ADS Security is the 21st-largest electronic security alarm firm in the nation according to the rankings compiled by Security Distributing & Marketing, a leading industry publication. The company provides a full range of burglar and fire alarms, closed-circuit television systems, access control systems, process and environmental monitoring systems, audio and video intercoms and music systems. Among its 13 offices, ADS operates the only Underwriters Laboratories-listed and CSAA-certified central station monitoring operation in middle and eastern Tennessee. All of ADS Security s on-premise smoke detectors, motion detectors, and door and window contacts are monitored via a fiber optic telephone network or a radio network. ADS Security is headquartered in Nashville, Tenn.