• Designed Security, Inc.

• Detection Systems Inc.

• Detex Corporation

• Dexter Research Center

• Diamond Electronics

• Diebold Incorporated

• Digital Techniques, Inc.

• Domokur Robinson Edwards

• Dorlen Products

• Draeger Safety, Inc.

• Dukane Corp.

• Duseung Trading Co.

• Dynalock Corp.

• Dynamation Gas Detectors

• ELK Products

• EMX Industries

• EO Integrated Systems, Inc.

• Edko, Inc.

• Edwards Door Systems Ltd.

• Elcom Industries

• Electrical Products Company

• Electronic Locking Specialties

• Electronic Specialties of Connecticut

• Electronic Systems USA

• Eltec Instruments

• Essex Electronics, Inc.