<PAGE>

                                                                     Exhibit 4.6
                         VOTING AND TAG ALONG AGREEMENT

      This Voting AND TAG ALONG Agreement (this "Agreement") is made and entered
into as of April 11, 2000, by and among the persons whose names are set forth on
the attached Schedule I (collectively, the "Investors") and Richard T. Aab
("Aab"), Melrich Associates, L.P., a New York limited partnership ("Melrich"),
Tansukh V. Ganatra ("Ganatra") and Super STAR Associates Limited Partnership, a
Georgia limited partnership ("Super STAR"). Aab, Melrich, Ganatra and Super STAR
are collectively referred to herein as the "Class B Stockholders."

                              STATEMENT OF PURPOSE

      A. The Class B Stockholders own and hold of record the following shares of
Class B Common Stock, par value $0.01 per share ("Class B Common Stock"), issued
by US LEC Corp., a Delaware corporation (the "Company"), which constitute all of
the issued and outstanding shares of Class B Common Stock:

                    Class B                              Number
                    Stockholders                       of Shares
                    -----------------------          ---------------

                    Aab                                 8,480,770
                    Melrich                             4,309,500
                    Ganatra                               294,000
                    Super STAR                          3,750,000
                                                       ----------
                      Total                            16,834,270
                                                       ==========

      B. The Class B Stockholders have entered into a Second Amended and
Restated Stockholders Agreement, of even date herewith (the "Stockholders
Agreement"), pursuant to which, among other things, Melrich, Ganatra and Super
STAR (i) agreed to vote all of their shares of Class B Common Stock in the same
manner as Aab and (ii) granted to Aab an irrevocable proxy, with full power of
substitution, for and on their behalf to attend all meetings of stockholders of
the Company and to act, vote and execute consents with respect to all of their
shares of Class B Common Stock, which proxy continues in full force and effect
for the period specified in the Stockholders Agreement (the "Irrevocable
Proxy").

      C. The Board of Directors of the Company has designated a new series of
Series A Convertible Preferred Stock (the "Preferred Stock") pursuant to a
Certificate of Designation (the "Designation") amending the Company's Restated
Certificate of Incorporation (as so amended and as further amended from time to
time, the "Restated Certificate").

      D. Concurrently with the execution of this Agreement, the Company and the
Investors are entering into a Preferred Stock Purchase Agreement (the "Purchase
Agreement") which provides for (i) the purchase by the Investors of an aggregate
of 200,000 shares of the Preferred Stock, (ii) the issuance of an option to the
Investors (the "Option") to purchase up to an aggregate of 100,000 shares of the
Company's Series B Convertible Preferred Stock (the "Option Preferred Stock")
having the terms set forth in the Series B Certificate of Designation (the
"Option Designation") attached as an exhibit to the Option Agreement (as defined
in the Purchase Agreement) and (iii) a Corporate Governance Agreement which
obligates the

<PAGE>

Company to take certain actions in connection with the Purchase Agreement (the
"Corporate Governance Agreement").

      E. Shares of the Preferred Stock and shares of Option Preferred Stock,
when issued under the Option Agreement, will be convertible into shares of the
Company's Class A Common Stock, par value $.01 per share ("Class A Common
Stock"). "Common Stock" means any Class A Common Stock, Class B Common Stock or
any other class of common stock created by the Company. "Subject Common Stock"
means any Common Stock now or hereafter held by the Class B Stockholders.

      F. As an inducement to the Investors to enter into the Purchase Agreement,
the Class B Stockholders are willing to enter into and be bound by this
Agreement pursuant to which, among other things, the Class B Stockholders grant
to the Investors, certain tag-along rights and voting agreements with respect to
the shares of Subject Common Stock upon the terms set forth herein.

      NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, and intending to be legally bound
hereby, the parties hereby agree as follows:

      1. Representations, Warranties and Covenants of the Class B Stockholders.
The Class B Stockholders hereby represent, warrant and covenant to the Investors
as follows:

            (a) Ownership of and Proxy Held With Respect to the Class B Shares.
      Aab owns and holds of record 8,480,770 shares of Class B Common Stock and
      holds an irrevocable proxy with respect to the 4,309,500 shares of Class B
      Common Stock owned and held of record by Melrich, 294,000 shares of Class
      B Common Stock owned and held of record by Ganatra and 3,750,000 shares of
      Class B Common Stock owned and held of record by Super STAR.

