Why Use Fiber Links for Perimeter Communications

Why Use Fiber Links for Perimeter Communications

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When assisting system integrators, A&Es, and end-users with physical security site designs, the topic of network communication links to edge devices such as fence or buried perimeter intrusion detection sensors and IP surveillance cameras often arises. Senstar supports a range of networking and integration interfaces for its perimeter intrusion detection sensors, including Ethernet, RS-422, and fiber (both single-mode and multi-mode), as well as the repurposing of dark fibers within the sensing cables themselves.

While each physical network medium has its own merits, this article focuses on the unique benefits of fiber-based approaches and how they simplify various site planning issues.

Electrical Isolation of Indoor/Outdoor Equipment

For sites with high-voltage equipment near the perimeter, such as electrical transmission and distribution substations, as well as sites experiencing frequent lightning strikes, electrical isolation is essential for safety. Although conductive equipment can be safely installed and grounded according to regulations, additional planning and equipment are typically necessary (including site surveys, inspections, as-built drawings, lightning arrestors, etc.). By linking perimeter devices to the site’s equipment hut via fiber, indoor/outdoor equipment becomes inherently electrically separated and protected through non-conductive connections, simplifying planning significantly. It should be noted, however, that if conductive armor is employed to protect the fiber, the armor must be properly grounded.

Simplified RFI and Induced Current Planning

Fiber communication links can effectively mitigate potential radio frequency interference (RFI) in environments with high RF noise, such as factories or electrical substations. Furthermore, the non-conductive materials of fiber eliminate any risk of dangerous induced current caused by nearby high-voltage lines. While RFI and induced voltage issues can be addressed with proper planning, utilizing fiber links completely removes these concerns.

Longer Distances at Lower Costs

A significant advantage of fiber communications over twisted-pair cable is the extended coverage distance, particularly for long homerun links back to the control room. Senstar’s single-mode fiber optic communication card can transmit data over distances of up to 10 km (32,000 feet). Additionally, fiber optic sensor cables, such as FiberPatrol, can feature lead-in (non-sensing) lengths in the tens of kilometers and can repurpose unused fibers for network communications. This extended range simplifies infrastructure requirements for sites with large perimeters, such as airports and petrochemical facilities.

The cost per meter/foot of fiber is generally lower than that of commercial-grade twisted pair cables, and significantly lower for higher-end multi-conductor cables that require improved shielding. Although installation labor costs are higher for fiber, its widespread usage means that a large pool of certified fiber installers is available.

High Bandwidth Applications

Incorporating intelligent devices and high-resolution cameras (HD or even 4K) around the perimeter enhances overall situational awareness within the facility. However, this also increases the volume of data being transmitted back to the control room. Fiber communication links support various network protocols and high-bandwidth applications. Each physical cable consists of numerous individual fibers that can serve different purposes, including sensing for perimeter intrusion detection, sensor status and control, as well as video streams. The extensive network bandwidth of fiber makes it particularly suitable for current security applications and ensures preparedness for future upgrades.

Tamper-Resistant Physical Links for Improved Cybersecurity

One significant concern with adding intelligent devices such as sensors or cameras to the perimeter is the potential risk of sophisticated hackers tapping into communication cables (especially those based on copper Ethernet). This could lead to scenarios where control rooms or security operations centers are misled into believing that sensors and cameras are operational when they are, in fact, not. The risk posed by these attacks can be effectively mitigated through various methods, including low-tech solutions such as physically securing cables, proprietary protocols, and implementing cybersecurity best practices.

Fiber-based communications further alleviate cybersecurity concerns since tampering with fiber communications mid-cable without initiating multiple alarms is nearly impossible. To streamline deployment, communications can also be integrated as part of a fiber-based sensing solution, establishing a single protected fiber backbone around the perimeter.

For More Information

For additional information regarding the available options for connecting perimeter intrusion detection sensors to your control room's video or security management system (VMS/SMS), reach out to your local Senstar representative.