EXHIBIT 99.4 PLEDGE AGREEMENT This PLEDGE AGREEMENT, dated as of August 26, 2002, betweenDigital Recorders, Inc., a North Carolina corporation (“Pledgor”) andJohn D. Higgins (“Secured Party”). RECITALS A. Pledgor and Secured Party entered into a Convertible Loan Agreement of even date herewith (the “Loan Agreement”). Capitalized terms used but not defined herein shall have the meanings set forth in the Loan Agreement. B. Pursuant to the terms of the Loan Agreement, Secured Party will lend to Pledgor the aggregate principal amount of $250,000 to be evidenced by the Pledgor’s 8.00% Convertible Debentures of even date herewith (the “Debentures”). C. Pledgor is the owner of the shares (collectively, the “Shares”) of capital stock hereto issued by each Subsidiary described onSchedule A, and Pledgor has agreed to pledge and assign to Secured Party a security interest in the Shares, together with any additional shares of capital stock of any U.S. subsidiary subsequently acquired by Pledgor or an affiliate, subject with respect to such U.S. subsidiaries only, to the prior pledge to Guaranty Business Credit Corporation (“GBCC”), Renaissance US Growth & Income Trust PLC (“RUSFIT”) and BFSUS Special Opportunities Trust PLC (“BFSUS”) to secure payment of the Obligations of Pledgor under the Loan Agreement and Debentures. NOW, THEREFORE, in consideration of the foregoing recitals and the mutual covenants, the parties agree as follows: 1. Pledge of Shares. Pledgor hereby pledges and assigns to the Secured Party the Shares, subject with respect to any U.S. subsidiaries only, to the prior pledge to GBCC, BFSUS and RUSFIT, for the purpose of securing the full and prompt payment, when due, by Pledgor of the Obligations. 2. Delivery of Shares. In the event that GBCC, BFSUS and RUSFIT release its security interest in the Shares of the U.S. subsidiaries, the Pledgor shall deliver such Shares to Secured Party with duly executed stock powers, in blank. Secured Party shall hold all such certificates and stock powers subject to the terms of this Pledge Agreement. 3. Voting of Shares and Receipt of Dividends. Subject to the rights of GBCC, BFSUS and RUSFIT with respect to the shares of the U.S. subsidiaries, Pledgor shall have the right to vote the Shares, except as provided herein and in the Loan Agreement and Debentures, upon the occurrence of an Event of Default or a Default. 4. Representations and Warranties. Pledgor hereby warrants, represents and covenants as follows: 1 |