Essential guide to pick a PoE Injector

Do you get any challenge to figure out how to power your IP devices, such as wireless access points, VoIP phones, and IP cameras? These pieces of equipment require communicating network and power source to bring it up. The convention switch only provides the network for communicating but no power. There is still power supply problem you will need to deal with.

The power over Ethernet (PoE) technology allows single Ethernet cable to transmit power and data to your remote IP devices. Both PoE switch and PoE injector are able to add the power to single Ethernet cable. If you already have an existing non-PoE switch and only have desire of adding PoE to the network, PoE injector(or midspan injector) is a good choice to solve the power supply problem instead of purchasing a new PoE switch.

If you are a green hand in shopping for PoE injectors, you must overwhelmed by the technical features available as well as be confused with various optional products. So in order to select a cost-effective PoE injector, somethings that you should pay attention to and understand

What is PoE injector?

First of all, let’s understand the concept of PoE. Like we mentioned previously, the PoE utilizes a single Ethernet cable to provide both data connection and electric power to your powered devices (PD) such as wireless access points, IP cameras, and VoIP phones. This feature allows remote devices to be powered with no need of a separate power supply or an electrical AC outlet nearby.

Therefore PoE injector(Midspan) is a type of PSE(Power Source Equipment), which injects power without affecting the data through Ethernet cable(Cat 5e/Cat 6).

There are two types of PoE injector, passive PoE injector and active PoE injector.

  • Passive injector

In the common “passive” PoE system, 2 twisted pairs (4 wires) in Ethernet cable are simply merged into two wires to transport the electric power from an external power adapter.

While active injector is integrated with power source with the voltage and wattage are determined by the injector.

In addition to, active PoE injector also divides into standard and non-standard type. What’s the difference is whether the injector and the powered device have some protocols in common or not. The standard PoE injector complies with three standards, namely, IEEE 802.3af, IEEE 802.3at or IEEE 802.3bt power negotiation protocols while non-standard PoE injector transmits power to the powered device without negotiation of its required voltage or wattage from remote ip devices, and merely supplies power at all times, that is why it is also known as “always ON”.

This below are some tips for selecting a suitable PoE injector.

  • Tip one: Confirm the Voltage

You should check the maximum input voltage of the PoE powered devices and the output voltage of the PoE injector, in case that they fail to match. PoE injector has different types in accordance with the output power voltage, generally dividing into 12V, 24V, 48V. Technically, higher voltage injector can be used in farther distance, because the voltage will drop down sharply along with the increasing distance.

  • Tip two: Estimate power budget.

You should estimate the power of the PoE powered devices require, preventing unnecessary waste in purchasing high power budget injector. As we know, power consumption is existing during the power transmission. So distance should be took into consideration. You are supposed to pick an injector with a little higher power than your powered devices need.

  • Tip three: Try not to use passive injector if possible.

Although passive injector is in low cost, it is unsafe for people without basic technical knowledge.

What’s more, in the following we will elaborate on the details of typical PoE injector products.

  • Passive PoE injector

This is the common passive PoE injector you can find in the market, most of them are unbranded products. It may have different color or shape, technically it works exactly the same. Two of twisted pair into two cables to transit low voltage power. As we know, only 2 twisted pair are being taken to transmit 10/100mpbs fast network, leave 2 spare twisted to send the power. The passive PoE switch doesn’t support gigabit network which needs all 4 pairs to transport the data. If passive PoE are using with gigabit network, the bandwidth will low down to 100mbps fast network automatically. The passive PoE usually works in pairs, a passive splitter are required at remote end to separate the power wire from Ethernet cable. As no power negotiation and protection, the passive PoE system only can handle the low voltage and the short distance power. If the cable is too long, such as 30 meters, some of the power will loss on the cable which is converted to heat, the remained voltage may become too low to supply you IP devices. Why the passive PoE are still popular? Except for cost-effective, the passive PoE accept the external power adaptor. If your front-end devices needs some uncommon voltage from its customs power adaptor, you may need the passive PoE system to take in the power from its original power adaptor.

Tips: switch off the system power before making any connection. As zero protection with passive injector, the plug in process during the connection may create power surge and damage your remote devices.