            (b) Authority; No Conflict. This Agreement has been duly executed
      and delivered by the Class B Stockholders and constitutes the legal, valid
      and binding obligation of each of them, enforceable against each of them
      in accordance with its terms, except as limited by (i) applicable
      bankruptcy, insolvency, reorganization, moratorium and other laws of
      general application affecting enforcement of creditors' rights generally
      and (ii) general principles of equity, regardless of whether asserted in a
      proceeding in equity or at law. Neither the execution and delivery of this
      Agreement nor the performance by the Class B Stockholders of the
      obligations contemplated hereby will result in a violation of, or a
      default under, or conflict with, any contract, trust, commitment,
      agreement, understanding, arrangement or restriction of any kind to which
      a Class B Stockholder is a party or bound or to which the shares of
      Subject Common Stock are subject. Performance by the Class B Stockholders
      of the obligations contemplated hereby will not violate, or require any
      consent, approval, or notice under, any provision of any judgment, order,
      decree, statute, law, rule or regulation applicable to the Class B
      Stockholders or the shares of Subject Common Stock.


                                       2

<PAGE>

            (c) Investors' Reliance. The Class B Stockholders understand and
      acknowledge that the Investors are entering into the Purchase Agreement in
      reliance upon the Class B Stockholders' execution and delivery of this
      Agreement.

      2. Additional Documents

      The Class B Stockholders hereby covenant and agree to execute and deliver
any additional documents necessary or desirable, in the reasonable opinion of
the Investors, to carry out the intent of this Agreement.

      3. Agreement to Vote For Directors

            (a) If, pursuant to the Restated Certificate, the Class B
      Stockholders are authorized to vote on a proposal to elect one or more
      Investor Directors (as defined in the Corporate Governance Agreement)
      presented at any meeting of stockholders of the Company, the Class B
      Stockholders shall vote each share of Subject Common Stock as to which
      they hold voting power in favor of the election of any Investor Director
      at such meeting and any adjournment thereof.

            (b) If, pursuant to the Restated Certificate, the Class B
      Stockholders are authorized to vote on a proposal to elect one or more
      persons as directors to the Board (as defined in the Corporate Governance
      Agreement) presented at any meeting of stockholders of the Company called
      upon (i) the exercise by the Investor Agents (as defined in the Corporate
      Governance Agreement) of a remedy they are entitled to exercise pursuant
      to Section 3.4 of the Corporate Governance Agreement, or (ii) the exercise
      by the Permitted Owners (as defined in the Corporate Governance Agreement)
      of any rights they are entitled to exercise under Section 5 of the
      Designation and the Option Designation, the Class B Stockholders shall
      vote each share of Subject Common Stock as to which they hold voting power
      in favor of the election of such persons as directors as may be designated
      or nominated by the Investor Agents or Permitted Owners, as applicable
      (including any Investor Directors as defined in the Corporate Governance
      Agreement); provided that the Class B Stockholders shall not be required
      to vote their shares of Subject Common Stock in favor of more than such
      number of persons so designated or nominated who, upon their election,
      would then constitute (together with any incumbent Investor Directors) a
      majority of the members of the Board.

            4. Potential Change of Control Transfers

            The Class B Stockholders agree not to Transfer for value any shares
of Subject Common Stock if, as a result of such Transfer, a Change of Control
(as defined in the Designation and the Option Designation) would occur unless
either (i) the outstanding shares of Preferred Stock and Option Preferred Stock
have been converted into Class A Common Stock prior to such Change of Control or
(ii) the Company is legally able, and has the resources necessary, to comply
with the provisions of Section 5.1(b) of the Designation and the Option
Designation upon the exercise by the holders of Preferred Stock and Option
Preferred Stock of their rights to require the Company to redeem the Preferred
Stock and Option Preferred Stock.


                                       3

<PAGE>

            5. Tag Along Rights

            No Class B Stockholder (each such stockholder, a "Prospective
Selling Class B Stockholder") shall Transfer for value (a "Sale") any shares of
Common Stock ("Shares") to any Person (a "Prospective Buyer") except in
compliance with this Section 5. Any attempted Sale of Shares not in compliance
with this Section 5 shall be null and void, and the Company shall not in any way
give effect to any such impermissible Sale.

