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What is PoE -Part 2

PoE, abbreviation of Power over Ethernet, is a technology that allows network cable(Ethernet cable) to transmit electrical power for PoE-enable devices. It is a cost-saving solution for you to deploy IP device conveniently with existing CAT-5 Ethernet infrastructure without the need to make any modifications. While it has developed over 10 years, people still have doubts and misconception to PoE. This article intend to explain PoE in depth but simply.

PoE has compatibility issue? Actually it is not. In the early time, PoE confronted with compatibility problem because there is no standard for the power and voltage. Therefore, different PoE products from different vendors can not work together. However, this issue was settle in 2003 when PoE is defined as IEEE 802.3af standard by the Institute of Electrical and Electronic Engineers (IEEE), which is the largest technical professional organization in the world. Nowadays, most of PoE devices on the market is complied with IEEE 802.3af/at standards, even from different vendors.

PoE Standard

802.3af PoE Standard: This standard is able to support 15.44 watts of power, but in practice, powered devices (PDs) reliably receive 12.95 watts due to power losses through the circuit.

802.3at PoE Standard: Also known as PoE+, this standard supports 30 watts of power, but as with the 802.3af standard, power losses lower the amount supplied to 25.5 watts.

802.3bt or PoE++ Standard: It is a higher powered PoE standard, also called the next generation standard that may provide up to 90 watts by using 4 pairs of balanced twisted-pair cabling.

Active PoE vs. Passive PoE

If the PoE device is compatible with PoE IEEE802.3af/at/bt standard with a fixed 48V power voltage, it can be considered as active PoE. Active PoE devices will auto-detect the power requirement of powered devices(PDs) and power can be transmitted accurately, avoiding over-powering or under-supplying issue. While passive PoE is on the contrary, it means any device using PoE that is not IEEE 802.3 standard. And it supply power to powered devices without negotiation, which easily damages the PoE devices or shortens their life. Therefore, according to different IEEE 802 standards, there are 4 class types to categorize power requirement for powered devices.

PoE Class Types

Classification ensures that powered devices receive the appropriate level of power. This also allow the PSE to allocate the left unused power to other PDs. The below table will present the range of power allocated with different class types for 802.3 standard powered devices(PDs).

Mode A vs. Mode B

The power supply of PoE devices is divided into two methods, namely Mode A and Mode B. Ethernet cable is 4 pair twist copper cable with 8 pinouts.

Mode A: It is also known as Alternative A, which refers using 2 pairs data pinouts 1-2 and 3-6 to transmit or receive power and data, and the other two pairs 4-5 and 7-8 pinouts are unused. Mode A devices are sometimes referred to as end-span units.

Mode B:  When devices operate in Mode B, it means all data pairs are used. Mode B sends data using pinouts 1-2 and 3-6.  Power is sent using data pin pairs 4-5 and 7-8. Mode B devices are also referred to as midspan devices.

What are the advantages of Power over Ethernet?

  • Money saving – PoE technology requires few electricity technical knowledge, you can finish the installation following instruction, saving the cost for hiring professional electrical installers. What’s more, there’s no need to build extra wire cabling as power and data are transmitted over single Ethernet.
  • Flexibility- PoE is popularly applied in the places where hard to find power supply(AC outlet) or reach easily, such as ceiling, outdoor deployment, industrial environment.
  • Standardization – Majority of PoE devices are complied with IEEE 802.3af/at/bt standard, which implies most of powered devices that you own will not confront compatibility problem, proving convenience when choosing PoE devices.
  • Easy to use – connect power sourcing equipment (PSE) to PDs with twisted-pair Ethernet cable, such as IP cameras, VoIP phones, or WAPs, if you have existing ethernet switch or require high power, adding PoE injector can help to deal with power supply for powered devices, such as IoT applications, pan-tilt-zoom (PTZ) IP cameras, Point of Sales (POS) etc.
  • Scalability – PoE devices are designed plug and play, you can add new equipments fast without expensive and inconvenient new powerline installation.
  • Safety – PoE devices work in low power voltage so that it is safe enough to reduce electrical accident for the network system.

