For security projects that require the best perimeter protection available, the FD525 Alarm Processing Units (APUs) from Fiber SenSys are the solution. These all-fiber-optic intrusion detection systems are capable of detecting simultaneous intrusion attempts on multiple zones along your perimeter. Know instantly when an intruder or a group of intruders is attempting to breach your perimeter. The unique capabilities of the FD525s provide the highest perimeter security in the market. The FD525 cable assembly consists of up to 25 individual sensor elements branching off a rugged, insensitive backbone cable. Sensor elements placed along the backbone cable define each zone location.