Voltage: depends on external power source

Watt: same as voltage

Distance: less than 15 meters, even shorter

Power negotiation: NO

Short Circuit protection: No

Over load protection: No

Power surge protection: NO

  • Active PoE injectors

non-standard PoE injectors

The second types is 24VDC/48VDC non-standard active PoE injectors. Why we said no standard because these injectors doesn’t follow any specification such as IEEE802.3 which requires power negotiation before releasing the power. properly there is no protection as well. The ieee802.3 introduces two verification steps also name PD signature. Firstly, the Inejctor send low voltage (5V) to front end IP device meanwhile measure the current feedback. If the return current is right, the injector will go to step 2 to classify the ip device to determine what the maximum power the injector should provide. The non-standard injectors have none of these protocols. One of the reason the reason is both injector and splitter needs chipset to complete the PD signature process. At the beginning, different manufacturers were facing the compatible issue even both injector and splitter claim to be IEEE802.3 standard products, because return signal has been set to different value in above power negotiation process. In this case, the Non standard injector may skip the compatible issue because it send the power once the injector is plug in a AC outlet. Of course, it is not safe operation. Ubiqui is one of exceptions who provides non-standard PoE injector but still add the protection to the injector. However these products may doesn’t power standard PoE IP devices.

Standard PoE injector

The main stream injector are compatibile with ieee802.3 standard now. The benefits of standard PoE product are plug and play. Basically need no concern to the voltage and distance. What you need to choose is the power budget. There are three standard IEEE802.3 af/at/bt.

IEEE 802.3af

This IEEE 802.3af (PoE) standard supports the delivery of power up to 15.4W, offering DC 48V power over Ethernet cables. The 2nd classification step we mentioned above can determine the maximum power transport over the Ethernet cable. This suits for the powered devices such as wireless access points, IP cameras, and VoIP phones. According to the distance between the PoE injector and the powered devices where you want to set up should be less than 100m as voltage will sharp down.

Voltage: 48V

Watt: 15.4W

Distance: within 100m

Power negotiation: IEEE 802.3af

Short Circuit protection: Yes

Over load protection: Yes

Power surge protection: Yes

IEEE 802.3at

The IEEE 802.3at (PoE+) standard increase the power up to 30W. The remain power budget is set to 25.5W at the splitter, which delivers around 2 times power to remote devices. It benefit the high power demanding equipment such as PTZ camera, access control. Both PoE and PoE+ has been in the market for more than 10 years. There was compatible issues at beginning especially for PoE+ because the PD signature process require more precise feedback value. Now most of the PoE injectors are compatible with PoE and PoE+.

High power 30W power Capability

PoE extender

quick and easy install

Power source integrated – All in one


IEEE 802.3bt

The IEEE802.3bt PoE injector is new standard which is capable of output 90W maximum power. Similar as few years ago when PoE+ (30W) appeared, only few 90W PoE injector are available in the market. You need to choose 90W PoE splitter to match the injector as the splitter module is not integrated in the front devices yet. The ieee802.3bt employ 4 twisted pair ethernet cable to transport the power and data. The remain power budget is set to 71W.  This can benefit the power hungry device such as LED lighting, PTZ camera, Point of Sale terminals, touch screen computer. The IEEE802.3bt injector uses dual PD signature verification process. The first Pd signature will verify it is backwards compatible with PoE and PoE+, after first signature pass, it moves to second signature which means there are two power negotiation before releasing 90W power. Another similar protocols but doesn’t belong to ieee802.3 is AoH which can injector 95W power, the remain power budget is 72W. The 100W is almost the limit power over single Ethernet cable. In order to bring up the power, either increase voltage or current will create the safe issue which fails to meet the regulation. The next technology is the digital power which can transport higher power budget safety. The below is the video about the 95W PoE system which support both IEEE802.3bt and PoH standard.

Advanced next generation PoE

All-in-One touch PC

95W 4 pairs

intellgent LED indicator for real time

Ultra PoE splitter

PoH Power over HD-Based-T 95W

3X power

Leave a comments below if you have any questions.


How to build a PoE network system for high powered devices?

