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                                                             EXHIBIT 10.4


                    FIRST AMENDMENT TO EQUITY CALL AGREEMENT


                  THIS FIRST AMENDMENT TO EQUITY CALL AGREEMENT (this
"Amendment"), dated as of November 20, 2001, is made by and among Orius Corp., a
Florida corporation ("Holdings"), NATG Holdings, LLC, a Delaware limited
liability company ("Borrower"), the investors party to the Equity Call Agreement
in their capacities as Equity Investors (collectively, the "Equity Investors")
and Bankers Trust Company, in its capacity as administrative agent
("Administrative Agent") for the Lenders (as defined in the hereinafter defined
Credit Agreement).

                              W I T N E S S E T H :

         WHEREAS, Holdings, Borrower, the financial institutions from time to
time party thereto, including Bankers Trust Company, in their capacities as
lenders thereunder (collectively, the "Lenders," and each individually, a
"Lender"), and Administrative Agent have entered into the Amended and Restated
Credit Agreement dated as of July 5, 2000, as amended, providing for the making
of Loans and the issuance of, and participation in, Letters of Credit as
contemplated therein (as used herein, the term "Credit Agreement" means the
Amended and Restated Credit Agreement described above in this paragraph, as the
same may be amended, modified, extended, renewed, replaced, restated or
supplemented from time to time, and including any agreement extending the
maturity of or restructuring of all or any portion of the Indebtedness under
such agreement or any successor agreements);

         WHEREAS, Holdings, Borrower, the Equity Investors and Administrative
Agent have entered into the Equity Call Agreement dated as of July 27, 2001 (as
used herein the term "Equity Call Agreement" means the Equity Call Agreement
described above in this paragraph, as the same may be amended, modified,
extended, renewed, replaced, restated or supplemented from time to time)
providing for the making of Capital Infusions by the Equity Investors under
certain circumstances described therein;

         WHEREAS, Holdings, Borrower, the Lenders and Administrative Agent are
party to a Fourth Amendment to Amended and Restated Credit Agreement dated as of
the date hereof (the "Fourth Amendment"); and

         WHEREAS, it is a condition precedent to the Fourth Amendment and to
continued extensions of credit pursuant to the Credit Agreement that the Equity
Investors, Holdings and Borrower shall have executed and delivered this
Amendment;

         NOW, THEREFORE, in consideration of such benefits and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, intending to be legally bound, and with full knowledge that
Administrative Agent and the Lenders will rely on the contents of this Amendment
in providing extensions of credit to Borrower under the Credit Agreement,
Holdings, Borrower and each Equity Investor hereby certify to and covenant and
agree with Administrative Agent as follows:

         1. Definitions. Capitalized terms used herein, but not expressly
defined herein, shall have the meanings given to such terms in the Equity Call
Agreement.
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         2. Amendments to Equity Call Agreement. The Equity Call Agreement is
hereby amended as follows:

         (a) Section 2 of the Equity Call Agreement is amended by amending and
restating such Section in its entirety to read as follows:

