PATENT ACQUISITION AGREEMENT

Exhibit 10.1

PATENT ACQUISITION AGREEMENT

This Patent Acquisition Agreement (“Agreement”) is entered into effective as of this 31 day of May, 2005 (“Effective Date”), by and among Summit Telecom Systems, Inc., a New Jersey corporation having a principal place of business at 158 Chateau Thierry Avenue, Madison, New Jersey 07940 (“Assignor”), and Arbinet-thexchange, Inc., a Delaware corporation, having a principal place of business at 120 Albany Street, Tower II, Suite 450, New Brunswick, NJ 08901 (“Assignee”).

WITNESSETH

WHEREAS, Assignor is willing to sell its right, title and interest in certain of its patents and patent applications to Assignee; and

WHEREAS, Assignee wishes to acquire such patents and patent applications in a transaction described herein (the “Acquisition”).

NOW THEREFORE

In view of the foregoing premises and the mutual covenants set forth herein, the parties agree as follows:

1.1 Assigned Patents . The U.S. and non-U.S. patents and patent applications, including any divisional, continuation, continuation-in-part, reissue or re-examination applications, or patents issuing therefrom (and further including any foreign counterpart patents and applications corresponding thereto), as more particularly set forth in Schedule I hereto, but excluding the Non-Assigned Patent as defined and described herein.

1.2 Assigned Application . U.S. Patent Application No. 09/925,758, which published on February 13, 2003 as U.S. Patent Application Publication No. US2003/0033238 Al (the “ ‘758 Application”), including any divisional, continuation, reissue or re-examination applications, or patents issuing therefrom (and further including any foreign counterpart patents and applications corresponding thereto).

1.3 Non-Assigned Patent . U.S. Patent No. 6,167,124, including any reissue or re-examination applications, or patents issuing therefrom, as well as any other patents which do not claim priority to any of the Assigned Patents or Assigned Application.

The closing of the Acquisition is subject to the following conditions:

2.1 Due Diligence for Assigned Patents . The Assignee and its attorneys shall have satisfactorily completed their due diligence investigation of the Assignor and the Assigned Patents. Between the Effective Date and the closing, these representatives shall be given full access to all files owned or controlled by Assignor (excluding all documents covered by

Assignor’s attorney-client privilege) relating to the ownership, prosecution or issuance of the Assigned Patents (collectively, the “Assigned Patents Files”). Assignor agrees to cause its officers and management to cooperate fully with Assignee’s representatives and agents and to make themselves available to the extent reasonably necessary to complete the due diligence process and the closing of the Acquisition.

2.2 Due Diligence for Assigned Application . The Assignee and its attorneys shall have satisfactorily completed their due diligence investigation of the Assignor and the Assigned Application. Between the Effective Date and the closing, Assignee and its attorneys shall be given full access to all files provided to Assignor or its affiliates by patent counsel for the ‘758 Application and to all documents executed or prepared by Assignor or its affiliates or attorneys as a result of the filing and prosecution of the ‘758 Application with the USPTO or to effect the assignment to Assignor of the entire right, title and interest in the ‘758 Application of two of the eight co-inventors named therein (excluding, in each case, all documents covered by attorney-client privilege) (collectively, the “Assigned Application Files”). Assignor agrees to cause its officers and management to cooperate fully with Assignee’s representatives and agents and to make themselves available to the extent reasonably necessary to complete the due diligence process and the closing of the Acquisition.

2.3 Closing Date . The closing of the Acquisition shall take place on a date to be mutually agreed by Assignor and Assignee, but in no event later than June 28, 2005 (the “Closing Date”), provided, however, that Assignor allows the due diligence process set out in Sections 2.1 and 2.2 above (“Due Diligence”) to commence at least two weeks prior to the Closing Date. If Assignor fails to do so, then the Closing Date shall be two weeks from such date.

2.4 Document Return or Disposition . In the event the Acquisition fails to close on or before the Closing Date specified in Section 2.3 above, unless otherwise agreed to in a writing signed by the Assignor and Assignee, Assignee shall (i) immediately return to Assignor all files and materials made available by Assignor to Assignee or its attorneys or agents under Section 2.1 or Section 2.2 hereof or otherwise under this Agreement (together with all copies of such files and materials made by Assignee or its attorneys or agents, expressly excluding any materials containing information protected by attorney-client privilege, attorney work product, or any other applicable privilege), and (ii) immediately destroy and discard, or cause to be destroyed or discarded, all notes, memoranda, analyses, opinions, recordings, and any other written or recorded information or media prepared by Assignee or its attorneys or agents (including materials containing information protected by attorney-client privilege, attorney work product, or any other applicable privilege) as a result of, or in connection with, the review by Assignee of any non-public files or materials made available by Assignor to Assignee under Section 2.1 or Section 2.2 hereof or otherwise under this Agreement.

