Document:

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                                                                   Exhibit 10.56

                  TERMINATION OF STOCKHOLDERS' VOTING AGREEMENT

      The undersigned, Viacom Inc., a Delaware corporation (successor to CBS
corporation, a Pennsylvania corporation) (the "Purchaser"), ePresence, Inc., a
Massachusetts corporation, (formerly Banyan Systems Incorporated, a
Massachusetts corporation) ("ePresence), and Switchboard Incorporated, a
Delaware corporation (the "Company"), hereby agree that the Stockholders' Voting
Agreement dated as of June 30, 1999 by and among the undersigned is hereby
terminated in its entirety and shall have no further force or effect, effective
as of January 1, 2001.

      ePresence agrees that if ePresence transfers shares of capital stock of
the Company held by it such that, after giving effect to such transfer,
ePresence's indemnification obligations under Section 8 of the Common Stock and
Warrant Purchase Agreement by and among the undersigned dated as of June 1, 1999
(the "Purchase Agreement") would have terminated as a result of such transfer
pursuant to Section 8.4(b)(y) of the Purchase Agreement, ePresence's
indemnification obligations pursuant to Section 8 shall nonetheless continue in
full force and effect in accordance with the terms of Section 8 and subject to
Section 8.4(b)(x), notwithstanding Section 8.4(b)(y).

      Executed as of January 1, 2001.

                                     Viacom Inc.

                                     By: /s/ Fredrik G. Reynolds
                                         -------------------------------
                                         Name: Fredrik G. Reynolds
                                         Title: Executive Vice President
                                         & Chief Financial Officer

                                     ePresence, Inc.

                                     By: /s/ Richard M. Spaulding
                                         -------------------------------
                                         Name: Richard M. Spaulding
                                         Title: Senior Vice President &
                                         Chief Financial Officer

                                     Switchboard Incorporated

                                     By: /s/ Douglas Greenlaw
                                         -------------------------------
                                         Name: Douglas Greenlaw
                                         Title: Chief Executive Officer<PAGE>
                                                                   Exhibit 10.57

                                PRESENCE, INC.
                     NON-QUALIFIED STOCK OPTION AGREEMENT
                     ------------------------------------

1.  Grant of Options. ePresence, Inc. , a Massachusetts corporation (the
    "Company"), hereby grants to William P. Ferry (the "Optionee"), an option,
    pursuant to the Company's 1992 Stock Incentive Plan (the "Plan"), to
    purchase an aggregate of 300,000 shares of Common Stock ("Common Stock") of
    the Company at a price of $5.81 per share, purchasable as set forth in and
    subject to the terms and conditions of this option and the Plan. The date of
    grant of this option is January 25, 2001. Except where the context otherwise
    requires, the term "Company" shall include the parent and all present and
    future subsidiaries of the Company as defined in Sections 424(e) and 424(f)
    of the Internal Revenue Code of 1986, as amended or replaced from time to
    time (the "Code").

2.  Non-Qualified Stock Option.  This option is not intended to qualify as
    an incentive stock option within the meaning of Section 422 of the Code.

3.  Exercise of Option and Provisions for Termination.

    a.  Vesting Schedule. This option shall vest and become exercisable equally
        over 16 months at the rate of 18,750 shares per month commencing on
        February 1, 2001 and on the first day of each month thereafter. Except
        as otherwise provided in this Agreement, this option may be exercised
        prior to the tenth anniversary of the date of grant (hereinafter the
        "Expiration Date"). This option may not be exercised at any time on or
        after the Expiration Date. The right of exercise shall be cumulative so
        that if the option is not exercised to the maximum extent permissible
        during any exercise period, it shall be exercisable, in whole or in
        part, with respect to all shares not so purchased at any time prior to
        the Expiration Date or the earlier termination of this option.