            (a) Notice. A written notice (the "Tag Along Notice") shall be
      furnished by the Prospective Selling Class B Stockholders to the Company,
      and to each Permitted Owner of the Underlying Common Stock (as defined in
      the Corporate Governance Agreement) known to them based on the records
      maintained by the Company (each, a "Tag Along Holder") at least ten
      Business Days (as defined in the Purchase Agreement) prior to such Sale.
      The Tag Along Notice shall include:

                  (i) The material terms of the proposed Sale, including the
            number of Shares to be purchased from the Prospective Selling Class
            B Stockholders, the percentage of the total number of Shares held by
            the Prospective Selling Class B Stockholders or their Affiliates (as
            defined in the Purchase Agreement) which such number of Shares
            constitutes (the "Tag Along Sale Percentage"), the maximum and
            minimum per share purchase price (which maximum price shall not be
            more than 110% of the minimum price) and the name and address of the
            Prospective Buyer; and

                  (ii) An invitation to each Tag Along Holder to make an offer
            to include in the proposed Sale to the Prospective Buyer an
            additional number of Shares (not in any event to exceed the Tag
            Along Sale Percentage of the total number of shares of Underlying
            Common Stock held by such Tag Along Holder) owned by such Tag Along
            Holder, on the same terms and conditions, with respect to each Share
            sold, as the Prospective Selling Class B Stockholders shall sell
            each of their Shares.

            (b) Exercise. Within ten Business Days after the effectiveness of
      the Tag Along Notice, each Tag Along Holder desiring to make an offer to
      include Shares in the proposed Sale (each a "Participating Seller" and,
      together with the Prospective Selling Class B Stockholders, collectively,
      the "Tag Along Sellers") shall send a written offer (the "Tag Along
      Offer") to the Prospective Selling Class B Stockholders, with a copy to
      the Company, specifying the number of Shares (not in any event to exceed
      the Tag Along Sale Percentage of the total number of shares of Underlying
      Common Stock held by such Participating Seller) which such Participating
      Seller desires to have included in the proposed Sale. Each Tag Along
      Holder who does not accept the Prospective Selling Class B Stockholders'
      invitation to make an offer to include Shares in the proposed Sale shall
      be deemed to have waived all of its rights with respect to such Sale, and
      the Tag Along Sellers shall thereafter be free to sell to the Prospective
      Buyer, at a per share price no greater than the maximum per share price
      set forth in the Tag Along Notice and on other principal terms which are
      not materially more favorable to the Tag Along Sellers than those set
      forth in the Tag Along Notice, without any further obligation to such
      non-accepting Tag Along Holder.


                                       4

<PAGE>

            (c) Irrevocable Offer. The offer of each Participating Seller
      contained in its Tag Along Offer shall be irrevocable, and, to the extent
      such offer is accepted, such Participating Seller shall be bound and
      obligated to sell in the proposed Sale on the same terms and conditions,
      with respect to each Share sold, as the Prospective Selling Class B
      Stockholders, up to such number of Shares as such Participating Seller
      shall have specified in its Tag Along Offer; provided, however, that if
      the principal terms of the proposed Sale change with the result that the
      per share price shall be less than the minimum per share price set forth
      in the Tag Along Notice or the other principal terms shall be materially
      less favorable to the Tag Along Sellers than those set forth in the Tag
      Along Notice, each Participating Seller shall be permitted to withdraw the
      offer contained in its Tag Along Offer and shall be released from its
      obligations thereunder.

            (d) Reduction of Shares Sold. The Prospective Selling Class B
      Stockholders shall attempt to obtain the inclusion in the proposed Sale of
      the entire number of Shares which the Tag Along Sellers requested to have
      included in the Sale (as evidenced in the case of the Prospective Selling
      Class B Stockholders by the Tag Along Notice and in the case of each
      Participating Seller by such Participating Seller's Tag Along Offer). In
      the event the Prospective Selling Class B Stockholders shall be unable to
      obtain the inclusion of such entire number of Shares in the proposed Sale,
      the number of Shares to be sold in the proposed Sale shall be allocated
      among the Tag Along Sellers in proportion, as nearly as practicable, to
      the respective number of Shares which each Tag Along Seller requested to
      be included in the proposed Sale.

