<PAGE>
                                                                   Exhibit 10.11


                                SECOND AMENDMENT

                                       TO

                SECURED CONVERTIBLE DEBENTURE PURCHASE AGREEMENT

                                      AMONG

                        DIGITAL DESCRIPTOR SYSTEMS, INC.

                                       AND

                         THE INVESTORS SIGNATORY HERETO






                           Dated as of August 10, 2001


<PAGE>

         SECOND AMENDMENT TO SECURED DEBENTURE PURCHASE AGREEMENT ("Second
Amendment") dated as of August 10, 2001, among Digital Descriptor Systems, Inc.,
a Delaware corporation (the "Company"), and the investors signatory hereto (each
such investor is a "Purchaser" and all such investors are, collectively, the
"Purchasers").

                                   WITNESSETH:

                  WHEREAS, as of December 28, 2000, the Company and Purchasers
entered into a Secured Convertible Debenture Purchase Agreement (the "Original
Agreement"), which, among other things, provides that, subject to the terms and
conditions set forth in the Original Agreement and in accordance with ss.4(2)
under the Securities Act and Rule 506 promulgated thereunder, the Company would
issue and sell to Purchasers and the Purchasers, severally and not jointly,
would purchase the Debentures and Warrants from the Company; and

                  WHEREAS, pursuant to the terms of the Original Agreement, as
of December 28, 2000, the Company and the Purchasers delivered the following:
(A) the Company executed and delivered a (i) Debenture in the principal amount
of $100,000 to each Purchaser (each, an "Original Debenture" and collectively,
the "Original Debentures"), (ii) Warrant to purchase 200,000 shares of Common
Stock to each Purchaser, (iii) direction letter to the Company's transfer agent
(the "Original Direction Letter"); and (B) the Company and Purchasers executed
and delivered a (i) registration rights agreement (the "Original Registration
Rights Agreement"), and (ii) a security agreement (the "Original Security
Agreement"); and (C) each Purchaser paid $100,000 to the Company; and

                  WHEREAS, subject to the terms and conditions set forth in a
First Amendment to the Original Agreement and in accordance with ss.4(2) of the
Securities Act and Rule 506 promulgated thereunder, the Company and Purchasers
desire to (A) amend the (i) Original Agreement to increase the aggregate
purchase price for the Debentures to $800,000 (the "New Aggregate Purchase
Price") and to provide that, subject to the amendments set forth herein, the
First Additional Funding Date will be the date hereof, (ii) Original
Registration Rights Agreement to reflect new time periods and the New Aggregate
Purchase Price, (iii) Original Security Agreement and Original Direction Letter
to reflect the New Aggregate Purchase Price; and (B) issue allonges to the
Original Debentures to reflect the New Aggregate Purchase Price, and

                  WHEREAS, pursuant to the terms of the First Amendment to the
original Agreement, as of March 5, 2001, the Company and the Purchasers
delivered the following: (A) the Company executed and delivered a (i) Debenture
in the principal amount of $100,000 to each Purchaser (each, an "Original
Debenture" and collectively, the "Original Debentures"), (ii) Warrant to
purchase 200,000 shares of Common Stock to each Purchaser, (iii) direction
letter to the Company's transfer agent (the "Original Direction Letter"); and
(B) the Company and Purchasers executed and delivered a (i) registration rights
agreement (the "Amended Registration Rights Agreement"), and (ii) a security
agreement (the "Amended Security Agreement"); and (C) each Purchaser paid
$100,000 to the Company; and

                  WHEREAS, subject to the terms and conditions set forth in this
Second Amendment to the Original Agreement and in accordance with ss.4(2) of the
Securities Act and Rule 506 promulgated thereunder, the Company and Purchasers
desire to (A) amend the Original Agreement to change the date of the issuance of
the final convertible debenture of $400,000 to be issued upon the effective date
of the applicable registration statement.

                                      -1-
<PAGE>

                  NOW, THEREFORE, IN CONSIDERATION of the mutual covenants
contained in the First Amendment, and for other good and valuable consideration
the receipted adequacy of which are hereby acknowledged, the Company and
Purchasers agree as follows:

                  A. Defined Terms. All defined terms used in this Second
Amendment, including the defined terms used in the preliminary clauses hereto,
which are not otherwise defined herein shall have the meanings ascribed to them
in the Original Agreement.

                  B. Amendments to Original Agreement. The Company and
Purchasers hereby agree that the Original Agreement is amended as follows:

                     1. Section 1.1(a) of the Original Agreement is hereby
amended as follows:

                        (i)  the reference in subsection (iv) to "then on the
                             tenth (10th) Trading Day ("Second Additional
                             Funding Date") after the Effectivenenss Date, ),
                             (A) the Company will, against delivery of the
                             amounts set forth in clause (B) in this paragraph,
                             deliver to each Purchaser, Debentures in the
                             aggregate principal amount of 50% of the purchase
                             price indicated below such Purchaser's name on the
                             signature page to this Agreement" shall be deleted
                             and substituted therefore with the following:

                             "then upon the third (3rd) Trading Day ("Second
                             Additional Funding Date") after the Effectiveness
                             Date (as defined herein), (A) the Company will,
                             against delivery of the amounts set forth in clause
                             (B) in this paragraph, deliver to each Purchaser,
                             Debentures in the aggregate principal amount of 50%
                             of the purchase price indicated below such
                             Purchaser's name on the signature page to this
                             Agreement" .

                        2. Section 1.1(b)(i) of the Original Agreement and First
Amendment is hereby amended as follows:

                        (i)  Subsection (iii) is hereby amended by deleting the
                             words " June 11, 2001" and by substituting
                             therefore the words "August 31st".

                  C. Representation of Company. To induce Purchasers to enter
into this Second Amendment and to consummate the funding on the Second
Additional Funding Date, the Company hereby represents and warrants to the
Purchasers that no event has occurred or failed to occur which by itself or with
the giving of notice or the passage of time, or both, would constitute a default
or event of default under the Original Agreement, the Debentures or any of the
Transaction Documents.

                                      -2-
<PAGE>

                  The Company also hereby represents and warrants to the
Purchasers that all the conditions necessary for the second funding to occur
have occurred have been satisfied, as laid out in this document.

                  D. Fees. There will be no fees in connection with the
preparation of this Second Amendment and any related documentation.

                  E. No Other Changes. Except as expressly set forth in this
Second Amendment, the terms and conditions of the Original Agreement and First
Amendment remain in full force and effect, unmodified and unchanged.

                  IN WITNESS WHEREOF, the parties hereto have caused this Second
Amendment to be duly executed by their respective signatory as of the date first
indicated above.

                               DIGITAL DESCRIPTOR SYSTEMS, INC.


                               By: /s/ Michael J. Pellegrino
                                 ----------------------------------------------
                                 Michael J. Pellegrino, Chief Financial Officer

                               PURCHASERS:

                               AJW Partners, LLC
                               By: SMS Group, LLC, Manager



                               By: /s/ Corey S. Ribotsky
                                 ----------------------------------
                                        Corey S. Ribotsky

                               New Millennium Capital Partners II, LLC
                               By: First Street Manager II, LLC, Manager



                               By: /s/ Glenn A. Arbeitman
                                 ----------------------------------
                                        Glenn A. Arbeitman




                                      -3-