Practical Tips to Improve your WiFi Signal

Confronting awful WiFi signal coverage is annoying right? When you are walking into the stairs, the WiFi suddenly disappeared. If you have tried the common solutions like upgrade firmware and play with antenna to improve your WiFi signal, but they didn’t make good result. Here are some practical tips to offer. First of all, let’s figure out what causes the poor WiFi connectivity.

The WiFi employs 2.4Ghz or 5.8Ghz to transmit the signal in the air which is easier to weaken by the obstructions such as the walls. One wall will weaken WiFi signal to 80%, and two walls will go down to 50% left. Some people think 5.8Ghz WiFi router can improve WiFi signal, which may not always true. If the WiFi is weaken by obstructions, the 5.8Ghz WiFi router only makes it worse. Although the 5.8Ghz WiFi router is capable of carrying higher volume data, meanwhile it compromises the penetrating capacity, which means its transmission distance is shorten than the 2.4Ghz WiFi router. An instinct way to bypass the obstructions is relocating the WiFi router. However, sometimes you will have no condition to move the router. Because WiFi router has to set closed to the network entrance. The first practical tip is that you can use a repeater to receive the WiFi signal from the main router and transmit forward to the destination. Look at the image below. There are 4 walls between the WiFi router and the bedroom which causes the dark zone. Now if we place a repeater at the living room will reduce the obstructions to 2 walls. The key is to find the path for the WiFi signal to bypass the obstructions, usually it is the L shape. The repeater should be placed at the turning point of the L.

There are two ways to repeat the WiFi signal. If you already have an old WiFi router in hand, now this is a chance to re-use it. What you should do is to connect your old router to the main router through WiFi. Actually it is not complicated as you think.

  • Re-use your Existed WiFi Router

Firstly, power up the old router and make the connection by using a laptop or Mobil phone, then login the router in the web browser. If you don’t remember the IP address or the login account, usually you can find the information at the bottom of the router. Find the reset button and depress for more than 10 seconds after the router is powered up. This operation can restore the factory setting which allows you to login with default account. In the Wifi setting page, you can see the WDS option unchecked. Mark the checkbox and it will present the network search option in the page. Use this search option to connect this router to your main WiFi network. There are two more steps to go through. Turn off the DHCP and change the IP address of this router in case that it may have IP conflict with your main router. Once you have done these setting properly, the WiFi router will work as WiFi repeater.

  • Pick WiFi Repeater

If you feel too much bother to tweak the setting in the router, you can simply buy a WiFi repeater. WiFi repeater (aka WiFi extender) works much similiar as your old router here. But the setting is simpler. The DHCP and IP address conflict issues are avoided by the default setting as the product is designed for WiFi repeating purpose. Simply plug the repeater to the AC outlet, it will create internal WiFi which allows you to access by using the mobile phone or tablet. After you login the repeater, you can connect the repeater to your main WiFi network, and the repeater will start forwarding the WiFi which works exactly the same as the above WiFi router.

  • Move Antenna Outside

The WiFi signal is being transmitted through the antenna. While there are thick walls that weaken the signal, move the antenna to another side to bypass the walls which could improve the WiFi signal. This solution doesn’t always work, because some of the WiFi signal could be consumed while transmitting along with the extension cable. It’s too weak for the remained signal to spread out. People mentioned to turn to high power antenna, I don’t recommend it, as the antenna needs to match the original power design of your router. Replace with high power antenna while the router can’t provide enough power which makes the case worse.

WiFi router and repeater try to bypass the obstructions by changing the direction. It only reduces the obstructions but not eliminates it. The seconds practical solution is to mix wire and WiFi connection. Use the wire cable to transmit network signal to the dark zones and create WiFi signal from there. There are several ways to make it.

  • Powerline Adaptor

The power line adaptor takes used or existed AC power line to transmit network data. The network signal is converted before being injected to the power line with adaptor and picked up at other AC outlet by another adaptor. After that, it will generate new WiFi signal. If you have WiFi birdhouse camera in the garden, it relies on the WiFi connectivity. Use the power line adaptor can easily extend the WiFi signal closed to the camera as long as the AC outlet is nearby. Two important things about the power line solution. The adaptor only works in the same electric meter. Both transmitter adaptor and receiver adaptor need to stay in the same meter. And the second thing is that power line requires qualification cables in the building. If the building is very old with poor cabling job, the power adaptor may have problem to transmit the data.

