Physical Security Detection & Deterrence has changed dramatically due to events in the world. It was once thought that the perimeter of security for any facility was the “skin” of the building. However, this is no longer the case. The perimeter of any security protection is now the fence line or property line. IST has been a part of this evolution and is knowledgeable and adept at implementing the numerous methods of providing detection and deterrence for this requirement. These include: Perimeter Intrusion Detection  Turnstiles     Barriers, Gates & Booths