How Gigabit POE switches are powered

How does a gigabit switch supply poe power principle:

For example, if the distance between the 5-port PoE relay switch and the PoE switch or PoE power supply module is 100 meters, one of the ports of the 5-port PoE relay switch is PD and the other ports are PSE ports. In this way, the device can obtain 30W of power from the upper end through the PD port, and the obtained power can be output through other PSE ports, and then 100 meters can be transmitted after the output. Therefore, the purpose of long-distance transmission is achieved.

PoE products are mainly divided into two categories according to the application category: 1. PoE power supply equipment (PoE switches); 2. PoE powered equipment (such as IP**). Looking at the market, in Category 1, PoE switches are mainly used, while in Category 2, PoE switches have also appeared in the last one or two years.

To extend the PoE power supply distance, only one device is required, which has both PoE power receiving and PoE power supply functions, and the original PoE transmission distance can be reversed.

The standard Category 5 cable has four pairs of twisted pairs, but only two of them are used in L0MBASE-T and 100MBASE-T, while L000mBASE-T uses all four pairs. Two usages are allowed:

1. When the idle foot is used for power supply, the foot is connected to the positive pole and the foot is connected to the negative pole.

2. When applying the power supply of the data foot, add the DC power supply to the midpoint of the transmission transformer, which will not affect the transmission of data. In this way, and can be of arbitrary polarity.

The standard does not allow the above two cases to be applied at the same time.

I don't understand what you are asking, how is the power supply of the PoE switch connected or how is the PoE interface supplied power to the device?

The Ethernet standard stipulates that the maximum transmission distance is 100 meters, that is to say, the PoE switch uses standard network cable power supply and transmission distance of up to 100 meters, and uses super Category 5 or Category 6 oxygen-free copper network cable, and data delay and packet loss may occur when it exceeds 100 meters.

In fact, the PoE power supply distance is determined by the transmission distance of the data signal, and the simple power supports long-distance transmission in the normal state of the circuit, but the transmission distance of the data signal is determined by the network cable, and the transmission distance of the data signal of the ordinary Class 5 line is about 100 meters, and the project is generally 80-90 meters in order to ensure the construction quality.

Many manufacturers have marked that the transmission distance of their PoE switches can reach 150 meters, but in practical applications, ordinary PoE switches have strict requirements for the quality of network cables in order to achieve a transmission distance of 150 meters, and they must use more than 6 types of lines, which increases the cost of use.

How many meters can be transmitted by using a Category 6 network cable powered by a PoE switch? Category 6 PoE power supply can transmit 100 meters. PoE power supply is the PoE device through the network cable to the remote power receiving equipment, PoE power supply can theoretically transmit 100 meters, but in practical applications can also reach 120-130 meters, no matter how far away may not be able to supply power, so if you want to transmit a longer distance, you can add another PoE switch, so that you can extend another 100 meters.

Detection: At first, the PoE switch outputs a small voltage on the port until it detects that the cable termination is connected to a standard-supporting powered end device.

PD Device Classification: When a PD is detected on the power receiver device, the PoE switch may classify the PD device and evaluate the power loss required by the PD device.

Start power: During a boot period with a configurable time (typically less than 15 seconds), the PoE switch starts supplying power to the PD device from a low voltage until it provides 48V DC power.

Power supply: Provide stable and reliable 48V DC power for PD equipment to meet the power consumption of PD equipment.

Power outage: If a PD device is disconnected from the network, the PoE switch will quickly (within 300 to 400 ms) stop powering the PD device and repeat the detection process to detect whether the endpoint of the cable is connected to the PD device.

The PoE power switch itself uses redundant pairs to supply power to each other, and if your digital monitoring device also supports PoE power supply, you only need to connect the twisted pair to the devices at both ends.

The surveillance camera or AP supports PoE power supply, and the switch also supports PoE power supply. Just use a network cable and you're good to go. Data and power are transmitted using network cables.

A PoE power supply switch is a PoE switch that adds a PoE power supply module or PoE power supply circuit to the traditional switch so that the network port can output power.

Power supply distance of the PoE switch:

Theoretically, the maximum impedance of a normal 100-meter network cable is 20 ohms, and the voltage drop is 7V under the condition of 350mA power supply, the loss of the network cable is watts, and the maximum power available at the receiving terminal is watts. When the power consumption of the receiving terminal is not large, the PoE transmission distance can reach 100 meters. However, if you use a network cable with poor quality or a non-copper cable, the line loss will be increased and the PoE transmission distance will be affected.

The PoE switch can supply power to ordinary routers, because the router port itself does not provide power**, all need to add an additional PoE power supply module, and the connection method is as follows:

1. The LAN port of the router is connected to the LAN port of the POE power supply module with a network cable;

2. Then the PoE port of the power supply module is connected with the PoE port of the switch with a twisted pair;

3. The power supply module itself needs to be connected to the power supply.

Note: For POE power supply, the twisted pair must be made of high-quality 8-core copper core wire, according to the standard T568A or T568B connection.