sent other than by the United States mails,
such notice shall be effective when actually received by the party being
notified.

                  (b) ASSIGNMENT. This agreement may not be assigned in whole or
in part by the Optionee except with the consent of the Committee.

                  (c) FURTHER ASSURANCES. The Optionee shall execute and deliver
such other instruments and do such other acts as may be necessary to effectuate
the intent and purposes of this Agreement.

                  (c) CAPTIONS. The captions contained in this Agreement are
inserted only as a matter of convenience and in no way define, limit, extend or
prescribe the scope this Agreement or the intent any of the provisions hereof.

                  (e) COMPLETENESS AND MODIFICATION. This Agreement constitutes
the entire understanding between the parties hereto and supersedes all prior and
contemporaneous agreements or understandings among the parties hereto concerning
the grant by the Grantor to the Optionee of stock options and shall not be
terminated or amended except in writing executed by each of the parties hereto.

                  (f) WAIVER. The waiver of a breach of any term or condition of
this Agreement shall not be deemed to constitute the waiver of any other breach
or the same or any other term or condition.

                  (g) SEVERABILITY. The invalidity or unenforceability in whole
or in part, of any covenant, promise or undertaking, or any section, subsection,
paragraph, sentence, clause, or word or of any provisions of this Agreement
shall not affect the validity or enforceability of the remaining portions
thereof.

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                  (h) CONSTRUCTION. This Agreement shall be governed by and
construed in accordance with the internal laws of the State of Delaware without
regard to any conflict of law rule or principle that would result in the
application of the laws of another jurisdiction.

                  (i) BINDING EFFECT. This Agreement shall be binding upon and
inure to the benefit of the heirs, successors, estate and personal
representatives of the Optionee and the Grantor.

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         IN WITNESS WHEREOF, the Grantor has executed this Agreement for the
benefit of the Optionee as of the date first above written.

                                            GRANTOR:

                                            FIRSTCOM CORPORATION

                                            By: /s/ Douglas G. Geib II
                                                -----------------------------
                                            Name: Douglas G. Geib II
                                            Title: Chief Financial Officer

                                            OPTIONEE:

                                            /s/ Patricio E. Northland
                                            ---------------------------------
                                            Patricio E. Northland

                                       8Exhibit 4.5

                          AMENDMENT TO RIGHTS AGREEMENT

     This  Amendment  (this  "Amendment")  dated as of August 6, 2001 is entered
into  between  Artisoft,  Inc.,  a Delaware  corporation  (the  "Company"),  and
ComputerShare  Investor  Services  (formerly  known as Harris  Trust and Savings
Bank) (the "Rights Agent").

     The Company and BankOne  Arizona,  NA (the "Original Rights Agent") entered
into that certain Rights  Agreement dated as of December 23, 1994 (as amended to
date, the "Rights Agreement").

     The  Original  Rights  Agent  resigned  as rights  agent  under the  Rights
Agreement,  the Company  appointed  the Rights Agent as  successor  rights agent
under the Rights Agreement, and the Rights Agent accepted such appointment,  all
effective as of July 1, 1998.

     The Company now desires to modify certain terms of the Rights Agreement, as
provided  in this  Amendment,  and the Rights  Agent is willing to agree to such
modifications.

     Capitalized  terms used in this  Amendment and not otherwise  defined shall
have the respective meanings ascribed to them in the Rights Agreement.

     NOW, THEREFORE, the parties hereto agree as follows:

     1.  AMENDMENT.  Section 1(a) of the Rights  Agreement is hereby  amended by
deleting  such  Section 1(a) in its entirety and  inserting  the  following  new
Section 1(a) in lieu thereof:

          (a)  "Acquiring  Person" shall mean any Person who or which,  together
     with all Affiliates and Associates of such Person,  shall be the Beneficial
     Owner of 25% or more of the Common Shares then  outstanding,  but shall not
     include the Company,  any Subsidiary of the Company or any employee benefit
     plan of the  Company or of any  Subsidiary  of the  Company,  or any entity
     holding  Common  Shares  for or  pursuant  to the  terms of any such  plan.
     Notwithstanding the foregoing, no Person shall be deemed to be an Acquiring
     Person (i) as the result of an  acquisition of Common Shares by the Company
     which,  by  reducing  the  number  of  shares  outstanding,  increases  the
     proportionate  number of shares beneficially owned by such Person to 25% or
     more of the  Common  Shares  of the  Company  then  outstanding;  PROVIDED,
     HOWEVER,  that if a Person shall become the Beneficial Owner of 25% or more
     of the Common  Shares of the Company  then  outstanding  by reason of share
     purchases  by the  Company  and shall,  after such share  purchases  by the
     Company, become the Beneficial Owner of any additional Common Shares of the
     Company,  then such Person  shall be deemed to be an Acquiring  Person,  or
     (ii) if within  eight days  after such  Person  would  otherwise  become an
     Acquiring  Person (but for the operation of this clause (ii)),  such Person
     notifies the Board of Directors that such Person did so  inadvertently  and
     within two days  after such  notification,  such  Person is the  Beneficial
     Owner of less  than 25% of the  outstanding  Common  Shares,  or (iii) as a
     result of becoming the  Beneficial  Owner of securities  issued or issuable
     pursuant to the terms and provisions of the Purchase Agreement dated August
     8, 2001 between the Company and the  Investors  set forth on the  signature
<PAGE>
     pages thereto or issued or issuable upon conversion or exercise of any such
     securities  (collectively  "Purchase  Agreement  Securities"),  unless,  in
     addition to such Purchase  Agreement  Securities,  such Person  becomes the
     Beneficial Owner of other outstanding Common Shares of the Company.

     2. Section 1(k) of the Rights  Agreement is hereby amended by deleting such
Section 1(k) in its entirety and  inserting  the  following  new Section 1(k) in
lieu thereof:

          (k) "Final Expiration Date" shall mean December 31, 2001.

     3. Exhibit B to the Rights Agreement,  the Form of Rights  Certificate,  is
hereby  amended by changing the date  "December 26, 2004" to "December 31, 2001"
each time it appears in such Exhibit.

     4. Exhibit C to the Rights Agreement,  the Stockholder  Rights Plan Summary
of Rights,  is hereby  amended  by  changing  the date  "December  26,  2004" to
"December 31, 2001" each time it appears in such Exhibit.

     5. EFFECT ON RIGHTS.  Each Right  heretofore or hereafter  issued under the
Rights Agreement (as amended and in effect from time to time) shall be deemed to
be amended in accordance with this Amendment.

     6.  CONTINUING  EFFECT.  Except as modified by this  Amendment,  the Rights
Agreement  and all Rights  heretofore  or hereafter  issued  shall  continue and
remain in full force and effect.

     7.  GOVERNING  LAW.  This  Amendment  shall be governed by and construed in
accordance with the laws of the State of Delaware  applicable to contracts to be
made and performed entirely within such State.

     8.  COUNTERPARTS.   This  Amendment  may  be  executed  in  any  number  of
counterparts and each of such  counterparts  shall for all purposes be deemed to
be an original,  and all such counterparts shall together constitute but one and
the same instrument.

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     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
duly executed as of the day and year first above written.

                                      ARTISOFT, INC.

                                      By: /s/ Michael J. O'Donnell
                                          -------------------------------
                                          Name:  Michael J. O'Donnell
                                          Title: Chief Financial Officer

                                      COMPUTERSHARE INVESTOR SERVICES,
                                      as Rights Agent

                                      By: /s/ Kenneth J. Vlk
                                          -------------------------------
                                          Name:  Kenneth J. Vlk
                                          Title: Relationship Manager

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