  • PoE WiFi access point

PoE WiFi access point receives network signal by using the Ethernet cable and generates new WiFi dignal in the field. The connection between PoE WiFi access point and the main router is cable link, which can provide reliable high speed up to 1000 gigabytes. Moreover, multiple WiFi access points can be deployed to improve the WiFi signal to coverage different areas. The advantages of PoE WiFi access point is both power and data can be transmitted to the access point by using signal Ethernet cable. Wherever the cable is, the power source follows. The power is added to cable at the router by using the PoE injector.

  • Long distance WiFi PoE extender

As we know that the cat5/cat6 cable connection is limited to 100 meters. If the WiFi signal needs to be extended over 100 meters, such as from the lake to the house, you may need the PoE extender to repeat the network signal. The PoE extender can repeat the network signal up to 500 meters. The PoE WiFi access point will be installed at the end of 500 meters and create the WiFi signal to cover the area. It’s of great convenience that the PoE extender doesn’t require power source closed to each repeater. The power is added to the cable inline by PoE injector. The power adaptors are eliminated in the daisy chain setup.

The last but not least, sometimes the poor WiFi is not caused by the obstructions, but jamed with neighbor’s WiFi, because there are too many WiFi working in the field. I saw people has more than 25 WiFi hot spots picking up in his phone, the WiFi signal is so craw so it gets jam. Sometimes you experience the poor WiFi connection occasionally such as at night or at weekend. Properly the WiFi is too crowded. People use WiFi more often in these time frames. You can simply check the WiFi hot spot with mobile phone. If in such case, except for bringing your WiFi more closely, you can switch the WiFi channel in your WiFi router to avoid the jam.

  • Channel switch

What is WiFi channel?

Think of the walkie-talkie which has different channels to communicate with each other. The WiFi router has around 13 channels, it is set to auto selection in default. What you can do is to login your WiFi router and manually switch the channel to test whether the situation improved. It is important to choose the moment to make the change when WiFi connectivity became worse. Only this moment you can know which channel is being jam. Reboot the router after you switch to new channel, your mobile device will make the WiFi connection to the new channel.

The above is the all the possible solutions that I offer for help. If you do have any new idea or all above tips still can’t improve your WiFi network, please leave a message in the comment section. Here is the article about how to set up home network with PoE switch.

Using PoE System in Office Building

In the past, two cables were used to send power and data separately. Cabling becomes complex jobs when many devices need to be powered in the field. With the rise of PoE technology, it is possible to send power and data on the same Ethernet cable. This technology provides new network solution in commercial installation like office building.

What are the advantages of PoE?

Simplifying installation
The PoE combines two cables into single one which reduces about half of the cable in the system. As long as the Cat 5e or Cat 6 cable has been put up properly, the network devices are ready to be installed. The power is going through each Ethernet cable before reaching to the remote powered devices.

Saving Cost
As we mentioned below, what you need are the Ethernet cable, PoE switch and powered device. Simple plug and play helps to set up the network fast. If you choose to build commercial network without PoE support, a professional electrician is required to take care of the power line. The installation cost could be higher.

PoE is quite flexible, especially when the power source is absent in the field. Where the cable goes, the power source follows. The technology enables the transportation of power and data on single Ethernet cable. So powered device is not necessary to plug in the power outlet directly.

It is easier to manage network system with PoE technology. The visual PoE switch . All the powered devices’ condition can be monitored with this kind of visual switch.

What application will use PoE in office building?

LED lights are one of them. LED light is a low voltage device, and usually it consumes 13-15 watts power. The standard PoE provides 15.4 watts of power. So a PoE injector which meets this standard can be used when power the LED light. Connecting LED lights to PoE device gives users access to manage smart lighting. LED lighting can be controlled through mobile devices like tablet or mobile phone.

Wireless access point (or WAP)is another network devices which can take advantage of PoE technology. Lack of WiFi coverage is inconvenient for everyone in the office. Adding access point will improve the WiFi signal coverage. Now single Ethernet cable can provide power and data to each access points. Repeating the WiFi signal becomes an easy job with PoE.