                  2. Equity Call Commitment. Each Equity Investor hereby
         commits, severally and for itself alone, subject to the terms and
         conditions of this Agreement, but otherwise irrevocably, to
         Administrative Agent and Lenders that if, at any time: (i) on or prior
         to July 21, 2002 the aggregate amount of cash balances of Borrower and
         its Subsidiaries (it being acknowledged and agreed by all of the
         parties hereto that the amount of such cash balances shall be deemed to
         include the amount of any Capital Infusion not yet made but for which
         an Equity Call Notice has been made in accordance with the terms hereof
         so long as such Capital Infusion is actually made within the time
         period required hereunder, and shall be deemed to include $10,000,000
         from and after the Third Amendment Effective Date until such time as
         Holdings and Borrower receive the WSP Equity Infusion in accordance
         with the terms of the Third Amendment so long as such $10,000,000 is
         actually received by Holdings and Borrower on or prior to the tenth
         (10th) Business Day following the Third Amendment Effective Date) held
         in accounts with financial institutions and Cash Equivalents of
         Borrower and its Subsidiaries plus the amount of Availability falls
         below $15,000,000 for three (3) consecutive Business Days (a "Liquidity
         Shortfall"); (ii) on or prior to July 21, 2002 the Equity Investors
         receive a certificate from a Responsible Officer of Borrower certifying
         on behalf of Borrower that the Board of Directors of Borrower has
         elected to request that the Equity Investors make a Capital Infusion
         pursuant to this Agreement (a "Borrower Request"); (iii) upon an Event
         of Default under Section 10.1(a) of the Credit Agreement (a "Payment
         Default"); (iv) upon an Event of Default under Section 10.1(e) or (f)
         of the Credit Agreement (a "Bankruptcy or Insolvency Event"); (v) on or
         prior to July 21, 2002 the Majority Equity Investors elect to have the
         Equity Investors make a Capital Infusion and give written notice
         thereof to Borrower and Administrative Agent (an "Equity Investors
         Election"); or (vi) upon the occurrence of a Trigger Date (a "Trigger
         Event" and, together with each Liquidity Shortfall, Borrower Request,
         Payment Default, Bankruptcy or Insolvency Event and Equity Investors
         Election, each an "Equity Call Event"), each Equity Investor shall
         within twelve (12) Business Days after written notice is delivered by
         (1) Administrative Agent or Borrower (with a copy to Administrative
         Agent) to the Equity Investors, in the case of a Liquidity Shortfall or
         Trigger Event, (2) Administrative Agent to the Equity Investors, in the
         case of a Payment Default or a Bankruptcy or Insolvency Event, (3)
         Borrower to the Equity Investors and Administrative Agent in the case
         of a Borrower Request, and (4) the Majority Equity Investors to
         Borrower, Administrative Agent and the other Equity Investors, in the
         case of an Equity Investors Election (any such notice described in
         clauses (1), (2), (3) and (4) above, an "Equity Call Notice"), make
         such Equity Investor's Pro Rata Share of a Capital Infusion to Holdings
         (with Holdings being obligated to simultaneously make a capital
         contribution in the same amount as such contribution to Borrower)