    b.  Change in Control. Upon the occurrence of a Change in Control, as
        defined in the February 4, 1997 Employment Agreement, as last amended as
        of November 16, 2000, between the Company and the Employee (the
        "Employment Agreement"), this option shall become vested and exercisable
        as to 100% of the number of shares covered hereby that would not
        otherwise then be vested and exercisable as provided for in Section 8(b)
        of the Employment Agreement.

    c.  Certain Events.  The vesting of this option shall also be subject
        to continuation in accordance with the provisions of Section 5 of the
        Employment Agreement.
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    d.  Exercise Procedure. Subject to the conditions set forth in this
        Agreement, this option shall be exercised by the Optionee's delivery of
        written notice of exercise to the Treasurer of the Company, specifying
        the number of shares to be purchased and the purchase price to be paid
        therefore and accompanied by payment in full in accordance with Section
        4 hereof.

    e.  Continuous Employment Required. Except as otherwise provided in this
        Section 3, this option may not be exercised unless Optionee, at the time
        he exercises this option, is, and has been at all times since the date
        of grant of this option, an employee of the Company. For all purposes of
        this option, (i) "employment" shall be defined in accordance with the
        provisions of Section 1.421-7(h) of the Income Tax Regulations or any
        successor regulations, and (ii) if this option shall be assumed or a new
        option substituted therefore in a transaction to which Section 424(a) of
        the Code applies, employment by such assuming or substituting
        corporation (hereinafter called the "Successor Corporation") shall be
        considered for all purposes of this option to be employment by the
        Company.

    f.  Exercise Period Upon Termination of Employment. If the Optionee ceases
        to be employed by the Company for any reason, then, except as provided
        in paragraphs (g) and (h) below, the right to exercise this option shall
        terminate three months after the later of cessation of employment or
        cessation of vesting (but in no event after the Expiration Date),
        provided that this option shall be exercisable only to the extent that
        the Optionee was entitled to exercise this option on the date of such
        cessation. The Company's obligation to deliver shares upon the exercise
        of this option shall be subject to the satisfaction of all applicable
        federal, state and local income and employment tax withholding
        requirements, arising by reason of this option being treated as a non-
        statutory option or otherwise.

    g.  Exercise Period Upon Death or Disability. If the Optionee dies or
        becomes disabled (within the meaning of Section 22(e)(3) of the Code)
        prior to the Expiration Date while he is an employee of the Company, or
        if the Optionee dies within three months after the Optionee ceases to be
        an employee of the Company (other than as a result of a discharge for
        "cause" as specified in paragraph (h)

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        below), this option shall become exercisable within the period of one
        year following the date of death or disability of the Optionee (but in
        no event after the Expiration Date), by the Optionee or by the person to
        whom this option is transferred by will or the laws of descent and
        distribution. Notwithstanding the immediately preceding sentence, if the
        Optionee dies or becomes disabled during a vesting continuation period
        under Paragraph 3 (c) above and prior to the Expiration Date, this
        option shall become exercisable within the period of one year following
        the cessation of such vesting (but in no event after the Expiration
        Date) as to only such options that become exercisable by the Optionee
        during such vesting continuation period, by the Optionee or by the
        person to whom this option is transferred by will or the laws of descent
        and distribution. This option shall be exercisable only to the extent
        that this option was exercisable by the Optionee on the date of his
        cessation of employment and/or cessation of vesting, as the case may be.
        Except as otherwise indicated by the context, the term "Optionee", as
        used in this option, shall be deemed to include the estate of the
        Optionee or any person who acquires the right to exercise this option by
        bequest or inheritance or otherwise by reason of the death of the
        Optionee.

    h.  Exercise Period Upon Discharge for Cause. If the Optionee, prior to the
        Expiration Date, ceases his employment with the Company because he is
        discharged for "cause" (as defined in Section 5 (b) (1) and 5 (b) (2) of
        the Employment Agreement), the right to exercise this option shall
        terminate 30 days after such cessation of employment.

