When a company considers adding a video surveillance camera system, the first question is often: How much is this going to cost? But as with anything, the adage—you get what you pay for—comes into play, especially with PoE switches, which are a mainstay in today’s sophisticated surveillance camera systems.
Manufacturers offer this technology in a variety of types and at a host of price points, but not all PoE switches are created equal and some are smarter than others.
While surveillance system engineers and integrators prefer to specify managed PoE switches over their less-intelligent unmanaged counterparts, deciding between the two typically comes down to what customers want to pay. The smarter managed devices can cost up to twice that of unmanaged PoE switches.
But going with the cheaper option may be a shortsighted approach. The truth is the biggest bang for a company’s video surveillance system buck often comes from investing in a more expensive PoE product upfront, which offers a list of benefits others do not.
What Is PoE?
PoE stands for Power over Ethernet. In its basic form, a PoE switch supplies power to devices on a network via the same Ethernet Cat 5 cable that transmits data, eliminating the need to change Cat 5 cable network infrastructure to accommodate a new surveillance system. Any network device that requires minimal amounts of power to operate and communicate on a network can plug into a PoE switch.
In addition, the technology itself is not new. PoE has been used in video surveillance systems for many years. It is a mature technology that works well in network surveillance systems that transmit tons of data and consume plenty of power.
How PoE Switches Work
A PoE switch draws its power from a three-prong jack that plugs into a regular wall outlet. The switch then converts this power into a lower voltage power source and sends it out over the Ethernet to devices on a network.
How is this possible? Ethernet cables have a total of eight cables inside and a PoE switch uses one of these four pairs of cables to run positive and negative power to other devices, leaving the remaining cables to transmit data for other systems. This allows engineers to locate IP cameras and wireless access points where they are needed the most and enables them to easily move these devices as necessary.
The Benefits of PoE Switches
PoE switches save time and money in surveillance system installations because an electrician is not required to install Ethernet cables. In addition, quite often these cables are already in place.
PoE switches also help protect a video surveillance system from receiving too little or too much power. In addition, these devices are both reliable and scalable. There are four-, eight-, 16-, 24- and 48-port PoE switches available. Engineers can stack them in system and build a trunk between them so they operate as one device.
These facts are true no matter what type of PoE switch is used. What is new is the fact that these devices have gotten smarter.
Managed vs Unmanaged PoE Switches
Two primary PoE switches exist: Unmanaged and managed. Understanding your investment requires knowing the difference between the two.
Unmanaged switches are aptly called “dumb” switches. Manufacturers preprogram these devices to function in specific ways, and do not allow for customization. Unmanaged switches offer plug-and-play connectivity and are very cost effective when price is a concern. These switches do not care what devices attach to them, they simply plug in and send out PoE.
Managed switches, meanwhile, are smart, which means authorized users can program them to function in definitive ways to optimize a video surveillance network’s performance. Authorized users also can remotely access the surveillance system and run performance checks via these switches, which is a huge advantage over their less-smart counterparts. In addition, managed PoE switches are highly secure and scalable.
More Power Output With PoE+
There are also PoE+ devices available. The biggest difference here is that PoE+ delivers more power than a standard managed PoE switch. They can transmit up to 30 watts over Cat 5 cables, versus the average 15.4 watts offered by standard managed PoE switches. The use of PoE+ has increased in popularity as video surveillance systems move toward power hungry, high-definition, analytic IP cameras.
The use of PoE Injectors in video surveillance system design is also increasing. These devices support gigabit speeds while powering a compliant device over a single cable. They boost power coming to a device that might need more power, such as a Pan-Tilt-Zoom (PTZ) camera, which has more moving parts requiring power to operate.
Control Power Output Remotely
Managed PoE switches have an IP address. This enables authorized users to log in to that managed PoE switch via a Graphical User Interface (GUI) on a standard web browser, allowing users to adjust bandwidth and perform traffic shaping from their desktop PC, tablet computer or smartphone.
In traffic shaping, an authorized user tells a PoE switch how much power to send to specific IP cameras on a network. For instance, one camera might only receive 5 megabits per second (Mbps) while another camera may receive 50 Mbps.
Users can also regulate voltage coming out of each port on a managed PoE switch, so if one camera only requires 7 watts of power but another requires 15 watts, the switch can send 7 watts to one and 15 watts to the other.
Why? Because a managed PoE switch has a total power rating, and if the total power output of the ports does not exceed that power rating, it’s possible to shape each port on the switch individually.
This becomes useful in situations where there is a 24-port PoE switch, for example, connected to 23 cameras and a speaker. To operate properly, the speaker needs more power.
The user can program the cameras in this system to draw less power so enough power remains available to operate the speaker and have the sound it emits be loud enough for people to hear. Or, say the system is connected to 23 cameras and lighting. Here, users can set up a PoE switch’s power distribution in such a way that when an analytics event is triggered, enough power is available to turn lights on.
Easier Trouble Shooting
Finally, a sophisticated managed PoE switch, for example, can use a GUI interface to provide a topology view of the network and everything connected to it. This aids in troubleshooting when a system goes down.
Each port on the PoE switch can be programmed to send an automatic alert to authorized users when a camera goes down. Then authorized users can log in, use topology view to see which camera is down, and reboot it. If a reboot doesn’t work, users know exactly where to send a technician for the repair, speeding up the troubleshooting and repair process and minimizing downtime.
When one understands the impact managed PoE switches have on a video surveillance system’s capability, the choice to spend the money upfront on these more expensive devices becomes easy.