EXHIBIT 99.6 SUBSIDIARY SECURITY AGREEMENT This SECURITY AGREEMENT is made and entered into as of this 26th day of August, 2002, amongTwinVision of North America, Inc., a North Carolina corporation andDigital Audio Corporation, a North Carolina corporation (each a “Guarantor” and collectively, the “Guarantors”), andJohn D. Higgins (referred to as “Lender”). WHEREAS, Lender andDigital Recorders, Inc. (the “Borrower”), have entered into a Convertible Loan Agreement of even date herewith (the “Loan Agreement”), pursuant to which Lender will lend to the Borrower the aggregate principal amount of $250,000 evidenced by the Borrower’s 8.00% Convertible Debentures of even date herewith (the “Debentures”); WHEREAS, as a condition for entering into the Loan Agreement and providing the Loan, Lender required that Guarantors, each a subsidiary of the Borrower, guarantee the Obligations of the Borrower and grant a security interest in the assets of Guarantors as collateral for such Guarantee; and WHEREAS, Guarantors executed a Guarantee of even date herewith in favor of Lender (the “Guarantee”), whereby Guarantors guaranteed the due performance and full and prompt payment of all obligations and indebtedness of the Borrower arising under the Loan Agreement; NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements set forth herein, the parties hereby agree as follows: 1. Grant of Security Interest. In order to secure payment when due of all Obligations now existing or hereafter incurred, Guarantors hereby irrevocably grant to Lender a continuing security interest in the following property of Guarantors (the “Collateral”), whether now owned or existing, or hereafter acquired, owned, existing or arising (whether by contract or operation of law), and wherever located, which shall be retained by Lender until the Obligations have been paid in full and the Loan Agreement has been terminated;provided, however, that such Liens in the Collateral shall at all times be subject and subordinate in all respects to the Liens granted by Guarantors to the holders of Senior Obligations. |