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         which Capital Infusion shall be (w) in the case of a Trigger Event, in
         an aggregate amount necessary for the Revolving Loan Availability Ratio
         and the Capital Infusion Availability Ratio to be equaled as nearly as
         possible (subject to rounding) treating all Loans or Letters of Credit
         made or issued on or after the Fourth Amendment Effective Date (to the
         extent outstanding on the Trigger Date) as having been requested on
         such date rather than on the dates actually requested for purposes of
         determining the Revolving Loan Availability Ratio and the Capital
         Infusion Availability Ratio (provided that, in the case of a Trigger
         Event due to clause (i) of the definition of Trigger Date, Working
         Capital Loans outstanding on the Trigger Date shall be reduced by the
         amount of the Capital Infusion to be made as a result of such Trigger
         Event for purposes of calculating the amount of such Capital Infusion
         and the applicable Revolving Loan Availability Ratio and Capital
         Infusion Availability Ratio), (x) in the case of a Payment Default or a
         Liquidity Shortfall, in an aggregate amount then necessary to cure such
         Payment Default or Liquidity Shortfall (or, if the Maximum Infusion
         Balance at the time of determination thereof is less than the amount
         necessary to effect such cure, in the entire amount of the Maximum
         Infusion Balance), (y) in the full amount of the Maximum Infusion
         Balance in the case of a Bankruptcy or Insolvency Event, and (z) in
         such amount as requested by Borrower in a Borrower Request or specified
         by the Majority Equity Investors in an Equity Investors Election
         (limited to the Maximum Infusion Balance at such time); provided,
         however, that, notwithstanding the foregoing, in no event shall the
         Equity Investors be required pursuant hereto to make any payments or be
         obligated for any amounts other than the Capital Infusions in an
         aggregate amount not to exceed the Maximum Infusion Amount; and
         provided further, that if the Maximum Infusion Balance is insufficient
         to obtain the cure of any such Trigger Event, Payment Default or
         Liquidity Shortfall, the Equity Investors nonetheless shall be obliged
         to make a Capital Infusion to the full extent of the Maximum Infusion
         Balance then available in mitigation thereof. Administrative Agent,
         Borrower and/or the Majority Equity Investors, as applicable, may make
         one Equity Call Notice or multiple Equity Call Notices; subject,
         however, to the foregoing limitation on the maximum amount of Capital
         Infusions. Each Equity Call Notice sent by Administrative Agent or
         Borrower regarding a Liquidity Shortfall shall specify the amount of
         such Liquidity Shortfall and include the amount of Availability used to
         calculate the Liquidity Shortfall and be accompanied by a copy of the
         most recent daily cash balance report received by Administrative Agent
         pursuant to Section 7.17 of the Credit Agreement. Each Equity Call
         Notice sent by Administrative Agent regarding a Payment Default shall
         specify the amount of such Payment Default. Each Equity Call Notice
         regarding a Trigger Event shall specify the amount of Capital Infusion
         necessary to cure such Trigger Event, the Revolving Loan Availability
         Ratio and Capital Infusion Availability Ratio and the outstanding
         principal amount of Loans and Letters of Credit made or issued on or
         after the Fourth Amendment Effective Date. Promptly upon receipt by
         Holdings of any Capital Infusion, Holdings shall simultaneously make a
         capital contribution in the same amount in cash to Borrower, provided
         that the proceeds of each Capital Infusion made pursuant to a

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         Trigger Event pursuant to clause (i) of the definition of Trigger Date
         or a Payment Default shall be paid over and delivered by the Equity
         Investors by wire transfer of immediately available funds directly to
         Administrative Agent, and not to Holdings, for application to the
         Obligations within twelve (12) Business Days after an Equity Call
         Notice is delivered to the Equity Investors. In the event that a
         Bankruptcy or Insolvency Event and a Trigger Event under clause (i) of
         the definition of Trigger Date occurs on the same date, then the
         Capital Infusion relating to such Trigger Event shall be fully
         satisfied as provided above prior to the making of a Capital Infusion
         pursuant to such Bankruptcy or Insolvency Event. Administrative Agent
         will apply the proceeds of each Capital Infusion received by
         Administrative Agent (i) pursuant to a Payment Default to the payment
         of the defaulted Obligations which caused such Payment Default and (ii)
         pursuant to a Trigger Event under clause (i) of the definition of
         Trigger Date to the payment of Working Capital Loans in accordance with
         the Credit Agreement. Promptly upon learning of a Liquidity Shortfall
         (other than through the receipt of an Equity Call Notice from
         Administrative Agent relating to a Liquidity Shortfall), Borrower shall
         notify in writing Administrative Agent and the Equity Investors of the
         amount thereof (it being acknowledged and agreed by all of the parties
         hereto that (i) such notice may be satisfied by Borrower's prompt
         delivery of an Equity Call Notice regarding a Liquidity Shortfall which
         satisfies the requirements set forth above in this Section 2 and (ii)
         the failure by Borrower to deliver such notice shall not in any way
         limit the right of Administrative Agent to deliver an Equity Call
         Notice regarding a Liquidity Shortfall and the Equity Investors'
         obligations to make a Capital Infusion with respect thereto). Holdings
         and Borrower hereby acknowledge and agree to the terms hereof and their
         obligations hereunder.