PoE technology and IoT application influent each other. You are supposed to embrace them with expectation. Want to know more about PoE solution, contact us to get suitable PoE devices for building your wired cabling system.

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What is PoE-Part 1

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

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What is PoE-Part 1

How commonplace PoE technology is, and the answer reveals while we think of the popularity of wireless access points(WAPs), IP security cameras, voice-over-IP (VoIP) phones, and building automation and control systems. It seems to penetrate deeply into our work and living.

In other words, PoE is actually a kind of new product generated by the information technology era as people demand of more power and better network to be transmitted via cabling in order to satisfy their high power consumption PoE network devices.

PoE, also known as Power over Ethernet, is designed to make power signal and Ehernet network do not interfere each other so that allows power and data to be transmitted over single Ehernet cable to PoE devices. Simply, more power is able to transmit to PoE network devices from Ehernet cable, because it converts main power supply into low voltage supply, but power dissipation is inevitable.

Besides, PoE is a technology for wired Ethernet local area networks (LANs) that carrys the needed electrical current for operation of devices by data cable instead of power cord, which means the number of wires that must be strung for the installation of network cabling will be minimized.

Two technical teminologies you need to know in figuring out PoE, one is Power sourcing equipment (PSE), commonly called an endspan (switch) or mid-span (injector) provides power source to the Ethernet cable, the other is powered device (PD), any device powered by PoE, such as wireless access points, VoIP phones, and IP cameras.

PoE was originally developed in 2003 to support devices like Wi-Fi access points (APs), which enable to simplify its installation at some locations where hard to find AC outlets, such as ceiling. The Institute of Electrical and Electronics Engineers (IEEE) defined PoE with standards, which combines with other vendors to attemp to solve power supply issue. And PoE technology has been through decades of development so far. From 2003, the PoE technology had a litmitation for supplying devices with power consumption less than 12.9W, then by 2009, its supplying power was increased to up to 25.5W, while in last year, 2018, the PoE is able to deliver at a maximum of 71W to PoE-enabled devices, meeting the various needs for high power supply.

The development of PoE technology is still keep moving forward as the IoT(Internet of Things) has become the trend around the world. Most of eletronic devices used at work or home will be connected to the internet, and more and more IoT devices require high power so that to work,such as LED lighting system. Therefore, PoE+ or PoE++ that provides more power is going to be the key project for experts to study and essential technology for modern society to adopt.

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Using IEEE802.3af/at/bt devices

How to extend the cat5 network up to 500 meters

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Tips for Outdoor Applications Deployment

Although WiFi connection has become a common way for people to get access to network, it has several downsides that can’t be solved by now, such as narrow coverage of WiFi signal. Actually, wired cabling is a rather more reliable way to get higher bandwidth for data transmission as well as more resistant to electromagnetic interference. As to wired cabling, one thing with which you might confront is outdoor deployment. There are several things you should know before you dive head first into the world of outdoor wired cabling deployment. Today we’ll talk about how you can accomplish outdoor applications deployment.

1. High temperature is a main problem you need to overcome

Outdoor deployment means all the devices are exposed under the sunshine for a long time, and the internal temperature of devices increase as the time flows, which may affect the electrical components within and their lifespan will decrease, especially when they are in use. Moreover, excessive heat can even lead to a leakage in the integrated circuits of microprocessors. Most likely the mode of failure would be a premature failure of the power supply or an internal component from the heat. And this even results in fire accidentally. While anything electrical could catch on fire in some circumstance, it probably could catch on fire just as easily if you had it installed in an outdoor space.

The optimal operating temperature for most of the electrical equipment lies between 40℃ (105℉) and 50℃(122℉). Therefore, temperature control and heat reduction are extremely critical, and you are required to utilize devices with designs can stand high temperature or reduce heat to save yourself the trouble due to temperature related issues in the future.