4.  Payment of Purchase Price.

    a.  Method of Payment. Payment of the purchase price for shares purchased
        upon exercise of this option shall be made by delivery of cash or check
        in the amount equal to the exercise price of such options or, with the
        prior consent of the Company (which may be withheld in its sole
        discretion), by (A) delivery of shares of Common Stock owned by the
        Optionee for at least six months, valued at their fair market value, as
        determined in (b) below, (B) delivery of a promissory note of the
        Optionee to the Company on terms determined by the Compensation
        Committee of the Company's Board of Directors (the "Compensation
        Committee") (C) delivery of an irrevocable undertaking by a broker to
        deliver promptly to the Company sufficient funds to pay the exercise
        price or delivery of irrevocable instructions to a broker to deliver

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        promptly to the Company cash or a check sufficient to pay the exercise
        price, (D) payment of such other lawful consideration as the
        Compensation Committee may determine, or (E) any combination of the
        foregoing.

    b.  Valuation of Shares or Other Non-Cash Consideration Tendered in Payment
        of Purchase Price. For the purposes hereof, the fair market value of any
        share of the Company's Common Stock or other non-cash consideration
        which may be delivered to the Company in exercise of this option shall
        be determined in good faith or in the manner determined by the
        Compensation Committee from time to time.

    c.  Delivery of Shares Tendered in Payment of Purchase Price. If the
        Optionee exercises options by delivery of shares of Common stock of the
        Company, the certificate or certificates representing the shares of
        Common Stock of the Company to be delivered shall be duly executed in
        blank by the Optionee or shall be accompanied by a stock power duly
        executed in blank suitable for purposes of transferring such shares to
        the Company. Fractional shares of Common Stock of the Company will not
        be accepted in payment of the purchase price of shares acquired upon
        exercise of this option.

    d.  Restrictions on Use of Option Stock. Notwithstanding the foregoing, no
        shares of Common Stock of the Company may be tendered in payment of the
        purchase price of shares purchased upon exercise of this option if the
        shares to be so tendered were acquired within six months before the date
        of such tender through the exercise of this option or any other stock
        option or restricted stock agreement.

5.  Delivery of Shares; Compliance with Securities Laws, etc. The Company will
    not be obligated to deliver any shares of Common Stock or to remove
    restrictions from shares previously delivered (i) until all conditions of
    the option have been satisfied or removed, (ii) until, in the opinion of
    Company's counsel, all applicable federal and state laws and regulations
    have been complied with, (iii) if the outstanding Common Stock is at the
    time listed on any stock exchange, until the shares to be delivered have
    been listed or authorized to be listed on such exchange upon official notice
    of notice of issuance, and (iv) until all other legal matters in connection
    with the issuance and delivery of such shares have been approved by the
    Company's counsel.

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6.  Non-transferability of Option. This option is personal and no rights granted
    hereunder may be transferred, assigned, pledged or hypothecated in any way
    (whether by operation of law or otherwise) nor shall any such rights be
    subject to execution, attachment or similar process, except that this option
    may be transferred (i) by will or the laws of descent and distribution or
    (ii) pursuant to a qualified domestic relations order as defined in Section
    414(p) of the Code. Upon any attempt to transfer, assign, pledge,
    hypothecate or otherwise dispose of this option or of such rights contrary
    to the provisions hereof, or upon the levy of any attachment or similar
    process upon this option or such rights, this option and such rights shall,
    at the election of the Company, become null and void.

7.  No Special Employment or Similar Rights. Nothing contained in this option
    shall be construed or deemed by any person under any circumstances to bind
    the Company to continue the employment or other relationship of Optionee
    with the Company for the period within which this option may be exercised.

8.  Rights as a Shareholder. The Optionee shall have no rights as a shareholder
    with respect to any shares which may be purchased by exercise of this option
    (including, without limitation, any rights to receive dividends or non-cash
    distributions with respect to such shares) unless and until a certificate
    representing such shares is duly issued and delivered to the Optionee. No
    adjustment shall be made for dividends or other rights for which the record
    date is prior to the date such stock certificate is issued.

