Keeping unauthorized intruders from entering a business location is a critical part of protecting corporate assets. In many cases, fencing or walls are adequate deterrents. Other times, more sophisticated intrusion detection systems, such as security cameras, thermal energy detectors, and sensor cables, are required. In these scenarios, the data recorded by these field devices need to be transmitted in real time over a network to a communication control room.

The physical cables used for data transmission are generally fiber optic or copper. While data transmission distances over fiber can exceed 180 km, it is sometimes not readily available and can be expensive to install. Copper cabling is often already installed and can be cheaper to maintain, but the data transmission distance is limited to 100 m. To overcome that distance barrier, technicians will reach for an Ethernet extender.

AcoustAlert recently completed a project that utilized this technology to sercure site perimeters.  

“We had an inquiry from a gold mine in Ghana,” said Cliff Rose, managing director at AcoustAlert. “Their perimeter fences were being breached on a regular basis, and they needed a system that would detect the breach and pinpoint the location of it so that their security team could investigate further.”

Dual fences with AcoustAlert perimeter intrusion detection systems (PIDS) on both inner and outer fence lines were erected. The fence was divided into eight zones of around 300 m each. The fence perimeter stretches 2.4 km with the field equipment protected inside custom steel cabinets and located between the two fences. In the event of a fence breach, the field analyzer transmits details of its location to the datacom room on-site for interpretation and action.

“Our initial proposal was to use fiber optic cable around the site to LAN-link the AcoustAlert field processors,” Rose said. “The IT team on-site was more familiar with copper cabling and reluctant to take on the maintenance of the fiber LAN infrastructure. Due to the size of the mine’s perimeter, the 100-m Ethernet distance was just not sufficient. That is where the Perle Ethernet Extenders come into play.”

Two Perle Ethernet Extenders, with four ports each, were installed in each field enclosure and connected to the AcoustAlert field processors to act as both a switch and Ethernet extender.

“The spare Ethernet ports give us flexibility for additional installations should security cameras or other surveillance equipment need to be installed,” Rose said.

When the AcoustAlert system detects fence movement, an alarm indicating the position and description of the zone is displayed on a computer screen to the control room operator. The operator also has several soft outputs that can be controlled on the user interface to open or close gates, switch lights on and off, or monitor cameras.