ADT is Canada's oldest and largest electronic monitoring security company.

Established in 1874, ADT operates in several countries around the world. Over 125 years ago, American District Telegraph (ADT) messengers could report a fire in three minutes flat. Today, ADT's fastest detection system works in less than a second. From humble beginnings to world - wide operations, ADT has become a leader in providing state of the art technology for the protection of people, property and businesses.

When you're protected by ADT, you're protected by the largest, oldest, and one of the best security companies in the nation.

Throughout its 125+ year history, ADT has led the way in the innovation of security services, from the simple Call Boxes of the early 1900's to the interactive video surveillance of the year 2000. And this expertise is recognized. A significant number of Fortune 500 companies rely on ADT for their security needs, as does the largest residential customer base in the electronic security industry. In fact, with over 500,000 customers nationwide, ADT's market share is nearly three times greater than its nearest competitor.