            (e) Additional Compliance. If (i) prior to consummation, the terms
      of the proposed Sale shall change with the result that the per share price
      to be paid in such proposed Sale shall be greater than the maximum per
      share price set forth in the Tag Along Notice or the other principal terms
      of such proposed Sale shall be materially more favorable to the Tag Along
      Sellers than those set forth in the Tag Along Notice, the Tag Along Notice
      shall be null and void, and it shall be necessary for a separate Tag Along
      Notice to be furnished, and the terms and provisions of this Section 5
      separately complied with, in order to consummate such proposed Sale
      pursuant to this Section 5; provided, however, that in the case of such a
      separate Tag Along Notice, the applicable period to which reference is
      made in Sections 5(a) and 5(b) shall be five Business Days and (ii) the
      Prospective Selling Class B Stockholders have not completed the proposed
      Sale by the end of the 90th day following the date of the effectiveness of
      the Tag Along Notice, each Participating Seller shall be released from its
      obligations under its Tag Along Offer, the Tag Along Notice shall be null
      and void, and it shall be necessary for a separate Tag Along Notice to be
      furnished, and the terms and provisions of this Section 5 separately
      complied with, in order to consummate such proposed Sale pursuant to this
      Section 5, unless the failure to complete such proposed Sale resulted from
      any failure by any Participating Seller to comply with the terms of this
      Section 5.

            (f) Excluded Transactions. Notwithstanding the foregoing, the Class
      B Stockholders shall not be obligated to comply with the foregoing
      provisions of this Section 5 and none of the Permitted Owners shall have
      any right of participation pursuant to the terms of this Section 5, or
      otherwise, in each case, with respect to any Sale of Shares:


                                       5

<PAGE>

                  (i) by a Class B Stockholder to another Class B Stockholder or
            to a Permitted Transferee who agrees to be bound by this Agreement
            as a Class B Stockholder;

                  (ii) in a public offering of Common Stock with respect to
            which holders of Registrable Securities (as defined in the
            Registration Rights Agreement) have piggyback registration rights
            pursuant to the Registration Rights Agreement (as defined in the
            Purchase Agreement); or

                  (iii) if, after giving effect to such Sale, the Class B
            Stockholders and their Permitted Transferees will continue to own in
            the aggregate not less than 85% of the shares of Subject Common
            Stock held by the Class B Stockholders as of the date of this
            Agreement.

            (g) Further Assurances. Each Participating Seller, whether in its
      capacity as a Participating Seller, stockholder, officer or director of
      the Company, or otherwise, shall take or cause to be taken all such
      actions as may be necessary or reasonably desirable in order expeditiously
      to consummate each Sale pursuant to this Section 5 and any related
      transactions, including, without limitation, executing, acknowledging and
      delivering consents, assignments, waivers and other documents or
      instruments; furnishing information and copies of documents; filing
      applications, reports, returns, filings and other documents or instruments
      with governmental authorities; and otherwise cooperating with the
      Prospective Selling Class B Stockholders and the Prospective Buyer;
      provided, however, that Participating Sellers shall be obligated to become
      liable in respect of any representations, warranties, covenants,
      indemnities or otherwise to the Prospective Buyer solely to the extent
      provided in the immediately following sentence. Without limiting the
      generality of the foregoing, each Participating Seller agrees to execute
      and deliver such agreements as may be reasonably specified by the
      Prospective Selling Class B Stockholders, to which such Prospective
      Selling Class B Stockholders will also be party, including, without
      limitation, agreements to (A) make individual representations, warranties,
      covenants and other agreements as to the unencumbered title to its Shares
      and the power, authority and legal right to sell such Shares and the
      absence of any adverse claim with respect to such Shares and (B) be liable
      (whether by purchase price adjustment, indemnity payments or otherwise) in
      respect of representations, warranties, covenants and agreements in
      respect of the Company and its subsidiaries; provided, however, that,
      except with respect to individual representations, warranties, covenants,
      indemnities and other agreements of Participating Sellers of the type
      described in clause (A) above, the aggregate amount of such liability
      shall not exceed the lesser of (x) such Participating Seller's pro rata
      portion of any such liability, to be determined in accordance with such
      Participating Seller's portion of the total number of Shares included in
      such Sale or (y) the proceeds to such Participating Seller in connection
      with such Sale; and provided, further, that with respect to individual
      representations, warranties, covenants, indemnities and other agreements
      of Participating Sellers of the type described in clause (A) above, the
      aggregate amount of such liability shall not exceed the proceeds to such
      Participating Seller in connection with such Sale.

            (h) Sale Process. The Prospective Selling Class B Stockholders
      shall, in their sole discretion, decide whether or not to pursue,
      consummate, postpone or abandon any


                                       6

<PAGE>

      proposed Sale and the terms and conditions thereof. No Prospective Selling
      Class B Stockholder or any Affiliate of any Prospective Selling Class B
      Stockholder shall have any liability to any other holder of Shares arising
      from, relating to or in connection with the pursuit, consummation,
      postponement, abandonment or terms and conditions of any proposed Sale
      except to the extent such Prospective Selling Class B Stockholder shall
      have failed to comply with the provisions of this Section 5.

