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PoE Passthrough Switch Introduction and Applications

PoE switch plays a crucial role in data networking to simplify network installation in hard-to-reach areas like ceilings or places where there is no existing network/electrical infrastructure. It offers a cost-effective solution to transmit both power and data through the same network cable to the powered devices, such as PTZ cameras, wireless access points, network bridges and POS machines, within a maximum distance of 100 meters. And with the expansion of the Internet of Things (IoT), the quickest and cheapest way to expand your Ethernet ports is to add a PoE switch to your network.

But the question is: since the PoE switch itself needs to be powered up in the first place, network expansion with a normal PoE/network switch won’t be feasible in places where there is no power source nearby to operate the switch and the devices. Traditional solutions to this problem may include running extension cables, hiring an electrician to install new electrical wiring or installing PoE injectors to power the connected devices, but these approaches can be quite expensive if multiple devices are to be installed at the edge. Therefore, in today’s blog, we’ll introduce a powerful network device called the PoE Passthrough Switch to help you incorporate a PoE switch into the network where the power source is highly restricted and make for a cleaner installation.

What is PoE Passthrough Switch?

PoE passthrough may sound complicated, but in reality, it’s a simple technology that allows switches and other network devices to receive PoE power over the existing Ethernet cable from an upstream PoE switch. PoE allows the network devices such as WAPs, IP cameras and VoIP phones to receive power from PoE-enabled switch ports, while PoE passthrough allows a switch to receive power from an upstream switch and pass it through to PoE devices. The network switch built with such features is normally called the PoE passthrough switch or the PoE powered switch, which allows various devices to be connected to the network and the power source without needing direct connections to your central unit.

The PoE passthrough switch can work as both a powered device (PD) and a power sourcing equipment (PSE), which means that the switch itself can be powered by a PSE (PoE switch or PoE injector) while simultaneously providing power to the connected PDs. Since the PoE passthrough switch has the passthrough features built in it, it can be installed in any place without the constraints of an AC outlet. The PoE passthrough switch can be applied in hard-to-access spaces, such as attics, closets, above drop ceilings, basements and tunnels, or some places where the existing power outlets are already occupied for other uses. And like the regular PoE switch, the PoE passthrough switch will only supply power to PoE-compatible devices, so if you accidentally connect a non-PoE device to it, only data will flow through.

4/8-Port PoE Powered Switch

Fastcabling has specially designed two types of PoE passthrough switch to provide an easy, time and cost-saving solution for installers to power PoE-enabled devices at the edge of the network. The 4-port PoE powered switch has 4*10/100/1000 Mbps PoE ports and 1*1Gbps PoE passthrough port. It is compliant with the IEEE802.3at standards, featuring a maximum power output of 30W per port (65W in total) and is able to power multiple network devices like WAPs and VoIP, etc. This PoE powered switch comes in a compact size and requires no additional power cabling, ideal for space-constrained applications. Each port is equipped with 6kV surge protection to ensure the ongoing functionality of the switch and connected devices. It’s built with a fanless cooling design, suitable for installation in dusty spaces like ceilings and basements. And we’ve also launched an 8-port PoE powered switch that comes with more PoE interfaces to allow you to set up 7 IP cameras at a time. It features a larger power budget of 71W and can operate at a wider operating temperature of -20°C~70°C.

Expand Ethernet with One Cable

By deploying the PoE passthrough switch, you can use only ‘one cable’ to realize network expansion and make for a cleaner setup since the connection between the upstream PoE switch and the passthrough switch is completed by Ethernet cables only. So, if you have purchased an 8-port network switch, you can use one Ethernet (uplink) port to connect the switch to your router and then use the remaining ports to connect another 7 network devices. And by using the PoE passthrough switch, you can easily extend PoE for another 100 meters by transmitting power and data simultaneously via one network cable. But if you plan to install multiple power-hungry IP devices at remote places, it’s always recommended to draw the power from the installation site for power loss will get severe in the long cable runs.

How to Use the PoE Passthrough Switch

Here are basically two methods to install the PoE passthrough switch: using a PoE injector or a PoE switch. PoE switches don’t actually consume too much power, but typically they need around 15-30W to operate. So to power up the PoE passthrough switch, you’ll need to use a high-power PSE.

1) Used with the 90/95W 802.3bt PoE Injector

As the demand for higher power increases, choosing a high-power PoE injector can be a much better option to supply enough power to the PoE passthrough switch because very few PoE switches can offer more than 60W per port. Fastcabling’s 90/95W 802.3bt PoE Injector is compatible with both PoH protocol and IEEE802.3bt standards to deliver 72W max. to the powered device and supports a transmission speed of 10/100/1000Mbps. It is highly reliable, featuring carrier-grade surge protection to protect the device against ESD events. This PoE injector can be used together with the 4-port PoE powered switch to install multiple network devices without running tons of cables. How to connect: 1) use a short patch cord to connect the PoE injector and the router; 2) power up the injector with AC power; 3) use an Ethernet cable to connect the PoE injector and the PoE passthrough switch.

2) Used with the 802.3bt PoE Switch

As previously mentioned, few switches can deliver more than 60W per port, but Fastcabling has launched a high-power PoE switch that can offer a maximum power of 90W to install power-hungry devices like LED lighting, information kiosks, etc. It has 6 PoE ports and two of these can support a power output of up to 90W (30W max. for the 4 remaining PoE ports). This 802.3bt PoE switch is equipped with auto-sensing ports to automatically detects the power class of the PDs and deliver an appropriate amount of power to them accordingly. The PoE switch also features a simple plug-and-play installation with easy configuration. Since it features a larger power budget (120W), it can be used together with the 8-port PoE powered switch to install more IP devices. How to connect: 1) use a short patch cord to connect the 802.3bt PoE switch and the router; 2) power up the PoE switch with AC power; 3) use an Ethernet cable to connect the port#1 of the 802.3bt PoE switch and to the PoE passthrough port of the PoE powered switch.

Tips for Installing the PoE Passthrough Switch

Here are some tips you might find helpful when deploying the PoE passthrough switches.

1) Choose Pure Copper Cables over Copper Clad Aluminum (CCA) Cables

There is always power loss during the transmission. Theoretically, the longer the distance, the more power loss will be. The power will be dissipated as heat, and you’ll experience severe voltage drops over the long cable runs. For long-distance applications, you should use pure copper cables at best. The pure copper cable is made of 100% copper and it has great conductivity. But if you’re using a CCA cable, its performance will start to deteriorate when it hits 10 meters, and it’ll experience greater DC resistance and generate larger power loss.

2) Use PoE Splitters for Installing Non-PoE Devices

Users can run into lots of issues when connecting the PoE equipment to a non-PoE device. Since most legacy devices don’t come with an RJ45 interface, to connect a PoE-enabled PSE with a not PoE-compatible PD, you’ll need a PoE splitter. It powers a non-PoE device by splitting PoE from a unified network cable and delivering power and data through separate outputs. And the PoE splitter can also be used to bring a high DC 48V current down to a low voltage electrical current (regulated DC 5/12/24V).

3) Prevent Power Surges with the Surge Protectors

If you’re using network devices or running Ethernet cables outdoors, you should always take some precautions to protect your devices and appliances from power surges. Even though your PoE passthrough switch is installed for indoor use, you’re still supposed to install the surge protectors at both ends to regulate the electricity flow. The surge protector makes sure your events function more reliably and protects the connected devices from damages during sudden power surges. And for outdoor applications, we highly recommend you to try our Outdoor Waterproof PoE Pass Through Switch to set up a safe network connection outdoors.

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