ADT is one of today's most trusted and well-known brands in the security industry and currently serves more than six million customers, making us the largest company of our kind in both the U.S. and Canada. Our broad and pioneering set of products and services—from interactive home and business solutions to home health services—meet a range of customer needs for today's active and increasingly mobile lifestyles. Serving the entire state of IL including, but not limited to, Chicago, Peoria, Springfield, Decatur, Aurora, Evanston, Waukegan, Arlington Heights, Elgin, Cicero, Oak Lawn, Skokie, Champaign, East St. Louis, Oak Park, Schaumburg, Mount Prospect, Berwyn, Rock Island, and Moline.. Call today to enjoy home security for less than $1 a day or for great deals on security for your business.