What's Different About A Switch With POE Function

- Apr 02, 2020-

In corporate network layout, place WiFi coverage, security monitoring, commercial places, and communications engineering, we often hear a noun or a device called a "POE switch."

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1. POE switch concept:


"POE switch" refers to a device that transmits data and provides power at the same time. That is to say, the difference from a general Ethernet and network switch is that it can provide power. Ordinary switches can only transmit data, power needs to be prepared separately

hongrui-poe switch


2.How many devices can a POE switch implement to transmit data and power?


In general, the number of devices that a POE switch can access will be affected by several factors, including the power supply standard of the POE switch, the total power supply of the POE switch, and the transmission data and power required by the access device and the number of POE ports.


(1) There are two types of power supply standards for POE switches on the market, one is IEEE802.3af and the other is IEEE802.3at. They define the maximum power supply of each port of the POE switch as 15.4W and 30W.


(2) The total power supply of the POE switch is of course related to the power supply rate of each port of the switch. It is affected by the switch standard and the number of switch interfaces. For example, the total power supply rate of a POE switch with a maximum power supply rate of 15.4W24 per IEEE802.3af standard is about 370W (≈24 * 15.4), while the maximum power supply rate of a POE switch with a maximum power supply per port of 30W24 is 802.3at The total power supply rate is about 720W (≈24 * 30W).

hrui-poe-swotch-network-switch

(3) Different transmission data and power required by access devices due to factors such as categories, application standards, etc. will also cause their respective required transmission data and power to be different.


Take the camera as an example, a 720P (1 million pixel) camera code stream is 4.5M, a 1080P (2 million pixel) camera code stream is 6M, then an 8-port bandwidth is 40Mbps and the transmission rate is 100 A mega POE switch can access 8 (40Mbps / 4.5M) 720P cameras, but can only connect up to 6 1080P cameras.


(4) And the camera meets the requirement that a single POE switch accessing the IEEE802.af standard cannot exceed 15.4W, and a single POE switch accessing the IEEE802.at standard cannot exceed 25W.


In short, the number of POE switch access devices is affected by the switch standard, the total power supply (the number of single ports on the switch), and the transmission data and power of the access device. You can select the required POE switch according to the actual situation of the connected equipment. Want to know more can contact us.