Installing and maintaining hard-to-reach devices such as surveillance cameras or access points can be challenging, especially when they need to be maintained with both power and data cables. Power over Ethernet (PoE) technology that simultaneously supplies power and data through twisted pair Ethernet cables. The most popular device type in our PoE accessory line is the PoE injector. However, there are many questions that can be asked about this topic. This article explains the basics of the PoE injector.
Power over Ethernet (PoE) is a technology that, in addition to the data normally carried by the cable, routes power through a twisted pair Ethernet cable to active devices (PD), such as wireless access points, IP cameras, and VoIP phones. PSE devices send power and data to a connected PD via the Ethernet cable. PSE devices are classified as “Midspan” or “Endspan”. A common type of PoE midspan is a PoE injector.
What is a PoE injector and what can it do?
A PoE injector, also referred to as a PoE adapter, can be implemented to make a non-PoE compatible switch work with PoE devices by powering compatible devices through a single Ethernet cable. Typical use of a PoE injector requires 3 devices. The PoE injector itself, a connection to the network, usually a router or switch, and the device that requires the PoE injector.
If a non-PoE compatible network switch (which you do not want to upgrade) is used with a PoE device, a power source is required to power the connection. A PoE injector is a device that supplies power to an Ethernet cable for PoE devices. In particular, a PoE injector can be used to connect a wireless access point, IP phone, network camera, or any IEEE 802.3af / at-powered (PD) device to a network switch.
The PoE injector is a PoE compatible device. This is why it uses PoE technology, which means that delivering data and power over a standard Ethernet cable eliminates the need for AC / DC power supplies and outlets to power PD devices that need to be installed in a location where an outlet is not available. PoE installation is fast and inexpensive, especially when compared to older, outdated methods that require two separate cables, one for power and one for data. Plus, PoE installation doesn’t usually require a professional or bankrupt.
In addition, PoE injectors will not damage devices, even if the devices are not designed for PoE applications. Before the PSE sends power to a connected PD, the PSE initiates a handshake process that determines how much power the connected device requires.
Passive PoE Injector and Active PoE Injector
A PoE injector follows the PoE standard IEEE802.3af, IEEE802.3at or IEEE802.3bt, which is believed to use active PoE. The injector will only deliver power if it considers it sufficient and complies with the standards / requirements of the connected device. Otherwise, the device will not turn on.
While a passive PoE injector is usually a PoE injector that uses PoE technology that is not compliant with 802.3af, 802.3at or 802.3bt standard. There is no handshake with the device to determine the power requirement. Hence, it can sometimes be dangerous to use it when connected to an incompatible device.
How much power can the PoE injector provide?
There are three standards for PoE injectors: IEEE802.3 af standard (PoE), IEEE802.3 at standard (PoE +) and IEEE802.3 bt standard (PoE ++). The main difference between these types is the amount of power sent through the line. IEEE compliant PoE injectors can deliver an output from 12 watts to over 70 watts. The PoE can deliver 15.4 watts through Cat5 cable, while PoE + can deliver 30 watts through Cat5 cable.
How does the PoE injector work?
A PoE injector almost always has two RJ45 Ethernet ports, one of which is labeled Information In and the other is labeled PoE / Data Out. The injector plugs into a power outlet and data source and does the rest by electrifying the Ethernet cable and powering connected devices.
Before you buy a PoE injector, make sure it is right for you. While they are practical, they are not always the best solution. You may need to consider the number of devices, PoE standard, and voltage.
Where can I buy the PoE injector? Fastcabling offers different types of PoE injectors to meet your needs. Here are some recommendations:
30W PoE Injector, corresponds to IEEE802.3at, which comes with maximum 30W. Output power for connecting IP devices. Integration into an existing network system is secure and the compact size allows for flexible installation.
The 95W PoE Injector is an advanced PoE injector that supports 90W inputs and is suitable for power-hungry IP devices. The whole system works with a 95 W PoE splitter and offers a maximum power of 72 W for PoE and non-PoE devices. In addition, the displays provide an intuitive and easy way to monitor the operational status of the connected devices.
The 60W Outdoor PoE Injector is a standard 802.3bt device and delivers up to 60W for the Edge devices. That’s twice the power of the 802.3at, which is up to 30 W. Thanks to the sturdy metal housing and waterproof IP67 design, it can also be used outdoors.