A.B. Clark established DSI Security Services in 1969. The company employs more than 450 people and has clients in more than 25 states in the southeastern and eastern United States. DSI Security Services clients include large manufacturers, small private businesses, construction sites, shopping centers, hospitals and homes. In addition to providing security guards, the company also markets an electronic line of security equipment available to commercial, institutional and residential clients. The company remains a family owned and operated organization. While DSI Security Services maintains corporate headquarters in Dothan, Ala., it also has regional managers in Alabama, Georgia, Florida, North Carolina, Pennsylvania, Virginia, Mississippi, Tennessee, Arkansas, Texas and South Carolina.