         3. Representations and Warranties. In order to induce Administrative
Agent to enter into this Amendment and the Lenders to continue to make Loans and
issue Letters of Credit pursuant to the Credit Agreement, each of Holdings and
each Equity Investor hereby represents and warrants as of the date hereof to
Administrative Agent and the Lenders that:

                  (a) Such Person (i) is a duly organized and validly existing
corporation, limited liability company or other entity and is in good standing
under the laws of the jurisdiction of its organization, and has all necessary
power and authority to own its property and assets and to transact the business
in which it is engaged and presently proposes to engage and (ii) is duly
qualified and is authorized to do business and is in good standing in each
jurisdiction where the conduct of its business requires such qualification
except for failures to be so qualified which, individually or in the aggregate,
could not reasonably be expected to have a MAE.

                  (b) Such Person has all necessary power and authority to
execute, deliver and perform the terms and provisions of this Amendment and has
taken all necessary action to authorize the execution, delivery and performance
by it of this Amendment. Such Person has duly executed and delivered this
Amendment and this Amendment constitutes the legal, valid and binding obligation
of such Person enforceable in accordance with its terms, except to the extent
that the enforceability hereof or thereof may be limited by applicable
bankruptcy,

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insolvency, reorganization, moratorium or other similar laws affecting
creditors' rights generally and by equitable principles (regardless of whether
enforcement is sought in equity or at law).

                  (c) Neither the execution, delivery or performance by such
Person of this Amendment, nor compliance by it with the terms and provisions
hereof (i) will contravene any applicable provision of any law, statute, rule or
regulation, or any applicable order, writ, injunction or decree of any court or
governmental instrumentality, (ii) will conflict with or result in any breach
of, any of the terms, covenants, conditions or provisions of, or constitute a
default under, or result in the creation or imposition of (or the obligation to
create or impose) any Lien upon any of the property or assets of such Person
pursuant to the terms of any indenture, mortgage, deed of trust, loan agreement
or any other agreement, contract or instrument to which such Person or any of
its Subsidiaries is a party or by which it or any of its property or assets is
bound or to which it may be subject or (iii) will violate any provision of the
Organizational Documents of such Person.

                  (d) No order, consent, approval, license, authorization or
validation of, or filing, recording or registration with (except as have been
obtained or made prior to the Fourth Amendment Effective Date), or exemption by,
any governmental or public body or authority, or any subdivision thereof, is
required to authorize, or is required in connection with, (i) the execution,
delivery and performance of this Amendment, or (ii) the legality, validity,
binding effect or enforceability of this Amendment with respect to such Person.

                  (e) There are no actions, suits or proceedings pending or, to
the best knowledge of such Person, threatened with respect to such Person (i)
that could reasonably be expected to have a MAE or (ii) with respect to this
Amendment or on the ability of such Person to perform its respective obligations
hereunder.

         4. GOVERNING LAW. THIS AMENDMENT SHALL BE DEEMED TO BE A CONTRACT MADE
UNDER THE LAWS OF THE STATE OF NEW YORK, AND FOR ALL PURPOSES SHALL BE CONSTRUED
IN ACCORDANCE WITH THE LAWS AND DECISIONS OF SAID STATE, INCLUDING SECTIONS
5-1401 AND 5-1402 OF THE NEW YORK GENERAL OBLIGATIONS LAW BUT EXCLUDING ALL
OTHER CHOICE OF LAW AND CONFLICTS OF LAW RULES.

         5. Miscellaneous.

                  (a) This Amendment and the Equity Call Agreement constitute
the sole and entire agreement among the Equity Investors, Holdings, Borrower and
Administrative Agent with respect to the subject matter hereof.

                  (b) Time is of the essence of this Amendment.

                  (c) Wherever possible, any provision in this Amendment which
is prohibited or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective only to the extent of such prohibition or
enforceability without invalidating the remaining provisions hereof, and any
such prohibition or enforceability in any one jurisdiction shall not invalidate
or render unenforceable such provision in any other jurisdiction.