2. Use weatherproof products or housing to protect the devices from water.

No matter you choose to bury under the ground or hang in the air, water is an unavoidable risk in outdoor deployment. It’s common knowledge that water does bad things to electronics. Water in its purest form is not conductive. Instead, it is the impurities in the water such as salts, dust, and so on, that enables it to conduct electricity. Water penetration or heavy rain may cause short circuit to devices when they are powered if these kinds of water stay in the internal component. Besides, this may lead to oxidation or corrosion if allowed to stay in place with heavy moisture for a long time. In this case, choose weatherproof products or take some measures to resist water are necessary, such as enclosure.

3. Surge protective devices can help you deal with lightning issue.

As the devices and cable are placed at outdoor environment, lightning may create bad results on the devices directly or indirectly. There is no way can prevent directly lightning strike, while this is small probability event, here we say no more. In fact, when lightning strikes near a power line, it can increase the amount of electrical current flowing to a wall outlet. This extra burst of electricity is often too much for common electronic devices, which can easily lead to power surge damage. Home or businesses may need to take extra measures of precaution to protect data communications systems from a power surge. Depending on the your needs, you are able to look into surge protection devices or grounding systems, which are the most efficient solution to limit surges generated by lightning to an acceptable level for equipment and installations.

4.  It’s hard to find power supply at outdoor environment.

Generally, people are not intend to pre-install AC outlets at outdoor in the initial cabling deployment, and add new AC outlets for particularly use is complicated and time-consuming. What’s more, some locations of outdoor deployment are difficult to reach, not to speak of installing AC outlets. Some people say they can set a power sourcing unit(PSU) close to the devices for power supply. But PSU is not suitable to place at outdoor as the high temperature probably cause explosion of the PSU, which not only leads to property loss and is not safe enough for the passerby.

5.Figuring out how to choose cable is essential to deploy wired cabling at outdoor.

There are two kinds of cable for convenient outdoor wired cabling. Ethernet cable and fiber optic cable. Ehternet cables such as Cat 5e are commonly used at indoor, short and medium distance deployment. But if you choose the direct burial cable or use a conduit for your cable runs, Ethernet cable still can be a convenient solution for outdoor deployment. Nevertheless, there is specific fiber optic cable designed for outdoor deployment, this kind of cable is more durable and can withstand high temperature effectively. In short, fiber optic cable has more benefit than copper cable. For example, fiber optic cable is glass material, which doesn’t conduct electricity, so it is more secure and reduces power surges incidents.

6. Last but not the least, you are supposed to select suitable equipments with discretion in outdoor deployment.

Industrial grade solution is a good choice. You know that outdoor environment has greater possibility to withstand bad ultra low or high temperature. While industrial grade devices are used qualified components to provide better stability and reliability during operation. Generally, these devices support wider working temperature range and durable metal housing to resist strong sunlight, snow, dust, vibration etc.

Fastcabling issues various industrial grade products combined with excellent waterproof capacity to meet the demands of outdoor deployment or harsh environment deployment. All the product in this series are specially designed with one unit waterproof metal housing. Moreover, they features high security power surge protection to help protect against electrostatic discharge (ESD) events and reduce surge damage caused by lightning strike or unexpected power surge.

If you want to expand Ethernet for multiple IP devices, here outdoor waterproof PoE powered switch is recommended. It is an advanced device that integrated PSU and PD in one unit, that means it receives power and network from back-end PSE, and passthrough to front-end IP devices conveniently and safely, so it doesn’t require local power supply, which is perfect for location that hard to find AC outlet at outdoor.

What’s more, if your ready to mount IP devices are quite remote from the control room, the outdoor waterproof PoE switch with SFP. The switch provides fiber optic link, because it has one build-in SFP slots in order to connect the devices with fiber optic cable. Besides, there are 4 gigabit Ethernet ports to transmit power and networks, thus installing multiple IP devices in the same area is not a big deal. A maximum of 30W output power and gigabit network will be transmitted to your IP devices, which is ideal for outdoor applications deployment where are hard to find AC outlet.

If you have specific IP device that is a little be far away and hard to find AC power supply from devices that don’t support standard PoE, you will need some devices to provide PoE and requires to install at outdoor environment, outdoor waterproof PoE injector are perfect choice to help you. It supports PoE technology and complied with IEEE 802.3at standard to provide a maximum of 30W output power to IP devices. As to power supply issue, it is a convenient and reliable power system with wide input power range from 24V to 55V DC, which enable you to place the PSU near the injector or a little far away.