The PoE switch also helps setup of door access control with the next PoE system standard IEEE 802.3bt, which can output 95W power in single Ethernet cable. The door access control usually demands high power because of the door striking. The 95W PoE injector delivers enough power for most of the door control system. The standalone access control unit or reader can be linked to PoE switch to acquire both power and network. PoE solution simplifies the system design of access control system.

VoIP phone is a typical application in business. One Ethernet cable will be enough for each VoIP after PoE solution is employed. Uninterrupted power supply becomes possible as the power source is centralized in the PoE switch. People still can make call when the power is cut off in emergency.

There are many products form integrated with PoE technology click to find out what is new today?

DIY Power over Ethernet with Right Pinout

PoE (Power over Ethernet) allows single cable to transport both power and data to the remote IP devices. It benefits the application that power source is absent in the field. Where the cable goes, the power source follows.

The T568B and T568A are the two color codes used for wiring the RJ45 connector. Both of the standards work no difference for PoE pinout. The 12-36 pinout are taken for data in the fast network. It leaves 45-78 two spare pairs which can be used for power transporting. This is one way to send the power over Ethernet cable.

The typical products we can see taking 45-78 pinout for power is the passive PoE injector. The passive injector simply combines 45 twisted cable in one and 78 twisted as another. The low voltage power can be sent over these two combined twisted pair. The passive PoE injector doesn’t have any protection for the power so it is the primitive PoE solution. The voltage drop will turn into serious issues when the cable is longer than 20 meters.

The IEEE 802.3 active PoE injector also takes 45-78 for power. Instead of simply adding power to the twisted pair, the PoE injector has protection mechanism to guarantee the power is being sent to the right place. The PD signature has two steps to verify and classify whether the remote ip device is IEEE802.3 compliant products. Otherwise the injector will not release the power at all.

Now the PoE switch – (simliar as PoE injector) usually takes 12-36 data pair to send the power. You may confuse why the power can go over data pair. The network is moving to gigabit which needs all 4 twisted pair for data. There are no spare twisted pair in gigabit network. One of the components named network transformer can separate the power from the data easily. The 12-36 becomes preferred pinout in IEEE 802.3 standard products.

In the next generation PoE IEEE 802.3bt, all four twisted pairs are occupied to send the power as well as data. This new standard is capable of transporting 95W power over single Ethernet cables . It benefits for the high power demanding application such as cellular base stations, access control with door locks, televisions and interactive displays, Point of Sales (POS) and information kiosks, etc. The voltage drop is the issue needed to be taken care of no matter which pinout are taken to send the power. Click here to find out what voltage can be used in Power over Ethernet.


Tips for Outdoor Applications Deployment

Fiber Optic Cable Solution for Security IP cameras

What is PoE IP Camera?

Before moving to the PoE IP camera, let’s make clear what is IP camera first. IP camera, also referred to Internet Protocol camera, is a digital video camera which captures image and transmits it over the network. IP camera needs power and communicating network to function.Therefore it has to be used with Ethernet cable to send data and the power to supply the camera. PoE IP camera has integrated with Power over Ethernet technology. Both data and power are transported through single Ethernet cable(Cat 5e/Cat 6) and videos are transmitted in the same cable. The PoE IP camera simplifies the cabling job and gets rid of the power adaptor closed to each cameras.

There are many ways to power a PoE IP camera. We will go through each of them below.

PoE IP camera can be connected and powered by PoE NVR. PoE NVR, or name PoE network video recorder, is little different from the traditional NVR. PoE switch is built in the video recorder, which can provide power and data to the cameras. Cat 5 or Cat 6 ethernet cable is the standard network cable to transmit data and supply power in PoE. To link PoE IP camera to PoE NVR, only one Ethernet cable is needed. Simplified installation reduces time and cost. PoE NVR can record video files and export it as forensic footage. It isolates IP video camera system from the main network. Usually PoE NVR has four or eight Ethernet ports. If you want to set up few IP cameras in the system, PoE NVR is a good choice.

PoE switch can also power PoE IP camera. The PoE switch connect to the cameras for power supplying and data exchanging. Using PoE switch can link multiple IP cameras and the network video recorder all together. You can choose the number of ports of PoE switch based on the system design. There are 8/16/24/48 ports PoE switch available in the market. This solution is made for those who want to set up PoE IP cameras for small-medium system.

