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                                                                  EXHIBIT 4.19.1

              AMENDMENT NO. 1 TO SECURITIES EXCHANGE AGREEMENT AND
          RELATED REGISTRATION RIGHTS AGREEMENT OF ABLE TELCOM HOLDING
                                      CORP.
                       [RGC INTERNATIONAL INVESTORS, LDC]

         This Amendment No. 1 ("Amendment No. 1") dated as of July 7, 2000 to
the Securities Exchange Agreement dated as of February 4, 2000 ("Exchange
Agreement"), by and between RGC International Investors, LDC ("Holder") and Able
Telcom Holding Corp. (the "Company"), and an amendment to a related Registration
Rights Agreement entered into by the Holder and the Company pursuant to the
Exchange Agreement as specifically described herein.

                                    RECITALS

         WHEREAS, in June 1998 the Company issued, pursuant to a Purchase
Agreement (the "Series B Purchase Agreement") to the Holder, 2000 shares of
Series B Preferred Stock, and in connection therewith, the Holder and the
Company entered into a Registration Rights Agreement substantially in the form
of Exhibit A hereto (the "Series B Registration Rights Agreement"), the Articles
of Amendment substantially in the form of Exhibit B hereto (the "Series B
Articles of Amendment") and other documents related to the issuance of Series B
Preferred Stock and included as exhibits to the Company's public filings with
the Securities and Exchange Commission (the "Series B Agreements" and
collectively with the Series B Registration Rights Agreement and the Series B
Articles of Amendment, the "Series B Documents"); and

         WHEREAS, in February 2000 the Holder and the Company entered into the
Exchange Agreement, a copy of which is attached as Exhibit C and incorporated by
reference herein, whereby, in exchange for the surrender to the Company by the
Holder of 375 Preferred Shares (constituting all the Company's Series B
Preferred Shares then still held by the Holder), the Company issued 500,000
shares of Company Common Stock, $0.001 par value per share (the "Common Stock"),
plus $5,031,978 in cash, and the registration rights and warrants described in
the next succeeding paragraphs; and

         WHEREAS, the Company and the Holder, as of February 4, 2000, entered
into a Registration Rights Agreement ("Exchange Registration Rights Agreement")
substantially in the form of Exhibit D attached hereto and incorporated by
reference herein, to provide for the registration of the shares of Common Stock
issued to the Holder pursuant to the Exchange Agreement and the shares
underlying the Warrants issued pursuant to the Exchange Agreement; and

         WHEREAS, the Company issued to the Holder warrants for 100,000 shares
of Common Stock, referred to as the "Warrants", a form of the Warrant being
substantially in the form as Exhibit F hereto which form shall be incorporated
by reference herein; and

         WHEREAS, the Company and the Holder are entering into this Amendment
No. 1 in connection with the Company's settlement of its obligation to Sirit
Technologies, Inc. ("Sirit"), as


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described in the Settlement Agreement between the Sirit Parties and the Able
Parties (as each of those terms are defined in the Sirit Settlement Agreement)
dated as of July 7, 2000 (the "Sirit Agreement"); and

         WHEREAS, the Holder and the Company wish in this Amendment No. 1 to
amend the Exchange Agreement and the Exchange Registration Rights Agreement, but
not the Warrant or the other Series B Documents (together, the "Transaction
Documents"); and

         WHEREAS, the Company will, as promptly as possible, call and hold a
shareholders meeting to consider and approve (1) an amendment to the Company's
Articles of Incorporation to increase the number of shares of authorized Common
Stock to 100,000,000 shares of Common Stock; (2) one or more proposals to issue
the shares of Common Stock pursuant to this Amendment No. 1 and pursuant to
certain other agreements between the Holder and the Company; (to the extent
shareholder approval of such issuance is required) and (3) a proposal to issue
shares of Common Stock pursuant to the Sirit Agreement (matters (1), (2) and (3)
together, the "Shareholder Proposals").

         NOW, THEREFORE, intending to be legally bound hereby, the Parties agree
that all capitalized terms not defined herein shall have the meanings ascribed
to them in the Exchange Agreement and as follows:

1.       Recitals. The above recitals are true, correct and incorporated herein
by reference.

2.       Amendment to Exchange Registration Rights Agreement to Revise
Definition of Registration Deadline.

         The term "Registration Deadline" in Section 1 of the Exchange
Registration Agreement shall be amended and restated in its entirety to read as
follows:

                           "Registration Deadline" shall mean the date
                  the Company, using its Best Efforts, is able to
                  secure the effectiveness of the Registration
                  Statement (defined herein); provided, however, that
                  in no event shall the Registration Deadline be later
                  than November 30, 2000."

