Selecting a PoE Switch

You just picked up some new Power over Ethernet devices – a few of the hottest new IP cameras. However, after opening the box you run into a series of unexpected problems. No its a really powerful decision.

First: Each camera comes equipped with its PoE injector capable of supplying the appropriate level of power.  However, prior to even mocking up your panel it becomes clear – four PoE injectors and a standard Ethernet switch will not fit.
In an effort to maintain a reasonable panel size, you ditch the PoE injectors in favor of a Power over Ethernet switch, a single product that will replace all four injectors and provide Ethernet switching.  So far so good.

Second: After deciding that a PoE switch will best suit your need, you set out on a search for the cheapest PoE switch you can find.  Before long you realize the injectors were provided so that the cameras receive the exact amount of power they are optimized to run at.  With this new concern in mind, the search moves from the “cheapest switch” to the ”right switch.” In order to identify the right switch, you will need some information… but where do you look?

You are able to find a small label printed on the bottom near the Ethernet port of the camera – something that specifies how this camera can be powered. Now you have some numbers to shoot for, but what exactly do they mean?

While listed on the label in the above order, Power over Ethernet is best addressed in this order:-

1.     Is this a Power over Ethernet device?

A.     Will the device accept Power and data through the Ethernet port? Has the device been designed to make use of Power over Ethernet.

2.     Is this device IEEE 802.3af or IEEE 802.3at compliant?

A.     How much power will the device draw? Both IEEE 802.3af and 802.3at are based off +48VDC voltage but differ in wattage.

B.     IEEE 802.3af = “Standard PoE” = devices consuming up to 12.95W of PoE power IEEE 802.3at = “PoE Plus, High-Power PoE” = devices consuming up to 25.50W of PoE power

3.     Which class of Powered Devices (PD) is the device a member of?

A.     PoE capability and power level compliance – the class level of Powered Devices further specifies how much power the device will draw

Class 1 = 0.44 – 3.84W “Very low power”
Class 2 = 3.84 – 6.49W “Low power” 
Class 3 = 6.49 – 12.95W “Mid power” 
Class 4 = 12.95 – 25.5W “High power, suitable only for IEEE 802.3at PoE”

Translating the above power label again we find:

1.     Is this a Power over Ethernet device? Yes, this camera can accept PoE

2.     Is this device IEEE 802.3af or IEEE 802.3at compliant? IEEE 802.3af – the maximum it will draw is 12.95W at 48VDC

3.     Which class of Powered Devices (PD) is the device a member of? Class 2 – this device will draw between 3.84 and 6.49W – it is a “low power” device

After finding a Power over Ethernet switch that will provide suitable power conditions on a per-port basis, there is one final element to consider – power budget.

Will the switch you choose provide enough power per port for each camera? You bought four cameras to use four cameras, not to use just one or two.  Your choice in a Power over Ethernet switch needs to reflect this… Will the switch provide suitable power to all ports at all times?

Finally, after considering space in your panel, power demands of one camera, power ability of a switch for one port, and powering ability of a switch across all ports, you are prepared to make a decision!

Tukang Ngeblog | June 17, 2015 | Class 1, Class 2, Class 3, Class 4, IEEE 802.3af or IEEE 802.3at, IP Camera, PoE injector, PoE switch, Power over Ethernet devices, Selecting a PoE Switch

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PoE network camera in Global market

Development of PoE network camera in Global market

Since the launching of Power over Ethernet (PoE) standard, global enterprise are eager to utilize this emerging technology in just a few years. According the latest survey, in just six years from 2008 to now, the annual increasing rate of power equipment with PoE technology will reach 33%. In 2014, global market of power devices with PoE technology will be over $5.2 billion, compound annual growth rate will be 38%.

Along with the development of worldwide security market, users start to consider deploying some network cameras and other network security devices. Network surveillance based on PoE is more and more accepted by users and have great development.

PoE (Power over Ethernet) means keeping the current Ethernet cat-5 deployment, assure interface AP for wireless network security cameras and other IP signal devise based on IP signal, at the same time, it is able to power ac electric for those kinds of devices. PoE technology use one general Ethernet cable to transmit Ethernet signal and ac electrical source simultaneously, allowing power and date to be integrated into the same cable system. In the case of guaranteeing the construction cable safety, keep normal answer operation. PoE network camera use PoE technology to realize the network video surveillance, which has power device function to use direct current main provided by power device equipment to transmit to power device via twisted-pair.

Compared to normal network camera, PoE network camera has following advantages: apart from power the connected device through Ethernet cable, PoE reduce the investment cost, as a result, it decrease the overall the deployment costs to  organize the device based on IP infrastructure. Poe not only provide the need for installing wall power connection, which dramatically reduce the plug costs related supporting end devices but also install the network connection device on the place where is hard to deploy the local alternating current power supply, to some content, provide more flexibility. We can separate PoE network camera form power device end in the practice, which can be divide into two types, normal cameras and PoE adaptor. Front end has Ethernet switch for PoE power, and back end has PoE adaptor, which will transmit the twisted cable power to network camera for the working power. Because power device is able to identify the rate of power, when we use ups to power, the advantage of saving energy is more obvious.

Tukang Ngeblog | November 26, 2014 | HD IP, IP Camera, PoE Adaptor, PoE camera, PoE injector, PoE NVR, PoE Ports, PoE Power, PoE reduce the investment cost, PoE switch, PoE Technology

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