The third way to power the PoE IP camera is by connecting to a PoE injector. The injector can add the power to Ethernet cable and the power is transported to remote IP camera as well as data. Power is taken from AC outlet before converting to DC48V. Usually the injector has two RJ45 ports. The data port will be linked to network hub to receive the data. PoE port will be connected IP camera for transporting the power and data. Since there is only one PoE port, single injector can power one PoE IP camera with this solution.

The PoE injector is able to work with PoE IP camera. If the camera doesn’t support PoE, a PoE splitter can be added to convert non-PoE IP camera to PoE available. The PoE injector and splitter usually work in pair. PoE splitter receives both data and power from the injector, and then separates them into two different outputs to the IP camera.

Last way to power PoE IP camera is to use passive PoE injector. The passive injector doesn’t have any protection for the power transporting. The users should possess the basic know-how to operate passive PoE splitter. The passive PoE injector simply forwards power from the external power adapter to remote IP cameras. It can only power up low voltage device. The passive PoE injector is the primitive PoE solution which works in a short distance.

The cable distance is limited to 100 meters in PoE system. Using PoE extender can extend the network beyond 100 meters.

Different Types of Power over Ethernet Adaptor

PoE adaptor (also name PoE injector) is a product which can send power and data through single Cat 5e/Cat 6 to remote powered devices. The PoE adaptor provides power solution to a wide range of network equipments such as IP cameras, access point and VoIP phone. Due to transparency to TCP/IP protocols, no configuration is required. The PoE adapter is a plug and play product.

PoE adaptor has different types based on power voltage. There are 12V/24V/48V adaptor. 12V PoE adaptor is the most primitive adaptor. As we know, an Ethernet cable has four twisted pairs. Two of the pairs are used for data delivery, and the spare pairs sent power to remote devices. No protection protocol is used in this type of adaptor. When the 12V adaptor is powered, electricity will be sent directly to PoE devices. Usually there is passive splitter at the other end to separate the power for remote device. As the voltage will drop down sharply while the distance is increasing, the 12V PoE adaptor can only be used in the short distance transportation.

Another type of PoE adaptor, 24V adaptor, can supply more power to devices. The DC24V injects the power to the Ethernet cable and the DC12V regulator is required at the remote device in order to output correct voltage. 24V adaptor sends power to 50 meter far. Voltage drop is being taken care of by the voltage regulator.

The last type of PoE adaptor is 48V adaptor. Before introducing the 48V PoE adaptor, one point should be known. That is passive and active PoE adaptor. Non-standard adaptor has no built-in PD signature detection. The adaptor will release DC48V directly when the powered device is plugged in at the end of RJ45 connector. The standard PoE adaptor will verify the remote device before adding the power to the Ethernet cable. The PD signature guarantees the safe process for power over Ethernet solution. Signature detection can avoid the device burned out and protect from the power surge. If the powered device fails to be verified as standard PoE devices, the adaptor will stop the power.

12V PoE adaptor can be used in 12V IP access point and other low voltage devices in short distance. A passive splitter is needed to split the power from the data. As no protection is added, you must have basic knowledge about how to operate the passive PoE adaptor. If you mix up with the twisted pairs, the remote device will be damaged immediately. The 24V PoE adaptor usually works with specific products. The regulator has to be included inside to convert to DC12V. It is better to limit the distance to 50 meters because of the voltage drop. The standard 48V PoE adaptor complies with the IEEE 802.3 specification. As long as the powered device also meet IEEE802.3 standard, the solution is plug and play. The adaptor can deliver data and power up to 100 meters.

To learn more about PoE adaptor or injector, check how to choose the right PoE injector for your network.

How PoE Injector Works with Splitter for Power over Ethernet?

When building a network system, PoE technology is always good to be considered. PoE (Power over Ethernet) makes power supply and data exchange via one Ethernet cable possible. PoE injector and splitter are two major equipments for transporting the power and data over single ethernet cable. The injector adds the electricity power to Ethernet cable, and the splitter separates the power from the data at the other end. Injector usually has two RJ45 ports, one for receiving data from switch and another for sending out power/data combined signal to the remote devices. Similar as injector, the splitter also has two RJ45 ports. Instead of sending out power and data, the splitter receives data and power and then separates them for non-PoE device.

