Power over Ethernet (PoE)

Power over Ethernet (PoE) is technology that allows Ethernet cables to transmit power and data simultaneously using a single network cable. It enables one RJ45 cable to provide both electric power and data connection to powered devices (PDs), instead of having a separate cable for each. This enables network installers to deploy PDs in locations that lack electrical circuitry. PoE eliminates the cost of installing additional electrical wiring, requiring professional electrical installers to ensure that strict conduit regulations are followed. Common types of PoE applications include: IP cameras, VOIP phones, wireless access points, ATMs, IP intercoms, IP clocks, security card readers and PoE lighting.
PoE switches are network switches that can provide PoE from each interface while still being able to forward frames. Both managed and unmanaged PoE switches are available. A PoE switch requires one uplink to an existing network to expand and increase ports.
PoE injectors are devices commonly used between a non-PoE-capable switch and a PoE-capable PD (such as an IP camera). They add power to a network cable to ensure that a connected PD can receive power and operate without a connected DC power supply. When the cost of a switch is not practical, PoE injectors provide a solution when fewer PoE ports are required. Injectors allow administrators to populate and properly support LANs with both compliant and non-compliant devices.
Products
Basics of Switches, Routers and Hubs
Ethernet Hubs
Ethernet hubs are the least intelligent of the three devices. They simply take any message that is received and transmits it to every other device connected to that hub. For example, if CPU 1 on a network wants to send a message to CPU 5, it will send that message through the hub.The hub will then take that message and send it out to every connected device on that hub regardless of the intended target. When CPU 5 receives that message and wants to respond, it will send its response through the hub which sends it to every connected device. Ethernet hubs do not manage any data that is sent and tend to bog down networks. They also do not offer much security for the network. For these reasons, Ethernet hubs are are being replaced with network switches.
Switches
Switches transmit data from one device to another on the same network. Unlike a hub, switches use a switch table to learn where data came from and where to send it. Switch tables store Mac addresses and device ports. By storing this data, a switch can operate more efficiently than a hub, greatly reducing the traffic within the network.
Routers
Routers transfer data between devices while learning the location of those devices within the network. They are also a junction between two or more networks. An example of this would be a home router where the home network is connected to the Internet. Another example would be when the router connects two or more networks with different business functions. In addition to connecting two or more networks, a router offers important security features that help protect the network.