The above is the general introduction about outdoor waterproof series product, if you want to get more detailed information of specific product, please turn to the corresponding product page to find suitable devices to serve your needs. If you still have any question, leave us a comment or contact us now.

If you still have any question, leave us a comment or contact us now.

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Fiber Optic Cable Solution for Security IP cameras

Today, we will mainly focus on the connecting ways by using fiber products from Fastcabling to settle down long distance IP cameras deployment problem. If you are confronting with similar situation or interested in the connecting ways, please keep reading.

As the great execution of IoT, Power over Ethernet is prevalently utilized in various IoT devices. PoE is a technology to transmit power and data simultaneously over single Ethernet cable, which provides steady power and fast network capacity for powered devices without new power and network cabling. However, PoE has a limit of distance with 100m because of energy loss. In other words, if you want to deploy IP camera beyond 100 meters or far more remote, PoE connection can not reach, while fiber optical cable is one solution for dealing with this issue.

To begin with, let’s understand the value of fiber optical system to figure out why utilizes fiber to connect IP camera.

Fiber optic transmission is faster than copper wire. It is easily for fiber optical system to deliver 10G network. The higher speed network such as 40G, 100G, 400G are all employed fiber optical transmission.

Fiber optic transmission is in less attenuation. The signal always decreases as the distance increasing but the fiber optic cable can deliver lower attenuation which means that the transmission creates less signal loss. For example, if you want to deploy a IP camera over 100m, using fiber optic cable only causes 3% signal loss, while on the contrast, copper wire will lose 94% signal of the same distance.

Fiber optic cables are impervious to electromagnetic interference. Copper wire will produce electromagnetic currents that can interfere with other wires and wreak havoc on the network after improper installation. While fiber optic cables are more stable after deploying in the field, which eliminates frequent cable replacement.

The last but not least, since the fiber optical simply transmits the light in the system, which can prevent fire accident since it doesn’t conduct electricity. What’s more, it proves higher security because tapping the data from light is more difficult than electrical copper.

All in all, the fiber optical link is suitable for long term operating. Once the link is setup, it can be used for years without extra maintaining. Therefore, it is a relatively good tool used to connect security IP camera, especially in the long distance deployment.

Now, let’s get to the point. In the following, we will demonstrate 3 main solutions of connecting IP cameras with fiber optical cable.

1.Use a pair of media converters

The Fastcabling’s media converters allow you to deploy IP cameras far away from the main network by using multimode or singlemode fiber optical cables, reaching a maximum distance of 80km. Media converters are useful devices to convert electric signal to fiber optical signal or versed so that the camera’s video can be transported over the fiber cable. Two media converters are needed at both sides to build the fiber link. By using Fastcabling’s media converters, you can gain stable and fast network transmission with low consumption, providing various options of network speed to meet your needs, gigabit network can be accessed. Due to mini compact size, you are able to accomplish installation flexibly and easily.

What if there are more than one cameras that you need to connect in the same area. 5850-51 PoE media converter can help you deal with network and power issue for two PoE IP cameras. 5850-51 PoE media converter equips with 2 PoE RJ45 ports with gigabit data rate and a maximum of 30W output power, which is convenient and saving cost and time on separate cabling as well as provides guarantee on video data streaming with sufficient power for IP devices, especially when the camera image is required high resolution to catch clear details.

How to choose fiber cable and which connector to use depends on the SFP module (SFP transceiver) installed in the media converters. The SFP module is the critical components to generate the optical light. We also offer you various types of SFP modules, which suits for people who demand for different data rates and transmission distances. 

In this media converter solution, power supplying needs to be dealt with separately. The fiber optical technology simply transmits the light which can’t carry the electricity.