3.1 Assignment of Assigned Patents . Assignor agrees to sell, transfer and assign its entire right, title and interest in the Assigned Patents to Assignee pursuant to the Patent Assignment attached hereto as Exhibit A, free and clear of all liens, mortgages, pledges, security interests, prior assignments and encumbrances of any kind or nature whatsoever. On the Closing Date, Assignor shall execute and have notarized a Patent Assignment in the form attached hereto as

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Exhibit A for filing by Assignee with the U.S. Patent and Trademark Office (the “USPTO”) and any foreign patent office that is relevant. Upon the closing of the Acquisition, this Patent Assignment shall be effective and, thereafter, (i) Assignee shall have sole responsibility and authority to prosecute any pending patent application included in the Assigned Patents, and (ii) Assignee shall assume responsibility for all fees and expenses associated with the Assigned Patents including, without limitation, all maintenance, annuity and prosecution-related fees and expenses.

3.2 Further Assurances as to Assigned Patents . At any time and from time to time after the closing of the Acquisition, at Assignee’s reasonable request and expense, Assignor shall promptly execute and deliver, and shall cause its officers and employees (when appropriate) to execute and deliver, in a form reasonably acceptable to Assignor, such instruments of sale, transfer, conveyance, assignment and confirmation as may reasonably be required, and shall take such other action as Assignee may reasonably request, to more effectively transfer, convey and assign to Assignee all of Assignor’s right, title and interest in the Assigned Patents and to confirm such sale, transfer, conveyance and assignment by Assignor to Assignee. In the event that a party becomes aware of any existing patent or pending patent application that is covered by the definition of Assigned Patents but which is not currently listed on Schedule I, such patent or patent application shall automatically be added to Schedule I and shall be deemed to constitute Assigned Patents for all purposes hereunder. Prior to the closing of the Acquisition, Assignor will procure a certification from Jack J. Johnson (“Johnson”) and William F. Coyle (“Coyle”) (together, the “Assigned Patents Co-Inventors”), in the form attached hereto as Exhibit C, in which the Assigned Patents Co-Inventors each certify that (i) the co-inventors named in the issued U.S. patents and pending applications listed in Schedule 1 of this Agreement are the joint inventors of the claimed subject matter therein, (ii) the co-inventors have no knowledge of any misjoinder or nonjoinder of inventorship in the Assigned Patents, (iii) each has assigned all of his ownership interests in the Assigned Patents (excluding U.S. Patent No. 5,606,602) to Assignor, and (iv) each has assigned all of his ownership interest in U.S. Patent No. 5,606,602 to Geophonic Networks, Inc. (“Geophonic”). Assignor will also procure, prior to the closing of the Acquisition, a certification from Geophonic, in the form attached hereto as Exhibit D, in which Geophonic certifies that it has assigned all of its ownership interest in U.S. Patent No. 5,606,602 to Assignor.

3.3 Assignment of Assigned Application . Assignor agrees to sell, transfer and assign to Assignee all right, title and interest Assignor may hold in the Assigned Application, as the assignee of the entire right, title and interest of two of the eight named co-inventors listed in the Assigned Application, pursuant to the Patent Assignment attached hereto as Exhibit B. On the Closing Date, Assignor shall execute and have notarized a Patent Assignment in the form attached as Exhibit B for filing by Assignee with the USPTO and any foreign patent office that is relevant. Assignor is unaware of any divisional, continuation, continuation-in-part, reissue or re- examination applications, or any patents issuing therefrom (or any foreign counterpart patents or applications corresponding thereto) that rely on U.S. Application No. 09/925,758 for priority. Within five days after closing, Assignor will notify Accenture’s counsel in writing of the change of ownership.

