Power over Ethernet Switch Explained: Why Choose PoE switch over PoE Injector?

December 28, 2016

Wireless network makes a better connected world. Power over Ethernet (PoE) technology revolutionizes the wireless network by providing data and electricity over the same Ethernet cable. It is the most common method to build enterprise wireless network. So how to build PoE technology over wireless network? What is PoE switch? Why would you choose Power over Ethernet switch rather than Power over Ethernet injector? And how to choose, select & buy best PoE switch for IP cameras? Today, we share some insights and help solve the above questions.

Power over Ethernet Wiki

What is Power over Ethernet technology? Power over Ethernet or PoE is a revolutionary technology that integrates data and power on the same cables. It allows power devices (PDs) to receive power in parallel to data over existing twisted-pair Ethernet infrastructure without making any modifications in it. Typical PDs include IP cameras, wireless access points, and the power sourcing equipment (PSE) would normally be a Power over Ethernet switch or a midspan power PoE injector, patched in to add PoE capability to a non-PoE network switch channel or similar. There are three types of PoE networking architectures based on different PSE:

Endspan PoE Switch+PDs

Endspan PoE Switch + PDs

Ethernet Switch+PoE Injector+ PDs

Ethernet Switch (RJ45 port) + Midspan Power PoE Injector or Hub + PDs

Ethernet Switch+ PoE Fiber Media Converter +PDs

Ethernet Switch (SFP port) + PoE Fiber Media Converter + PDs

What Is PoE Switch? Choose PoE Switch or PoE injector?

There are two methods to install high-power PoE technology: by upgrading the PoE switch, or by installing PoE injector in the existing networking infrastructure.

Upgrade to PoE Wireless Network with a PoE Switch

Power over Ethernet switch is a network switch that has Power over Ethernet injection built-in. When connecting with other devices, it can detect whether they are PoE-compatible and supply power automatically for the remote-powered devices. With the plug-and-play design, customers can easily connect PoE-enabled devices using standard Cat5e or Ethernet cables without additional hardware.

power over ethernet switch

As figure 1 shows, PoE Gigabit switch certificated by IEEE 802.3af standard, sends power and data to PoE devices over a single cable, which requires no additional wiring, power sources, or adapters. POE switches are available to suit all applications from low-cost unmanaged edge switches with a few ports, up to complex multi-port rack-mounted units with sophisticated management.

PoE Injector Can Be Installed

A midspan (or PoE injector) is used to add POE capability to regular non-POE network links seen in Figure 2. Midspans can be used to upgrade existing LAN installations to POE, and provide a versatile solution where fewer PoE ports are required. Upgrading each network connection to POE technology is as simple as patching it through the midspan, and as with POE switches, power injection is controlled and automatic. PoE injectors are available as single-port or multiport device, or the injector can be built into a network switch, which is called a power over Ethernet switch.

How to Build Wireless Networks over Power over Ethernet Switch?

A basic PoE-based system usually consists of three main components: PSE, e.g. a PoE switch or PoE injector, network Ethernet cable and remote-powered devices, which could be an IP camera, IP access panel, IP intercom, VoIP or wireless access point (WAP). The following video helps deploy a PoE-based network.

Power over Ethernet Switch Provides Data and Power for Wireless Network

A power over Ethernet switch can provide both data and power to wireless devices over the same Ethernet cable. To build enterprise PoE wireless network, the power over Ethernet switch connects to a router that connects to the Internet. The network provides network connectivity among PoE wireless network devices and computers that have a wired connection to the switch. The PoE wireless access points connect to a PoE switch that provides them with power. Each wireless access point connects multiple wireless devices to the network.

PoE Switch

Using a PoE Wireless AP for WiFi Connection

The easiest way to provide WiFi access to mobile devices is to deploy wireless access points either mounted on the wall or ceiling. Data network can be transmitted by running Cat5e or Cat6 network cable from the WAP to the nearest power over Ethernet switch, and power can be also provided over the same cable. Therefore, you don’t need to worry about the power outlets when installing WAP on the ceiling.

wireless access point WAP

Ethernet Network Cable Is Essential

Ethernet network cable is an essential accessory in enterprise PoE wireless network building. Both Cat5e and Cat6 cables use copper wires, typically 4 twisted pairs in each cable. The specification for Cat6 features more stringent specifications for crosstalk and system noise, and can support 10 Gigabit Ethernet. Cat5e cable, in contrast, performs up to 1 Gigabit Ethernet. Be careful when picking your Ethernet cable and consider the specification. Never use inferior Cat5e and Cat6 cables.

How to Choose a Power over Ethernet Switch?

Gigabit Port Number of PoE Switch

PoE switches are available in several port number options—4-port, 8-port, 16-port, 24-port, 48-port, etc. The port number largely depends on your actual need, namely the number of powered devices. For example, if you are looking for PoE switch for more than 4 cameras, it’s important to check the port number, such as a PoE switch with 8 ports, PoE switch with 16 ports, PoE switch with 24 ports, or PoE switch with 48 ports.

Understand Power Requirement

After finding a PoE Ethernet switch that will provide suitable power conditions on a per-port basis, there is another element to consider—power budget. According to the IEEE 802.3af standard, the amount of power available after 100 meters of Cat5 or cat 5E cable, is up to 12.95 watts. IEEE802.3af power is 15.4 watts at the power source and 12.95watts at the Powered Device.

However, part of the standard’s specification involves testing the class of power, which refers to the specific power requirement of the end device. Thus when selecting power over Ethernet switches, you should check the sizing of external power supply voltage before deciding which one to use.

Managed or Unmanaged PoE Switch

The major differences between an managed and unmanaged PoE switch is the functionality, configurability, and of course, the price tag. Managed power over Ethernet switch (more expensive) allows you to configure networking protocols, as features such as VLANs, IGMP Snooping or more while unmanaged PoE switch is a plug-and-play with no setup required. For most home networks, an unmanaged PoE switch fits the budget and meets the needs for powering PoE IP cameras.


It is quite easy to build a wireless PoE network based on the power over Ethernet switch, PoE wireless devices and Cat5e or Cat6 Ethernet network cables. FS.COM power over Ethernet switches are available in 8, 24, and 48-port, which can provide fiber connectivity options for easy expansion of your networks. Besides, we also provide a full range of Cat5e, Cat6, Cat6a, and Cat7 Ethernet patch cables with many lengths and colors options. For more information, please visit or contact us over

Related ArticlesUsing 8-Port PoE Switch for IP SurveillanceDeploying 48-Port Gigabit PoE Managed Switch in Different NetworksWhy and How to Use PoE Switch for IP Camera Systems


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