PoE injector and PoE splitter usually work in pairs. The injector sends out power and data to splitter, and PoE splitter separates data and power into two different cables to make devices work. The PoE injector and splitter solution is designed for non-PoE devices or a mixture of PoE compatible and non-PoE compatible devices.

Except for PoE injector and splitter, a non-PoE switch is required in a typical network system. A non-PoE switch provides platform for connected devices to exchange data. As the PoE injector doesn’t process the data, it has to be connected to a non-PoE switch for data exchange. The PoE injector usually has AC input so it should be plugged in AC power outlet. Now the injector can take the power from outlet and combine it with the data from non-PoE switch before sending out. The splitter stays at the other end of the cable closed to powered device (PD) such as IP camera, access point, VoIP. These powered devices receive the power and data separately from a splitter.

There are three IEEE 802.3 standards for PoE technology. As long as PoE injector and splitter comply with IEEE802.3 standard, it guarantees the power transporting with pre-defined power budget in the system safely.

Different standard provides different power budget. IEEE 802.3at, 802.3af and 802.3bt standard are commonly used. IEEE 802.3af supplies 15.4W, which is the lowest among the three standards. 30.8W power can be provided when the injector and splitter are compatible with IEEE 802.3at (also named PoE+). The IEEE 802.3bt standard is the next generation PoE which increases maximum PoE power up to 95W by taking all 4 twisted pairs wires to transporting the power.

Voltage is another factor in the PoE injector/splitter power system. DC12V and 5V are two main types of power voltage being used in the market. A lot of PoE splitter are designed for DC12V power output. If you use low voltage device like IP camera, 12V PoE splitter is the right one.

Both Cat 5e/Cat 6 ethernet cable can be used to setup PoE injector/splitter power system. Cat 5e/Cat 6 consists of four twisted pairs of wires. Two of the twisted pairs are used for data sending in fast network, which is also called data pair. The spare pairs could be employed to transport the power. Pure copper Ethernet cable should be chosen because pure copper can reduce the power loss on the cable. The electricity transporting on conducts will generate energy loss and be converted to heat. If the low quality cable is picked, the power loss will become serious.

Using PoE injector and splitter solution simplifies network system setup. The AC outlet is removed at the front end and the power is sent by the injector from the center. It is cost-effective and money-saving. Attention should be paid when choosing the PoE injector and splitter.

Power over Ethernet voltage 12V-24V-48V-57V

The power over Ethernet inject the power to cat5e or cat6 network cable, so the remote ip devices is able to retrieve both power and data from single cable at the other end. According to the standard EN62368 (for AV & IT Equipment), the limit at which under no safeguards are required is DC60V or 2mA. We are seeing different voltage not higher than or equal to DC57V are being used on power over Ethernet. Let’s talk about the differences about these voltage on power over Ethernet.

One thing need to be addressed before we move ahead is the voltage drop. While using cable to send the power, there is always power loss inline cable which will be converted to the heat. The consequently result is the voltage drop at the other end. If the voltage drop down lower than the remote devices require, the whole system will stop working. For example, the WiFi router requires DC9V, but the remain voltage is only 7V after 100 meters transporting, the power will not be able to supply the WiFi router.

DC12 voltage power

This is the raw solution. The power is injected to the spare pairs of the Ethernet cable and being sent to the remote network devices. There is no process and protection for the power. This is the most simplest PoE solution which could still work for short distance and low power consumption on indoor application. If use this solution to transport power longer than 20 meters, the remain voltage will drop down sharply at the other end.

DC24 voltage power

It is popular in some telecom application. Some of electrical devices require DC12V input. Injecting DC24V to the cable can adapt to the voltage drop after medium distance transportation such as 50 meters. The other side usually requires voltage regulator to convert remain voltage to DC12V. There is around 12V margin to adapt to the voltage drop, that is why the maximum distance could be longer.

