When installing wireless transmission equipment, POE is a device that can be accessed frequently. The ordinary POE is mostly a 100M interface. However, with the advancement of wireless transmission technology, many 802.11AC-type devices are mostly Gigabit interfaces. The POE that needs to be powered for also requires the use of Gigabit POE, so what is the difference between the specific 100M POE and the Gigabit POE in power supply? Let us give you a popular science today.
The standard five types of network cables have four pairs of twisted pairs, but only two of them are used in 10MBASE-T and 100M BASE-T.
1. One hundred megabytes In the case of the IEEE80 2.3af standard, two connections are allowed:
1. Apply idle power supply, 4, 5 connect positive, 7 and 8 connect negative, if use idle line (4, 5, 7, 8) to transfer 48v power
100M PoE uses 1, 2, 3, 6 line sequence to transmit data, 4, 5, 7, and 8 line sequences for power supply
2. Simultaneously transmit signals and 48v power using signal lines (1, 2, 3, 6)
When applying data pin power, the DC power supply is added to the focus of the transmission transformer. In this way, the pair 1, 2 and the pair 3, 6 can be of any polarity. The core wire used for transmitting data can simultaneously transmit DC power, and the transmission uses a different frequency from the Ethernet data signal, and does not affect the data transmission.
Second, Gigabit BASE-T PoE power supply system
The four line-sequence pairs of the PoE power supply system transmit data, so there is no idle pair, and the data is used for power supply. In Figure 6, the pins 1, 2, 3, and 6 are divided and separated by the voltage and signal of the network transformer. The voltage is linked to the bridge rectifier for rectification, as shown in the following figure:
Third, the PoE workflow
In text, when a network is deployed with a PSE device, the PoE power supply process is as follows:
Detection: At the beginning, the PSE will output a small voltage until it detects that the cable termination is connected to a standard powered terminal device;
PD end device: After detecting the power receiving device PD, the PSE can classify the PD device and evaluate the power consumption required by the PD device;
Start powering: During a configurable period of time, the PSE device begins to supply power from the low voltage to the PD device up to 48v DC power;
Power supply: Provide stable and reliable 48v DC power for PD equipment, the total power consumption of the equipment can not exceed 15.4w;
Power off: If the PD device is disconnected from the network, the PSE will quickly stop powering the device and repeatedly detect whether the terminal is connected to the PD device.
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