2. Fiber with copper wire

The second way is replace the front-end media converter with our Fastcabling fiber PoE extender, which can be considered a special type of media converter.  Except for converting the video stream to fiber signal, the extender also provides PoE to remote IP cameras. As thisfiber PoE extender enables to accept power input and pass through to IP cameras via Ethernet cable. In this case, copper wires and fastcabling pre-terminated fiber optical cables can be employed to send the DC power48V. The connectivity between the fiber PoE switch and the camera stays with convenient Ethernet cable, supplying both gigabit data and 30W output power of each port simultaneously. By using this fiber PoE extender, the maximum distance between the fiber PoE extender and the camera can be 100m. Thanks to PoE technology, the power sources are eliminated, and with no need to be closed to each of the camera. It simplifies network design and saves the total cost. Actually, this is useful for IP camera set up, because cameras deployment locations are always hard to find or install AC outlets for power supply.

If there are several security IP cameras gather around in the same area, fiber PoE extender  is the handy tool. This 5840-524 port fiber PoE extender  in Fastcablingcan provide multiple PoE ports for taking in more than one security IP cameras. Instead of wiring each fiber optical cable to each security IP cameras, one fiber link is enough between the media converter and the fiber PoE extender.

However, there is controversial opinion with this solution. Because one of the fiber link fails to work, it will affect the rest of the cameras. However, using fiber optical cable to connect security cameras is easier than people expected after picking the right components.

 All solutions mentioned above, hope can provide useful information for you. If you have any questions or concerns, welcome to contact us.

Mentioned products listing:

5838-18 Fiber PoE ExtenderSFP transceiver;

5837-26 Fast Ethernet media converter; 5537-42 Gigabit Ethernet Media Converter;

5538-65 4 Port Industrial Hardened PoE Switch; 5838-72 8 Port Industrial Hardened PoE Switch ;

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

Power hungry applications have been used in office and home widely, therefore the demands of new high power PoE are increasing, which means advanced PoE technology and standard are urgenly needed for providing steadier power and network to these power hungry IP devices. Thankfully, you’re not completely out of luck, you can find cost-saving and safe solutions in Fastcabling, meanwhile, the solutions we provide is also suitable for your existing non-PoE system.

What is high power PoE?

As the explosion of IoT that requires powerful network capacity, more and more IP devices are invented in this modern society, and because of the limitation of wireless technology, Power over Ethernet is an accessible solution to deal with power and data issue with single Ethernet cable for remote IP devices.

Power over Ethernet (PoE) has become powering strategy for wider array of higher-wattage devices and IoT applications. In this way, there is no need to run the power and network cable separately, simplifying installation and saving cost, while adding new intelligent device control capabilities. Athough there are pros and cons of PoE technology, we can not deny its convenience,flexibility and safety.

PoE systems typically include only two items – powered devices (PDs) and power sourcing equipment (PSE). As their names imply, PD’s use the electrical energy delivered through the cable while the PSE supplies it. High-Power PoE defines a method of safely powering a PD over a cable by a PSE, and then switching off power if a PD is disconnected from the cable.

Actually, some of IoT devices are high power input devices,such as emerging applications including:

• Building infrastructure such as LED lighting

• Retail POS systems and digital signage

• High Performance Wireless Access Points that support IEEE 802.11ax and 802.11ac Wave 2

• High definition pan-tilt-zoom(PTZ) security cameras with heaters for harsh environments

Driven by the need to connect emerging power hungry IoT devices, The industry has steadily increased the amount of power that PoE can deliver over Ethernet cabling so that a broader range of devices can be supported.Industry PoE standards are advancing to meet the needs. In 2018,PoE technology has progressed with the introduction of the IEEE 802.3bt standard, which is new technology uses all 4 pairs in an Ethernet cable and includes support for 10GBASE-T, 5GBASE-T, and 2.5GBASE-T over CAT5e or higher.This enables the PSE to support 45W-90W power budge. While the first Standard was IEEE 802.3af, which only supported 15.4W for device. Then came IEEE 802.3at, which supported up to 30W. With the advent of high-power IEEE 802.3bt standards, it is more important than ever to deliver power as efficiently as possible.In addition, the 802.3bt standard will also be able to reduce power dissipation.

After knowing these basic knowledge, let’s get to the solutions.