DC48 volts power

DC48V is the specification from IEEE802.3 PoE standard. According to IEEE802.3, the power is capable of transporting up to 100meters as well as data. The other end requires regulator to convert to lower DC output such as 12V or 5V. IEEE802.3 also specified the power budget within 100meters including PoE PoE+, PoE bt. The higher power consumption, the higher the current inline, so the sharper voltage drop will be. As long as the products are IEEE 802.3 compatible, the voltage is no need to be concerned. Both issues has been considered when the standard was developed. Not only IEEE802.3 standard PoE use DC48V. Some of the passive PoE also use DC48V.

Over DC48 voltage

In these years the higher voltage such as DC55 has been applied to power over Ethernet including IEEE 802.3 compatible products. The benefits of high voltage PoE is reducing the power loss cable inline and relase the voltage drop issue. For example the IEEE 802.3bt PoE power system can transport 95w power over single Ethernet. If use DC48V, the voltage drap becomes seriously when the power is being full load. The DC53V is taken in, so the remain voltage is still enough after 100 meters transporting.

IEEE 802.3 PoE is considered as safe power system. That is because not only the power voltage has been designed for Ethernet cable, but also PD signature is introduced in the standard to guarantee the power PD signature is being sent to the device.


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Choose the Right PoE Injector for Your Network

The PoE technology has become a trend in power supply and network communicating. PoE ( Power over Ethernet) provides the solution to send power and data to remote devices by using single cable. There are many PoE related products, such as PoE switch, PoE extender, PoE injector and so on. All those PoE products play an important role for power supply and network extension. Here we will focus on PoE injector.

Before choosing the suitable PoE injector, let’s understand what is PoE injector.

A PoE injector or midspan injector can send the power and data through one Cat 5e/Cat 6 network cable. Electricity will be added to the injector and send over Ethernet. Eventually it reaches to the remote ip devices. The PoE injector usually has two RJ45 ports, one port for connecting the convenient switch to receive data, and another port for sending out both power and data to remote ip devices such as PoE IP cameras, access point, etc.

The PoE power system is perfectly safe. That is because of the PD signature detection. PD signature detection can avoid machine burned out. What is PD signature detection? The injector sends low voltage power to detect the front-end device before releasing the power. If the PoE injector confirms the remote device do accept the power over Ethernet, the injector will increase the voltage step by step until the end device is working stably. Therefore, the detection process can protect devices effectively.

There are several types of PoE injectors available in the market. Before you choose the right one to be applied in your network. One trap you should avoid. That is the passive injector.

People seldom pay attention to the difference between active injector and passive injector. Active injector complies with the IEEE802.3 standard which is the safe PoE. This kind of injector has PD signature detection as we mentioned above so it will detect whether the signal returns from remote ip device is correct or not. If signal is verified, the active PoE injector will increase the voltage gradually to make device work. Passive PoE injector has removed the function of signature detection, so it can’t detect the feedback signal. Once the Ethernet cable is plugged in, the injector will send the power directly to devices. And this may cause electrical damage to device. Watch the video to see the difference between passive PoE and active PoE.

Here are several types of injectors you can pick. First type is the PoE injector with IEEE 802.3af or 802.3at compatible. IEEE802.3af provides DC power up to 15.4W, while 802.3at up to 25.5W. Both power and data are injected through the PoE injector, then they will be sent to device over one Ethernet cable. The PoE injector belongs to active PoE injector. It can detect the power voltage automatically to avoid damage to device.

PoE switch is also a kind of injector. However it is little different from PoE injector. The PoE switch can be considered as an injector is built in to network switch. The PoE switch provides both power and data exchange for remote IP devices such IP cameras or access point. As the PoE switch has many ports like 8/16/24 ports, more IP devices will be able to connected to PoE switch to receive the power and data exchange.

95W PoE injector is the next generation of PoE injector. It not only meets the IEEE 802.3at/af standard but also 802.3bt, the newest standard. 95W power can be injected to Ethernet cable, so it is suitable for network devices demanding high power.

PoE NVR can be classified to PoE injector. NVR, also called network video recorder, controlS the connected cameras and storeS the video footage conveniently. PoE NVR has integrated PoE technology. It doesn’t need extra power supply and data for exchanging. Power and data will be delivered to cameras after they are connected to PoE NVR. It simplifies the surveillance system setup.

The PoE technology proves the value by saving the installation cost, simplifing the network design. Where the cable goes, the power source follows. You may want to consider even when you upgrade your existed devices.