EXHIBIT 2.5.10

                                    AGREEMENT

THIS AGREEMENT (the "Agreement") is dated as of the 15th day of March, 1999 (the
"Effective Date") by and between Able Telcom Holding Corp. (the "Company") and
WorldCom Network Services, Inc. (the "WorldCom"). (The Company and WorldCom are
sometimes individually referred to as a "Party" and collectively as the
"Parties").

                                    RECITALS

A. On or about April 26, 1998, Able entered into an Agreement and Plan of Merger
(the "MFSNT Document") which parties also included MFS Acquisition Corp., MFS
Network Technologies, Inc. and MFS Communications Company, Inc., which MFSNT
Document has been amended from time which, among other things, provides in
Section 17.d. thereof that in the event that the holder of the "Option", as
described below, exercises the Option in whole or in part and whether for cash
or on a "cashless" basis, the holder shall be entitled to designate a represent
to serve of the Company's Board of Directors.

B. On or about January 8, 1999, the Parties entered into (i) an agreement
whereby the an option to purchase 2,000,000 shares of common stock of the
Company ("Option") was modified which provided, in part, that unless and until
such time as shareholder approval is obtained by the Company (if ever) pursuant
to Nasdaq Marketplace Rule 4460(i)(1)(C) to approve the issuance of 20% or more
of the common stock of the Company, the Option was modified to a stock
appreciation rights award ("SAR") (the "Option Modification") and (ii) an
agreement (the "Intent Agreement") to enter into an "SAR Agreement", as that
term is defined in the Intent Agreement, upon the happening of certain
conditions.

C. The Parties now wish to modify certain terms of the Option Modification and
the Intent Agreement.

NOW, THEREFORE, in consideration of the mutual covenants set forth herein, and
other good and valuable consideration, the receipt and adequacy of which is
hereby acknowledged thereof, the parties hereto agree as follows:

1. INCORPORATION BY REFERENCE. The above recitals are true, correct and are
incorporated herein by reference.

2. MODIFICATION TO THE MFSNT DOCUMENT. Section 17.d. (Board Representation)
shall be deleted in its entirety from the MFSNT Document and all amendments
thereto, and as a result, the Company shall have no obligation to appoint a
person designated by WorldCom or any of its affiliates to the Company's Board of
Directors.

3. MODIFICATION TO OPTION MODIFICATION. Section 2.b. of the Option Modification
shall be modified in its entirety to read as follows:

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         EXERCISE PERIOD. The SARs shall be exercisable, in whole or in part, at
         the times and in the manner specified by Section 2.e. below commencing
         on the earlier of: (i) one (1) business day after the date upon which
         the potential issuance of Common Stock under this Agreement is voted
         upon by the shareholders of the Company and (ii) July 1, 1999 (the
         "Commencement Date"), and ending on January 2, 2002 (the "Termination
         Date"). All rights with respect to any unexercised SARs shall expire,
         and these SARs shall become null and void, at 5:00 on the Termination
         Date.

4. MODIFICATION TO INTENT AGREEMENT. Section 2.a. of the Intent Agreement shall
be modified in its entirety to read as follows:

         The Company shall issue to WorldCom a Stock Appreciation Agreement
         ("SAR Agreement") in substantially the form attached hereto as Exhibit
         "A" promptly upon the satisfaction of the Conditions to Issuance as set
         forth in Section 2.b. below; provided that to the extent (i) that the
         issuance of such SAR Agreement would otherwise cause a default in
         connection with any agreement or arrangement with any other third
         parties, including any of the Restrictive Agreements, or (ii) if the
         Conditions to Issuance have not been satisfied on or before July 1,
         1999, then in either of such events the Parties shall use their
         respective good faith efforts to agree upon such modifications to the
         terms of the SAR Agreement so that such SAR Agreement would not cause
         such a default or require a consent from a third party.

5. FURTHER ASSURANCES. The Parties hereby agree from time to time to execute and
deliver such further and other transfers, assignments and documents and do all
matters and things which may be convenient or necessary to more effectively and
completely carry out the intentions of this Agreement.

6. BINDING EFFECT. All of the terms and provisions of this Agreement, whether so
expressed or not, shall be binding upon, inure to the benefit of, and be
enforceable by the Parties and their respective administrators, executors, legal
representatives, heirs, successors and permitted assigns.

7. GOVERNING LAW. This Agreement and all transactions contemplated by this
Agreement shall be governed by, and construed and enforced in accordance with,
the internal laws of the State of Florida without regard to principles of
conflicts of laws.

8. ENTIRE AGREEMENT. This Agreement represents the entire understanding and
agreement among the Parties with respect to the subject matter hereof, and
supersedes all other negotiations, understandings and representations (if any)
made by and among such Parties.

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IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the date
first above written.

THE COMPANY:                                 WORLDCOM:

ABLE TELCOM HOLDING CORP.                    WORLDCOM NETWORK SERVICES, INC.


By:/s/ Billy V. Ray, Jr.                     By: /s/ David F. Meirs
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Name: Billy V. Ray, Jr.                      Name: David F. Meirs
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Its: President                               Its: VP & Controller
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