There are three High Power PoE Solutions:

1.90W PoE injector

Our Fastcabling’s 5720-74 90W PoE injector is a cost-effective device that meets IEEE 802.3bt standard with 90W high power budge to supply power and data for your various powered devices which needs high power input. By connecting this injector to your existing switch,you can integrate your existing non-PoE switch with PoE without extra power and network cabling and the injector will transmit power in a maximum of 72W and data for your high powered devices.

What’s more,the most energy-efficient way to deploy high-power PoE is using midspans that are installed between the existing switch and the network’s PD. 5720-74 90W PoE injector is a kind of mispan, which is a stand-alone plug-and-play device, residing between an ordinary Ethernet switch and the terminals. Midspans are ideal when there is no need to upgrade the network switch, and they can be specified in a wide range of port densities.

More importantly, from an efficiency perspective, midspans use distributed power architectures so that they solve the problem of quiescent power losses with PoE-enabled switches. They also offer remote-management and energy-saving capabilities that are not available with PoE-enabled switches.

  2.90W PoE injector+ 90W PoE splitter

If in the places where are hard to find AC outlets, and the power devices you want to deploy is non-PoE devices that require high power input, this issue can be solved by using the 5720-74 90W PoE injector and the 5721-23 90W PoE splitter together.Because the 5721-23 90W PoE splitter also adpopts IEEE 802.3bt standard, so this two devices generally work as a pair. By connecting these two devices to the main switch, the whole system can provide up to 72W power for your powered devices, which is perfect for many power hungry applications.

  • How this system works?How this system works?

The 90W PoE injector gets power and data from the back-end switch, and it is as a mispan to transmit to the 90W PoE splitter, and the splitter will separate power and data so that the non-PoE devices can receive data only and the power can ues to supply devices without network.

3. 90W PoE injector and PoE powered switch

What if you want to deploy more than one powered device at the same area where also hard to find AC outlet,there is solution in Fastcaling.Buying a common 24 ports switch is expensive and usually many ports will be spare.In this case, PoE power switch is a suitable choice. Our Fastcabling’s 5541-25 PoE powered switch is a device that integrates PSE and PDs in one to receive power and data and passthrough to powered devices.

There are 8 ports in the switch, one is for “PoE in” and the other 7 are for “PoE out”. Each port can output up to 30W with gigabit network, which is perfect for cleanly adding Ethernet ports to where are needed and expanding Ethernet ports in a rational way. Using this switch can help you to accomplish point to point or point to multi-point deployment with single Ethernet cable without power and network cabling, which saves time and provides great installation flexibility and cost saving. Every time you need to install a new powered device, you just need to connect an Ethernet cable to the new device.

Working with 5720-74 90W PoE injector, the whole system can supply up to 71W. Therefore, you can be deal with the supplying issue for high powered devices quickly and conveniently.

Hope these three solutions can help you build a cost-effective and safe PoE system for high powered device. If you have any question or want to get more information, Fastcabling are waiting for your consultation.

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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.

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How IP camera use Power over Ethernet

Same as all other electronic devices, IP cameras need power. IP camera is known as network camera. So the network is required for communicating. Power over Ethernet allows power and network transmit over single Ethernet cable. It eliminates the extra power cord to the camera. Using the PoE power system can save installation cost. It also meet NEC Class II and SELV regulations as the whole system uses 48V DC low voltage input.

How Power Over Ethernet work? There’s 4 twisted pairs in cat5e or cat6 Ethernet cable. Only 2 pairs are used for fast network (10/100mbps). It leaves 2 spare pairs twisted which will be used to carry the power. The power is injected to the those twisted pairs and send over to the IP camera. This is one way to understand the PoE, but it is not complete picture. We will come back to it a little bit later. In the typical PoE system, the power is located at the central together with the network switch. Technically it calls PSE (power supply equipment). When the power integrated into a switch. It becomes PoE switch, The PoE switch look no different from conventional switch. However, this switch can supply the power to the camera as well as network through single RJ45 cable.