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                  (d) The parties hereto agree and acknowledge that nothing
contained in this Amendment in any manner or respect limits or terminates any of
the provisions of the Equity Call Agreement other than as expressly set forth
herein and further agree and acknowledge that the Equity Call Agreement (as
amended hereby) remains and continues in full force and effect and is hereby
ratified and confirmed. Except to the extent expressly set forth herein, the
execution, delivery and effectiveness of this Amendment shall not operate as an
amendment of any rights, power or remedy of Administrative Agent under the
Equity Call Agreement, nor constitute an amendment of any provision of the
Equity Call Agreement. No delay on the part of Administrative Agent in
exercising any of their respective rights, remedies, powers and privileges under
the Equity Call Agreement or partial or single exercise thereof, shall
constitute an amendment thereof. On and after the date hereof each reference in
the Equity Call Agreement to "this Agreement," "hereunder," "hereof," "herein"
or words of like import, and each reference to the Equity Call Agreement in the
Credit Agreement and the other Loan Documents and all other documents delivered
in connection with the Credit Agreement shall mean and be a reference to the
Equity Call Agreement as amended hereby. None of the terms and conditions of
this Amendment may be changed, waived, modified or varied in any manner,
whatsoever, except in accordance with Section 13(d) of the Equity Call
Agreement.

                  (e) This Amendment may be executed in one or more counterparts
and each such counterpart shall constitute an original and all such counterparts
together shall constitute one and the same instrument.

                  (f) All Section headings herein are for convenience of
reference only and shall not limit or otherwise affect the meaning or
interpretation of the provisions of this Amendment.

                  (g) This Amendment is a Loan Document and shall be governed
and construed accordingly.

                            [signatures pages follow]

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered by their duly authorized officers as of the date
first above written.


                            WILLIS STEIN & PARTNERS III, L.P.
                            By: Willis Stein & Partners Management III, L.P.,
                                   Its General Partner
                            By:  Willis Stein & Partners Management III, L.L.C.,
                                   Its General Partner

                            By:        /s/      Robert C. Froetscher
                                ------------------------------------------------
                            Name:               Robert C. Froetscher
                            Title:              Managing Director


                            WILLIS STEIN & PARTNERS DUTCH III - A, L.P.
                            By: Willis Stein & Partners Management III, L.P.,
                                   Its General Partner
                            By:  Willis Stein & Partners Management III, L.L.C.,
                                   Its General Partner

                            By:        /s/      Robert C. Froetscher
                                ------------------------------------------------
                            Name:               Robert C. Froetscher
                            Title:              Managing Director


                            WILLIS STEIN & PARTNERS DUTCH III - B, L.P.
                            By: Willis Stein & Partners Management III, L.P.,
                                   Its General Partner
                            By:  Willis Stein & Partners Management III, L.L.C.,
                                   Its General Partner

                            By:        /s/      Robert C. Froetscher
                                ------------------------------------------------
                            Name:               Robert C. Froetscher
                            Title:              Managing Director


                            WILLIS STEIN & PARTNERS III - C, L.P.
                            By: Willis Stein & Partners Management III, L.P.,
                                   Its General Partner
                            By:  Willis Stein & Partners Management III, L.L.C.,
                                   Its General Partner

                            By:        /s/      Robert C. Froetscher
                                ------------------------------------------------
                            Name:               Robert C. Froetscher
                            Title:              Managing Director


                            ORIUS CORP.

                            By:        /s/      Ronald L. Blake
                                ------------------------------------------------
                            Name:               Ronald L. Blake
                            Title:     Chairman of the Board, Chief Executive
                                         Officer and President

                            NATG HOLDINGS, LLC

                            By:        /s/      Ronald L. Blake
                                ------------------------------------------------
                            Name:               Ronald L. Blake
                            Title:              Vice President


                    FIRST AMENDMENT TO EQUITY CALL AGREEMENT
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                            BANKERS TRUST COMPANY,
                            as Administrative Agent

                            By:        /s/      Robert Telesca
                                ------------------------------------------------
                            Name:               Robert Telesca
                            Title:              Vice President



                    FIRST AMENDMENT TO EQUITY CALL AGREEMENT