9.  Adjustment Provisions. In the event that the Compensation Committee, in its
    sole discretion, determines that any stock dividend, extraordinary cash
    dividend, recapitalization, reorganization, merger, consolidate, split-up,
    spin-off, combination or other similar transaction affects the Common Stock
    such that an adjustment is required in order to preserve the benefits or
    potential benefits intended to be made available under the Plan, then the
    Compensation Committee shall equitably adjust either or both (i) the number
    and kind of shares subject to this option, and (ii) the award, exercise or
    conversion price with respect to the foregoing, and if considered
    appropriate, the Compensation Committee may make provision for a cash
    payment with respect to this option, provided that the number of shares
    subject to this option shall always be a whole number.

10. Mergers, Consolidation, Distributions, Liquidations, etc. Subject to the
    provisions of Section 3(b) above, in the event of a consolidation, merger

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    or other reorganization in which all of the outstanding shares of Common
    Stock are exchanged for securities, cash or other property of any other
    corporation or business entity (an "Acquisition") or in the event of a
    liquidation of the Company, the Board of Directors of the Company, or the
    board of directors of any corporation assuming the obligations of the
    Company, may, in its discretion, take any one or more of the following
    actions as to this option: (i) provide that this option shall be assumed, or
    a substantially equivalent option shall be substituted by the acquiring or
    succeeding corporation (or an affiliate thereof) on such terms as the Board
    determines to be appropriate, (ii) upon written notice to the Optionee,
    provide that if unexercised, this option will terminate immediately prior to
    the consummation of such transaction unless exercised by the Optionee within
    a specific period following the date of such notice, (iii) in the event of
    an Acquisition under the terms of which holders of the Common Stock of the
    Company will receive upon consummation thereof a cash payment for each share
    surrendered in the Acquisition (the "Acquisition Price"), make or provide
    for a cash payment to the Optionee equal to the difference between (A) the
    Acquisition Price times the number of shares of Common Stock subject to
    outstanding options (to the extent then exercisable at prices not in excess
    of the Acquisition Price) and (B) the aggregate exercise price of all such
    outstanding options in exchange for the termination of such options, and
    (iv) provide that all or part of this option shall become exercisable or
    realizable in full prior to the effective date of such Acquisition.

11. Withholding Taxes. The Company's obligation to deliver shares upon the
    exercise of this option shall be subject to the Optionee's satisfaction to
    all applicable federal, state and local income and employment tax
    withholding requirements. The Optionee shall pay to the Company, or make
    provision satisfactory to the Compensation Committee for payment of, any
    taxes required by law to be withheld in respect of options under the Plan no
    later than the date of the event creating the tax liability. In the
    Compensation Committee's discretion, and subject to such conditions as the
    Compensation Committee may establish, such tax obligations may be paid in
    whole or in part in shares of Common Stock, including shares retained from
    the option creating the tax obligation, valued at their fair market value.
    The Company may, to the extent permitted by law, deduct any such tax
    obligations from any payment of any kind otherwise due to the Optionee.

12. Miscellaneous.

    a.  If any terms of this Option Agreement are contrary to or otherwise

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        conflict with the terms of the Employment Agreement, the terms of the
        Employment Agreement shall control.

    b.  All notices under this option shall be mailed or delivered by hand to
        the parties at their respective addresses set forth beneath their names
        below or at such other address as may be designated in writing by either
        of the parties to one another.

    c.  This option shall be governed by and construed in accordance with
        the laws of the Commonwealth of Massachusetts.

                              EPRESENCE, INC.

                              BY: /s/ Richard M. Spaulding
                                 ---------------------------
                                  Richard M. Spaulding
                                  Senior Vice President and
                                  Chief Financial Officer

                                       7
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                             OPTIONEE'S ACCEPTANCE

     The undersigned hereby accepts the foregoing option and agrees to the terms
and conditions hereof.

                              OPTIONEE:

                              /s/ William P. Ferry
                              ---------------------------------
                              William P. Ferry
-
                              Address:    P.O. Box 638
                                          Hyannis, MA  02601-0638

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