As you know, network video recorder has to be deployed to record the footage in the CCTV system. If both power and switch are integrated to a network video recorder, the recorder is called PoE NVR. The PoE NVR has extra Ethernet ports at the rear panel. Simple connect those ports to PoE IP camera, the camera can got both network and power. It simplify the system installation. All the Ethernet cables will return to the PoE NVR. However, as the power is integrated to the recorder which will generate extra heat and increase the temperature inside the recorder. The consequences is it may shorten the use life. Either the power or switch failed, the PoE recorder need to be replaced.

If no PoE switch or PoE NVR are available in the system, use PoE injector also can inject the power to your network. The PoE injector doesn’t process the data, just adds the power to the twisted pair. The PoE injector is flexible device when only few channel of cameras need PoE power. This solution also can leverage your exist network infrastructure.

As we mentioned at the beginning, there are 2 spare twisted pairs in the Ethernet cable which has been taken for the power. In the practical application, PoE switch usually doesn’t use the spare pair to send the power. The power will be added to the data pair (12-36) and transmit with the network. At the front end, the IP camera receives the data and power on the same twisted pairs and split the power by using the network transformer. PoE has no problem to work with Gigabit network which all 4 twisted pairs have been occupied for high speed communication because of that. The truth is both data pair and spare are capable of carrying the power. If data pair are used to send the power, we call end-span PoE device. If spar pairs are used, we call mid-span PoE device. Most of the PoE switch use data pair to send the power today, Some of the PoE device such as PoE NVR or PoE injector still prefer the spare pairs for carrying the power.

Should We know which twisted pairs the PoE switch are sending the power before buying. After all, The PoE switch only will choose one way or the other to send the power, either data pair or spare pair. Fortunately, there’s IEEE802.3af/at standard. According this industrial standard, the IP cameras should adapt to either data pairs or spare pairs power way from the PoE switch. So no matter how PoE send the power, the PoE IP camera will still work as long as both side have followed IEEE802.3.

This industrial standard has provided important power negotiation protocol which is named as power signature. The PoE system is working with 48V DC voltage. Before the PoE switch release the power it has to be sure the front end device is cable of taking in the power, otherwise it may fire your front end IP camera. The power signature make sure it doesn’t happen. When the PoE switch release power, it starts from very low voltage, meanwhile it detect the feedback current from the IP camera. Later the PoE switch increase the voltage step by step up to DC48V. If the PoE switch doesn’t receive the correct feedback signal, it will stop releasing the power. What you sees is the PoE indicator LEDs keep flash on/off, but it never stay ON for long. It could be the IP camera is damaged which change the feedback signal or your IP camera doesn’t support standard PoE at all. Now what is the passive PoE? the passive PoE removes the power negotiation to save cost, it doesn’t detect the current feedback. The passive PoE will inject the power directly once the cable is plugged in. For your system reliability sakes, stay away the passive PoE unless you have to.

You may hear IEEE802.3af/at. The maximum power budget of IEEE802.3af is 14.4w and the maximum of IEEE802.3at 25.5W. The available remain power between these two standard are different. You may need higher power for some infrared IP camera or PTZ camera. If the PoE switch detects your IP camera require more the power than it can supply, for example, the infrared IP camera needs 16W, but the PoE switch is only comply to IEEE802.3af which is capable of supplying 14.4W, the PoE switch will stop working at night when the infrared is turned on. Also only both PoE switch and the PoE camera are comply with IEEE 802.3 at standard will have 25.5 power budget get in the system. The last thing is you may have read 30W IEEE 802.3at. That 30W refers to the power injecting to the cable. It is not the available remain power at the camera end. The power injected to the twisted pair are different from the available power budget at the IP camera. The voltage drop is considered for 100 meters transmitting. The power limited is set to 25.5w even the actually cable is only 1 meters.

Power over Ethernet has been developed over decade. It provides cost and time benefits to us. Some of the new technologies is evolving which allow to carry much more power such as IEEE802.3bt standard or transmit longer distance up to 3km PoE after integrated with fiber optical such as power fiber system. All those solution will benefit new IoT thing and IP cameras as well.

