How to identify whether a POE switch is standard Poe power supply

- Dec 11, 2017-

To understand how to identify a POE switch whether the standard Poe power supply, we must first figure out what is the POE switch.

Poe Power switch refers to the switch which can provide network power to the remote terminal by cable, including two functions of network switch and Poe power supply, which is a common power supply equipment in Poe system.

Classification of Poe Switches

1. Standard POE Switch

Conforms to IEEE802.3AF, 802.3at Standard, is the standard Poe switch (commonly known as 48V), the complete Poe includes the power supply terminal equipment (PSE, Sourcing equipment) and the electrical Terminal equipment (PD, power device) two parts, Poe switch is a kind of PSE equipment. PSE is a power supply device for the terminal and also a manager of the Poe Ethernet power supply process. PD is a power supply terminal (48V GB equipment contains PD chips).

2, non-standard POE switch two categories.

Instead of the non-standard Poe switch ("non-standard" abbreviation "non-standard" commonly known as 24V, but non-standard has 48V, 24V, 12V, 5V, etc.).

The main application fields of POE switch

The POE switch mainly provides the network and the Power to the monitor (to the camera power), the wireless coverage (to the AP), the wireless transmission (to the Network Bridge power supply) and so on.

Working process of standard POE power supply switch

1. Testing: The POE switch outputs a very small voltage, and detects an electrically-terminated device containing support for the IEEE802.3AT/AF standard chip (support for the IEEE802.3AT/AF standard chip, "PD").

2. PD classification: After PD is detected, the POE switch classifies PD equipment and evaluates the power of PD equipment.

3, power supply: During the start-up period (generally less than 15μs), the POE switch from low voltage to PD power supply, until the voltage required for PD, for the PD equipment for stable and reliable DC power.

4, Power off: If the PD equipment is disconnected, the Poe switch will be quickly (generally within 300~400ms) to stop the PD power supply, and repeat the detection process to detect whether the cable terminal is connected to the PD device.

POE work draft.png

Test method of universal meter for true and False POE

Start the device, the multimeter to voltage measurement stalls, with multimeter two-meter pen respectively touch PSE Equipment power supply port(usually RJ45 port 1/2,3/6 or 4/5,7/8), if the detection of 48V or other voltage (12V, 24V, etc.) meter output equipment is non-standard products. Because in this process, PSE does not have the electrical equipment (here for the multimeter) to do the detection, directly using 48V or other voltage value power supply.

Conversely, if the voltage is not measured, the universal mater hands beats between the 2~10v, then the standard Poe. Because at this stage, PSE in the PD end (here for the multimeter) to detect, and multimeter is not a legitimate pd,pse will not power supply, no stable voltage generation.

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