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                                                                    EXHIBIT 10.6

                               SECURITY AGREEMENT

                  This Agreement is made as of the 26th day of August, 1999,
between US XCHANGE, L.L.C. ("Debtor"), 20 Monroe Ave. NW, Suite 450, Grand
Rapids, Michigan 49503, and RONALD H. VANDER POL, ("Secured Party"), 20 Monroe
Ave. NW, Suite 450, Grand Rapids, Michigan 49503.

                  1. Creation of Security Interest. Debtor creates a security
interest in favor of the Secured Party in the personal property, including all
proceeds, described on the attached Exhibit A ("Collateral"). This security
interest secures Debtor's repayment of all amounts or obligations owing or to be
owed by Debtor to Secured Party at any time (collectively "Liabilities").

                  2. Debtor's Representation and Promises. Debtor represents
that Debtor has full authority to execute this Agreement, has marketable title
to the Collateral and that the Collateral is free and shall remain free from all
other security interests and other encumbrances except as permitted by Secured
Party. Debtor promises to keep the Collateral fully insured against all risks of
loss or damage, naming Secured Party as an additional loss payee. Debtor
promises to execute and deliver all documents requested by Secured Party to
perfect its security interest under this Agreement.

                  3. Default and Remedies. If any of the following occur: (a)
Debtor's failure to pay or perform when due any part of the Liabilities, (b)
failure of any representation by Debtor or breach by Debtor of any other
provision of this Agreement, (c) issuance of any attachment or levy against any
part of the Collateral, (d) insolvency of Debtor, assignment for the benefit of
Debtor's creditors, or institution of any proceeding by or against Debtor under
any chapter of the federal bankruptcy laws, then the Liabilities shall, at
Secured Party's option, be immediately due and payable without notice or demand.
In addition, Secured Party shall have all the rights and remedies of a secured
party under the Uniform Commercial Code. No delay or omission of Security Party
in exercising any right shall be a waiver of that or any other right.

                  4. Miscellaneous. This Agreement contains all the terms of the
agreement between the parties with respect to the security interest created
under this Agreement and may be amended only by a writing signed by both
parties. This Agreement shall be governed in all respects by the laws of
Michigan.

                                       US XCHANGE, L.L.C.

                                       By  /s/  Richard Postma
                                         --------------------------
                                                Richard Postma

                                       Its  Chairman - CEO
                                          -------------------------
                                                                          DEBTOR

                                       RONALD H. VANDERPOL

                                       /s/  Ronald H. VanderPol
                                       ----------------------------
                                                                   SECURED PARTY


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                                    EXHIBIT A


         All assets of Debtor, including all telecommunications equipment,
         furniture, accounts, documents, chattel paper, instruments, creditor's
         rights, general intangibles, inventory, goods and fixtures now owned or
         hereafter acquired by Debtor, and wherever located, together with all
         accessions, parts, attachments and accessories, the proceeds thereof,
         and the proceeds of all insurance, eminent domain, and condemnation
         awards, and all tax refunds payable to Debtor by any taxing authority.





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