ADT is a business unit of Tyco (NYSE: TYC), the worldís largest company that specializes in fire protection and security. Tyco provides more than three million customers around the globe with the latest fire protection and security products and services. Tyco has more than 69,000 employees in more than 1,000 locations across 50 countries serving some of the worldís most demanding environments, including banking and financial services, oil and gas, marine, government, healthcare, retail, home security, transportation, and commercial and industrial. read full review »