3.       Agreement with Respect to Bankruptcy.

         The Holder agrees not to place Able in involuntary bankruptcy from the
date of this Agreement until either (a) if the Sirit Shares are issued prior to
December 1, 2000, 91 days following the issuance of the Sirit Shares; or (b) if
the Sirit Shares are not issued by December 1, 2000, for 91 days following the
date on which the Consent Judgment has been paid or satisfied in full (but in no
event later than May 31, 2001).


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4.       Proxy.

         The Holder shall execute a form of proxy attached to this Amendment No.
1 as Exhibit "F" whereby the Holder agrees to vote any shares of Common Stock
held by the Holder in support of the Shareholder Proposals.

5.       Condition to Effectiveness of Amendment No. 1.

         This Amendment No. 1 shall not be effective until all of the conditions
contained in Section XI (other than Condition XI.B. which is covered by this
Amendment No. 1) of the Sirit Agreement have been satisfied in full (unless
waived by the Investors).

         The Company shall inform the Holder in writing upon the satisfaction of
such conditions. The Holder may waive satisfaction of such conditions at any
time.

6.       Miscellaneous.

         a.       Entire Understanding. This Amendment No. 1, together with the
Transaction Documents, contains the entire understanding of the parties with
respect to the matters covered hereby. Except as set forth in this Amendment No.
1, the terms of the Transaction Documents shall remain in full force and effect.

         b.       Further Actions. The Company and the Holder acknowledge that
this Amendment No. 1 is being entered into in connection with the Company's
settlement of its obligation to Sirit arising out of certain litigation with the
Sirit. The Company and the Holder agree that they shall take such further
actions as may be required to effect the intent and purpose of this Amendment
No. 1, including the filing of amended Articles of Amendment and the execution
of any further amendments to any of the Transaction Documents, as may be
reasonably requested by the Company or any Investor, to carry out the purpose
and intention of this Agreement.

         c.       Governing Law. This Amendment No. 1 shall be governed by and
construed and enforced in accordance with the laws of the State of New York
applicable to agreements executed and to be performed entirely within such state
and, where applicable, federal law.

         d.       Counterpart Signatures. This Amendment No. 1 may be executed
in two or more counterparts, all of which shall be considered one and the same
amendment, it being understood that all parties need not sign the same
counterpart.

         e.       Construction. The language in this Amendment No. 1 will be
deemed to be the language chosen by the parties to express their mutual intent,
and no rules of strict construction shall be applied against any party.

         f.       Conflict with other Documents. To the extent that the
provisions of any of the Transaction Documents conflict with this Amendment No.
1, the terms of this Amendment No. 1 shall govern provided that, the parties
acknowledge and agree that if any references to section or paragraph number are
not accurately reflected in this Amendment No. 1, then this Amendment No.


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1 shall be amended to reflect such changes without any further actions on the
part of any of the parties.

                          [SIGNATURES ON THE NEXT PAGE]


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IN WITNESS WHEREOF, the Parties hereto have caused this Amendment No. 1 to be
executed as of the day and year first above written.

                                       HOLDER:

                                       RGC INTERNATIONAL INVESTORS, LDC
                                       By:    Rose Glen Capital Management, L.P.
                                              Investment Manager

                                       By:    RGC General Partner Corp.
                                              As General Partner


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

                                       ABLE TELCOM HOLDING CORP.


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


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                                   EXHIBIT "F"

                            ABLE TELCOM HOLDING CORP.
                                      PROXY

I appoint Michael Brenner and Edward Z. Pollock, or either one, the
undersigned's proxy to vote all of its shares of common stock of Able Telcom
Holding Corp. that are entitled to vote at any meeting of Able Telcom Holding
Corp. shareholders called to approve the Shareholder Proposals (as defined in
Amendment No. 1 to Securities Exchange Agreement and Related Registration Rights
Agreement of the Company and the undersigned dated as of July 7, 2000),
including the proposal to issue to Sirit Technologies shares of Common Stock
pursuant to the Settlement Agreement, dated as of July 7, 2000 (the "Sirit
Agreement"), between the "Sirit Parties" and the "Able Parties"; as each of
those terms is defined in the Sirit Agreement, a copy of which Sirit Agreement
is attached as Exhibit "A," in favor of the Shareholder Proposals. This proxy
shall expire and be of no further force and effect after December 1, 2000.

----------------, --------

(Complete above date and sign your name as it appears below. If more than one
name appears, each person should sign).

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                                             By:
                                                 -------------------------------
                                             Name:
                                                   -----------------------------
                                             Its:
                                                  ------------------------------
                                             Number of shares of common stock
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