            (i) Expenses. All reasonable costs and expenses incurred by the
      Prospective Selling Class B Stockholders or the Company in connection with
      any proposed Sale pursuant to this Section 5 (whether or not consummated),
      including without limitation all attorneys fees and expenses, all
      accounting fees and charges and all finders, brokerage or investment
      banking fees, charges or commissions, shall be paid by the Prospective
      Selling Class B Stockholders. The reasonable costs and expenses incurred
      by the Participating Sellers in connection with any proposed Sale pursuant
      to this Section 5 (whether or not consummated) including, without
      limitation, all attorneys fees and expenses, all accounting fees and
      charges and all finders, brokerage or investment banking fees, charges or
      commissions, shall be paid by the Participating Seller(s).

            (j) Closing. The closing of a Sale pursuant to the Section 5 shall
      take place at such time and place as the Prospective Selling Class B
      Stockholders shall specify by notice to each Participating Seller. At the
      closing of any Sale under this Section 5, each Participating Seller shall
      deliver the certificates evidencing the Shares to be sold by such
      Participating Seller, duly endorsed, or with stock (or equivalent) powers
      duly endorsed, for transfer with signature guaranteed, free and clear of
      any liens or encumbrances, with any stock (or equivalent) transfer tax
      stamps affixed, against delivery of the applicable consideration.

            (k) Termination. The provisions of this Section 5 shall terminate
      and have no further force or effect immediately after the Permitted Owners
      cease to hold at least 20% of the Underlying Common Stock.

      6. Subject Common Stock; Transfers to Permitted Transferees

            (a) Subject Common Stock. The Class B Stockholders agree that any
      shares of Subject Common Stock held or owned by them, or with respect to
      which they otherwise acquire beneficial ownership after the execution of
      this Agreement, including, without limitation, in the event of any stock
      split, stock dividend, recapitalization or other change in the capital
      structure of the Company affecting the Subject Common Stock, shall be
      subject to the terms and conditions of this Agreement to the same extent
      as if such shares constituted the shares of Subject Common Stock issued
      and outstanding as of the date hereof.

            (b) Transfers to Permitted Transferees. The Class B Stockholders
      agree that this Agreement and the obligations hereunder shall be binding
      upon any Permitted Transferee (as defined in the Restated Certificate) to
      which legal or beneficial ownership of any shares of Subject Common Stock
      shall pass, whether by operation of law or otherwise. No transfer of the
      legal or beneficial ownership of such shares to a Permitted Transferee
      shall be valid unless such Permitted Transferee agrees to be bound by this
      Agreement as a "Class B Stockholder."


                                       7

<PAGE>

      7. Miscellaneous

            (a) Severability. If any term, provision, covenant or restriction of
      this Agreement is held by a court of competent jurisdiction to be invalid,
      void or unenforceable, then the remainder of the terms, provisions,
      covenants and restrictions of this Agreement shall remain in full force
      and effect and shall in no way be affected, impaired or invalidated.

            (b) Binding Effect and Assignment. This Agreement and all of the
      provisions hereof shall be binding upon and inure to the benefit of the
      parties hereto and their respective successors and permitted assigns
      (including any Permitted Transferees); provided, however, except as
      otherwise specifically provided herein, neither this Agreement nor any of
      the rights, interests or obligations of the Class B Stockholders may be
      assigned by the Class B Stockholders without the prior written consent of
      the Permitted Owners holding a majority of the Underlying Common Stock.

            (c) Amendments and Modification. This Agreement may not be modified,
      amended, altered or supplemented except upon the execution and delivery of
      a written agreement executed by the Class B Stockholders and Permitted
      Owners holding a majority of the Underlying Common Stock.

            (d) Specific Performance; Injunctive Relief. The parties hereto
      acknowledge that the Investors will be irreparably harmed and that there
      will be no adequate remedy at law for a violation of any of the covenants
      or agreements of the Class B Stockholders set forth herein. Therefore, it
      is agreed that, in addition to any other remedy or remedies that may be
      available to the Investors upon any such violation, the Investors shall
      have the right to enforce such covenants and agreements by specific
      performance, injunctive relief or by any other means available to the
      Investors at law or in equity without posting any bond and without proving
      that monetary damages would be inadequate.

