PoE or Power over Ethernet is a technology in which power and data are transmitted over the same cable via separate wires. So here the cables perform the dual function of data and power transmission through the network. There are many types of PoE devices, such as PoE injectors, PoE switches, PoE extenders and PoE splitters, which are especially suitable for mixed copper and fiber optic networks. All of these devices perform specific functions and must be selected based on needs. But how to choose or differentiate these devices. This article discusses the differences between PoE injectors, PoE switches, PoE splitters, and PoE extenders in detail. 

PE Injectors, Switches, Splitters and Extenders

• What is a PoE injector?

PoE injectors are more of an auxiliary or supplementary role. It provides power in non-PoE networks. Such a network might have a normal Ethernet switch without PoE capability. The injector and the non-PoE switch are connected to the Ethernet cable and powered on. In general, through the injector, various other smart devices such as phones, webcams, etc. can be connected to the network. PoE injectors are primarily capable of connecting PoE-capable devices to non-PoE ports. In this way, PoE-enabled devices can transmit power and receive data over the network.

• What is a PoE switch?

A PoE switch is a network switch with a built-in injector. There are PoE and PoE+ switches, where the latter is an updated version of the former, providing double the power. PoE switches use the IEEE 802.3af standard, while PoE+ switches use IEEE 802.3at. These are managed switches that automatically determine compatibility with other devices on the network. Typically, these switches have 8 or more ports. There are ports for both copper and fiber optic networks, so most of these switches are compatible with both or a mix.

• What is a PoE splitter?

These devices are combined with PoE injectors and PoE switches. Unlike other PoE devices, these don't convert power and data inputs into a single output, but instead separate the data and power and feed the power to a separate input. PoE splitters are generally used in scenarios where non-PoE devices have no AC outlets.

• What is a PoE extender?

Power over Ethernet extenders or PoE repeaters are used to extend the distance between PDs and PSEs. These devices are installed between PD and PSE to extend the transmission distance by 100 meters on each side. Some extenders help connect multiple devices, which can help increase the distance up to 500 meters.

The Difference Between PoE Injectors, Switches, Splitters, and Extenders

All PoE devices, such as PoE injectors, PoE switches, PoE splitters, and PoE extenders, have specific applications. Here are some key differences between them.

• While PoE injectors are quick and easy to install, switches are for long-term and scalable use.
• There is no doubt that power supplies are cheaper than switches. But the overall cost depends on individual usage and needs, for example in case of expanding the network, the switch will become cost-effective in the long run.
• If you experience power outages in an area, power supplies are a better choice. This is because many devices connected to the switch will stop functioning. On the other hand, if there is a PoE injector on the network, only one connected device will be affected.
• If there is a network problem, it may only be necessary to replace the power supply. In the case of switches, it may take time to troubleshoot, resulting in downtime.
• PoE injectors, PoE splitters and PoE extenders are used according to typical conditions, while PoE switches are an integral part of most extended networks.
• PoE injectors and PoE splitters are used to power devices, but they work on the exact opposite principle. PoE injectors are often used as midspans to power data from end spans or non-PoE switches. This PoE injector uses network cables to supply power to PoE devices. A PoE splitter separates power from data and feeds it to a separate input. PoE extenders receive data and power from PoE injectors and PoE switches. It operates using part of the received power and passes the remaining power to other PoE devices on the line. In many applications, PoE extenders are replaced by extended mode PoE switches and PoE powered switches.
• Despite the many advantages of injectors, switches are recommended for large and complex networks.