Columbus’ Leading ADT Authorized Premier Provider Serving Columbus and All Surrounding Areas within 100 Mile Radius, 24 hours a day, 7 days a week. ADT, LLC. - America's leading security company, was founded over a century ago. For years, ADT has been the number one trusted source of protection for millions of families, homes and businesses. By signing up for ADT monitoring, you are ensuring that trained professionals with the most sophisticated and innovative security devices – including home security doors – are monitoring your home at all times, 24 hours a day, 7 days a week. Call us at (614) 432-8479.