Here are two truisms about today’s security marketplace: First, every security system, and every active component of those systems, requires power. This applies to all types of security systems and devices, including video surveillance, access control, electronic door locks and interlocks, occupancy sensors and intrusion alarms — all of them. And second, the preferred backbone for connecting all these active elements that make up security systems is IP networking based on an Ethernet infrastructure.  

Together, these two facts continue to drive the rapid development, market acceptance and broad adoption of PoE solutions that can be used to deploy a wide range of IP-enabled security systems and devices. PoE makes use of a single connection cable to carry both power and IP data. This approach has provided many benefits to both security dealers and integrators and end-user organizations.  

Now, a new higher-powered PoE standard called 802.3bt is available. Also known as 4PPoE or 4-Pair PoE, 802.3bt PoE is truly a game-changer for the security market, enabling security professionals to easily and cost-efficiently install security devices with power-hungry features such as PTZ cameras with IR illuminators or heaters and blowers for harsh environments. Understanding this new PoE standard is essential to ensure it is properly deployed and leveraged to its highest potential.  

Defining 802.3bt

Simply put, 802.3bt is an IEEE standard that specifies how power can be transmitted over Ethernet cables using all four pairs of wires in standard cables. By using all four pairs of conductors, this standard provides a substantial increase in the maximum power over previous versions (up to 90W per port), while also providing for improved power management.  

Power management is achieved using communication between the devices over the same connection cable. Importantly, IEEE 802.3bt supports multiple PoE classes and is backward compatible. Together, these enhancements to the specification enabled manufacturers provide new devices that could make use of the higher available power while better managing the power in the system. 802.3bt is backwards compatible, allowing systems to upgrade their power source to this standard to use new and existing PoE devices together. 

Benefits of Implementing 802.3bt

The 802.3bt standard leverages the myriad benefits of low voltage installation methods to power security endpoint devices by virtually eliminating the need for high-voltage inside the enclosure and associated costs such as permits, electrical cabling, and dedicated conduit.  

The low voltage cable used for power can run in the same cable trays and paths as other network cabling along with access control cable, which for service and maintenance eliminates the need for regulatory safety precautions such as lock-out tag-out. A key feature of the 802.3bt standard is that there is no voltage present on the cable from a power source until it is plugged into a powered device and a handshake occurs.  

Unplugging the Ethernet cable from the PoE-driven power supply is safe. Once the cable is plugged back in the handshake is performed with the power source and PoE is delivered to a powered device. The following is a list of additional benefits provided by the 802.3bt PoE standard.  

• Support More Devices — With more power available, it allows for a greater number of devices to be powered by a single category cable. For example, by upgrading the PoE power source with an 802.3bt midspan, it is now possible to add a PoE driven power supply with power distribution, such as the Tango1B. This allows for both 12VDC and 24VDC devices to be deployed utilizing PoE. 
• Support Upgraded Devices — An alternative scenario is to leverage the additional available power to replace an existing device with a newer, more capable device that requires more power. For example, new IP PTZ cameras are available that have improved functionality but require more power than previous models. Upgrading the PoE power source would support the upgraded cameras without having to make changes to the cabling infrastructure or other parts of the system.  
• Support Power-Hungry Accessories — Having more available power also accommodates PoE devices that demand more power than was previously possible using PoE. For example, devices such as illuminators, heaters, access control locking devices, and some wireless access points have required multiple power sources. Today, virtually all of these devices have PoE versions available thanks to the 802.3bt standard — opening new possibilities for security system integrators and installers.  
• Supply Multiple Voltages — It is important to note that implementing PoE does not mean that you are locked into a particular voltage. For example, there are remote power devices available such as the new Tango power supply/charger series products that use an 802.3bt connection as input, delivering a combination of voltage outputs, such as 12VDC and 24VDC simultaneously; ideal for powering access control systems.  

All Previous PoE Benefits Still Apply

These new capabilities and benefits only add to PoE systems – all the previous PoE benefits still apply to 802.3bt systems including:  

• Installation Benefits— Running a single low-voltage cable to provide both power and data connections is always more beneficial than running two cables and/or requiring an electrician to provide high-voltage power. Additionally, the additional time-saving benefits of plug-and-play networking contribute to installation savings.  
• Safety Benefits— Reducing the potential for high-voltage exposure improves safety for installers, service technicians, and users, while also reducing the chances of mishaps with wiring failures. For service and maintenance, the lack of high voltage inside powered enclosures eliminates the need for regulatory safety precautions.
• Flexibility Benefits— PoE simplifies the ability easily relocate endpoint devices, as well as the ability to implement system upgrades, expansions and changes. This new 802.3bt PoE standard, if anything, increases system designer and installers’ flexibility even further. 
• Reliability Benefits— PoE systems also provide for centralized or distributed backup power, eliminating a key factor in system reliability.  

Making the Move to 802.3bt 

Upgrading a system to the new 802.3bt PoE standard is rather straightforward. New midspan/injectors and hardened PoE switches that can provide up to 90W per port to accommodate almost any modern security devices that are currently available.  

The new PoE standard also accommodates backward compatibility, so video, access and other security devices from leading providers can be repurposed into upgraded and new system installations. When you add up all the benefits of the new 802.3bt PoE standard, it's pretty clear to see why it is such a game-changer for pro security systems.