            (e) Notices. All notices, requests, claims, demands and other
      communications hereunder ("Notices") shall be in writing and sent by
      certified or registered mail, return receipt requested, a recognized
      overnight courier service, telecopier or personal delivery, as follows:


                                       8

<PAGE>

                  (i) if to any Class B Stockholder:

                      Richard T. Aab
                      Melrich Associates, L.P.
                      Tansukh V. Ganatra
                      Super STAR Associates Limited Partnership
                      c/o US LEC Corp.
                      Transamerica Square
                      401 N. Tryon Street, Suite 1000
                      Charlotte, North Carolina 28202
                      Attention:  General Counsel
                      Telecopier:  (704) 319-3098

                      with required copies to:

                      Richard T. Aab
                      29 Woodstone Rise
                      Pittsford, NY  14534

                      Tansukh V. Ganatra
                      6523 Ashdale Place
                      Charlotte, North Carolina  28215

                      US LEC Corp.
                      Transamerica Square
                      401 N. Tryon Street, Suite 1000
                      Charlotte, North Carolina 28202
                      Attention:  General Counsel
                      Telecopier:  (704) 319-3098

                      and

                      Moore & Van Allen, PLLC
                      100 North Tryon Street, Floor 47
                      Charlotte, North Carolina 28202-4003
                      Attention:  Barney Stewart III
                      Telecopier:  (704) 331-1151

                  (ii) if to the Investors:

                       Bain Capital, Inc.
                       Two Copley Place
                       Boston, Massachusetts 02116
                       Attention:  Ian K. Loring
                       Telecopier:  (617) 572-3274

                       and


                                       9

<PAGE>

                       Thomas H. Lee Partners, L.P.
                       75 State Street, 26th Floor
                       Boston, Massachusetts 02109
                       Attention:  Anthony J. DiNovi
                       Telecopier:  (617) 227-3514

                       with a required copy to:

                       Ropes & Gray
                       One International Plaza
                       Boston, Massachusetts 02110-2624
                       Attention:  Philip J. Smith
                       Telecopier:  (617) 951-7050

      All such Notices shall be deemed to have been duly given: when delivered
      by hand, if personally delivered; when delivered by courier, if delivered
      by commercial overnight courier service; five Business Days after being
      deposited in the mail, postage prepaid, if mailed; and when receipt is
      acknowledged by the individual to whose attention the telecopy is sent, if
      telecopied. A party may change its address for purposes of this Agreement
      by Notice in accordance with this Section 7(e).

            (f) Governing Law. The laws of the State of Delaware (irrespective
      of its choice of laws, rules or principles) will govern the validity of
      this Agreement, the construction of its terms and the interpretation and
      enforcement of the rights and duties of the parties hereto.

            (g) Entire Agreement. This Agreement and the Purchase Agreement
      contain the entire understanding of the parties with respect to the
      subject matter hereof, and supersede all prior negotiations and
      understandings between the parties with respect to such subject matter.

            (h) Counterparts. This Agreement may be executed in counterparts,
      each of which shall be an original, but which together shall constitute
      one and the same agreement.

            (i) Effect of Headings. The section headings herein are for
      convenience only and shall not affect the construction or interpretation
      of this Agreement.

            (j) Definition of Transfer. For purposes of Sections 4 and 5 of this
      Agreement, a "Transfer" means any sale, assignment or other disposition of
      any Shares to any other Person, whether directly, indirectly, voluntarily,
      involuntarily, by operation of law, pursuant to judicial process or
      otherwise; provided that the term "Transfer" shall not include the pledge
      or granting of a security interest in the Shares or the subsequent
      disposition of any of such Shares upon the exercise by the pledgee or
      secured party, in accordance with its customary practices, of its rights
      upon a default with respect to any obligation owed to such pledgee or
      secured party by a Class B Stockholder.


                                       10

<PAGE>

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

                                    CLASS B STOCKHOLDERS:

                                    /s/ Richard T. Aab
                                    -----------------------------------------
                                    Richard T. Aab


                                    MELRICH ASSOCIATES, L.P.

                                    By: /s/ Richard T. Aab
                                        -------------------------------------
                                        Richard T. Aab, General Partner

                                    By: /s/ Joyce M. Aab
                                        -------------------------------------
                                        Joyce M. Aab, General Partner

                                    /s/ T. V. Ganatra
                                    -----------------------------------------
                                    Tansukh V. Ganatra


                                    SUPER STAR ASSOCIATES LIMITED
                                    PARTNERSHIP

                                    By: /s/ T. V. Ganatra
                                        -------------------------------------
                                        Tansukh V. Ganatra, General Partner


                                       11

<PAGE>

                                         US LEC CORP.