3.4 Further Assurances as to Assigned Application . At any time and from time to time after the closing of the Acquisition, at Assignee’s reasonable request and expense, Assignor shall

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promptly execute and deliver, and shall cause its officers and employees (when appropriate) to execute and deliver, in a form reasonably acceptable to Assignor, such instruments of sale, transfer, conveyance, assignment and confirmation as may reasonably be required, and shall take such other action as Assignee may reasonably request, to more effectively transfer, convey and assign to Assignee all of Assignor’s right, title and interest in the Assigned Application and to confirm such sale, transfer, conveyance and assignment by Assignor to Assignee. Prior to the closing of the Acquisition, Assignor will procure a certification from Johnson and Coyle, in the form attached hereto as Exhibit E, in which Johnson and Coyle each certify that (i) he has been listed as one of eight persons named in the Assigned Application as co-inventors of at least a portion of the claimed subject matter therein, and (ii) each has assigned all of his ownership interests in the Assigned Application to Assignor.

3.5 Retention by Assignor of Non-Assigned Patent . Assignor owns all right, title and interest in and to the Non-Assigned Patent and, after the closing of the Acquisition as described elsewhere in this Agreement, Assignor shall continue to own all right, title and interest in and to Non-Assigned Patent. No portion of the Non-Assigned Patent is being sold, transferred, conveyed or assigned by Assignor to Assignee under this Agreement or otherwise.

4.1 Payment . In full consideration of the assignment of rights made hereunder, and subject to Section 2.0 herein, Assignee shall pay to Assignor a total sum of One Million One Hundred Thousand U.S. Dollars ($1,100,000.00) (the “Purchase Price”) in two installments as follows: (i) the first installment shall be in the amount of Nine Hundred Thousand Dollars ($900,000.00) in cash and shall be paid to Assignor on the Closing Date (the “First Installment”); and (ii) the second installment shall be in the amount of Two Hundred Thousand Dollars ($200,000.00) in cash and shall be paid on January 5, 2006 (the “Second Installment”).

4.2 Escrow Account . To secure payment of the Second Installment, the Assignee shall deposit on the Closing Date the sum of Two Hundred Thousand Dollars ($200,000.00) in cash into a non-interest bearing escrow account (the “Escrow Account”) with an FDIC-insured national banking institution (the “Escrow Agent”) mutually acceptable to the parties. The Escrow Account shall be established pursuant to a mutually acceptable Escrow Agreement that shall contain instructions directing the Escrow Agent to pay all monies in the Escrow Account to Assignor on January 5, 2006 in full satisfaction of the payment of such Second Installment. The costs and expenses of such Escrow Agent shall be shared equally by Assignor and Assignee.

4.3 Method of Payment . The First Installment and the Second Installment shall each be paid to Assignor either by bank wire, with receipt confirmed by the receiving bank to an account designated by Assignor for this purpose, or by delivering to Assignee a bank certified or cashier’s check for the applicable amount.

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With respect to the Assigned Patents, Assignor represents and warrants to Assignee as follows in Sections 5.1 through and including Section 5.8:

5.1 Assigned Patents . Schedule I hereto lists all patents and patent applications included within the definition of Assigned Patents under this Agreement.

5.2 Ownership of Assigned Patents . Assignor is the sole and exclusive owner of the Assigned Patents, and it has the unencumbered right to sell and transfer its entire right, title and interest in the Assigned Patents to Assignee as contemplated hereby. The Assigned Patents are free and clear of all liens, mortgages, pledges, security interests, prior assignments or encumbrances, and any restrictions on transfer.

5.3 Files . Assignor shall use its best efforts to provide to Assignee all existing files and records specified in Section 2.1 hereof as the Assigned Patents Files.

5.4 Licenses as to Assigned Patents . Assignor has not granted any license or right under any of the Assigned Patents to any third party.

5.5 Status of Patents and Applications as to Assigned Patents . All maintenance fees required to be paid as of the Closing Date with respect to all issued U.S. patents listed in Schedule I hereto have been or shall be paid by Assignor. To the best of Assignor’s knowledge, U.S. Application No. 09/851,483 is pending at the USPTO and Japanese Patent Application No. JP 2000-527077 is pending at the Japanese Patent Office.

5.6 Sufficiency of Rights as to Assigned Patents . All issued patents included as Assigned Patents are subsisting and in full force and effect. At the closing of the Acquisition, Assignor will assign its entire right, title and interest in the Assigned Patents to Assignee. The execution of this Agreement will not result in the loss or impairment of the right, title and interest in the Assigned Patents that Assignor will convey to Assign