In the WiFi coverage or security monitoring of large and medium-sized places, we can often hear a term or a device called "PoE switch". But many friends don't know what a POE switch is, especially those who are new to the industry will inevitably have questions about it. So, today we will introduce to you what is a PoE switch? What is its function?
1. What is a PoE switch? What is the function of a PoE switch?
"PoE switch" refers to a device that can transmit data for some IP terminal-based devices (such as wireless APs, web cameras, etc.) without changing any existing Ethernet wiring infrastructure, while also achieving power supply functions. It can be understood as a switch that supports Power over Ethernet. The main function of the PoE switch is data transmission and power supply.
2.How many devices can a PoE switch transmit data and power for?
Generally, the number of devices that a PoE switch can access is 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.
(1) The power supply standard of PoE switches mainly covers two kinds on the market, one is IEEE802.3af, the other is IEEE802.3at. They respectively define the maximum power supply for each port of the PoE switch as 15.4W and 30W, but due to certain losses during transmission, the actual power supply for each port of the switch can only be 12.95W and 25W.
This also determines that the power of the devices connected to each port of the two standard PoE switches cannot exceed 12.95W and 25W respectively. Of course, no matter which standard PoE power supply switch is, it is self-adapting, that is, how much power the switch will provide when the power of the access device is.
(2) The total power supply of the PoE switch is of course related to the power supply rate of each port of the switch, which is affected by the standard of the switch and the number of switch interfaces. For example, the total power supply rate of a PoE switch with a maximum power supply rate of 15.4W per port in the IEEE802.3af standard is about 370W (≈24*15.4), while a PoE switch with a maximum power supply rate per port of 30W and 24 ports in the IEEE802.3at standard The total power supply rate is about 720W (≈24*30W).
(3) The required transmission data and power of the access equipment are different due to factors such as categories and application standards, which will also cause their respective required transmission data and power to be different.
Take the camera as an example. A 720P (1 million pixels) camera has a code stream of 4.5M, and a 1080P (2 million pixels) camera has a code stream of 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 at most 6 1080P cameras can be connected.
(4) And the camera meets that the power of a single POE switch connected to the IEEE802.af standard cannot exceed 15.4W, and the power of a single POE switch connected to the IEEE802.at standard cannot exceed 25W.
The above is a detailed introduction of what the PoE switch is and the role of the PoE switch. All in all, the number of access devices in a PoE switch is affected by switch standards, total power supply (single port number of the switch), and transmission data and power of the access devices. You can choose the required PoE switch according to the actual situation of the connected equipment.
The above information is provided by the PoE switch supplier.