                                         By: /s/ Michael K. Robinson
                                             -----------------------------------
                                             Name: Michael K. Robinson
                                             Title: Executive Vice President and
                                                     Chief Financial Officer


                                         BAIN CAPITAL CLEC INVESTORS, L.L.C.

                                         By: Bain Capital Fund VI, L.P.,
                                             its Administrative Member
                                         By: Bain Capital Partners VI, L.P.,
                                             its General Partner
                                         By: Bain Capital Investors VI, Inc.,
                                             its general partner

                                         By: /s/ Michael A. Krupka
                                             -----------------------------------
                                             Name: Michael A. Krupka
                                             Title: Managing Director


                                         THOMAS H. LEE EQUITY FUND IV, L.P.

                                         By: THL Equity Advisors IV, LLC,
                                             its general partner

                                         By: /s/ Anthony J. DiNovi
                                             -----------------------------------
                                             Name: Anthony J. DiNovi
                                             Title: Managing Director


                                         THOMAS H. LEE FOREIGN FUND IV-B, L.P.

                                         By: THL Equity Advisors IV, LLC,
                                             its general partner

                                         By: /s/ Anthony J. DiNovi
                                             -----------------------------------
                                             Name: Anthony J. DiNovi
                                             Title: Managing Director


                                       12

<PAGE>

                                        THOMAS H. LEE FOREIGN FUND IV, L.P.

                                        By: THL Equity Advisors IV, LLC,
                                            its general partner

                                        By: /s/ Scott M. Sperling
                                            -----------------------------------
                                            Name: Scott M. Sperling
                                            Title: Managing Director


                                        PUTNAM INVESTMENTS, INC.

                                        By: /s/ William H. Woolverton
                                            -----------------------------------
                                           Name: William H. Woolverton
                                           Title: Managing Director


                                        1997 THOMAS H. LEE NOMINEE TRUST

                                        By: /s/ Gerald Wheeler
                                            -----------------------------------
                                            Trustee


                                        THOMAS H. LEE CHARITABLE INVESTMENT L.P.

                                        By: /s/ Thomas H. Lee
                                            -----------------------------------
                                            Name: Thomas H. Lee
                                            Title: President

                                        /s/ David V. Harkins
                                        ---------------------------------------
                                        David V. Harkins


                                        THE HARKINS 1995 GIFT TRUST

                                        By: /s/ Sheryll J. Harkins
                                            -----------------------------------
                                            Trustee

                                        /s/ Scott A. Schoen
                                        ---------------------------------------
                                        Scott A. Schoen


                                       13

<PAGE>

                                       /s/ C. Hunter Boll
                                       ----------------------------------------
                                       C. Hunter Boll

                                       /s/ Scott M. Sperling
                                       ----------------------------------------
                                       Scott M. Sperling

                                       /s/ Anthony J. DiNovi
                                       ----------------------------------------
                                       Anthony J. DiNovi

                                       /s/ Thomas M. Hagerty
                                       ----------------------------------------
                                       Thomas M. Hagerty

                                       /s/ Warren C. Smith, Jr.
                                       ----------------------------------------
                                       Warren C. Smith, Jr.

                                       /s/ Seth W. Lawry
                                       ----------------------------------------
                                       Seth W. Lawry

                                       /s/ Kent R. Weldon
                                       ----------------------------------------
                                       Kent R. Weldon

                                       /s/ Terrence M. Mullen
                                       ----------------------------------------
                                       Terrence M. Mullen

                                       /s/ Todd M. Abbrecht
                                       ----------------------------------------
                                       Todd M. Abbrecht

                                       /s/ Charles A. Brizius
                                       ----------------------------------------
                                       Charles A. Brizius

                                       /s/ Scott Jaeckel
                                       ----------------------------------------
                                       Scott Jaeckel

                                       /s/ Soren Oberg
                                       ----------------------------------------
                                       Soren Oberg


                                       14

<PAGE>

                                       /s/ Thomas R. Shepherd
                                       ----------------------------------------
                                       Thomas R. Shepherd

                                       /s/ Wendy L. Masler
                                       ----------------------------------------
                                       Wendy L. Masler

                                       /s/ Andrew D. Flaster
                                       ----------------------------------------
                                       Andrew D. Flaster


