The usual modern IT-specialist cables type "twisted pair", with which a PC can be networked, is hidden a remarkable opportunity.The fact that they can be transmitted via not only a digital data stream, but also power.To do this, you should be involved additional devices - PoE-adapter.However, there are a large number of varieties and ways to connect these devices to the network.What are the specifics of the appliance?
basic information about the device
PoE-adapter - a device, enable the possibility of PoE-technology that allows you to transfer through an ordinary twisted-pair power to the desired device.At the same time the ability of Ethernet-cable to exchange digital signals is lost, and the network is fully functional.
Deciphering abbreviations PoE - Power over Ethernet.That is "powered by a standard Ethernet».PoE-Adapter is sometimes referred to as "the injector" - but the second type of device is still properly be considered a kind of first.We are studying the specific use of the reporting device in the context of realizing the potential of PoE-technology.
Read more about the technology
Power over Ethernet technology allows to provide power to the most different types of devices: Wi-Fi-routers, cameras, storage devices.The main advantage of this technology is that it involves the activation of a single set of wires - for the implementation of digital broadcast signals, and supply of electricity.
As a result, the installation of networks there is no need to lay cables for sockets, as well as to install the necessary additional electrical equipment.In some cases, installation of power cables can be complicated not quite optimal physical location of network components.For example, it happens that the Wi-Fi-adapter provides the best signal at the point in the building, which is to bring electricity to the problematic.The same can be said about the cameras: sometimes it may be necessary to monitor areas that are difficult to provide power.
PoE technology allows you to organize the connection of devices to an outlet that can, as we noted above, while output devices to the network and apply power to it.This approach can be employed in the case of upgrading the current network infrastructure.It is really to bring the power to the existing outlets.
Benefits of
So, if to summarize the key benefits of the technology in question, they may generate the following list:
- use the same cable possible for power supply and for the exchange of digital data;
- possible economic benefits associated with the absence of the need to install power cables and other necessary equipment;
- achieved a high level of security of the network infrastructure of the appropriate type, thanks to standards that provide the necessary protection components from power surges;
- have the ability to upgrade the current network infrastructure, organization of communication in areas that were previously unavailable for mounting by necessity in laying electric cables;
- it is possible to provide remote control of devices via network protocols.
We now study the basic standards on the basis of which operate PoE-network.
Standards
basic protocol personnel involved in the organization of appropriate infrastructure - IEEE 802.3af.It involves the incorporation of two types of network devices - power sources and consumers.They can be, as we noted above, Wi-Fi-routers, network drives.Excellent work in such a system camera.Among the well-known brand manufacturers, producing Soup, which can interact PoE-adapter - Axis.
Free Devices of the first type - sources - may be placed on the initial part of the network or between the handheld device supplying electric power, and consumer.Considered the standard allows the power supply by an unshielded twisted pair type of different classes - in particular, supports 5, 5e and 6 at a voltage of 48 V and power consumption within 15W.Thus any impact on the quality of the digital data transmission through the cable is not provided and a substantial upgrading of the current network infrastructure in terms of bandwidth is not assumed.
methods energizing
Network, which operates on the basis of the standard Power over Ethernet, can be provided with electricity through two schemes.
Firstly, it can be used in the final sections of lines of signal transformers, to be classified as high.The supply voltage is applied to the center tap them.Similarly with them, but also on the receiving side, the voltage is removed.This technology allows you to use the same pair of wires for broadcast high-frequency signals, and transmission of electricity.
Second, you can use to transfer power free pairs present in the appropriate type of cable.How is it possible?The fact is that in practice two pairs of 4 that is in-Ethernet cable, often not implemented.Of course, when it comes to their line technology 100 Base TX.
Award specifics of the organization of the network in the form PoE suggests that particular use injectors will depend on which way - first or second transmitted voltage.Thus, the possibility of marked 802.3af standard allows the transmission of electricity in pairs or in bunches of 1.2, for example, 4.5 cable.In turn, the injectors can be quite compatible with the technology 100 Base TX.However, if it is a splitter, then they should work under any of the above-mentioned power transmission schemes, even if the polarity of the connection is changed.
types of equipment PoE-
There are several classes of equipment capable of operating in the transmit mode Power over Ethernet.PoE-adapter - one of them (corresponding Soup have a large number of species - we will study their specificity).Along with him, there are also PoE-switches, as well as the consuming devices.In many cases they can be integrated into one system.We study the specifics of each of the selected types of equipment details.
consuming devices
consuming device - it is, in fact, those network devices that are powered over twisted pair.An important characteristic of them - the input impedance.The corresponding figure is usually determined in the range of 19-26,5 kW.Typically, the structure of the system, which are connected to consuming devices, there is also a capacitor.
Switches
PoE switch is used for the operation of the network in recognition of the correctness of the cable connections to the access points.Network appropriate type of work on the basis of protocols 802.3af, which we said above, as well as 802.3at.They allow you to provide interaction between different devices in a possible power surges.If PoE switch is not used, it is likely that due to random fluctuations of current in a twisted pair consuming device fails.
Adapters
Free Devices of this type, as we noted above, additional species are classified.So, PoE-adapter can be fed.In its structure there is the power supply, as well as an element of conjugation, which can be equipped with galvanic isolation in this case look like a small box or be a conventional wire.Power Adapter PoE, in fact, sometimes referred to as an injector.In the Russian market there are a large number of solutions of this type.For example, the popular Adapter PoE TP Link 150S.The most important technical data of the corresponding type devaysa - stabilized voltage.The best indicator is considered to be 48, if we talk about the model marked by TP Link.
Another type of PoE-adapter - take.He, however, also activated to provide power to devices via twisted pair, but only those that are not classified as consuming.In order for such equipment to function, it is desirable that its capacity does not exceed 24 watts.It may be noted that in the framework of this class of devices allocated Soup, classified as splitters.In fact, they can also be attributed to consuming devices.
Speaking of PoE-adapters, splitters are, they are designed to work with other types of devices - PoE-Switch.That is their main function - the separation of network data into separate streams for subsequent broadcast on a device that does not belong to the category of consuming devices.Splitters are responsible for converting the voltage, which are supplied to the levels that are optimal for the terminal equipment - for example, it may be an indication of a 5, 12 or 48 V.
In turn, splitters are also classified into two types -active and passive.As for the first, they can function both switches and with feeder adapters.These devices include, for example, the type of splitter DWL-P50 from D-Link.PoE-adapter is classified as a device of this type can also be passive.They can only work with injectors.However, they, as experts, are often sold together with them in a single package.
Nuances operation adapters
With proper connecting adapters employs technology Power over Ethernet, problems with the organization of the network should not occur.But some difficulties, because of the specific systems used in these standards can still occur.For example, PoE-Switch may determine that the active source device is not consuming, and the network can be temporarily de-energized by the fact that the system is operated in the passive splitter.It should, in turn, replace it with the active.Another possible problem - off voltage when you try to connect the consuming device to the switch.It can be solved by installing additional devaysa - PoE-converter.
interesting fact is that in terms of costs of the enterprise, which laid a network with a small number of devices consuming more profitable use passive Soup at large - active.Some IT-experts believe that even after the number of access points exceeds 3 pieces, you can use active adapters.
Optimum cable type
Technology Power over Internet suggests the involvement thus twisted pair.But they are, as is known, different types - e.g., with 2 or 4 pairs.Which one is best suited for the installation of the appropriate type of network?According to experts, the functionality of the system will save the use of any type of cable.But if it is a heavy load on the switch - for example, if you use all available its ports, the cable with 4 pairs - the best option.