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How to get the long distance Power over Ethernet

The PoE provides the solution to transmit the power and network communicating over single Ethernet cable. It saves the installation cost. However the PoE has limited of 100 meters which has relative to both network communicating and voltage drop of the power. In the IEEE802, the maximum network distance is 100 meters between two IP devices. The PoE system require the remain voltage need to be higher than DC38V at the front end device. Otherwise the power system will stop working. Usually the PoE switch inject DC 48V power to the Ethernet cable. After 100 meters transmitting, the remain voltage will drop down to DC 39V which can still satisfied the requirement. however if the power is sending over 100 meters without proper design, the correlated power loss will become issue. Here we need to deal with both network and power constraints to get longer distance PoE.

There are three way to extend the Power over Ethernet. The first one is the PoE extender, which can repeat the PoE up to 400 meters with daisy chain setup. Each PoE extender is capable of to boost up the network and the power. However, the energy loss inline the cable still need to be considered. As only two twisted pair is used to transmit the power, similar as 22AWG copper cable. Only 7.91W remain power left at the end of 400 meters. the missing power is converted to the heat in the twisted pairs. The power loss not only depends on transmitting distance but also the quality of Ethernet cable. Ethernet cable with pure copper is the best choice for repeating the PoE. Basing on our test, the maximum PoE distance can shorten down to 60 meters when we use low cost copper clad aluminum cable, and it can achieve up to 120 meters after we replaced with cat6 pure copper cable. The cat5e and cat6 grade only specific the data rate, it doesn’t specific the material of the Ethernet cable. When choosing Ethernet cable, always make sure the twisted pairs are made of pure copper.

The second solution is the PoE switch with CCTV mode or VLAN support. Once the CCTV mode is turned on in the switch, it can support up to 250 meters transmitting. There is downside with CCTV mode. The Network speed will be down grade to 10 Mbps network. The network speed (data rate) is trade off for the distance. As most of the IP camera request less than 8mbps bandwidth, this kind of solution will work for IP surveillance’s camera. However if you want to extend the network for access point or small cell, the CCTV mode PoE switch is not the right solution. After all 10Mbps is too small bandwidth for network which could have multiple users accessing at the same time. The CCTV mode also will activate the VLAN automatically. The VLAN make sure each ports has independent 10 Mbps bandwidth. Port-1 can’t take up the bandwidth from port-2. What is VLAN? the VLAN isolates the PoE ports. Each PoE ports only can communicate to uplink ports, but not other each. Basically the PoE ports don’t see each other in the LAN. The next question is how CCTV mode switch deal with the voltage drop? The CCTV mode PoE switch usually inject the higher voltage  power than DC48V, such as DC55V, so it can have more margin to adapt to voltage drop after 250 meters transmitting.

The last solution is the fiber power system. The fiber optical has barely limited for network communicating. 10 kilometers distance is the typical specification for most of the fiber network. The challenge left is the voltage drop. Thanks to the composite fiber cable which had copper cable integrated. Now both fiber optical and the power can be transmitting in the single composite cable.

The fiber power system work similar as conventional PoE system. In the center the power is injected to the composite fiber cable. When the power arrive at the front end together with fiber optical, there is PoE fiber extender which has integrated both power management and media conversions will convert to standard PoE output, so the PoE extender can supply conventional PoE device, such as PoE IP camera. The voltage drop depends on the thickness of the copper cable. The thickest size of composite copper is 12AWG in the market. This can minimize the voltage drop and supply the sufficient voltage after long distance transmitting. With properly design, the fiber power system can send the power over 2500 – 3000 meters far from the center with standard PoE output.

Other than long distance, people are also looking for high power output for new IoT thing. In the IEEE802.3 af/at standard, the maximum power output is 25.5W. The new PoE standard IEEE802.3bt has come up which employs all 4 twist pairs to send the power. The IEEE802.3bt devices are capable of output 71W maximum power. This will benefits the power hungry device such as LED lighting, PTZ camera, Point of Sale terminals, Thin Client, etc. The transmit the high power in long distance will become the new challenge in the next few year. As the higher current inline, the more correlated power loss will be. We are looking forward to see how the technology evolves.