With the growing maturity of PoE Ethernet power supply technology, more and more network products are providing support for PoE power supply standards. There are also various forms of PoE power supply in the market. Below, we analyze how to select PoE power supply that meets our requirements and what should be paid attention to when selecting PoE power supply.
1. According to the actual needs of the site, select the corresponding port number
PoE power supply has single port, double port, 4 ports, 8 ports, 12 ports, 16 ports and 24 ports, etc., which can meet the needs of PoE power supply on site. When using multi-port PoE power supply, one or two ports can be saved for actual use, in case of capacity increase or emergency standby.
2. The determination of power is the most important point in the selection of PoE power supply
With more and more products supporting PoE power supply, the power of PD powered devices may be high or low. When choosing PSE that matches the PSE, PoE power suppliers
whose output power is higher than the rated power of PD powered devices should be selected. When selecting multi-port PoE power supply, the sum of rated power of all power receiving devices should be less than the actual total output power of PoE power supply, leaving enough redundancy to make the PoE system work in a more stable state. Fengrunda PoE power supply has a variety of different power (single port output), such as 15.4w, 30W, etc., please confirm your needs before use.
3. Confirmation of network transmission rate
The data transmission of PoE power supply is divided into 10/100m adaptive and 10/100/1000m adaptive. When the transmission rate required by the network is gigabit transmission, the gigabit PoE power supply must be selected.
4. IEEE802.3af /at standards allow PSE to have three types of power supply sequence:
1. The 4 and 5 lines in the network are positive, and the 7 and 8 lines are negative.
2. The 1 and 2 lines in the network are negative, and the 3 and 6 lines are positive.
3. The 1 and 2 lines in the network line are positive, and the 3 and 6 lines are negative.
At present, most of the power receiving devices support any one of the above three line sequences for power supply. However, some power receiving devices, such as AP and network monitor, only support one power supply line sequence for power supply. Before selecting PoE power supply, confirm the power supply sequence of the receiving equipment through the product specification of the receiving equipment or with the manufacturer's technical support. Fengrunda's PoE power supply mode is by default the terminal bonding method (1/2, 3/6 line pair), and the intermediate bonding method (4/5, 7/8 line pair) is optional. The majority of users must confirm what type of equipment they own before purchase.
5. IEEE 802.3af standard
The standard clearly defines PSE's output voltage as DC44V ~ DC57V. Considering the loss of network cables, the input voltage of PD of the electrical equipment is between DC36V and DC57V, and the typical value is DC48V. Many current receiving devices support both power adapter and PoE power supply. Although the power adapter
terminal of many powered devices uses DC power supply lower than 48V, such as DC12V, DC5V, etc., PoE power supply of the powered devices can be directly supplied as long as the PoE power supply of the powered devices conforms to ieee802.3af standard.
6. Choose lightning protection PoE power supply
With the installation of electrical equipment in different locations, the external environment of lightning surge, static and other shocks are also increasing, in order to better protect the power supply system of switches in the network and PSE, lightening proof PoE power supply is needed. While using PSE to supply power to the electrical equipment, it can effectively prevent surges and static electricity from damaging the data exchange and PSE's internal power system through the network cable of the electrical equipment.