To understand how to distinguish whether a POE switch/industrial POE switch is a standard POE source, we must first understand what a POE switch/industrial POE switch is. A POE-powered switch is a switch that can provide network power to remote powered terminals through the network cable, which includes the functions of a network switch and POE source, and is a commonly used source device in the POE power supply system.

Classification of Industrial POE Switches

1) Standard Industrial POE switch: Compliant with IEEE802.3af, 802.3at standards, also known as standard POE switches (commonly referred to as 48V), the complete POE includes two parts: power supply and powered devices. The POE switch is a type of PSE device. PSE devices are the power supply devices for end devices and also the managers of the POE Ethernet power supply process. PD is the terminal device that receives power.

2) Non-standard POE switch: The opposite is a non-standard POE switch. Industrial POE switches mainly provide network and power for surveillance cameras (power supply), wireless coverage (power supply for AP), wireless transmission (power supply for bridges) and other devices.

Working Process of Standard POE Industrial POE Switches

1) Detection: The POE switch/industrial POE switch first outputs a very small voltage to detect the powered devices (PD) with chips supporting IEEE802.3at/af standards.

2) PD classification: After detecting the PD, the POE switch/industrial POE switch classifies the PD devices and evaluates their power.

3) Power supply: During the startup period (generally less than 15μs), the POE switch/industrial POE switch supplies power to the PD device from low voltage until it supplies the stable and reliable DC power that the PD device needs.

4) Power-off: If the PD device is disconnected, the POE switch/industrial POE switch will quickly (generally within 300-400ms) stop supplying power to the PD and repeat the detection process to check whether the end of the cable is connected to the PD device.

Testing Method for True and False POE Switches/industrial Poe Switches Using a Multimeter

Turn on the industrial POE switch, adjust the multimeter to the voltage measurement gear, and touch the power supply pin of the PSE device with two meter pens (usually 1/2, 3/6, or 4/5, 7/8 of the RJ45 port). If a device with a stable output of 48V or other voltage value (12V, 24V, etc.) is measured, it is a non-standard product because during this process, the PSE does not detect the powered device (here is the multimeter) and directly supplies power at 48V or other voltage value. On the contrary, if no voltage is measured, and the meter pointer jumps between 2-10V, it is a standard POE because during this stage, the PSE detects the PD end (here is the multimeter), and the multimeter is not a legal PD, so the PSE will not supply power, and no stable voltage will be generated.