                                       ROBERT SCHIFF LEE 1988 IRREVOCABLE TRUST

                                       By: /s/ Charles W. Robins
                                           ------------------------------------
                                           Trustee

                                       /s/ Stephen Zachary Lee
                                       ----------------------------------------
                                       Stephen Zachary Lee

                                       /s/ Charles W. Robins
                                       ----------------------------------------
                                       Charles W. Robins as Custodian for
                                       Jesse Lee

                                       /s/ Charles W. Robins
                                       ----------------------------------------
                                       Charles W. Robins as Custodian for
                                       Nathan Lee

                                       /s/ Charles W. Robins
                                       ----------------------------------------
                                       Charles W. Robins

                                       /s/ James Westra
                                       ----------------------------------------
                                       James Westra


                                       15

<PAGE>

                                       THL-CCI INVESTORS LIMITED
                                       PARTNERSHIP

                                       By: THL Investment Management Corp.,
                                       its general partner

                                       By:
                                          --------------------------------------
                                       Name:
                                       Title:

                                       /s/ Adam A. Abramson
                                       ----------------------------------------
                                       Adam A. Abramson

                                       /s/ Joanne M. Ramos
                                       ----------------------------------------
                                       Joanne M. Ramos

                                       /s/ P. Holden Spaht
                                       ----------------------------------------
                                       P. Holden Spaht

                                       /s/ Nancy M. Graham
                                       ----------------------------------------
                                       Nancy M. Graham

                                       /s/ Gregory A. Ciongoli
                                       ----------------------------------------
                                       Gregory A. Ciongoli

                                       /s/ Wm. Matthew Kelly
                                       ----------------------------------------
                                       Wm. Matthew Kelly

                                       /s/ Kevin F. Sullivan
                                       ----------------------------------------
                                       Kevin F. Sullivan

                                       /s/ Diane M. Barriere
                                       ----------------------------------------
                                       Diane M. Barriere

                                       /s/ Kim H. Oakley
                                       ----------------------------------------
                                       Kim H. Oakley


                                       16

<PAGE>

                                   SCHEDULE I

                                    Investors

<TABLE>
<CAPTION>
                                                           Number of Shares of Series A
                  Name                                       Preferred Stock Purchased
                  ----                                       -------------------------
<S>                                                                 <C>
Bain Capital CLEC Investors, L.L.C.                                 100,000.00
Thomas H. Lee Equity Fund IV, L.P.                                   83,533.00
Thomas H. Lee Foreign Fund IV-B, L.P.                                 8,113.00
Thomas H. Lee Foreign Fund IV, L.P.                                   2,859.00
Putnam Investment Holdings, LLC                                       1,374.00
1997 Thomas H. Lee Nominee Trust/1/                                   1,104.00
Thomas H. Lee Charitable Investment Limited Partnership                 543.00
David V. Harkins                                                        294.00
Scott A. Schoen                                                         245.00
C. Hunter Boll                                                          245.00
Scott M. Sperling                                                       245.00
Anthony J. DiNovi                                                       245.00
Thomas M. Hagerty                                                       245.00
Warren C. Smith, Jr.                                                    245.00
Seth W. Lawry                                                           102.00
Kent R. Weldon                                                           68.00
Terrence M. Mullen                                                       54.00
Todd M. Abbrecht                                                         54.00
Robert Schiff Lee 1988 Irrevocable Trust                                 50.00
Stephen Zachary Lee                                                      50.00
Charles A. Brizius                                                       41.00
The Harkins 1995 Gift Trust                                              33.00
Thomas R. Shepherd                                                       29.00
Charles W. Robins as Custodian for Jesse Lee                             25.00
Charles W. Robins as Custodian for Nathan Lee                            25.00
Charles W. Robins                                                        20.00
James Westra                                                             20.00
Wendy L. Masler                                                          20.00
Andrew D. Flaster                                                        17.00
Scott L. Jaeckel                                                         15.00
Soren L.  Oberg                                                          15.00
Adam A. Abramson                                                         12.00
Joanne M. Ramos                                                          12.00
P. Holden Spaht                                                           7.00
Nancy M. Graham                                                          12.00
</TABLE>

--------
/1/   For legal purposes, certificate should be issued to "State Street Bank as
      Trustee for 1997 Thomas H. Lee Nominee Trust"

<PAGE>

Gregory A. Ciongoli                                                      12.00
Wm. Matthew Kelly                                                        12.00
Kevin F. Sullivan                                                         2.00
Diane M. Barriere                                                         2.00
Kim H. Oakley                                                             1.00